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One of the most common methods to protect electronic and telecommunication systems in a high‐power electromagnetic (HPEM) environment is using a conductive enclosure. Amplifiers are the vital parts in transmitter and receiver systems as the main components of a telecommunication system, so investigating the effects of HPEM waveform on their performance is very important. The Presence of apertures in the body of the conductive enclosure, as well as non‐linear elements such as transistors in amplifiers, adds to the complexity of examining the coupling of electromagnetic fields on the performance of amplifiers. Considering the importance of the topic, in this study, the impact of the HPEM waveform on the power amplifier inside the conductive enclosure has been investigated. By using the finite difference delay modelling (FDDM) numerical method as a stable method followed by the vector fitting (VF) method, the electromagnetic problem has become a circuit problem, which allows examining the response of the power amplifier and any circuit, including non‐linear elements against the interference field. Responses of bipolar linear and non‐linear components in the perforated conductive enclosure by the proposed method have been compared with the results obtained by computer simulation technology microwave studio (CST‐MWS) for verification. [ABSTRACT FROM AUTHOR]

Herein, a DC and microwave performance of 2 μm gate length AlGaN/GaN high‐electron‐mobility transistor (HEMTs) on a Mn‐doped GaN substrate is demonstrated. The maximum drain current is 670 mA with a threshold voltage of −$-$2.5 V and with good pinch‐off characteristics. The breakdown voltage of the HEMT is ≈80 V. The HEMT shows Δ8% current collapse while referenced HEMT on a SiC substrates which is fabricated simultaneously shows large Δ30% current collapse. When the HEMT with a gate width of 100 μm is tuned for the maximum output power at 2.4 GHz with a drain voltage of 30 V, it delivers 500 mW (5 W mm−1) with the maximum drain efficiency of 54%. These output performances are in good agreement with ideal class‐A operation performance. Therefore, it is concluded that the HEMT on Mn‐doped GaN substrates is promising for future microwave and millimeter‐wave high‐power transistors. [ABSTRACT FROM AUTHOR]

Abstract One of the most common methods to protect electronic and telecommunication systems in a high‐power electromagnetic (HPEM) environment is using a conductive enclosure. Amplifiers are the vital parts in transmitter and receiver systems as the main components of a telecommunication system, so investigating the effects of HPEM waveform on their performance is very important. The Presence of apertures in the body of the conductive enclosure, as well as non‐linear elements such as transistors in amplifiers, adds to the complexity of examining the coupling of electromagnetic fields on the performance of amplifiers. Considering the importance of the topic, in this study, the impact of the HPEM waveform on the power amplifier inside the conductive enclosure has been investigated. By using the finite difference delay modelling (FDDM) numerical method as a stable method followed by the vector fitting (VF) method, the electromagnetic problem has become a circuit problem, which allows examining the response of the power amplifier and any circuit, including non‐linear elements against the interference field. Responses of bipolar linear and non‐linear components in the perforated conductive enclosure by the proposed method have been compared with the results obtained by computer simulation technology microwave studio (CST‐MWS) for verification.

Objective.Recent SiPM developments and improved front-end electronics have opened new doors in TOF-PET with a focus on prompt photon detection. For instance, the relatively high Cherenkov yield of bismuth-germanate (BGO) upon 511 keV gamma interaction has triggered a lot of interest, especially for its use in total body positron emission tomography (PET) scanners due to the crystal's relatively low material and production costs. However, the electronic readout and timing optimization of the SiPMs still poses many questions. Lab experiments have shown the prospect of Cherenkov detection, with coincidence time resolutions (CTRs) of 200 ps FWHM achieved with small pixels, but lack system integration due to an unacceptable high power uptake of the used amplifiers.Approach.Following recent studies the most practical circuits with lower power uptake (

In the present scenario of growing demand for high data rate, the need for free-space optical communication (FSOC) system around us has become an essential feature of communication systems. FSOC offers seamless communication with much higher data rate possessing advantages of both the optical fiber communication and wireless communication. The study of different mitigation techniques presently in use is important. One such method involves mitigation of attenuations by the use optical amplifiers of different types. Effects of different optical amplifiers have been studied in this present paper. The moderate turbulence scenario is considered with atmospheric and geometric losses at data rate of 10 GBPS for a 4-channel wavelength division multiplexing (WDM)-based FSOC system. The measuring parameters chosen are Q-factor, bit error rate (BER) and eye diagram. It has been observed that the erbium-doped fiber amplifier (EDFA) and the EDFA–EDFA hybrid amplifier give consistent good quality communication for long-distance transmission with large and clear eye opening and acceptable BER of 9.32E−10 and 8.21E−09 at maximum distance of 4 km, while the Raman amplifier and semiconductor optical amplifier (SOA) do not approach the maximum reach and fail to achieve acceptable performance beyond 2 km and 1 km, respectively. [ABSTRACT FROM AUTHOR]

The ability to control mammalian cells such that they self-organize or enact therapeutic effects as desired has incredible implications. Not only would it further our understanding of native processes such as development and the immune response, but it would also have powerful applications in medical fields such as regenerative medicine and immunotherapy. This control is typically obtained by synthetic circuits that use synthetic receptors, but control remains incomplete. The synthetic juxtacrine receptors (SJRs) are widely used as they are fully modular and enable spatial control, but they have limited gene expression amplification and temporal control. As these are integral facets to cell control, I therefore designed transcription factor based amplifiers that amplify gene expression and enable unidirectional temporal control by prolonging duration of target gene expression. Using a validated in silico framework for SJR signaling, I combined these amplifiers with SJRs and show that these SJR amplifier circuits can direct spatiotemporal patterning and improve the quality of self-organization. I then show that these circuits can improve chimeric antigen receptor (CAR) T cell tumor killing against various heterogenous antigen expression tumors. These amplifiers are flexible tools that improve control over SJR based circuits with both basic and therapeutic applications.

Abstract Low‐frequency noise, generated inherently by the number or mobility fluctuation of carriers, is a crucial concern for the design of analog and digital circuits. Unified modelling based on experimental validation of near‐DC noise in amplifiers is a long‐standing open problem. This article develops a model for low‐frequency noise by deriving new bounds for carrier capturing and releasing. According to the proposed model, a measurement system is suggested that operates in a wide frequency range and even at very low frequencies. The system is noise‐tolerant, since the amplifier is selected based on acceptable noise levels. Among the advantages are the independence from specialized structural noise models for each component and the low cost of the measurement system. The evaluation results show that the proposed method leads to a promising improvement in the low‐frequency noise measuring and is superior to conventional models in the normalized root mean square error indicator. Findings reveal that the proposed measurement method can estimate the flicker noise around the DC frequency, and the proposed model agrees reasonably with the proposed measurement circuit.

Low‐frequency noise, generated inherently by the number or mobility fluctuation of carriers, is a crucial concern for the design of analog and digital circuits. Unified modelling based on experimental validation of near‐DC noise in amplifiers is a long‐standing open problem. This article develops a model for low‐frequency noise by deriving new bounds for carrier capturing and releasing. According to the proposed model, a measurement system is suggested that operates in a wide frequency range and even at very low frequencies. The system is noise‐tolerant, since the amplifier is selected based on acceptable noise levels. Among the advantages are the independence from specialized structural noise models for each component and the low cost of the measurement system. The evaluation results show that the proposed method leads to a promising improvement in the low‐frequency noise measuring and is superior to conventional models in the normalized root mean square error indicator. Findings reveal that the proposed measurement method can estimate the flicker noise around the DC frequency, and the proposed model agrees reasonably with the proposed measurement circuit. [ABSTRACT FROM AUTHOR]

This paper presents an ultra-low power mixed-signal neural data acquisition (MSN-DAQ) system that enables a novel low-power hybrid-domain neural decoding architecture for implantable brain-machine interfaces with high channel count. Implemented in 180nm CMOS technology, the 32-channel custom chip operates at 1V supply voltage and achieves excellent performance including 1.07µW/channel, 2.37/5.62 NEF/PEF and 88dB common-mode rejection ratio (CMRR) with significant back-end power-saving advantage compared to prior works. The fabricated prototype was further evaluated with in vivo human tests at bedside, and its performance closely follows that of a commercial recording system.

Abstract This paper presents a high‐speed, high‐voltage, solid‐state Marx generator based on silicon carbide MOSFETs. The objective was to develop a high‐rate repetitive, short‐pulse, high‐voltage and efficient generator for medical particle accelerator applications. To achieve this goal, a 720 kV Marx generator forming from 1445 kV stages was designed. Each stage includes several SiC devices in series to reach desired voltage and speed. Compared to the existing Marx generators, the proposed Marx generator is capable of producing shorter pulses with higher voltage. We present the experimental results of a three‐stage prototype Marx generator capable of producing 15 kV at 40 A output with a 200 nS pulse with a repetition rate of 500 Hz.

The article is devoted to the study of four-wave mixing (FWM) in a semiconductor optical amplifier with quantum dots (QD-SOA). Experimental measurements of FWM signals are characterized in nonlinear media of GaAs-based QD-SOA with gain in the 1,550 nm region. Theoretical part of nonlinear effect of FWM is studied and important all-optical communication applications are listed. Experimental studies of a four-wave system are described and an analysis of FWM signals is given for various input powers of pump signals and injection currents. The devices are compared in terms of such parameters as conversion efficiency and signal-to-noise ratio. The results of the study made it possible to reveal the possibility of the effect of FWM signals on useful signals in channels with spectral division multiplexing wavelength division multiplexing (WDM) in the downstream and upstream in a semiconductor optical amplifier. Based on the experimental results, it was concluded that FWM does not affect adjacent channels of WDM signals and does not generate additional optical noise when scaling the WDM gigabit passive optical network (GPON) up to 60 km using semiconductor optical amplifiers (SOAs). [ABSTRACT FROM AUTHOR]

The monitoring of microvolt‐level biosignals such as electroencephalograms requires the application of low‐noise signal amplifier circuits, which, for single‐use cases, must be fabricated for disposability using low‐cost manufacturing techniques. One promising solution for the production of low‐cost amplifier circuits for digital biosensing is the emerging technology of low‐noise printed circuits. Here, a low‐noise‐electrode printing process for organic transistors that can carry out precision measurement of brain activity using a low‐noise organic amplifier is proposed. In the transistor fabrication process, Ag electrodes are processed via flat stamp parallel printing, and fine‐process optimization to minimize the charge‐trapping effect enables a three‐order reduction in transistor noise. The low‐noise transistors are used to produce an organic pseudo‐complementary metal‐oxide‐semiconductor amplifier with a small noise level of 2.2 µVp‐p at 10 Hz, which enables precision brain wave monitoring in a close correlation with signals obtained using a commercialized measurement system. [ABSTRACT FROM AUTHOR]

ObjectiveDecoding neural activity has been limited by the lack of tools available to record from large numbers of neurons across multiple cortical regions simultaneously with high temporal fidelity. To this end, we developed the Argo system to record cortical neural activity at high data rates.ApproachHere we demonstrate a massively parallel neural recording system based on platinum-iridium microwire electrode arrays bonded to a CMOS voltage amplifier array. The Argo system is the highest channel count in vivo neural recording system, supporting simultaneous recording from 65 536 channels, sampled at 32 kHz and 12-bit resolution. This system was designed for cortical recordings, compatible with both penetrating and surface microelectrodes.Main resultsWe validated this system through initial bench testing to determine specific gain and noise characteristics of bonded microwires, followed by in-vivo experiments in both rat and sheep cortex. We recorded spiking activity from 791 neurons in rats and surface local field potential activity from over 30 000 channels in sheep.SignificanceThese are the largest channel count microwire-based recordings in both rat and sheep. While currently adapted for head-fixed recording, the microwire-CMOS architecture is well suited for clinical translation. Thus, this demonstration helps pave the way for a future high data rate intracortical implant.

This study examined how filters and amplifiers affect pre-service science teachers’ pedagogical content knowledge (PCK) in a human and environment unit. The redefined consensus model for PCK and decision-making framework for identifying how personal and extra-personal factors act as filters and amplifiers were selected as theoretical frameworks. Two pre-service science teachers participated in the study. While pre-interviews were used to determine participants’ PCK before teaching, observations and post-interviews were used to reveal participants’ PCK after teaching, and how filters and amplifiers influenced PCK. Data were analyzed deductively to examine teachers’ PCK including interactions among components and the way filters and amplifiers act on PCK. Constant comparison analysis revealed five general assertions of how filters and amplifiers shaped the decision-making process when these teachers enacted their PCK. First, the number of amplifiers and filters affecting knowledge of instructional strategies was the highest. Second, the number of amplifiers and filters affecting knowledge of curriculum in science was the lowest. Third, the effect of filters and amplifiers on PCK components was idiosyncratic. Fourth, the more (or the less) the map was integrated; the less (or the more) amplifier and filter influenced the PCK. Fifth, the number of personal factors affecting knowledge of instructional strategies was highest. Implications are suggested considering the effects of filters and amplifiers on teachers’ PCK.

Abstract The monitoring of microvolt‐level biosignals such as electroencephalograms requires the application of low‐noise signal amplifier circuits, which, for single‐use cases, must be fabricated for disposability using low‐cost manufacturing techniques. One promising solution for the production of low‐cost amplifier circuits for digital biosensing is the emerging technology of low‐noise printed circuits. Here, a low‐noise‐electrode printing process for organic transistors that can carry out precision measurement of brain activity using a low‐noise organic amplifier is proposed. In the transistor fabrication process, Ag electrodes are processed via flat stamp parallel printing, and fine‐process optimization to minimize the charge‐trapping effect enables a three‐order reduction in transistor noise. The low‐noise transistors are used to produce an organic pseudo‐complementary metal‐oxide‐semiconductor amplifier with a small noise level of 2.2 µVp‐p at 10 Hz, which enables precision brain wave monitoring in a close correlation with signals obtained using a commercialized measurement system.

Copyright of Alustath is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Printed amplifiers are promising components for flexible and wearable devices. The circuits need to have small footprint, high amplification, and low power consumption, which is not simultaneously possible with conventional thin‐film transistors because multiple stages are required and introduce sources of variability, failure, or wasted area. Source‐gated transistors (SGTs) can in principle have extremely high intrinsic gain but this is not always the case because of lateral field control problems. A good solution is the use of field plate structures, which are straightforward to implement with top contacts but not so with bottom contacts. Here, a printed implementation of organic SGT with a field plate is presented, which can achieve a record high intrinsic gain of 920 V/V. The single‐stage common‐source amplifier with two organic SGTs also exhibits a high gain of 700 V/V. Simulations confirm the effectiveness of the printed field plate, making it a promising approach for future flexible and wearable electronics. [ABSTRACT FROM AUTHOR]

This paper presents a high‐speed, high‐voltage, solid‐state Marx generator based on silicon carbide MOSFETs. The objective was to develop a high‐rate repetitive, short‐pulse, high‐voltage and efficient generator for medical particle accelerator applications. To achieve this goal, a 720 kV Marx generator forming from 1445 kV stages was designed. Each stage includes several SiC devices in series to reach desired voltage and speed. Compared to the existing Marx generators, the proposed Marx generator is capable of producing shorter pulses with higher voltage. We present the experimental results of a three‐stage prototype Marx generator capable of producing 15 kV at 40 A output with a 200 nS pulse with a repetition rate of 500 Hz. [ABSTRACT FROM AUTHOR]

We present an image sensor incorporating angle-selective gratings for resolution enhancement in contact imaging applications. Optical structures designed in the CMOS metal layers above each photodiode form the angle-selective gratings that limit the sensor angle of view to ±18 °, rejecting background light and deblurring the image. The imager is based on a high-gain capacitive transimpedance amplifier pixel using a custom 11fF MOM capacitor, achieving [Formula: see text] sensitivity. The pixel includes a leakage current minimization circuit to remove signal-dependent reset switch leakage and the corresponding dark current is [Formula: see text]. The resulting 4.7 mm by 2.25 mm sensor (80 by 36 pixels) is designed specifically for intraoperative cancer imaging in order to solve the pervasive challenge of identifying microscopic residual cancer foci in vivo, where they can be removed. We demonstrate imaging and detection of foci containing less than 200 cancer cells labeled with fluorescent biomarkers in 50 ms with signal-to-noise ratios greater than 15 dB and the detection of microscopic residual tumor in mice models. The absence of large optical elements enables extreme miniaturization, allowing manipulation within a small, morphologically complex, tumor cavity.

This work introduces a sensor for dairy antibiotic detection of ciprofloxacin in milk. We provide an important tool for antibiotic detection in milk and the main contributions of this work are as follows. We introduce a technique based on florescence spectroscopy and lock-in amplification for sensing ciprofloxacin in milk that is capable of detection below the regulatory limit. We compare the system against one without the integrated lock-in amplification, as in traditional fluorescence sensors. We provide microchip capillary electrophoresis results and place our work in context for future integration with microchip capillary electrophoresis.

Continuous monitoring and treatment of various diseases with biomedical technologies and wearable electronics has become significantly important. The healthcare area is an important, evolving field that, among other things, requires electronic and micro-electromechanical technologies. Designed circuits and smart devices can lead to reduced hospitalization time and hospitals equipped with high-quality equipment. Some of these devices can also be implanted inside the body. Recently, various implanted electronic devices for monitoring and diagnosing diseases have been presented. These instruments require communication links through wireless technologies. In the transmitters of these devices, power amplifiers are the most important components and their performance plays important roles. This paper is devoted to collecting and providing a comprehensive review on the various designed implanted amplifiers for advanced biomedical applications. The reported amplifiers vary with respect to the class/type of amplifier, implemented CMOS technology, frequency band, output power, and the overall efficiency of the designs. The purpose of the authors is to provide a general view of the available solutions, and any researcher can obtain suitable circuit designs that can be selected for their problem by reading this survey. [ABSTRACT FROM AUTHOR]

Frequency Modulation (FM) transmitter is a small electronic gadget that has a wire (aerial), produces electromagnetic radio waves, and is capable of transmitting energy through space. It generates radio frequency signals that can be received by a well-designed antenna. At the point where signal reception occurs, the radio waves get energized by a rotating current in the receiving wire. It is therefore, a complex gadget considered to be a high voltage energy system. Its design is complex and thus demands critical maintenance procedures which are costly. In Kenya, there is rapidly growing demand for the use of FM transmitters both among individuals and institutions. This work is carried to design, construct and implement an FM transmitter that is cheaper to buy, easy to maintain and expected to be equally efficient when in operation. An FM transmitter was designed and constructed using transistors, resistors, coils, capacitors and microphone. It was mounted on testing a symbolic bed assumed to be of a patient (at Coast Level Five Hospital), who figuratively required the attention of medical personnel (doctor/nurse/caretaker). It was connected to 12V DC power source and tested. The results revealed that a locally designed FM transmitter that operates on low power can be designed to have an appreciable range of signal transmission. It is recommended that further investigations be carried out on the signal coupling circuit so as to improve the range of transmission further. [ABSTRACT FROM AUTHOR]

Abstract Printed amplifiers are promising components for flexible and wearable devices. The circuits need to have small footprint, high amplification, and low power consumption, which is not simultaneously possible with conventional thin‐film transistors because multiple stages are required and introduce sources of variability, failure, or wasted area. Source‐gated transistors (SGTs) can in principle have extremely high intrinsic gain but this is not always the case because of lateral field control problems. A good solution is the use of field plate structures, which are straightforward to implement with top contacts but not so with bottom contacts. Here, a printed implementation of organic SGT with a field plate is presented, which can achieve a record high intrinsic gain of 920 V/V. The single‐stage common‐source amplifier with two organic SGTs also exhibits a high gain of 700 V/V. Simulations confirm the effectiveness of the printed field plate, making it a promising approach for future flexible and wearable electronics.

Intensifiers are adverbials or adverbial phrases that are used to enhance the meanings of certain constructions. The study aims to investigate English intensifiers and their functions as devices of emotional enhancement .Moreover; they identify students with this grammatical item. The significance of the research is that intensifiers function as linguistic devices to maximize the meaning or, in a certain sense, intensify the emotional tone of words and expressions. Some commonly used intensifiers include very, too, at all, absolutely, extremely, really, wh-words or expressions, etc. e.g. what on earth are you doing? In terms of their semantic classes, intensifiers can be divided into Amplifiers, Emphasizers and Downtoners. The problem of this research is that the students find it difficult to comprehend the functions of English intensifiers. In terms of the method used in this research, the researcher tries to give a detailed analysis of the most common English intensifiers. An exercise relevant to the topic is adopted to enhance the research. The analysis of the results reveals that the third-year Iraqi college students succeed in operating intensifiers in a way that shows their ability to handle this grammatical item.

This study examined how filters and amplifiers affect pre-service science teachers' pedagogical content knowledge (PCK) in a human and environment unit. The redefined consensus model for PCK and decision-making framework for identifying how personal and extrapersonal factors act as filters and amplifiers were selected as theoretical frameworks. Two pre-service science teachers participated in the study. While pre-interviews were used to determine participants' PCK before teaching, observations and post-interviews were used to reveal participants' PCK after teaching, and how filters and amplifiers influenced PCK. Data were analyzed deductively to examine teachers' PCK including interactions among components and the way filters and amplifiers act on PCK. Constant comparison analysis revealed five general assertions of how filters and amplifiers shaped the decision-making process when these teachers enacted their PCK. First, the number of amplifiers and filters affecting knowledge of instructional strategies (KOIS) was the highest. Second, the number of amplifiers and filters affecting knowledge of curriculum in science was the lowest. Third, the effect of filters and amplifiers on PCK components was idiosyncratic. Fourth, the more (or the less) the map was integrated; the less (or the more) amplifier and filter influenced the PCK. Fifth, the number of personal factors affecting KOIS was highest. Implications are suggested considering the effects of filters and amplifiers on teachers' PCK. [ABSTRACT FROM AUTHOR]

This study examines how adverbs of degree tend to collocate with particular words produced by Georgian Learners of English, both from a quantitative and qualitative perspective. Various collocation measures are used to show the strength of the bond between selected amplifiers (maximizers and boosters). The research is based on the contrastive corpus analysis of native speakers' corpus (Michigan Corpus of Upper-Level Student Papers) and Georgian learners' corpora (compiled by me in accordance with international learner corpus research guidelines). The aims of our research are: a) To investigate whether natives and Georgian Learners of English demonstrate similar patterns of saliency and agreement in their judgments of adverb + adjective collocations; b) To reveal the difference between the syntactic patterns and lexical meaning of the adverb + adjective collocations produced in written language by Georgian learners of English and native speakers? It is hoped that in the light of the corpus-based evidence on the nature of collocations presented in this study, metalexicographers and learners will be informed about the gaps in terms of collocations acquisition and performance. Amplifier collocations might be expected to have a more explicit and prominent place in learner lexicographic research and the language teaching curriculum. [ABSTRACT FROM AUTHOR]

Source-gated transistors (SGTs) are emerging devices enabling high-gain single-stage amplifiers with low complexity. To date, the p-type printed organic SGT (OSGT) has been developed and showed high gain and low power consumption. However, complementary OSGT circuits remained impossible because of the lack of n-type OSGTs. Here, we show the first n-type OSGTs, which are printed and have a high intrinsic gain over 40. A Schottky source contact is intentionally formed between an n-type organic semiconductor, poly{[N,N′-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (N2200), and the silver electrode. In addition, a blocking layer at the edge of the source electrode plays an important role to improve the saturation characteristics and increase the intrinsic gain. Such n-type printed OSGTs and complementary circuits based on them are promising for flexible and wearable electronic devices such as for physiological and biochemical health monitoring. [ABSTRACT FROM AUTHOR]

A remotely pumped Erbium-doped system for the amplification of an optical signal for long-reach (LR) next-generation passive optical networks (NG-PONs) is presented in this paper. The next-generation networks will be deployed with/over the current point to multi-point technology with/without backward compatibility. Remote pumping allows extending the reach of the optical distribution networks and the magnification of the splitting ratio as well, which is most important for increasing the number of end users in the PON network. In our laboratory, we have successfully verified the functionality of the unidirectional and bidirectional remote pumping system based on an Erbium-doped fiber inserted into the route and remote pumping from a central office. Our measurement results prove that it is possible to extend the total reaching point to the multi-point system without the difficult incidence in the optical distribution network. Based on the results, the proposed amplifying passive optical network approach is capable of being used in passive optical networks in C band for extending the total reach of system or increasing the split ratio.

Abstract This paper develops an active magnetic near field probe (H‐field probe) by using a four‐layer printed circuit board (PCB) technique. Two‐turn detection structure and a low noise amplifier are used to improve probe's frequency response. The two‐turn detection structure can maximize the use of PCB stack resources, and a 14.5 dB gain amplifier can increase signal output capability. The probe can then be used for electromagnetic compatibility (EMC) test from 150 kHz to 3 GHz. Compared with traditional active shielded‐loop H‐field probe (TAHP) with loop area of 500 μm2, the frequency response of the proposed probe can improve 20 dB at 0.5 GHz. Different from the method of comparing the sensitivity of the probe only through the frequency response, this paper measures and analyzes the real sensitivity of the probing device composed of the proposed probe. Under the condition of the same receiver parameter setting, the sensitivity at 0.5 GHz is increased by 11.7 dB compared with commercial passive probing device and 20.2 dB at 0.5 GHz compared with the probing device with TAHP device. It reaches −32.4 dB μA. In addition, the proposed probe has acceptable spatial resolution of 1.28 mm at 1 GHz, which is more suitable for printed circuit board level EMI analysis.

Engineering of the eigenmode dispersion of slow wave structures (SWSs) to achieve desired modal characteristics is an effective approach to enhance the performance of high-power traveling wave tube (TWT) amplifiers or oscillators. We investigate here for the first time a new synchronization regime in TWTs based on SWSs operating near a third-order degeneracy condition in their dispersion. This special three-eigenmode synchronization is associated with a stationary inflection point (SIP) that is manifested by the coalescence of three Floquet-Bloch eigenmodes in the SWS. We demonstrate the special features of 'cold' (without electron beam) periodic SWSs with SIP modeled as coupled transmission lines and investigate resonances of SWSs of finite length. We also show that by tuning parameters of a periodic SWS, one can achieve an SIP with nearly ideal flat dispersion relationship with zero group velocity or a slightly slanted one with a very small (positive or negative) group velocity leading to different operating schemes. The SIP structure when synchronized with an electron beam has potential benefits for amplification which include: 1) gain enhancement; 2) gain-bandwidth product improvement; and 3) higher power efficiency, when compared to conventional Pierce-like TWTs. The proposed theory paves the way for a new approach for potential improvements in gain, power efficiency, and gain-bandwidth product in high-power microwave amplifiers.

Abstract The goal is to illustrate new errors about using the figures‐of‐merit NF and IIP, by investigating an AGC‐less microwatt ultrawideband gm‐boosted CMOS RF system with noise/distortion cancellation. The system composed of limiter and LNA is designed for 0.3–10.7 GHz at 1.8 V. Thanks to the limiter, the impact of noises and distortions is cancelled and the LNA acts linear without any saturation or block, as well as, it becomes AGC‐less. Additionally, achievements prove that NF and IIP sometimes can be accompanied by error, hence engineers must always consider all aspects of a system together during their evaluations. Although this work is not experimental, it applies different methods such as “Regenerating”, “Comparing Calculations with Simulations” and “Monte Carlo” to demonstrate the reliability of achievements for applying in a SAW‐less RFIC.

PbS quantum dots (QDs) are appropriate for use in tunable optoelectronic devices such as optical amplifiers because of their large Bohr exciton radii (18 nm). Laser-assisted local heating around Ag NPs can provide an effective method for site selective precipitation and for controlling the size of QDs. Continuous wave (CW) laser irradiation has been applied on a Ag+-ion exchanged glass which lead to the precipitation of QDs PbS QDs of 5-nm diameter were precipitated after 3 min of CW laser illumination at 1.5 W. The PbS QDs showed a PL peak at λ ∼ 1490 nm, which shifted toward longer wavelength side as duration of Ag+ ion exchange and of laser illumination increased. This method was further applied to prepare a rod containing three sections with different diameters of PbS QDs to propose the possibility of developing broadband amplifiers to cover the 1.3–1.7 μm communication window using one glass fiber. Co2+ also absorbs 532 nm laser light and converts it to thermal energy that results in the precipitation of PbS QDs in the glass matrix. The emission peak of the QDs covers 1020 nm

Volterra models allow modeling nonlinear dynamical systems, even though they require the estimation of a large number of parameters and have, consequently, potentially large computational costs. The pruning of Volterra models is thus of fundamental importance to reduce the computational costs of nonlinear calibration, and improve stability and speed, while preserving accuracy. Several techniques (LASSO, DOMP and OBS) and their variants (WLASSO and OBD) are compared in this paper for the experimental calibration of an IF amplifier. The results show that Volterra models can be simplified, yielding models that are 4–5 times sparser, with a limited impact on accuracy. About 6 dB of improved Error Vector Magnitude (EVM) is obtained, improving the dynamic range of the amplifiers. The Symbol Error Rate (SER) is greatly reduced by calibration at a large input power, and pruning reduces the model complexity without hindering SER. Hence, pruning allows improving the dynamic range of the amplifier, with almost an order of magnitude reduction in model complexity. We propose the OBS technique, used in the neural network field, in conjunction with the better known DOMP technique, to prune the model with the best accuracy. The simulations show, in fact, that the OBS and DOMP techniques outperform the others, and OBD, LASSO and WLASSO are, in turn, less efficient. A methodology for pruning in the complex domain is described, based on the Frisch–Waugh–Lovell (FWL) theorem, to separate the linear and nonlinear sections of the model. This is essential because linear models are used for equalization and cannot be pruned to preserve model generality vis-a-vis channel variations, whereas nonlinear models must be pruned as much as possible to minimize the computational overhead. This methodology can be extended to models other than the Volterra one, as the only conditions we impose on the nonlinear model are that it is feedforward and linear in the parameters. [ABSTRACT FROM AUTHOR]

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The problems resulting from the use of nano-MOSFETs in the design of operational trans-conductance amplifiers (OTAs) lead to an urgent need for new design techniques to produce high-performance metrics OTAs suitable for very high-frequency applications. In this paper, the enhancement techniques and design equations for the proposed single-stage foldedcascode operational trans-conductance amplifiers (FCOTA) are presented for the enhancement of its various performance metrics. The proposed single-stage FCOTA adopts the folded-cascode (FC) current sources with cascode current mirrors (CCMs) load. Using 65 nm complementary metaloxide semiconductor (CMOS) process from predictive technology model (PTM), the HSPICE2019-based simulation results show that the designed single-stage FCOTA can achieve a high open-loop differential-mode DC voltage gain of 65.64 dB, very high unity-gain bandwidth of 263 MHz, very high stability with phase-margin of 73°, low power dissipation of 0.97 mW, very low DC input-offset voltage of 0.14 uV, high swing-output voltages from -0.97 to 0.91 V, very low equivalent input-referred noise of 15.8 nV/vHz, very high common-mode rejection ratio of 190.64 dB, very high positive/negative slew-rates of 157.5/58.3 V/us, very fast settling-time of 5.1 ns, high extension input common-mode range voltages from -0.44 to 1 V, and high positive/negative power-supply rejection ratios of 75.5/68.8 dB. The values of the small/large-signal figures-of-merits (FoMs) are the highest when compared to other reported FCOTAs in the literature. [ABSTRACT FROM AUTHOR]

Abstract Many modern microwave systems, for example, in the field of satellite communications, remote sensing for Earth observation or radio astronomy, employ reflector antennas with beam‐shaping capabilities. A generalised description of multi‐channel receiver architectures with digital beamforming, employing scattering parameter formalism is presented here. Special emphasis has been placed on noise modelling, where noise sources have been included also at the input ports of the receive amplifiers. The performance of such a system is evaluated in terms of the signal‐to‐noise ratio (SNR) and the signal‐to‐interference ratio at the beamformer output. The basis for this analysis is a design example of a reflector antenna fed by a linear patch array, whose S‐parameters have been computed by means of electromagnetic simulations. In this work, two scenarios are addressed. In the first case, the effect of coupling has been neglected in the derivation of the beamforming weights. The main consequence appears to be a severely impaired interference suppression performance. In the second scenario, which has not been addressed in the literature so far, noise from the input ports of the receive amplifiers couple via the antenna radiators and can result in a loss of SNR at the beamformer output if neglected in the beamforming process.

Abstract In this paper a novel tuneable LNA is presented. This LNA is designed with two separated structures which both of them utilize noise cancellation technique and some other approaches such as gain boosting and T‐transformer feedback. Each proposed LNA has two stages that the first stage is designed based on noise cancellation and the second stage uses common gate structure. The proposed LNA type (A) utilises the switched capacitance in the first stage to tune the centre frequency and a gain boosting in the second stage to increase the gain. The second proposed LNA type (B) has implemented the parallel networks to decrease the change in the gain values of the LNA in different channels. The T‐transformer approach is used in each parallel network to decrease the inductors value and improve the input matching. In the second stage, the negative feedback is also employed to control the bandwidth. The proposed LNA is simulated in ADS software with TSMC 130 nm CMOS technology and the layout is designed by Cadence. The LNA type (A) has 22.7 dB gain in 28.8 GHz and the noise figure of 2 dB. The IIP3 for this LNA is 0 dBm in 25.42 GHZ. For the LNA type (B), the gain and noise figure standard deviations are 0.25 and 0.057 respectively which shows minimum variations by frequency tuning. For this LNA, the maximum gain is 20.5 dB and the noise figure is 2 dB at 31.42 GHz. Finally the performances of the proposed LNAs have been compared with those of LNAs which have been recently published.

The input stage of an operational or transconductance amplifier could be a common-source amplifier and it should be designed carefully, since it contributes in a significant way to the performance of the entire cell. In this document, we show the results of analysing a basic transconduction cell based on the multiple-input ffioating-gate transistor in a common-source amplifier configuration. A particular feature of the cell that we analyse is that it contains a feedback loop towards one of the coupled gates that serves to improve the linearity. This simple cell could be a input stage in more complex circuits. We present studies of linearity, gain, output resistance and distortion to be compared with an entirely MOS common-source amplifier. Experimental tests were conducted based on an implemented integrated circuit. In our comparison, we note that the cell based on the ffioating-gate transistor has a remarkable linearity in conditions in which the MOS version would not operate properly. In addition, we experimentally observe the phenomena predicted by the theory, such as gain and operation point manipulation, according to the values of the voltages at the other control gates. Thus, it is possible to improve the design of operational amplifiers, and other similar circuits, because they provide greater linearity and less distortion; however, we observed lower transconductance and an increase in the output resistance. [ABSTRACT FROM AUTHOR]

Cystic fibrosis (CF) is the most common monogenic disorder, caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Over the last 30 years, tremendous progress has been made in understanding the molecular basis of CF and the development of treatments that target the underlying defects in CF. Currently, a highly effective CFTR modulator treatment (Kalydeco™/Trikafta™) is available for 90% of people with CF. In this review, we will give an extensive overview of past and ongoing efforts in the development of therapies targeting the molecular defects in CF. We will discuss strategies targeting the CFTR protein (i.e., CFTR modulators such as correctors and potentiators), its cellular environment (i.e., proteostasis modulation, stabilization at the plasma membrane), the CFTR mRNA (i.e., amplifiers, nonsense mediated mRNA decay suppressors, translational readthrough inducing drugs) or the CFTR gene (gene therapies). Finally, we will focus on how these efforts can be applied to the 15% of people with CF for whom no causal therapy is available yet. [ABSTRACT FROM AUTHOR]

Operational Transconductance Amplifier (OTA) is an important circuit block used in the design of filter, amplifiers and oscillators for various analog-mixed circuit systems. However, design of a low-noise, high-gain OTA with low-power consumption is a challenging task in CMOS technology owing to high-power requirements of OTA for emulating high gain. This paper represents the design of gate-driven quasi-floating bulk recycling folded cascode (GDQFB RFC) OTA which has been shown to provide low-noise operation, emulates high gain and draws very less power. The design utilizes the gate-driven quasi-floating bulk (GDQFB) technique on a recycling folded cascode structure, which enhances the transconductance of OTA and improves its performance. All the post-layout simulation results have been obtained in 0.18-μm CMOS N-well technology using BSIM3V3 device models. The obtained results indicate very high gain of 100.4 dB, gain-bandwidth of 69 kHz, phase margin of 51.9∘ with power consumption of 2.31μW from ±0.9V supply voltage. The input referred noise emulated by proposed OTA is 0.684, 0.21 and 0.0592μV/√Hz @ 1 Hz, 10 Hz and 1 kHz, respectively. The input common mode range and output voltage swing are found to be −0.402 to 0.669 V and −0.493 to 0.610 V, respectively. Corner simulations and Monte Carlo analysis have been performed to verify the robustness of the proposed OTA. The proposed OTA can be used in design of filters and amplifiers for bio-instruments, sensor applications, neural recording applications and human implants etc. [ABSTRACT FROM AUTHOR]

In this letter, we report on the development of high-gain WR-1.5 amplifier circuits, utilizing a transferred-substrate InGaAs-on-insulator (InGaAs-OI) high-electron-mobility transistor (HEMT) technology on Si with 20-nm gate length. A six-stage and a nine-stage amplifier circuit are described, which are based on gain cells in cascode configuration. With more than 30 dB of measured gain in the frequency band of 660–700 GHz, the highest frequency of operation of transferred-substrate THz amplifiers is reported. These gain levels in excess of 30 dB, furthermore, correspond to the highest reported gain values and state-of-the-art performance around the targeted 670-GHz frequency band. [ABSTRACT FROM AUTHOR]

Amplifiers and filters are essential components in microwave systems. An amplifier is used to increase the signal strength, and it is usually cascaded by filters for frequency selection or harmonic rejection –. Their functionalities require a precise design of the individual parts as well as the way in which they are connected. The common approach is to make individual components with a system impedance that is usually ${50}\Omega{.}$ A generic example of the filters and amplifier in a generalized receiver is shown in. [ABSTRACT FROM AUTHOR]

Extremely electrically small antennas (XESAs) exhibit low gain performance, which seriously limits their applications in space-constrained wireless platforms. We report an active transmitting XESA whose gain-bandwidth product (GBWP) exceeds the passive Bode-Fano upper bound. It is realized by incorporating a highly efficient, electrically small, near-field resonant parasitic (NFRP) antenna into the feedback loop of an operational amplifier (OpAmp). Rather than a cascaded configuration, the innovative structural embedding of the NFRP antenna directly with the OpAmp circuit significantly increases its effective gain without consuming any additional real estate. The operating mechanisms of the integrated system are explained with an equivalent circuit model. An optimized prototype was fabricated, assembled, and tested. The electrical size of its radiating element is extremely small with ka = 0.15 at 414 MHz, i.e., $a~\approx \lambda $ /42. The measured results of this active XESA, in good agreement with their simulated values, demonstrate that its effective gain can be dynamically tuned within a 6.01 dB range. The measured maximum effective gain and, hence, the effective isotropic radiated power (EIRP) witnesses a 9.152 dB (8.23 times) improvement in comparison to its passive counterpart and its measured GBWP surpasses the corresponding passive Bode-Fano upper bound by approximately 15.2 times. [ABSTRACT FROM AUTHOR]