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This work addresses the challenge of deriving a simple but effective multi-physic model useful for the design and simulation of hyperthermia devices for ensuring a high-quality treatment. An existing compact patch antenna working at 434 MHz is re-designed using the proposed methodology. The proposed general approach is used to investigate the specific case of the hyperthermia treatment of abdominal rhabdomyosarcoma. Instead of using patient-specific geometries with discrete vascular tree models, a surface phantom with a continuum 3D blood perfusion model of tumors is used. The geometrical parameters of the antennas are selected to provide a robust design against the variation of the phantom parameters. The effectiveness of the antenna is evaluated simulating the treatment with a recent non-linear multi-physic model, considering the different description of tumor vasculature. A more robust and effective design is obtained, with respect to its previous version. Indeed, the antenna bandwidth is increased with about 7%. The treatment performed using the old version of the antenna lead to unsuccessful results (40 °C after 60 min), whilst the novel robust design could successfully treat the target region. The new version of the patch can withstand a temperature of 42.5 °C for 60 min of treatment. To further enhance the effectiveness of the treatment, the use of a time-modulated power is studied. The proposed model could be extended to different body regions and used to develop an application-oriented design of antennas for hyperthermia treatment.

Space debris (SD) is an important problem for space operations and a hot topic for space surveillance research. A structured network of radar sensors is available worldwide, offering vital information about debris status. Recently, the Sardinia Radio Telescope (SRT), a 64-m dish located in Sardinia, Italy, was introduced in the European plan for SD monitoring. Because the SRT is devoted to radio astronomy applications and is not optimized for SD echo detection, the need for an SD-dedicated channel has emerged. In this article, we present a detailed description and characterization of the new P-band receiving chain for SRT’s space debris-monitoring purposes. As a test of its capabilities, the new channel was used to detect the echoes that emanated from the Chinese space station Tiangong-1 when it reentered Earth’s atmosphere on its latest mission.

New possibilities in antenna and microwave manufacturing are opening up through the exploitation of additive manufacturing (AM) 3D printing techniques. Despite being used primarily for the fabrication of dielectric structures, with the right filament, these procedures could also be able to print conductive parts, giving birth to true fully-3D-printed radiating elements. However, to take full advantage of these thermoplastic materials, a rigorous electromagnetic characterization needs to be performed. Based on this, the dielectric properties of one of the most common plastic 3D-printable materials are investigated, and, in addition, the electric conductivity of one of the most promising conductive filaments (Electrifi) is experimentally evaluated in a wide frequency range (0.5-7.5 GHz) and then validated in the design of different fully-3D-printable patch antennas.

A wearable textile antenna based on the fundamental mode of an eighth-mode substrate-integrated waveguide is presented, operating in the UHF frequency band, at 915 MHz. The proposed structure has a compact size, and presents a very good isolation from the human body. Compared to its SIW resonator counterpart, the proposed antenna size has been reduced by almost 87.5%, without degrading its performance. It has been simulated using CST Microwave Studio, with a broadside radiation pattern. All these features make this antenna very promising for Lo-Ra systems and applications, such as internet of things (IoT) applications.

We present the design of a thermal isolator, based on a simple gap in a standard rectangular waveguide with external circular profile. The proposed solution allows to achieve high return loss and low insertion loss by a suitable selection of the of the external radius of the waveguide circular profile, which determines the waveguide wall thickness. High robustness to misalignment is obtained, improving the performance of a recently published work in the same topic.

A wearable textile antenna based on the fundamental mode of an eighth-mode substrate-integrated waveguide is presented, operating in the UHF frequency band, at 915 MHz. The proposed structure has a compact size, and presents a very good isolation from the human body. Compared to its SIW resonator counterpart, the proposed antenna size has been reduced by almost 87.5%, without degrading its performance. It has been simulated using CST Microwave Studio, with a broadside radiation pattern. All these features make this antenna very promising for Lo-Ra systems and applications, such as internet of things (IoT) applications.

Hyperthermia concerns the heating treatment of cancerous tissues, mostly using a radiator, i.e., an antenna, as a heat source. The main goal of this therapy, primarily used as adjuvant therapy along with radio and chemotherapy, is to reach a suitable temperature inside the neoplastic mass—about 7–8° above the normal body temperature—which can kill the cancerous cells without compromising the healthy tissues. Many factors contribute to this goal, such as the radiation characteristics of the antenna, the thermal profiles of the healthy and cancerous tissues, and the dynamic of the water flux inside the bolus. Moreover, despite being often overlooked, an important role is played by the perfusion characteristics of the tumor. In this work, we present a preliminary multi-physic analysis in a local hyperthermia scenario, considering a simple patch antenna resonating at 434 MHz as a heat source, a water bolus, a bi-layered body phantom, and, most importantly, a specific tumor (rhabdomyosarcoma) placed inside the phantom described employing a realistic space-dependent blood perfusion model. The results of this study show the effectiveness of the hyperthermia treatment using the physiopathology-driven perfusion model, and they may be useful in a real local hyperthermia case.

To avoid high recurrence rate, the hyperthermia treatment (HT) of bone tumors after surgical intervention was investigated. Innovative magnetic biomaterials can be used as thermoseeds to perform local thermal therapy. This work copes with the multiphysic modeling of the HT of residual Osteosarcoma (OS) cells using the so-called magnetic scaffolds. The goal is to develop a model that can serve as a tool to plan an accurate, safe, and high-quality treatment. Therefore, the electromagneto-thermal problem of radio-frequency heating is solved to determine the spatial and temporal evolution of the temperature field in a simplified 2-D geometry of proximal humerus. Different assumptions about the nonuniformity of the external magnetic field are verified. The possibility of nonideal distribution of magnetic nanoparticles in the biomaterial is accounted for the first time. The pattern of the magnetic field and of the induced electric field is studied. Moreover, the spatio-temporal evolution of temperature is investigated in the different cases. With these improvements to the state-of-the-art model of the HT of bone tumors, it was possible to identify the field parameter which allows to deliver the therapeutic thermal dose to OS cells.

Space debris is internationally recognized as a planetary threat. Efforts to enhance the worldwide radar monitoring networks have been intensified in the last years. Among the new radars employed for the observations, one of the most promising is the Bistatic Radar for Low Earth Orbit (LEO) Tracking (BIRALET), which employs the Sardinia Radio Telescope as a receiving segment. The Sardinia Radio Telescope (SRT) has recently been proven to be a reliable instrument for space debris monitoring and, for this purpose, over the years has undergone some substantial modifications in order to be able to rise to the status of a fully functional radar receiver. However, an extensive measurement campaign, in order to assess the real potential of the radar, has never been done before. In this paper, the authors present the first real space debris measurement campaign of the SRT, made between December 2018 and October 2019 using the new dedicated channel of the P-band receiver. A total of 27 objects were correctly detected during this campaign, characterized by a radar cross section (RCS) interval between 0.13 and 13.4 m2 and a range interval between 459 and 1224 km.

A wearable textile antenna based on the fundamental mode of an eighth-mode substrate-integrated waveguide cavity is presented for Low-Power Wide-Area Network (LPWAN) applications. The antenna operates in the UHF frequency band, at 867 MHz, and exhibits compact size, minimal manufacturing complexity and very low production cost. High isolation from the human body is observed, and a planar size reduction by more than 50% is achieved compared to similar SIW antennas in the literature. The proposed wearable antenna has been designed using CST Microwave Studio, then manufactured and tested, showing very good agreement with predicted performance.

Microwave heating offers a lot of advantages compared to conventional heating methods in the chemical reactions field due to its positive effects on reaction time and selectivity. Dielectric properties, and in particular permittivity, of substances and mixtures, are important for the optimization of microwave heating processes, notwithstanding this, specific databases are poor and far from being complete, and in the scientific literature very little data regarding these properties can be found. In this work, impedance measurements were carried out using a specially designed system to get the real and imaginary parts of the dielectric constant. The apparatus was tested in the estimation of permittivity of water&ndash, ethanol and water&ndash, NaCl mixtures, varying their composition to obtain a wide range of permittivity values. The results were compared to literature data and fitted with available literature models to verify the correspondence between them, finding that permittivity dependence on mixture composition can be effectively described by the models.

We present a new waveguide thermal isolator, based on a simple gap in a standard rectangular waveguide, developed for the $Q$ -band cryogenic receiver of the Sardinia Radio Telescope. The proposed component is very compact and consists of a single module, including both the horizontal and vertical polarization channels and the noise injection channel. The electromagnetic and thermal characteristics of this isolator have been fully investigated. High return loss and low insertion loss are obtained solely by a proper selection of the waveguide wall thickness, thus resulting in a very simple design, easily scalable in the whole microwave range. High robustness to misalignment and excellent thermal performance are achieved. A prototype of the proposed isolator has been manufactured and tested at room temperature, showing a very good agreement with predicted performance.

Microstrip patch antennas are widely employed in several applications, thanks to their low profile, low cost, and easy manufacturing. However, the demand for new technologies providing compactness and high performance poses a long-lasting challenge for the antenna designer. Traditional methods for bandwidth improvement and size reduction have some drawbacks, tied mostly to poor radiation performance or troublesome implementation. In this letter, a novel, simple, but effective patch antenna layout exploiting the customizable form factor guaranteed by 3-D printing (or other fabrication techniques) is presented. An appropriate modification in the vertical profile of the radiator is introduced. Specifically, without loss of generality, a cylindrical shape has been selected as a proof of concept. The proposed solution allows to increase the impedance bandwidth from 2.9% of a standard flat microstrip patch to 9%. Additionally, the projected antenna resonant size can be reduced up to 38% compared to its flat counterpart.

A microwave resonant cavity with rectangular section used as catalyzer for chemical reactions is presented, operating at the center frequency of 2.45 GHz, where two parallel metallic walls of the cavity are replaced with perfect magnetic conductors (PMC). This choice allows to obtain a uniform electric field distribution in each transversal section of the designed cavity, improving the power transfer to the fluid, if compared with the resonant cavity with electric walls. Moreover, the number of the tubes containing the reagent solution, can be significantly increased per surface unit. The cavity resonator has been designed using CST Microwave Studio, a commercial general purpose software for the electromagnetic simulation of three-dimensional high-frequency components.

Microwave hyperthermia is the process of raising the temperature of tumoral cells in the range 40-46°C, by means of electromagnetic radiation, without overheating the healthy tissues. Given the nature of the problem, which involves, other than electromagnetic radiation, a fluid dynamic component tied to the presence of a water bolus, and the heat transfer in a biological medium, a multidisciplinary approach is mandatory. However, one of the key aspects of the hyperthermia problem that is commonly disregarded is the presence of the tumor and the relevance of its dielectric and biological characteristics. In this work, we propose a multi-physic numerical study of microwave hyperthermia treatment at 434 MHz taking into account the EM field generated by a circular patch antenna, the presence of running water inside a bolus in direct contact with a simple bi-layered phantom and a novel perfusion model of a tumor.

Microwave hyperthermia is focused on raising the temperature of cancerous tissues a few degrees above the norm, in order to induce cellular death within the tumor but avoiding excessive heating of normal tissues, at the same time. The success of this therapy is based on the concurrence of different physics processes tied to the electromagnetic radiation, to the fluid dynamic and to the bio-heat transfer. However, the characteristics of the tumor play an important role in the delivery of the therapy. In this work an optimum design of microwave hyperthermia treatment, from a numerical point of view, is presented, taking into account the multi-physic coupling and a blood perfusion model of a muscle tissue tumor.

This work deals with the non-linear and multiphysic modeling of the hyperthermia treatment of bone tumors using novel biomaterials loaded with magnetic nanoparticles. The possible treatment of Osteosarcoma tumor with magnetic hydroxyapatite and poly-caprolactone doped with magnetite nanoparticles are analyzed. During the procedure, the materials and tissue physical properties modifies due to the heating, implying a coupled solution of thermal and electromagnetic equations. In the present study a numerical model, implemented using a commercial finite element software, is developed to include the intrinsic non-linearities of the hyperthermia multiphysic treatment. Therefore, an accurate in silico analysis is performed to identify the strength and frequency of the external magnetic field which would ensure an effective therapy, evaluated using the thermal dose damage analysis.

Il presente rapporto si prefigge l’obbiettivo di fornire una panoramica esaustiva sulle misure radar della stazione spaziale internazionale (ISS) effettuate dal gruppo di elettromagnetismo del DIEE in collaborazione con il personale dell’Osservatorio Astronomico di Cagliari (INAF-OAC). La campagna di misure si configura all’interno del progetto di ricerca DATA FUSION, riguardante la fusione dei dati provenienti da sensori ottici e radar per la determinazione orbitale di detriti spaziali. Gli echi radar della stazione spaziale sono stati ricevuti e registrati nelle date del 25-26 Settembre e del 2-11 Ottobre 2019. La configurazione radar utilizzata per osservare il passaggio della ISS è bi-statica, perciò costituita da una struttura trasmittente ed una ricevente.

Planar waveguide slot arrays (WSAs) have been used since 1940 and are currently used as performing antennas for high frequencies, especially in applications such as communication and RADAR systems. We present in this work a review of the most typical waveguide slot array configurations proposed in the literature, describing their main limitations and drawbacks along with possible effective countermeasures. Our attention has been focused mainly on the improved available design techniques to obtain high performance WSAs. In particular, the addressed topics have been reported in the following. Partially filled WSAs, or WSAs covered with single or multilayer dielectric slabs, are discussed. The most prominent second-order effects in the planar array feeding network are introduced and accurately modeled. The attention is focused on the T-junction feeding the array, on the effect of interaction between each slot coupler of the feeding network and the radiating slots nearest to this coupler, and on the waveguide bends. All these effects can critically increase the first sidelobes if compared to the ideal case, causing a sensible worsening in the performance of the array.

Space debris monitoring is nowadays a priority for worldwide space agencies, due to the serious threat that these objects present. More and more efforts have been made to extend the network of available radar systems devoted to the control of space. A meticulous review has been done in this paper, in order to find and classify the considerable amounts of data provided by the scientific community that deal with RADAR measurement for the debris monitoring and tracking. The information gathered is organized based on the volume of found data and classified taking into account the geographical location of the facilities.

Space debris represent a major risk for every spacecraft and satellite. In fact, other than cause serious damages to these structures, new collisions could exponentially increase the amount of debris and so the level of threat represented by the objects. To avoid new impacts, the monitoring of the space environment with space-based and ground-based measurement campaigns is necessary. The ground-based measurement can be implemented with optical or radar technologies. In this paper the upgrade of the Italian BIRALES radar system for space debris, that initially performed only Doppler measurements, is described. With its new features the BIRALES will be able to perform even range measurements.

Due to the large variability in human bodies characteristics, the main challenge to face to get an effective antenna for on-body clinical applications is to achieve a good robustness with respect to this variability (e.g., dielectric constant and geometry of the tissues). In this work we design a compact patch antenna which shows a significant robustness.

Space debris are orbiting objects that represent a major threat for space operations. The most used countermeasure to face this threat is, by far, collision avoidance, namely the set of maneuvers that allow to avoid a collision with the space debris. Since collision avoidance is tightly related to the knowledge of the debris state (position and speed), the observation of the orbital debris is the key of the problem. In this work a bistatic radar configuration named BIRALET (BIstatic RAdar for LEO Tracking) is used to detect a set of space debris at 410 MHz, using the Sardinia Radio Telescope as the receiver antenna. The signal-to-noise ratio, the Doppler shift and the frequency spectrum for each debris are reported.

Space debris is becoming a very important and urgent problem for present and future space activities. For that reason many public and private Institutions in the world are being involved in order to monitor and control the debris population increase and to understand which facilities can be used for improving the surveillance and tracking capabilities. In this framework in 2014 we performed some preliminary observations in a beam parking, CW mode and a bistatic configuration, with a transmitter of 4 kW of the Italian Air Force and the SRT (Sardinia Radio Telescope) a 64 meters radiotelescope used as a receiver. We performed the observations in P band at 410 MHz, receiving the signal diffused from some debris of different sizes and distances in LEO orbit, in order to understand the performances and capabilities of the system. In this article we will describe the results of this observations campaign, the simulation work done for preparing it, the RCS (radar cross section) observed, the level of the received signals, the Doppler measurements, and the work we are doing for developing a new and higher performing digital back end, able to process the data received.

A dual-band printed Log-periodic dipole array (LPDA) antenna for wireless communications is presented. The LPDA has been designed on a PET substrate and implemented by inkjet printing using a conductive ink, in order to obtain a low-cost antenna, and is fully planar, since it is fed by a coplanar waveguide. The proposed antenna can be used for wireless communications both in the S (2.4–2.484 GHz) and C (5.2–5.8 GHz) frequency bands, and a good out-of-band rejection has been obtained without using stop-band filters. The LPDA has been designed using a general purpose 3D CAD, CST Microwave Studio, and fully characterized, with measured results very close to the simulations.

Composites material made form Carbon NanoTubes have attracted much interest as shielding materials. A new model for the full-wave simulation of the shielding effectiveness is presented. The full-wave evaluation of that effectiveness is also discussed.