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Finding the source location of a radio-frequency (RF) transmission is a useful capability for many civilian, industrial, and military applications. This problem is particularly challenging when done “Blind,” or when the transmitter was not designed with finding its location in mind, and relatively little information is available about the signal before-hand. Typical methods for this operation utilize the time, phase, power, and frequency viewable from received signals. These features are all less predictable in indoor and urban environments, where signals undergo transformation from multiple interactions with the environment. These interactions imprint structure onto the received signal which is dependent on the transmission path, and therefore the initial location. Using a received signal, a signal characteristic known as the autocorrelation can be computed which will largely be shaped by this information. In this research, RF source localization using finger-printing (a technique involving matching to a known database) with signal autocorrelations is explored. A Gaussian-process-based method for autocorrelation based fingerprinting is proposed. Performance of this method is evaluated using a ray-tracing-based simulation of an indoor environment.

It has been suggested that the wireless network evolution to smaller carrier wavelengths (from 2G to 5G) increases radio frequency electromagnetic field (RF-EMF) absorption in western honey bees (Apis mellifera). It is unknown whether the radiation performance of antennas is stable when an insect appears in their vicinity. In this research, the absorbed power in a worker honey bee and the influence of the bee's presence on antennas' radiation performance are investigated for the newly used frequencies in 5G networks from 6 to 240 GHz. To these aims, numerical simulations using the finite-difference time-domain (FDTD) method were performed, in which a bee model, obtained by micro-CT scanning, was employed. These simulations showed that, in the near field, the absorbed power can increase by a factor of 53 from 6 to 240 GHz. This is a factor of 7 higher than the increase reported in the far-field in previous studies. Furthermore, the simulations revealed that antennas' radiation efficiency can decrease by up to -40% when a bee appears in the near field. Likewise, it was found that the gain pattern depends on the separation distance between the bee and the antenna with a stronger dependency for higher frequencies.

In this article it iimplemented a set of circuit models to be exploited in conventional circuit simulators used in engineering degrees. The models capture the physics of the graphene-based transistors, characterized by the ambipolar conduction, and its resulting V-shaped transfer characteristics (current vs. gate voltage). These models can be exploited by the engineering students to explore ambipolar electronics opening the possibility to 1) redesigning and simplifying of conventional circuits; and 2)seeking of new functionalities in both analogue/RF and digital domains. In thisregard, as an example by just considering that the V-shaped transfer characteristicsbehaves as a parabola, we present new insights for the design of graphene-based RFpower amplifiers, mixers, phase shifters and frequency multipliers that specifically, En este trabajo, se implementan un conjunto de modelos que resuelven la física de los transistores basados en grafeno, capturando la conducción ambipolar y proporcionando las peculiares curvas de corriente frente a voltaje de puerta con forma de “V”. Estas herramientas pueden ser potencialmente utilizadas por estudiantes de ingeniería para explorar la electrónica ambipolar, abriendo la posibilidad de 1) rediseñar y simplificar aplicaciones de microondas convencionales; y 2) buscar nuevas funcionalidades en el ámbito analógico y de alta frecuencia. A este respecto, como ejemplo, presentamos nuevos enfoques para el diseño de multiplicadores de frecuencia, amplificadores de potencia, mezcladores y desfasadores en radiofrecuencia que específicamente aprovechan la ambipolaridad, PAIDI 2020 y de European Social Fund Operational Programme 2014–2020 no. 20804, Contrato PTA, con referencia PTA2020-018250-I

International audience; A versatile industrial recipe of transferring nitride microelectronic components such as micro-electromechanical systems (MEMS) onto flexible and stretchable substrates is demonstrated. This method bypasses difficulties of temperature-related processing, and is applicable to large-scale and mass production. The technological process of fabrication is presented along with its underlying structural and radio-frequency characterizations. In particular, the Raman strain shifts of aluminum nitride (AlN) thin films are determined for uniaxial and biaxial mechanical deformations. The transferring process onto polymer is also demonstrated by an adhesive bonding of AlN-based MEMS onto a 200 mm silicon (Si) wafer. The devices microstructure is assessed using X-ray before and after transferring, as well as their electrical radio-frequency (RF) features when on Si and polymer substrates. Then, RF measurements are also performed on the transferred and flexible devices; some in their relaxed states, and others in an in situ manner under an increasing macroscopic strain. It is shown that bulk acoustic wave resonator MEMS are fully functional even under 12% uniaxial stretching of the substrate.

We demonstrate an ultra-high sensitivity rf optical magnetometer based on a compact 5×5×8 mm3 Rubidium-87 vapor cell in a mu-metal shielded environment. The rf field is detected via a Faraday rotation effect on the linear polarization of a probe beam, and the resonance frequency is tuned via Zeeman effect by applying a static bias magnetic field to the cell. Sensitivities down to 3 fT/√Hz are achieved between 10 kHz and 100 kHz, which is a performance comparable to that of prior larger cells. An increase in the sensitivity with frequency and temperature has been observed.

Convolutional neural networks (LeCun and Bengio 1998 The Handbook of Brain Theory and Neural Networks 255–58; LeCun, Bengio and Hinton 2015 Nature 521 436–44) are state-of-the-art and ubiquitous in modern signal processing and machine vision. Nowadays, hardware solutions based on emerging nanodevices are designed to reduce the power consumption of these networks. This is done either by using devices that implement convolutional filters and sequentially multiply consecutive subsets of the input, or by using different sets of devices to perform the different multiplications in parallel to avoid storing intermediate computational steps in memory. Spintronics devices are promising for information processing because of the various neural and synaptic functionalities they offer. However, due to their low OFF/ON ratio, performing all the multiplications required for convolutions in a single step with a crossbar array of spintronic memories would cause sneak-path currents. Here we present an architecture where synaptic communications are based on a resonance effect. These synaptic communications thus have a frequency selectivity that prevents crosstalk caused by sneak-path currents. We first demonstrate how a chain of spintronic resonators can function as synapses and make convolutions by sequentially rectifying radio-frequency signals encoding consecutive sets of inputs. We show that a parallel implementation is possible with multiple chains of spintronic resonators. We propose two different spatial arrangements for these chains. For each of them, we explain how to tune many artificial synapses simultaneously, exploiting the synaptic weight sharing specific to convolutions. We show how information can be transmitted between convolutional layers by using spintronic oscillators as artificial microwave neurons. Finally, we simulate a network of these radio-frequency resonators and spintronic oscillators to solve the MNIST handwritten digits dataset, and obtain results comparable to software convolutional neural networks. Since it can run convolutional neural networks fully in parallel in a single step with nano devices, the architecture proposed in this paper is promising for embedded applications requiring machine vision, such as autonomous driving.

Aim.To validate the National Danish Ablation Database (NDAD) by investigating to what extent data in NDAD correspond to medical records.Type of study. Non-blinded, registry-based, retrospective, validation study. Material and methods. A sample of patients who underwent ablation for atrial fibrillation in Denmark between 1 January 2016 and 31 December 2016 were included. By utilizing medical records as gold standard, positive predictive (PPV) and negative predictive values (NPV) for NDAD were assessed and presented as five main categories: arrhythmia characteristics, demographics, cardiac history, complications, and medication. PPV?s and NPV?s exceeding 90% were considered as high agreement. Results. 597 patients (71.0% males) were included in the study. Median age was 63.1 (IQR: 54.9?68.4) years. The median PPV and NPV estimates across all variables were respectively 90.4% (95% CI: 68%?95.2%) (PPV) and 99.4% (95% CI: 98.4%?99.8%) (NPV) at baseline, and 91.7% (95% CI: 67.4%?95.4%) (PPV) and 99.3% (98.2%?99.3%) (NPV) at follow-up. Conclusion. The data registered in NDAD agrees to a great extent with the patients? medical records, suggesting NDAD is a database with high validity. As a result of low complication rate, the PPV- and NPV-estimates among complication variables were prone to somewhat greater uncertainty compared to the rest. Aim.To validate the National Danish Ablation Database (NDAD) by investigating to what extent data in NDAD correspond to medical records. Type of study. Non-blinded, registry-based, retrospective, validation study. Material and methods. A sample of patients who underwent ablation for atrial fibrillation in Denmark between 1 January 2016 and 31 December 2016 were included. By utilizing medical records as gold standard, positive predictive (PPV) and negative predictive values (NPV) for NDAD were assessed and presented as five main categories: arrhythmia characteristics, demographics, cardiac history, complications, and medication. PPV’s and NPV’s exceeding 90% were considered as high agreement. Results. 597 patients (71.0% males) were included in the study. Median age was 63.1 (IQR: 54.9–68.4) years. The median PPV and NPV estimates across all variables were respectively 90.4% (95% CI: 68%–95.2%) (PPV) and 99.4% (95% CI: 98.4%–99.8%) (NPV) at baseline, and 91.7% (95% CI: 67.4%–95.4%) (PPV) and 99.3% (98.2%–99.3%) (NPV) at follow-up. Conclusion. The data registered in NDAD agrees to a great extent with the patients’ medical records, suggesting NDAD is a database with high validity. As a result of low complication rate, the PPV- and NPV-estimates among complication variables were prone to somewhat greater uncertainty compared to the rest.

The Radio Frequency Quadrupole (RFQ) of the European Spallation Source (ESS), operates at 352.21 MHz with an RF pulse length of 3.2 ms and repetition rate of 14 Hz. The RFQ focuses, bunches and accelerates the 62.5 mA proton beam from 75 keV up to 3.6 MeV. In an effort to study and compare the results from 3D electromagnetic codes, different models of the RFQ were simulated with CST Studio suite. This paper presents the selection of optimal parameters for simulation of the RFQ cavity voltage and comparison of the results with the RFQ design code Toutatis., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

Using radiofrequency energy for closure of the patent ductus arteriosus (PDA) has been reported by us previously. In this article we report the early and late outcome of the first group in whom patent ductus arteriosus has been occluded with radiofrequency. Six children with PDA were enrolled. The procedure was successful in five cases and transient hoarseness was observed in 2 cases as the only complication.

Planar transmission line on silicon substrate imposes certain challenges at higher frequencies and measurement of the same employing wafer probing techniques needs accurate characterization. Wafer measurement provides information related with the device performance which in turn helps to minimize parasitic related with package and assembly. Wafer probing at higher frequencies imposes certain challenges more so ever on silicon substrate. Silicon substrate due to semiconductor in nature is a lossy medium for radio frequencies and standard wafer is not suitable for the realization of RF circuits. Present article demonstrate realization of planar transmission line on high resistivity silicon substrate by employing thick oxide layer. Both simulated and measured results are presented in this article and the CPW line fabricated with the proposed process results in ~1dB loss with better than 12dB return loss at Ka-band. Measurement techniques for the line characterization are detailed in this article along with transmission line characterization at Ka-band.

Now that bulk Nb technology has reached it full maturity, improving SRF technology demands that new materials need to be developed. For reasons explained in the talk, all next generation SRF materials will be in the form of thin films. The IFAST project has the ambition to coordinate European activities on that topic, not only throughout its own program (that will be presented here), but also by keeping in touch with all actors worldwide, with the hope of developing a more efficient collaborative actions, in a limited funding context. In this talk, we will present the challenges presented by the development of new thin films materials, each developed for tailored applications and the main research direction proposed by the thin film community., Proceedings of the 65th ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e- Colliders, eeFACT2022, Frascati, Italy

The progress made toward the definition of a modular compact modeling technology for graphene field-effect transistors (GFETs) that enables the electrical analysis of arbitrary GFET-based integrated circuits is reported. A set of primary models embracing the main physical principles defines the ideal GFET response under DC, transient (time domain), AC (frequency domain), and noise (frequency domain) analysis. Another set of secondary models accounts for the GFET non-idealities, such as extrinsic-, short-channel-, trapping/detrapping-, self-heating-, and non-quasi static-effects, which can have a significant impact under static and/or dynamic operation. At both device and circuit levels, significant consistency is demonstrated between the simulation output and experimental data for relevant operating conditions. Additionally, a perspective of the challenges during the scale up of the GFET modeling technology toward higher technology readiness levels while drawing a collaborative scenario among fabrication technology groups, modeling groups, and circuit designers, is provided., European Commission 881603, Spanish Government European Commission RTI2018-097876-B-C21 European Commission, Departament de Recerca i Universitat 001-P-001702

The sustainable next generation particle accelerators require innovative solutions to overcome the current technological challenges set by existing bulk niobium superconducting radio-frequency (SRF) cavities. Thin film-based multilayer structures in the form of superconductor-insulator-superconductor (SIS) may be the long-sought-after breakthrough for higher performance SRF cavities by enhancing both accelerating gradients and quality factors. In order to understand better the underlying mechanisms of SIS structures to be coated onto (S)RF cavities, we study various material properties with the resultant superconducting properties of high-power im-pulse magnetron sputtering (HiPIMS)-coated S(I)S structures of Nb-(AlN)-NbN with different thicknesses which are designed to be coated mainly on OFHC copper (Cu) samples for more efficient SRF cavities. This contribution presents materials properties of the aforementioned HiPIMS-coated S(I)S structures as well as the superconducting and RF behaviours of these multilayers which are assessed comparatively via DC and AC magnetization techniques., Proceedings of the 31st International Linear Accelerator Conference, LINAC2022, Liverpool, UK

In this article, based on the developed methodology, the stages of designing two designs of high-performance radio-frequency single-pole single-throw microelectromechanical switches are investigated. These radio-frequency microelectromechanical switches are designed to operate at a central resonant frequency of 3.6 GHz and 3.4 GHz, respectively, as well as to work both in mobile communication devices and in the design of the architecture of 5G mobile networks, in particular in arrays of integrated antennas and radio-frequency interface modules. The manufacture and study of two designed structures are researched. For the first manufactured experimental sample in the open state the insertion loss is no more than −0.69 dB and the reflection loss is −28.35 dB, and in the closed state the isolation value is at least −54.77 dB at a central resonant frequency of 3.6 GHz. For the second in the open state the value of the insertion loss is no more than −0.67 dB and the reflection loss is −20.7 dB, and in the closed state the isolation value is not less than −52.13 dB at the central resonant frequency of 3.4 GHz. Both manufactured experimental samples are characterized by high linearity, as well as a small value of contact resistance in the closed state.

Mini-invasive techniques in medicine are the novel paradigm to achieve good treatment results while keeping the patient at ease and avoid heavy and painful application of standard techniques. This is the case of tumor treatment, with special reference to organs such as liver, lung, kidney. In this case, the application of a well-localized heat source can destroy tumor cells by means of a necrotic process. Such techniques are based on different technologies: Radio Frequency and Microwave are the most common ones. Nevertheless, several open issues are still present as the optimal choice of application time, the definition of the burning area, the best stimulus signal to be applied, the modeling of the target area concerning its electric/magnetic properties whose values can evolve during treatment. For all these reasons, and not limited to, the role of engineers is crucial to obtain better performance with limited amount of energy and limited side effects for the patient. Particularly, the measurement open issues and how such issues could lead to an enhancement of the industrial production processes of needed apparatuses are reported in this paper.

Objectives To assess the safety and effectiveness of in-office bipolar radiofrequency treatment of nasal valve obstruction. Study Design Prospective, nonrandomized, multicenter case series. Methods Adult patients with a Nasal Obstruction Symptom Evaluation scale (NOSE) score ≥60 were selected. Patients were clinically diagnosed with dynamic or static internal nasal valve obstruction as primary or significant contributor to obstruction and were required to have a positive response to nasal mechanical dilators or lateralization maneuvers. Bilateral radio-frequency treatment was applied intranasally using a novel device, under local anesthesia in a single session. Safety and tolerance were assessed by event reporting, inspection, and Visual Analogue Scale (VAS) for pain. Efficacy was determined using the NOSE score and patient-reported satisfaction survey at 26 weeks. Results Fifty patients were treated. No device or procedure-related serious adverse events occurred. Soreness, edema, and crusting resolved by 1 month. The mean baseline NOSE score was 79.9 (SD 10.8, range 60-100), and all had severe or extreme obstruction. At 26 weeks, mean NOSE score was 69% lower at 24.7 (P < .0001) with 95% two-sided confidence intervals 48.5 to 61.1 for decrease. The decrease in NOSE score did not differ significantly between patients who did or did not have prior nasal surgery. Patient satisfaction mean by survey was 8.2 of 10. Conclusion In office treatment of internal nasal valve obstruction using a bipolar radiofrequency device is safe and well-tolerated. Nasal obstruction, as assessed using the NOSE questionnaire at 26 weeks, was markedly improved with high patient satisfaction. Level of Evidence 2b, prospective cohort.

Orientador: Jacobus Willibrodus Swart Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação Resumo: O aumento no número de usuários, assim como a demanda por maior taxa de transferência de dados, está impulsionando o desenvolvimento de novas tecnologias, uma vez que o padrão clássico de comunicação está atingindo sua saturação. Vídeos em alta definição, chamadas em vídeo-conferência e downloads em alta velocidade deixaram de ser uma particularidade para se tornarem básicos, oferecendo constantes desafios em todos os níveis de projeto de um dispositivo. Atualmente, a maneira adotada para se criar um canal de comunicação sem fio (wireless) baseia se na modulação da informação de interesse em torno de uma freqüência muito mais alta, chamada portadora. Para cada protocolo tem-se reservada uma banda do espectro, porém, dependendo da região e do número de usuários dividindo a banda, tende-se a ter esta banda saturada, reduzindo a capacidade de comunicação para cada usuário. Freqüentemente, observam-se cenários onde algumas bandas de freqüência estão extremamente ocupadas e regiões vizinhas no espectro completamente vazias. De modo a operar o espectro com maior inteligência, surgiram conceitos com o de Rádios Cognitivos (CR - Cognitive Radios), onde algoritmos monitoram o espectro de modo a utilizar um canal somente quando este estiver livre, mudando de banda se necessário. Isto requer circuitos susceptíveis à operação em banda larga. Sendo assim, este projeto propõe a realização de um amplificador de banda larga empregando um novo método de cancelamento de ruído, além do projeto de um misturador de baixo ruído utilizando técnicas recentes exploradas na literatura, de modo a obter uma cadeia de recepção para uso em banda larga. O LNA apresenta casamento de impedância e ganho de potência de 12dB na banda de 50 MHz até 5 GHz, com NF variando de 1,4 - 2,4 dB, enquanto consome 15 mW de potência sob tensão de alimentação de 1,5 V. O desempenho em NF, quando levado em consideração a potência consumida e o nó tecnológico, é o melhor comparado aos recentes projetos que o autor tem conhecimento. O cancelamento de ruído é obtido através de uma condição específica do circuito, requerendo uma corrente extra de polarização, já inclusa na potência total do circuito. Para compor a cadeia de recepção e, consecutivamente, a conversão do sinal em banda base de modo homodyne, projetou-se um par de Misturadores de modo a re-utilizar a corrente extra requerida pelo LNA no cancelamento do ruído. Desta maneira, obteve-se na cadeia de recepção o ganho de tensão de 26 dB na saída de cada Misturador, em Fase (I) e Quadratura (Q), para uma banda de 50 MHz até 6,5 GHz, com SSB NF variando de 6,1 - 9,2 (3,1 - 6,2 dB para DSB), consumindo os mesmos 15 mW e tendo a banda estendida pelos Misturadores. Os circuitos foram fabricados na tecnologia UMC 0,13'mu'm Mixed/RF CMOS e algumas medidas preliminares foram obtidas e serão mostradas nesta dissertação. O LNA apresentou ganho, casamento de impedância e potência próximos aos valores obtidos nas simulações, mostrando boa confiabilidade dos valores projetados Abstract: The increase in the number of users as well as the demand for higher data transfer rate is driving development of new technologies, since the classical communication is reaching its saturation. Videos in high definition, video-conference calls and high-speed downloads are no longer a special feature to become basic, offering constant challenges at all levels in the design of a device. Currently, the way adopted to create a wireless communication channel is based on the modulation of interesting information about a much higher frequency, called carrier. For each protocol, a reserved bandwidth of the spectrum has been assigned, however, depending on the region and the number of users sharing the band, it tends to have saturated the band, reducing the communication ability of each user. Often, there are scenarios where some bands are extremely busy and neighboring regions in the spectrum are completely empty. In order to operate the spectrum with higher intelligence emerged with the concept of Cognitive Radio (CR), where algorithms monitor the channel in order to use them only when it is free, and changing band if necessary. This requires circuits to be susceptible for broadband operation. Therefore, this project proposes a broadband amplifier using a new method for noise cancellation, and the design of a low noise mixer using techniques explored in the recent literature, in order to get broadband receiver chain. The LNA provides impedance matching and power gain of 12dB from 50MHz to 5GHz band with NF ranging from 1.4 - 2.4 dB, while consuming 15mW of power under a supply voltage of 1.5 V. Its NF performance, when taken into consideration the power consumption and technology node, is the best compared to recent projects that the author is aware of. The noise cancellation is achieved by a specific condition of the circuit, requiring an extra biasing current, already included in the total circuit power. To compose the chain of reception and, consecutively, the conversion of the baseband signal in homodyne mode, a pair of Mixers were designed, re-using the extra current required by the LNA for noise cancellation. Thus, it was achieved at receiver chain a voltage gain of 26dB at the output of each Mixer, at Phase (I) and Quadrature (Q), for bandwidth of 50MHz to 6.5 GHz with SSB NF ranging from 6.1 - 9.2 (3.1 - 6.2dB for DSB), also consuming the same 15mW and having a band enhancement provided by the Mixers. The circuits were fabricated in UMC technology 0.13'mu'm Mixed/RF CMOS and some preliminary measurements were obtained and are shown in this dissertation. The LNA presented gain, impedance matching and power close to the values obtained in the simulations, showing good reliability on the projected values Mestrado Eletrônica, Microeletrônica e Optoeletrônica Mestre em Engenharia Elétrica

This review paper focuses on radio-frequency (RF) biosensors for real-time and continuous glucose sensing reported in the literature, including our recent research. Diverse versions of glucose biosensors based on RF devices and circuits are briefly introduced, and their performances are compared. In addition, the limitations of the developed RF glucose biosensors are discussed. Finally, we present perspectives on state-of-art RF biosensing chips for point-of-care diagnosis and describe their future challenges.

In the past decade, graphene has been widely researched to improve or overcome the performance of conventional radio-frequency (RF) nanodevices and circuits. In recent years, novel RF bio and gas sensors based on graphene and its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), have emerged as new RF sensing platforms using a wireless remote system. Although the sensing schemes are still immature, this review focuses on the recent trends and advances of graphene and GO (rGO)-based RF bio and gas sensors for a real-time and continuous wireless health care system.

Today one of the key triggers of the development of research and development in the field of electronics, radio-frequency components, and systems, system integration and design, as well as information and communication technologies are such data network concepts as the Internet of Things, Internet of Everything, Tactical Internet and the most important among them is 5G – the 5th generation of mobile radio communications. This article presents a vision for the use of devices manufactured using microelectromechanical systems technology, namely passive radio-frequency microelectromechanical devices and systems in synergy with energy-harvesting microelectromechanical devices and systems in such new structural paradigms. The authors present their results on the development, manufacture and research of experimental samples of radio-frequency microelectromechanical switches that can meet the growing need for cutting-edge performance for currently deployed 5G NR FR1 (below 6 GHz) mobile networks or high-performance applications., На сегодняшний день одним из ключевых драйверов (триггеров) развития научно- исследовательских и опытно-конструкторских разработок в области электроники, радиочастотных компонентов и систем, системной интеграции и проектирования, а также информационно-коммуникационных технологий являются такие концепции сети передачи данных, как Интернет Вещей, Интернет Всего, Тактильный Интернет и наиболее важный среди них – 5G – пятое поколение мобильной радиосвязи. В статье представлено видение использования устройств, изготовленных с применением технологии микроэлектромеханических систем: пассивных радиочастотных микроэлектромеханических устройств и систем в синергии с энергособирающими микроэлектромеханическими устройствами и системами в новых структурных парадигмах. Представлены результаты разработки, изготовления и исследования экспериментальных образцов радиочастотных микроэлектромеханических переключателей, способные удовлетворить растущую потребность в ультрасовременной производительности для развертываемых в настоящее время мобильных сетей 5G NR FR1 (менее 6 ГГц) или высокопроизводительных приложений.

The multipactor phenomenon is a major concern in modern satellites that operate with highpower transmission in many frequency bands. It occurs when electrons inside RF componentsare accelerated by the RF fields. These electrons then hit walls inside the device, produc-ing secondary electrons. As the number of electrons increases, it may create noise inside thecomponent, thus deteriorating the original signal-to-noise ratio. When designing radio fre-quency equipment for space applications, it is therefore important to know at which powerlevels this occurs. Multicarrier simulations are time consuming and demand high amounts ofcomputer resources. In this thesis the hybrid L1/L2 method has been tested, which is a methodthat separates the geometric and multicarrier simulations into two parts resulting in a shortercomputation time. The conclusion is that the method is more reliable than single carrier sim-ulations, and that it can be used as a first step in the designing process of RF components.It is also a way of estimating a preliminary threshold before starting a full-scale multicarriersimulation.

Fifth generation networks (5G) will be associated with a partial shift to higher carrier frequencies, including wavelengths of insects. This may lead to higher absorption of radio frequency (RF) electromagnetic fields (EMF) by insects and could cause dielectric heating. The yellow fever mosquito (Aedes aegypti), a vector for diseases such as yellow and dengue fever, favors warm climates. Being exposed to higher frequency RF EMFs causing possible dielectric heating, could have an influence on behavior, physiology and morphology, and could be a possible factor for introduction of the species in regions where the yellow fever mosquito normally does not appear. In this study, the influence of far field RF exposure on A. aegypti was examined between 2 and 240 GHz. Using Finite Difference Time Domain (FDTD) simulations, the distribution of the electric field in and around the insect and the absorbed RF power were found for six different mosquito models (three male, three female). The 3D models were created from micro-CT scans of real mosquitoes. The dielectric properties used in the simulation were measured from a mixture of homogenized A. aegypti. For a given incident RF power, the absorption increases with increasing frequency between 2 and 90 GHz with a maximum between 90 and 240 GHz. The absorption was maximal in the region where the wavelength matches the size of the mosquito. For a same incident field strength, the power absorption by the mosquito is 16 times higher at 60 GHz than at 6 GHz. The higher absorption of RF power by future technologies can result in dielectric heating and potentially influence the biology of this mosquito., PLoS Computational Biology, 17 (10), ISSN:1553-734X, ISSN:1553-7358

SPIDER radio-frequency (RF) inductively coupled ion source is a full-size prototype of ITER Heating Neutral Beam Injector ion source,equipped with 100 keV accelerator system for the particles. It is in operation since June 2018 in the premises of Neutral Beam Test Facility located in Padova, Italy. The ion source includes a plasma source where plasma is generated and heated by8 RF drivers operating with Hydrogen/Deuterium at a gas pressure of ~ 0.3 Pa and maximum RF power of 100 kW per driver at 1 MHz frequency. There are 4RF circuits present in SPIDER, each comprises of a RF generator and a RF load. The RF load is defined bya transmission line:a capacitor-basedmatching network and two driver coils connected in series. To qualify the performance of the driver, an estimation of the power transfer efficiency (PTE) to the plasma is important. It is defined as the ratio between the power absorbed by the plasma and the total RF input power. The power absorbed by the plasma cannot be measured experimentally and is found to be dependent on several parameters coupled together. Previously, a methodology has been developed based on the integration of various input parameters, plasma heating mechanisms and an electrical model which can provide an estimation of PTE to the plasma. One of the essential input parameters is the plasma electron density.It is possible to experimentally measure this parameter and currently different methods are being explored,but usually they also require a detailed and time consuming data analyses. In this perspective, are liable and a fast model will be beneficial for the estimation of electron density. This work will focus on the description, application,and comparison of different ways to estimate the electron density.Based on the available literature, two main approaches are highlighted for the estimation of electron density1) from the power balance equation and 2) through the measurements of the electrical parameters in the RF power circuits.The results in terms of electron density will be compared to the first experimental results obtained from spectroscopic and/or electrostatic probe measurements.

Iako neizostavan dio komunikacijskih sustava, pojačalo je kritičan element koji unosi nelinearnosti u sustav u obliku neželjenih komponenti u spektru koje se ne mogu ukloniti filtriranjem jer se nalaze na frekvenciji ulaznog signala. Te komponente uzrokuju neispravnu demodulaciju i potencijalno neispravno dekodiranje signala, a rješavaju se pred-distorzijom signala. Kako se zadnjih godina digitalni dio odašiljača (ali i prijemnika) pomaknuo prema izlaznom pojačalu (ulazu u prijemnik), tako i digitalna pred-distorzija dobiva prednost pred analognom. Glavni cilj pred-distorzije je predizobličiti ulazni signal kako bi on ostao linearan prolaskom kroz nelinearno pojačalo. Za to je bilo potrebno promatrati izlazni i ulazni signal te na temelju njihove usporedbe dobiti funkcije koje su osnova modeliranja sustava za digitalnu pred-distorziju RF signala. Osnovna podjela je bezmemorijske i memorijske modele, a memorijski su opsežniji i bolji jer obuhvaćaju i utjecaj prošlih komponenata signala na trenutnu. Uz linearnost, za komunikacijske sustave najbitnija je efikasnost. Bilo je potrebno postići linearan prijenos signala uz što manju disipaciju snage. To je postignuto praćenjem ovojnice signala i njezinom upotrebom u modulatoru napajanja RF pojačala snage. Bitno je bilo vremenski uskladiti RF granu s granom u kojoj se nalazi modulator napajanja kako ne bi došlo do dodatnih nepoželjnih distorzija te je bilo bitno naći optimum između zahtjeva za linearnošću i efikasnošću. Primjenom navedenih algoritama postignuta su vrlo dobra poboljšanja oba tražena parametra. Power amplifier is crtitical part of communication system which disrupts system linearity by adding unwanted frequency components into signal spectrum. Those components are responsible for incorrect demodulation which could cause wrong information extraction on receiver. Digital predistortion is the main tool for fixing this problem. The objective of digital predistortion use was to to predistort signal so it becomes linear after passing through power amplifier. Analysis of output and input was important for extrapolation of AM/AM and AM/PM characteristics of power amplifier. Based on those characteristics memory or memoryless model for digital predistortion algorithm is chosen. Memory ploynomials are more precise because they include signal history into power amplifier modeling giving more extensive and more precise model. Apart from linearity, efficiency is the most important parameter of communication system. Envelope tracking method for efficiency enhacement was used for power supply modulation. Time alignment between RF and power supply branches was crucial because without it new distortions would be added into signal. Optimum between linearity and efficiency was found by combining those algorithms.

Radiofrequency electromagnetic fields (EMFs) are used to enable a number of modern devices, including mobile telecommunications infrastructure and phones, Wi-Fi, and Bluetooth. As radiofrequency EMFs at sufficiently high power levels can adversely affect health, ICNIRP published Guidelines in 1998 for human exposure to time-varying EMFs up to 300 GHz, which included the radiofrequency EMF spectrum. Since that time, there has been a considerable body of science further addressing the relation between radiofrequency EMFs and adverse health outcomes, as well as significant developments in the technologies that use radiofrequency EMFs. Accordingly, ICNIRP has updated the radiofrequency EMF part of the 1998 Guidelines. This document presents these revised Guidelines, which provide protection for humans from exposure to EMFs from 100 kHz to 300 GHz. Health Phys. 118(5):483–524; 2020. Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Health Physics Society. This is an open-access article distributed under the terms of the Creative Commons AttributionNon Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

The study and control of resonant instabilities in magnetised plasmas is of fundamental interest over a wide range of applications from industrially relevant plasmas to plasma sources for spacecraft propulsion. In this work electrostatic probes were employed to measure a 4-20 kHz instability in the ion saturation current downstream of an electric double layer (DL) in an expanding helicon plasma source. The amplitude and frequency of the instability were found to vary in inverse proportion to the operating argon gas pressure (0.2-0.6 mTorr) and in direct proportion to the applied rf power (100-600 W) and applied solenoid current (3-8 A). A spatially resolved characterisation of the maximum instability amplitude determined two radial maxima, corresponding to the locations of most positive radial ion density gradient. Control and inhibition of the instability were achieved through the application of a kHz voltage amplitude modulation to the 13.56 MHz radio-frequency (rf) power supplied to the helicon antenna. Through the application of voltage amplitude modulations in the frequency range 2-12 kHz the instability was reduced by up to 65 %, exhibiting a greater reduction at higher applied modulation frequencies. This effect is described through a variation in the radial ion density gradient via asymmetrically attenuated ion acoustic density perturbations induced by the applied voltage modulation. The application of voltage amplitude modulations has been demonstrated as a potential control mechanism for density gradient driven instabilities in magnetised plasmas.

In this study, the total electromagnetic dose, i.e., the combined dose from fixed antennas and mobile devices, was estimated for a number of hypothetical network topologies for implementation in Switzerland to support the deployment of fifth generation (5G) mobile communication systems while maintaining exposure guidelines for public safety. In this study, we consider frequency range 1 (FR1) and various user scenarios. The estimated dose in hypothetical 5G networks was extrapolated from measurements in one of the Swiss 4G networks and by means of Monte Carlo analysis. The results show that the peak dose is always dominated by an individual&rsquo, s mobile phone and, in the case of non-users, by the bystanders&rsquo, mobile phones. The reduction in cell size and the separation of indoor and outdoor coverage can substantially reduce the total dose by &gt, 10 dB. The introduction of higher frequencies in 5G mobile networks, e.g., 3.6 GHz, reduces the specific absorption rate (SAR) in the entire brain by an average of &minus, 8 dB, while the SAR in the superficial tissues of the brain remains locally constant, i.e., within &plusmn, 3 dB. Data from real networks with multiple-input multiple-output (MIMO) were not available, the effect of adaptive beam-forming antennas on the dose will need to be quantitatively revisited when 5G networks are fully established.

This article deals with the extrinsic and intrinsic parameters of the Galium-Nitride RF transistor. These parameters are essential in any design of large-signal analysis of RF amplifiers. Package parasitics are the biggest problem of integrated circuits (ICs), especially at high frequencies. Each IC package gives unwanted parasitics to the primary function of the IC. The analysis of these package parasitics can be performed by the transistor manufacturer, which provides a non-linear model of the transistor, where parasitics elements are separated from the transistor. With these separated package parasitics, the highest efficiency, power output, and accurate harmonic termination can be achieved. The main purpose of this article is to describe these problems.

Measuring time-activity budgets over the complete individual life span is now possible for many animals with the recent advances of life-long individual monitoring devices. Although analyses of changes in the patterns of time-activity budgets have revealed ontogenetic shifts in birds or mammals, no such technique has been applied to date on insects. We tested an automated breakpoint-based procedure to detect, assess and quantify shifts in the temporal pattern of the flight activities in honeybees. We assumed that the learning and foraging stages of honeybees will differ in several respects, to detect the age at onset of foraging (AOF). Using an extensive dataset covering the life-long monitoring of 1,167 individuals, we compared the AOF outputs with the more conventional approaches based on arbitrary thresholds. We further evaluated the robustness of the different methods comparing the foraging time-activity budget allocations between the presumed foragers and confirmed foragers. We revealed a clear-cut learning-foraging ontogenetic shift that differs in duration, frequency and time of occurrence of flights. Although AOF appeared to be highly plastic among bees, the breakpoint-based procedure seems better capable to detect it than arbitrary threshold-based methods that are unable to deal with inter-individual variation. We developed the aof r-package including a broad range of examples with both simulated and empirical datasets to illustrate the simplicity of use of the procedure. This simple procedure is generic enough to be derived from any individual life-long monitoring devices recording the time-activity budgets, and could propose new ecological applications of bio-logging to detect ontogenetic shifts in the behaviour of central-place foragers.

Radio-frequency electromagnetic fields (RF-EMFs) can be absorbed in all living organisms, including Western Honey Bees (Apis Mellifera). This is an ecologically and economically important global insect species that is continuously exposed to environmental RF-EMFs. This exposure is studied numerically and experimentally in this manuscript. To this aim, numerical simulations using honey bee models, obtained using micro-CT scanning, were implemented to determine RF absorbed power as a function of frequency in the 0.6 to 120 GHz range. Five different models of honey bees were obtained and simulated: two workers, a drone, a larva, and a queen. The simulations were combined with in-situ measurements of environmental RF-EMF exposure near beehives in Belgium in order to estimate realistic exposure and absorbed power values for honey bees. Our analysis shows that a relatively small shift of 10% of environmental incident power density from frequencies below 3 GHz to higher frequencies will lead to a relative increase in absorbed power of a factor higher than 3.

In this paper, surrogate modeling techniques are applied for passive component modeling. These techniques are exploited to develop and compare two alternative strategies for automated radio-frequency (RF) circuit design. The first one is a traditional approach where passive components are designed during the optimization stage. The second one, inspired on bottom-up circuit design methodologies, builds passive component Pareto-optimal fronts (POFs) prior to any circuit optimization. Afterwards, these POFs are used as an optimized library from where the passive components are selected. This work exploits the advantages of evolutionary computation algorithms in order to efficiently explore the circuit design space, and the accuracy and efficiency of surrogate models to model passive components.

The ITER Ion Cyclotron Resonance Heating (ICRH) system is designed to couple to the plasma 20 MW of RF power from two antennas in the 40-55 MHz frequency range during long pulses of up to 3600 s and under various plasma conditions with Edge Localized Modes. Radio-Frequency (RF) contacts are integrated within the ITER ICRH launcher in order to ensure the RF current continuity and ease the mechanical assembly by allowing the free thermal expansion of the Removable Vacuum Transmission Line coaxial conductors during RF operations or during 250{\textdegree}C baking phases. A material study has been carried out to determine which materials and associated coatings are relevant for RF contacts application in ITER. In parallel, RF tests have been performed with a new prototype of Multi-Contact (r) LA-CUT/0,25/0 contacts made of silver-coated CuCrZr louvers. During these tests on a RF vacuum resonator, currents between 1.2 kA and 1.3 kA peak have been reached a few tens of times in steady-state conditions without any visible damage on the louvers. A final 62MHz pulse ending in a 300s flat top at 1.9kA resulted in severe damage to the contact. In addition, a test bed which performs sliding test cycles has been built in order to reproduce the wear of the contact prototype after 30 000 sliding cycles on a 3 mm stroke at 175{\textdegree}C under vacuum. The silver coating of the louvers is removed after approximately a hundred cycles whilst, to the contrary, damage to the CuCrZr louvers is relatively low., Fusion Engineering and Design, Elsevier, A Para{\^i}tre

Objective(s): Nowadays, the electromagnetic field-emitting devices are used routinely in our lives. Controversial reports exist concerning the effects of mobile radiofrequency (RF) on different parts of the body, especially stress hormones. The main goal of the present work was to study the long-term effects of mobile RF900 MHz exposure with special focus on the adrenal gland pathophysiology and function. Materials and Methods: Adult male Wistar rats were exposed to mobile RF 6 hr daily for 4–8 weeks. Intact and switched-off exposed animals were considered as controls. Plasma ACTH and cortisol levels were measured by the ELISA method. At the end of the experiment, a histological study was done on adrenal gland and brain tissues by hematoxylin and eosin staining. The thickness of the fasciculate layer of the adrenal gland, and its cell count and perimeter were measured using the Fiji software. Results: Enhanced plasma ACTH and cortisol levels were found after prolonged exposure to mobile RF. The fasciculata layer of adrenal cortex eventually thickened following mobile RF radiation. While the number of cells in zona fasciculata remained constant, the cell size and perimeter increased during RF exposure. Finally, we found that vacuolization in brain tissue and the number and size of vacuoles considerably increased during two months of RF exposure. Conclusion: Cell phone RF exposure induced significant hormonal and structural changes in adrenal gland and brain tissues. Therefore, the public should be aware and limit their exposure as much as possible.

Human activity monitoring is essential for a variety of applications in many fields, particularly healthcare. The goal of this research work is to develop a system that can effectively detect fall/collapse and classify other discrete daily living activities such as sitting, standing, walking, drinking, and bending. For this paper, a publicly accessible dataset is employed, which is captured at various geographical locations using a 5.8 GHz Frequency-Modulated Continuous-Wave (FMCW) RADAR. A total of ninety-nine participants, including young and elderly individuals, took part in the experimental campaign. During data acquisition, each aforementioned activity was recorded for 5–10 s. Through the obtained data, we generated the micro-doppler signatures using short-time Fourier transform by exploiting MATLAB tools. Subsequently, the micro-doppler signatures are validated, trained, and tested using a state-of-the-art deep learning algorithm called Residual Neural Network or ResNet. The ResNet classifier is developed in Python, which is utilised to classify six distinct human activities in this study. Furthermore, the metrics used to analyse the trained model’s performance are precision, recall, F1-score, classification accuracy, and confusion matrix. To test the resilience of the proposed method, two separate experiments are carried out. The trained ResNet models are put to the test by subject-independent scenarios and unseen data of the above-mentioned human activities at diverse geographical spaces. The experimental results showed that ResNet detected the falling and rest of the daily living human activities with decent accuracy.

Conventional thawing processes adopted by food industry are characterized by longer operation times and food quality losses. Recently, batch and continuous radio-frequency (RF) assisted thawing were proposed as alternative and faster process, but their economic feasibility at industrial level is far to be assessed. Undoubtedly, longer penetration depth and ability to generate volumetric heat enable RF assisted heating a very promising technology to apply at industrial scale. On the other hand, most of the RF systems in operation are built following heuristic criteria, more than being designed and tailored on specific products or processes: this has limited the development of RF based system for food thawing as well as the proposal of simple but effective control systems. The literature has contributed with a number of theoretical and modeling based works for RF processes, but design-based studies in general are limited. Therefore, the objective of this study was to present a strategy for virtual design of a continuous RF thawing process. For this purpose, a previously developed and experimentally validated mathematical model was modified to take into account the movement of food product through a continuous RF system, the movement of RF electrode and subsequent effects of temperature and electric field changes. Power uniformity index (PUI) for various proposed configurations was analyzed, and possible scenarios were suggested for an industrial scale process. With this concept, this study was assumed to be significant for design and optimization of industrial RF and RF thawing processes. (C) 2017 Elsevier Ltd. All rights reserved.

This paper proposes a Tunnel FET (TFET)-based power management circuit (PMC) for ultra-low power RF energy harvesting applications. In contrast with conventional thermionic devices, the band-to-band tunneling mechanism of TFETs allows a better switching performance at sub-0.2 V operation. As a result, improved efficiencies in RF-powered circuits are achieved, thanks to increased rectification performance at low power levels and to the reduced energy required for a proper PMC operation. It is shown by simulations that heterojunction TFET devices designed with III–V materials can improve the rectification process at received power levels below −20 dBm (915 MHz) when compared to the application of homojunction III–V TFETs and Si FinFETs. For an available power of −25 dBm, the proposed converter is able to deliver 1.1 ${\mu }\text{W}$ of average power (with 0.5 V) to the output load with a boost efficiency of 86%.

This thesis aims to develop robust and fiabilist optimiztion means in order to face the future requirements of the radio-frequency (RF) filter market. The goals of this thesis are: to reduce the optimization process timespan, to be able to find a solution that fully satisfies a tough bill of specifications and to reduce failure rate due to manufacturing uncertainties. Several research works has been done to achieve these goals.During the formulation phase of an engineering design optimization (EDO) process, ambiguities, leading to unsatisfying solutions, could happen. In this case, some phases of the EDO process has to be iterated increasing its timpespan. Therefore, a Framework to properly formulate an optimization problem has been developed. During a run of optimization, for the algorithm to solve the problem according to designer preferences and thus avoid un-satisfying solution, two challenges, among others, have to be faced. The variable challenge is about handling mixed variables with different order of magnitudes while the satisfaction challenge is about properly computing satisfaction. The Normalized Evaluations Approach has been developed to face these challenges. The resolution method efficiency strongly relies on the choice of its core element: the algorithm. Hence, the high number of optimization algorithms is a challenge for an optimizer willing to choose the correct algorithm. To face this challenge, a Benchmark, being a tool to assess the algorithm performance and to be able to select the correct algorithm for a given problem, has been developed. Algorithm efficiency depends on the values given to its parameters, its setting. A common practice is to tune parameters manually which does not guarantee the best performance. A solution to this problem is to perform meta-optimization (MO) which consists in optimizing an algorithm efficiency by tuning its parameters. A MO approach using a benchmark to evaluate settings has been tested. A fiabilist optimization method, taking the uncertainties into account, has to be developed. However, this method has to do so without degrading resolution time, which is usually the case with fiabilist method. Therefore, a Sparing Fiabilist Optimization method taking uncertainties into account without increasing too much the numerical resolution timespan has been developed.These methods have been applied to optimize a RF filter, with a tough bill of specifications, for which no fully satisfying solution where found before the thesis. By using methods developed during this thesis, a determinist solution, not taking uncertainties into account, which fully satisfies the bill of specifications, has been found. Moreover, a fiabilist solution having a 71% success rate has been found. As a conclusion, it appears that optimization methods developed during these thesis where sufficient to face the future requirements of the radio-frequency filter market.; Cette thèse vise à développer des moyens d'optimisation robuste et fiabiliste dans le but de faire face aux besoins du marché des filtres radio-fréquence (RF). Les objectifs de cette thèse sont: réduire la durée du processus d'optimisation, être capable de trouver une solution qui satisfasse complètement un cahier des charges difficile et réduire le pourcentage de rebut dû aux incertitudes de fabrication. Plusieurs travaux de recherche ont été menés pour atteindre ces objectifs.Durant la phase de formulation d'un processus d'optimisation en conception (EDO), des ambiguïtés, conduisant à des solutions insatisfaisantes, peuvent survenir. Dans ce cas, certaines phases du processus d'EDO doivent être itérées augmentant sa durée. Par conséquent, un cadre pour formuler correctement les problèmes d'optimisation a été développé. Durant un run d'optimisation, pour que l'algorithme résolve le problème conformément aux attentes du concepteur et ainsi éviter les solutions insatisfaisantes, deux défis, parmi d'autres, doivent être surmontés. Le défi des variables consiste à gérer des variables mixtes ayant des ordres de grandeur différents tandis que le défi de la satisfaction consiste à correctement calculer celle-ci. L'approche par évaluations normalisées a étée développée pour faire face à ces défis. L'efficacité de la méthode de résolution dépend fortement du choix de son élément central: l'algorithme. De ce fait, le grand nombre d'algorithmes d'optimisation est un défi pour un souhaitant choisir un algorithme adapté. Pour faire face à ce défi, un benchmark, qui est un outil pour évaluer la performance d'un algorithme et être capable de choisir l'algorithme adapté à un problème, a été développé. L'efficacité d'un algorithme dépend des valeurs données à ses paramètres, son paramétrage. Une pratique commune est de régler les paramètres manuellement, ce qui ne garantit pas les meilleures performances. Une solution à ce problème est de réaliser une méta-optimisation (MO) qui consiste à optimiser l'efficacité d'un algorithme en réglant son paramétrage. Une approche de MO utilisant un benchmark pour évaluer des paramétrages a été testée. Une méthode d'optimisation fiabiliste, prenant en compte les incertitudes, doit être développée. Cependant, cette méthode ne doit pas dégrader le temps de résolution, ce qui est généralement le cas des méthodes fiabilistes. Ainsi, a méthode d'optimisation fiabiliste économe prenant en compte les incertitudes sans trop augmenter le temps de calcul ont été développée.Ces méthodes ont été appliquées pour optimiser un filtre RF, avec un cahier des charges difficile, pour lequel aucune solution totalement satisfaisante n'avait été trouvé avant la thèse. En utilisant les méthodes développées durant cette thèse, une solution déterministe, ne prenant pas en compte des incertitudes, respectant totalement le cahier des charges, a été trouvée. De plus, une solution fiabiliste ayant un pourcentage de succès de 71% a été trouvée. En conclusion, il apparaît que les méthodes développées durant cette thèse sont suffisantes pour faire face aux besoins futurs du marché des filtres radiofréquences.

This thesis aims to develop robust and fiabilist optimiztion means in order to face the future requirements of the radio-frequency (RF) filter market. The goals of this thesis are: to reduce the optimization process timespan, to be able to find a solution that fully satisfies a tough bill of specifications and to reduce failure rate due to manufacturing uncertainties. Several research works has been done to achieve these goals.During the formulation phase of an engineering design optimization (EDO) process, ambiguities, leading to unsatisfying solutions, could happen. In this case, some phases of the EDO process has to be iterated increasing its timpespan. Therefore, a Framework to properly formulate an optimization problem has been developed. During a run of optimization, for the algorithm to solve the problem according to designer preferences and thus avoid un-satisfying solution, two challenges, among others, have to be faced. The variable challenge is about handling mixed variables with different order of magnitudes while the satisfaction challenge is about properly computing satisfaction. The Normalized Evaluations Approach has been developed to face these challenges. The resolution method efficiency strongly relies on the choice of its core element: the algorithm. Hence, the high number of optimization algorithms is a challenge for an optimizer willing to choose the correct algorithm. To face this challenge, a Benchmark, being a tool to assess the algorithm performance and to be able to select the correct algorithm for a given problem, has been developed. Algorithm efficiency depends on the values given to its parameters, its setting. A common practice is to tune parameters manually which does not guarantee the best performance. A solution to this problem is to perform meta-optimization (MO) which consists in optimizing an algorithm efficiency by tuning its parameters. A MO approach using a benchmark to evaluate settings has been tested. A fiabilist optimization method, taking the uncertainties into account, has to be developed. However, this method has to do so without degrading resolution time, which is usually the case with fiabilist method. Therefore, a Sparing Fiabilist Optimization method taking uncertainties into account without increasing too much the numerical resolution timespan has been developed.These methods have been applied to optimize a RF filter, with a tough bill of specifications, for which no fully satisfying solution where found before the thesis. By using methods developed during this thesis, a determinist solution, not taking uncertainties into account, which fully satisfies the bill of specifications, has been found. Moreover, a fiabilist solution having a 71% success rate has been found. As a conclusion, it appears that optimization methods developed during these thesis where sufficient to face the future requirements of the radio-frequency filter market.; Cette thèse vise à développer des moyens d'optimisation robuste et fiabiliste dans le but de faire face aux besoins du marché des filtres radio-fréquence (RF). Les objectifs de cette thèse sont: réduire la durée du processus d'optimisation, être capable de trouver une solution qui satisfasse complètement un cahier des charges difficile et réduire le pourcentage de rebut dû aux incertitudes de fabrication. Plusieurs travaux de recherche ont été menés pour atteindre ces objectifs.Durant la phase de formulation d'un processus d'optimisation en conception (EDO), des ambiguïtés, conduisant à des solutions insatisfaisantes, peuvent survenir. Dans ce cas, certaines phases du processus d'EDO doivent être itérées augmentant sa durée. Par conséquent, un cadre pour formuler correctement les problèmes d'optimisation a été développé. Durant un run d'optimisation, pour que l'algorithme résolve le problème conformément aux attentes du concepteur et ainsi éviter les solutions insatisfaisantes, deux défis, parmi d'autres, doivent être surmontés. Le défi des variables consiste à gérer des variables mixtes ayant des ordres de grandeur différents tandis que le défi de la satisfaction consiste à correctement calculer celle-ci. L'approche par évaluations normalisées a étée développée pour faire face à ces défis. L'efficacité de la méthode de résolution dépend fortement du choix de son élément central: l'algorithme. De ce fait, le grand nombre d'algorithmes d'optimisation est un défi pour un souhaitant choisir un algorithme adapté. Pour faire face à ce défi, un benchmark, qui est un outil pour évaluer la performance d'un algorithme et être capable de choisir l'algorithme adapté à un problème, a été développé. L'efficacité d'un algorithme dépend des valeurs données à ses paramètres, son paramétrage. Une pratique commune est de régler les paramètres manuellement, ce qui ne garantit pas les meilleures performances. Une solution à ce problème est de réaliser une méta-optimisation (MO) qui consiste à optimiser l'efficacité d'un algorithme en réglant son paramétrage. Une approche de MO utilisant un benchmark pour évaluer des paramétrages a été testée. Une méthode d'optimisation fiabiliste, prenant en compte les incertitudes, doit être développée. Cependant, cette méthode ne doit pas dégrader le temps de résolution, ce qui est généralement le cas des méthodes fiabilistes. Ainsi, a méthode d'optimisation fiabiliste économe prenant en compte les incertitudes sans trop augmenter le temps de calcul ont été développée.Ces méthodes ont été appliquées pour optimiser un filtre RF, avec un cahier des charges difficile, pour lequel aucune solution totalement satisfaisante n'avait été trouvé avant la thèse. En utilisant les méthodes développées durant cette thèse, une solution déterministe, ne prenant pas en compte des incertitudes, respectant totalement le cahier des charges, a été trouvée. De plus, une solution fiabiliste ayant un pourcentage de succès de 71% a été trouvée. En conclusion, il apparaît que les méthodes développées durant cette thèse sont suffisantes pour faire face aux besoins futurs du marché des filtres radiofréquences.

High-power continuous-wave radio-frequency (RF) systems in the megawatt range are commonly used in nuclear fusion experiments. Such kinds of RF systems being rather rare, Master’s students do not know how these systems are used in practice – even students engaged in nuclear fusion courses. This is the reason why, as part of the French and European Master’s in fusion physics and technologies, dedicated practical work on topics related to plasma RF heating are proposed to students. Over a few days, these students discover how to perform RF measurements and succeed in characterizing real-scale components used in plasma RF heating experiments. This paper details four hands-on approaches which have been conducted over eight years with several tens of students having no prior knowledge in RF engineering.

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We demonstrate the generation of radio-frequency (RF) signals using stabilized integrated semiconductor lasers. The lasers are monolithically integrated on the same chip using InP active-passive integration technology. They are locked to different resonances of the same external optical cavity using the Pound-Drever-Hall locking technique. The locking is implement with single control loop for each laser and by voltage controlled tuning thus avoiding significant thermal effects. The generated RF signal can be tuned discretely to frequencies that are multiples of the external optical cavity free spectral range. Examples of beat tones at 12.436, 24.8735 and 40.4194 GHz are demonstrated. The linewidth of the generated signals at all frequencies is less than 40 kHz. The single-side-band phase noise is about -54 dBc/Hz for frequencies offsets from the carrier at 12.436 GHz between 1 kHz and 10 kHz and -60 and -67 dBc/Hz at 100 kHz and 1 MHz respectively.

Zukünftige Beschleunigerprojekte und Nutzerexperimente erfordern für ihren Betrieb einen hochbrillanten Elektronenstrahl mit hohem mittlerem Strom. Eine Elektronenquelle mit dem Potential die Anforderungen erfüllen, ist ein supraleitender Hochfrequenz (SHF) Photoinjektor im Dauerstrichbetrieb. Die Strahldynamik eines solchen Photoinjektor Systems bestimmt die maximal zu erreichende Strahlbrillanz und wird ihrerseits von den Design und Betriebsparametern des Photoinjektors beeinflusst. Ziel ist immer die entscheidenden Design- und Betriebsparameter der Elektronenquelle hinsichtlich einer maximalen Strahlbrillanz zu wählen. Diese Aufgabe verlangt ein detailliertes Verständnis der Strahldynamik-Prozesse. Ferner ist es notwendig, eine Optimierung des Photoinjektors als Ganzes, mit dem Ziel einer maximalen Strahlqualität bei hohem mittlerem Strom, vorzunehmen. Dieses ermöglicht auch, die physikalischen Grenzen eines gegebenen Designs zu ermitteln und im Betrieb vollständig auszunutzen. Diese Doktorarbeit befasst sich mit der Strahldynamik in einem SHF Photoinjektor, unter Berücksichtigung interner Raumladungseffekte. Die Erkenntnisse zur Strahldynamik werden für die Entwicklung eines Optimierungsprogramms verwendet, um die Leistung des Injektors hinsichtlich der Strahlbrillanz zu verbessern. Die entwickelte Methode basiert auf Pareto-Optimierung mehrerer Zielfunktionen, unter Verwendung eines generischen Algorithmus. Das zentrale Ergebnis dieser Arbeit umfasst ein universelles Optimierungsprogramm, das für Photoinjektoren unabhängig von ihrem Design und Anwendungsgebiet genutzt werden kann. Für den Betrieb mit hoher Strahlbrillanz ist es möglich aus den erhaltenen Pareto-optimalen Lösungen einen stabilen Satz an Einstellwerten für den Photoinjektor zu extrahieren. Durch die allgemeine Optimierungsstrategie lässt sich das entwickelte Programm auch für andere Beschleunigerabschnitte, oder die Optimierung einer ganzen Anlage mit erweiterter Zielsetzung anpassen. An increasing number of future accelerator projects, light sources and user experiments require high brightness, high average current electron beams for operation. Superconducting radio-frequency (SRF) photoinjectors running in continuous-wave (cw) mode hold the potential to serve as an electron source that generates electron beams of high brightness. Different operation and design parameters of the SRF photoinjector impact the beam dynamics and, thus, the beam brightness. Therefore, an in-depth understanding of the beam dynamics processes in an SRF photoinjector and the dependency of the beam dynamics on the photoinjector set parameters is crucial. A high brightness beam operation requires a global optimization of the SRF photoinjector that allows to find suitable photoinjector settings and to figure out and extend the physical performance limits of the investigated injector design. The dissertation at hand offers a detailed analysis of the beam dynamics in an SRF photoinjector regarding internal space charge effects. Furthermore, the impact of the photoinjector elements on the electron beam is discussed. The lessons learned from this theoretical view are implemented in the development of an optimization tool to achieve a high brightness performance. A universal multi-objective optimization program based on a generic algorithm was developed to extract stable, optimum gun parameter from Pareto-optimum solutions. This universal tool is able to optimize and find the physical performance limit of any (S)RF photoinjector independent from the individual application of the electron source (energy recovery linac, free electron laser, ultra-fast electron diffraction). This thesis thereby verifies and complements existing theoretical considerations regarding photoinjector-beam interactions. The global optimization strategy can be introduced to variable optimization objectives as well as it can be extended to an optimization of further parts of the accelerator facility.

Plasma-based surface modification is recognized as an effective way to activate biomaterial surfaces, and modulate their interactions with cells, extracellular matrix proteins, and other materials. However, treatment of a luminal surface of a tubular scaffold remains non-trivial to perform in small diameter tubes. Polyvinyl alcohol (PVA) hydrogel, which has been widely used for medical applications, lacks functional groups to mediate cell attachment. This poses an issue for vascular applications, as endothelialization in a vascular graft lumen is crucial to maintain long term graft patency. In this study, a Radio Frequency Glow Discharges (RFGD) treatment in the presence of NH3 was used to modify the luminal surface of 3-mm diameter dehydrated PVA vascular grafts. The grafted nitrogen containing functional groups demonstrated stability, and in vitro endothelialization was successfully maintained for at least 30 days. The plasma-modified PVA displayed a higher percentage of carbonyl groups over the untreated PVA control. Plasma treatment on PVA patterned with microtopographies was also studied, with only the concave microlenses topography demonstrating a significant increase in platelet adhesion. Thus, the study has shown the possibility of modifying a small diameter hydrogel tubular scaffold with the RFGD plasma treatment technique and demonstrated stability in ambient storage conditions for up to 30 days.

In this paper, the advances in radio-frequency (RF)/microwave biosensors based on graphene nanomaterials including graphene, graphene oxide (GO), and reduced graphene oxide (rGO) are reviewed. From a few frontier studies, recently developed graphene nanomaterials-based RF/microwave biosensors are examined in-depth and discussed. Finally, the prospects and challenges of the next-generation RF/microwave biosensors for wireless biomedical applications are proposed.

Researchers in the field of MRI (Magnetic resonance imaging) are pushing towards the use of stronger and stronger magnets in MRI scanners. These extremely strong magnets are used because the signal-to-noise ratio in MRI scans increases with increasing magnetic field strength. A higher signal-to-noise ratio implies that MRI scans can be acquired at higher resolution. Standard MRI machines operating at a field strength of 3 “Tesla” are able to resolve structures with details up to 1mm, while less common 7 Tesla MRI machines can go to 0.5mm. A few research centers around the world are building MRI scanners with magnets stronger than 7 Tesla, with the aim of imaging the finely detailed structures of the brain and the body. In addition to a very strong static magnetic field, all MRI scanners use radio-frequency (RF) antennas to transmit and receive the signals that generate MRI scans. For MRI scanner operating at ultra-high field strength, the design of these radio-frequency antennas becomes vital to the image quality. If the antennas are not designed or operated properly, the image quality deteriorates. In this thesis, several improvements have been made to RF antennas for body imaging at 7 Tesla and the world’s first 10.5 Tesla. In addition, critical safety aspects of these RF antennas have been studied. The new RF antenna designs are applied to image prostate cancer and the heart at unprecedented resolutions. Finally, the potential gains of MRI scanners operating at even stronger fields (14 Tesla) are demonstrated through a simulation study.

Researchers in the field of MRI (Magnetic resonance imaging) are pushing towards the use of stronger and stronger magnets in MRI scanners. These extremely strong magnets are used because the signal-to-noise ratio in MRI scans increases with increasing magnetic field strength. A higher signal-to-noise ratio implies that MRI scans can be acquired at higher resolution. Standard MRI machines operating at a field strength of 3 “Tesla” are able to resolve structures with details up to 1mm, while less common 7 Tesla MRI machines can go to 0.5mm. A few research centers around the world are building MRI scanners with magnets stronger than 7 Tesla, with the aim of imaging the finely detailed structures of the brain and the body. In addition to a very strong static magnetic field, all MRI scanners use radio-frequency (RF) antennas to transmit and receive the signals that generate MRI scans. For MRI scanner operating at ultra-high field strength, the design of these radio-frequency antennas becomes vital to the image quality. If the antennas are not designed or operated properly, the image quality deteriorates. In this thesis, several improvements have been made to RF antennas for body imaging at 7 Tesla and the world’s first 10.5 Tesla. In addition, critical safety aspects of these RF antennas have been studied. The new RF antenna designs are applied to image prostate cancer and the heart at unprecedented resolutions. Finally, the potential gains of MRI scanners operating at even stronger fields (14 Tesla) are demonstrated through a simulation study.

International audience; AlGaN/GaN high electron mobility transistors (HEMTs) on Silicon substrates grown by molecular beam epitaxy have been investigated using small-signal microwave measurements, to see performance Radio-frequency of components. Passivation of HEMT devices SiO2/SiN a different pretreatment is used to reduce the effects of trapping and consequently has a large effect on these radio-frequency parameters. We used cold-FET and hot FET technique to extract the intrinsic and extrinsic parameters in order to show the effect passivation of parasitic elements; the parasitic capacitances, resistances and inductances. From this point we discover the extent of their impact on power and microwave performance.

A multi-band body-worn distributed exposure meter (BWDM) is designed and calibrated for diffuse fields in a reverberation chamber (RC) for personal exposure assessment in indoor environments. The BWDM uses 22 nodes distributed over the torso and measures the incident power density ( $S_{\mathrm{ inc}}$ ) on body for 11 telecommunication bands in the frequency range of 790–5513 MHz. In order to calibrate the measurement device in diffuse fields, a protocol is proposed for on-body calibration of the BWDM. This protocol is applicable to wearable personal exposure meters in general. The BWDM and the proposed calibration protocol are validated in five indoor locations and five frequency bands (the downlink bands at 800, 900, 1800, and 2100 MHz as well as Wi-Fi 2 GHz) using a tri-axial broadband antenna and a spectrum analyzer (SA). The calibration shows that the BWDM has a relatively low measurement uncertainty with a 68% confidence interval on its antenna apertures, in the range 3.4–5.5 dB. A maximum difference of 0.9 dB is obtained for the total exposure in the test areas between the measurements of the BWDM and SA, which is an excellent agreement.

Quantum computation promises to solve presently intractable problems, with hopes of yielding solutions to pressing issues to society. Despite this, current machines are limited to tens of qubits. The field is in a state of continuous scaling, with groups around the world working on all aspects of this problem. The work of this thesis aims to contribute to this effort. It is motivated by the goal of increasing both the speed and bandwidth of experiments conducted within our laboratory. Low-loss radio-frequency multiplexers were characterised at cryogenic temperatures, with some shown to operate at below 7mK. The Analog Devices ADG904 was one of these, and its insertion loss was measured at