This paper focuses on the determination and analysis of an accurate small-signal equivalent circuit for gallium-nitride high electron-mobility transistors under different bias conditions. Our experimental results show that a channel capacitance has to be added conventional forward "cold" model modeling device-under-test. The validity proposed extraction procedure been verified by very good agreement between simulated measured scattering parameters up 50 GHz

This paper presents a new modeling approach accounting for the nonlinear description of low-frequency dispersive effects (due to thermal phenomena and traps) affecting electron devices. The theoretical formulation is quite general includes as particular cases different models proposed in literature. A large set experimental results, oriented microwave GaN power amplifier design, provided give an exhaustive validation under realistic device operation.

Telehealth systems and applications are extensively investigated nowadays to enhance the quality-of-care and, in particular, detect emergency situations monitor well-being of elderly people, allowing them stay at home independently as long possible. In this paper, an embedded telehealth system for continuous, automatic, remote monitoring real-time fall emergencies is presented discussed. The system, consisting a radar sensor base station, represents cost-effective efficient healthcare...

Abstract Gallium nitride high electron‐mobility transistors have gained much interest for high‐power and high‐temperature applications at frequencies. Therefore, there is a need to the dependence on temperature included in their models. To meet this challenge, present study presents neural approach extracting multi‐bias model of gallium including ambient temperature. Accuracy developed verified by comparing modeling results with measurements. Copyright © 2014 John Wiley & Sons, Ltd.

This paper presents a new approach for the definition and identification of transistor model suitable low-noise amplifier (LNA) design. The resulting is very robust to layout modifications (i.e., source degeneration) providing accurate predictions device noise-performance small-signal parameters. Moreover, described procedure since it does not require any numerical optimization, with possibly related problems like local minima unphysical adopted topology based on lumped element parasitic...

The purpose of this letter is to present an experimental analysis the temperature effects on small-signal equivalent circuit a GaN HEMT. With aim contributing exploration and advancement technology for high-power high-temperature applications, major intrinsic RF figures merit together with positive derivative real parts impedance parameters versus frequency are deeply investigated ambient temperature.

A new technique is developed for determining analytically a millimeter-wave small-signal equivalent-circuit model of GaAs pseudomorphic HEMTs from scattering parameter measurements. In order to obtain good agreement between simulations and measurements up 90 GHz, the conventional intrinsic output conductance substituted by voltage-controlled current source with time delay. Consequently, simple accurate extraction procedure proposed taking into account introduction

This paper, for the first time, analyzes in detail kink phenomenon S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sub> as observed GaN HEMT technology. To gain a comprehensive understanding, effect (KE) is studied with respect to temperature and bias conditions. The achieved results clearly show that dependence of KE on operating condition should be mainly ascribed transconductance, which plays determinant role appearance this effect....

This paper describes the design, fabrication, and assessment of an on-wafer measurement platform for noninvasive quantitative characterization small volumes liquids over frequency range from 500 kHz to 1 GHz. The platform, integrated with a micrometer scale SU-8 microfluidic channel, allows accurate placement very liquid at well-defined location. For first time, miniaturized one-port interdigital capacitor (IDC) sensor is used dielectric spectroscopy measurements RF/lower microwave range....

The small-signal equivalent circuit modeling of microwave field-effect transistors (FETs) is an evergreen and ever flourishing research field that has to be up-to-date with technological developments. Hence, techniques must continuously adapted extended suit best evolving technologies. extraction a FET high-frequency very active broad area significant interest, owing its use as prerequisite for noise large-signal modeling. aim this invited article provide in-depth knowledge, critical...

In the present study, inkjet-printing (IJP) technique is used for development of a planar microwave sensor aimed at dielectric characterization biological samples. The proposed consists two capacitively coupled split-ring resonators (SRRs) fabricated using microstrip technology. A silver-based conductive ink deposited by IJP on conventional 1.6-mm-thick FR4 substrate, thus creating resonant structure. experimental analysis carried out considering water–ethanol mixture as test solution in...

Abstract In this paper, an automatic multi‐objective particle swarm optimization (AMOPSO) method is developed for the design of Doherty power amplifiers (DPAs). comparison to well‐known built‐in optimizer available in commercial simulators, proposed not only reduces time, but also provides superior added efficiency (PAE) final amplifier. According reported measurements, output PAE fabricated DPA exceeds 50% at 6 dB backoff, saturated more than 61%, and (Pout) over 43 dBm target frequency...

ABSTRACT A novel approach for optimizing the hyperparameters of a support vector regression (SVR) model is presented radio frequency (RF) power transistors. In standard SVR models, are enhanced using grid search optimization (GSO), which can be inefficient. this study, particle swarm (PSO) introduced as method in that increases efficiency significantly comparison with GSO while maintaining high level performance. To verify accuracy and effectiveness model, 10‐W GaN transistor produced by...

ABSTRACT Spoof surface plasmon polariton (SSPP) is a technique for controlling and manipulating electromagnetic waves within the microwave frequency range through ultrathin corrugated metallic strips. According to current research, SSPPs are primarily used designing passive circuits single‐ended power amplifiers (PAs). This work employs SSPP theory design of broadband high‐efficiency Doherty amplifier (DPA). The input output matching networks carrier (CPA) peak (PPA) designed based on...

ABSTRACT Spoof surface plasmon polariton (SSPP) controls and manipulates electromagnetic waves in the microwave frequency range through ultrathin corrugated metallic strips, making it suitable for use with devices. In current state of research, SSPPs are primarily used to design passive circuits single‐device power amplifiers (PAs). This study combines SSPP methodology sequential load modulated balanced (SLMBA) topology develop a high back‐off (BO) efficiency load‐modulated PA. By using...

Summary The purpose of this invited paper is to give readers a comprehensive and critical overview on how extract equivalent‐circuit models for GaN HEMTs, which are the preferred devices high‐power high‐frequency applications. This meant provide practical modeling know‐how advanced type transistor, in order support its development improving device technology circuit design. With aim broaden knowledge empower models, experimental results presented as illustrative examples most crucial...

Abstract A reliable modeling procedure is developed for extracting an equivalent circuit able to reproduce the small‐signal and noise performance of gallium nitride (GaN) high‐electron mobility transistor (HEMT) technology. The main advantages this model are its simplicity straightforward extraction based on only pinch‐off scattering ( S ‐) parameter measurements. validity achieved verified by good agreement between high‐frequency experiments simulations three devices with different sizes....

The gallium-nitride (GaN) high electron-mobility transistor (HEMT) technology has emerged as an attractive candidate for high-frequency, high-power, and high-temperature applications due to the unique physical characteristics of GaN material. Over years, much effort been spent on measurement-based modeling since accurate models are essential allowing use this advanced at its best. present analysis is focused scattering (S-) parameter measurements a 0.25 μm HEMT silicon carbide (SiC)...

Although many successful techniques have been proposed in the last decades for extracting small signal equivalent circuit microwave transistors from scattering parameter measurements, modeling is still object of intense research. Further improvement and development methods are incessantly required to take into account continuous rapid evolution transistor technology. The purpose this article facilitate choice most appropriate strategy each particular case. For that, we present a brief but...