ABSTRACT Small‐signal model of a MOSFET is an equivalent circuit that represents its electrical components and specifies the device's electrical characteristics. The non‐quasi‐static (NQS) model is among the most precise small‐signal models utilized in the design of analog and RF circuits. This work introduces an innovative device design known as Gate Stack Silicon on Insulator Schottky Barrier (GS‐SOISB CGAA) cylindrical MOSFET and analog/RF characteristics are extracted utilizing the Silvaco 3D device simulator. An analytical model of GS‐SOISB CGAA is also introduced and validated against the simulation findings. The NQS model of the GS‐SOISB cylindrical MOSFET is formulated to ascertain the extrinsic and intrinsic parasitic components utilizing Y ‐parameters in both the on and off states, respectively. The analog/RF characteristics and NQS model parameters of the GS‐SOISB cylindrical MOSFET have been compared with those of the SOISB cylindrical MOSFET and the SB cylindrical MOSFET. The revolutionary device has a lower gate‐source capacitance ( C GS ) of 7.95% and 8.79%, a gate‐drain capacitance ( C GD ) of 7.22% and 4.57%, and an overall gate capacitance ( C GG ) of 7.91% and 8% than SB and SOISB cylindrical MOSFETs. Compared to conventional SB cylindrical and SOISB cylindrical MOSFET structures, the proposed device shows reduced extrinsic parameters of the NQS model by 7.93% and 3.99% in C gde and C gse , respectively, and 33.4% and 23.9% in R D and R S . The revolutionary device's intrinsic gate‐drain capacitance ( C gd ) reduces by 7.13% and 4.29%, and its intrinsic gate‐source capacitance ( C gs ) reduces by 7.93% and 8.79% as compared to SB and SOISB cylindrical MOSFETs.

ABSTRACT In this article, ultra‐wideband (UWB) single‐element and two‐port multiple‐input‐multiple‐output (MIMO) antenna structures with circular polarization (CP) characteristics are designed to support numerous modern wireless systems. The basic CP element is designed to obtain an ultra‐wide operating bandwidth. In the design process, a circular stub is integrated into the ground plane, and a circular slot is structured into the patch to achieve CP. On the other hand, a rectangular stub is used to improve the axial ratio bandwidth (ARBW). The elemental antenna achieves an impedance bandwidth (IBW) of 97.96% (4.13–12.06 GHz), an ARBW of 49.62% (5–8.3 GHz), a peak gain of 5.75 dB, and a minimum efficiency of 80%, maintaining small dimensions of 20 mm 20 mm 1.6 mm (0.275 λ 0 × 0.275 λ 0 × 0.022 λ 0 ). Meanwhile, a two‐element UWB MIMO radiator of 20 mm 44 mm 1.6 mm (0.275 λ 0 × 0.606 λ 0 × 0.022 λ 0 ) is designed and experimentally validated. It addresses the challenges of achieving wide impedance and axial‐ratio bandwidths while maintaining a compact size and high isolation for MIMO operation with attractive diversity performance. It achieves an impressive ultrawide IBW of 100% (4–12 GHz), ARBW of 42.73% (4.6–7.1 GHz), and 10.90% (7.8–8.7 GHz) while offering improved isolation. The MIMO geometry exhibits outstanding diversity performance, with an envelope correlation coefficient (ECC) < 0.01, diversity gain (DG) > 9.92 dB, total active reflection coefficient (TARC) < 10 dB, and channel capacity loss (CCL) < 0.2 bits/s/Hz. These features render the proposed UWB MIMO antenna exceptionally appropriate for various wireless communication uses, such as microwave C‐band (4–8 GHz), WiMAX (5.725–5.850), WLAN (5.150–5.825 GHz; 5.925–7.125 GHz), and satellite communication in X‐band (downlink: 7.25–7.745 GHz and uplink: 7.9–8.4 GHz).

ABSTRACT Current unmanned aerial vehicle (UAV)‐based remote sensing systems for soil moisture detection face several challenges, including large antenna size, low efficiency, and measurement errors caused by non‐overlapping dual‐polarization coverage. To address these issues, this study proposes an efficient and compact L‐band shared‐aperture dual‐polarized microstrip antenna design. The key innovation lies in the integration of four techniques. First, an air gap between parasitic patches and the dielectric substrate broadens the operational bandwidth. Second, a high‐impedance surface (HIS) structure suppresses surface waves, significantly improving efficiency, gain, and radiation characteristics. Third, metallic patches combined with a Chebyshev impedance matcher provide precise frequency tuning and wideband impedance matching. Finally, a compact stacked structure with a multilayer symmetric feed network enables a shared‐aperture dual‐polarized layout, overcoming coverage misalignment and size limitations typical of non‐coaxial airborne antennas. The proposed antenna achieves excellent performance in the target frequency band. It demonstrates an average efficiency of 95%, a voltage standing wave ratio (VSWR) below 1.37, a peak gain of 13.42 dB, a 3‐dB beamwidth of 44.1°, and a sidelobe level below −12.79 dB. Comparative analysis shows that this shared‐aperture design offers substantial performance improvements and establishes a new benchmark for efficient, compact dual‐polarized microstrip antennas in low‐altitude L‐band remote sensing applications.

ABSTRACT To further enhance the precision of transistor modeling, the bidirectional long short term memory‐long short term memory (BiLSTM‐LSTM) neural network is utilized for the inverse modeling of the scattering parameters (S‐parameters) for the gallium arsenide pseudomorphic high electron mobility transistor (GaAs pHEMT) here. The modeling results show that the optimal mean square error (MSE) is up to 0.0001, the coefficient of determination ( R 2 ) is 0.9972 with the optimal mean absolute error (MAE) of 0.0049. Therefore, BiLSTM‐LSTM has superior advantage for the nonlinear relationship modeling for the S‐parameters of GaAs pHEMT.

ABSTRACT This paper proposes a design method for broadband power amplifier (PA) using irregular matching structure based on an improved multi‐objective optimization algorithm, aiming at expanding its operating bandwidth. Initially, the gravitational search algorithm is enhanced by reconstructing the gravitational constant function for improving its global optimization capability. Subsequently, a fast non‐dominated sorting mechanism combined with a crowding distance strategy is introduced for multi‐objective optimization problems. Furthermore, to effectively overcome the bandwidth limitations that are inherent in conventional PA, the proposed multi‐objective gravitational search algorithm is employed for optimizing the irregular structure matching network. For verification, a broadband high‐efficiency PA is designed and fabricated, covering a frequency range of 0.4–4.0 GHz with a relative bandwidth of 163%. Measurement results show that the PA with the irregular matching structure maintains an efficiency of 59.1%–64.4% across the entire operating band, with a saturated output power of 40.3–41.8 dBm.

ABSTRACT This paper presents a low‐voltage, low‐power second‐generation voltage conveyor (VCII) that achieves enhanced bandwidth and reduced power consumption. The proposed VCII employs dynamic threshold MOS (DTMOS) technique to operate under reduced supply voltages, while resistive compensation is incorporated to extend the bandwidth. Two novel memristor emulator designs are introduced based on the proposed VCII. The grounded memristor emulator utilizes a single VCII, a resistor, a capacitor, and an NMOS transistor, whereas the floating emulator configuration employs two VCIIs, a resistor, and an NMOS transistor. The proposed VCII achieves a bandwidth of 325 MHz, an output impedance of 38 Ω at terminal Z , and a power consumption of 0.068 mW. Simulation results further demonstrate that the proposed grounded and floating memristor circuits exhibit distinct pinch hysteresis loops (PHL) in the voltage–current plane up to a frequency of 80 MHz and 1.5 GHz and power consumption of 0.12 and 0.25 mW, respectively. The designs have been validated using 180 nm CMOS technology parameters, operating at a low DC supply voltage of ±0.45 V. Both proposed memristor designs show robust and satisfactory performance across a wide frequency range. The layout and postlayout simulation results of the proposed VCII and both memristor emulators have also been carried out, occupying areas of 2116.13, 2205.02, and 4759.53 μm 2 , respectively. In addition, the process corner simulation of the proposed memristor is also included. The practical relevance of the memristor is demonstrated through the successful realization of low‐pass, high‐pass, and band‐pass filter circuits, highlighting their suitability for next‐generation memristive computing.

ABSTRACT Nuclear magnetic resonance (NMR) spectroscopy is a powerful technique for molecular analysis, yet its widespread use is limited by the bulky size and high cost of conventional radio frequency (RF) coils, which restrict portability and accessibility in clinical and field applications. To address this challenge, we propose a miniature birdcage coil implemented on a flexible printed circuit board (F‐PCB) with a Flame Retardant‐4 (FR‐4) substrate. The compact design, with a thickness of only 0.25 mm, enables the development of portable and user‐friendly NMR spectrometers without compromising performance. The coil generates a highly homogeneous magnetic field with 95% uniformity across a wide range of Larmor frequencies and achieves a magnetic field strength of 327 μT. Unlike traditional fixed‐frequency coils, the proposed design incorporates a programmable band‐pass function controlled by variable capacitors and a microcontroller, allowing electronic tuning across 1–13 MHz without hardware modifications. Finite element method (FEM) simulations confirm the coil's ability to maintain field homogeneity and high signal‐to‐noise ratio (SNR) over diverse operating conditions. Compared to existing RF coil designs such as planar, Helmholtz, or conventional birdcage coils, the proposed mini‐birdcage coil offers superior portability, tunability, and uniform excitation, thereby enhancing NMR signal acquisition and broadening applicability. This advancement holds promise for medical, pharmaceutical, biological, and geological applications, enabling portable NMR systems that improve diagnostic capabilities and expand accessibility in resource‐limited environments.

ABSTRACT A harmonic‐included canonical section‐wise piecewise linear (CSWPL) model with both bias and frequency information is presented in this study. This new model is verified by means of fundamental and harmonic load‐pull simulation data for a 10‐W gallium nitride (GaN) packaged transistor considering a wide range of input power. According to the proposed model, the harmonic behavior of the device under test (DUT) can be captured more accurately than what is currently available in the existing fundamental‐only CSWPL model, which is very helpful for the designers of power amplifiers (PAs). Further, the proposed model is implemented in Keysight advanced design system (ADS) simulator by using a frequency‐domain defined device (FDD), which is then applied to the design of a single‐ended broadband PA. In accordance with the results achieved, the GaN‐based PA has a power added efficiency (PAE) greater than 60% and an output power greater than 40 dBm over the frequency range of 2 to 3 GHz. A very good match exists between the simulation results of the proposed model and the actual measurements of real PAs, which demonstrates the suitability of the presented model for practical PA applications.

ABSTRACT The photovoltaic (PV), wind turbine (WT), and battery energy storage (BES) based hybrid system design and optimal placement using chaotic quasi‐oppositional crayfish optimization algorithm (CQOCOA) in a radial distribution network (RDN) under load uncertainty is the main objective of this study. Here, crayfish optimization algorithm (COA) is modified and improved by adding quasi‐oppositional behavior to it. Then chaos theory is added to speed up the convergence pace and avoid the local optimality. For optimal placement of hybrid PV/WT/BES system, simultaneous active power loss and annual operation costs minimization is taken as the objective to enhance the efficacy of the RDN. The uncertainty modeling of PV and WT distributed generation (DG) is considered for power generation as solar irradiance and wind speed can change. This algorithm is validated on 69‐bus and 94‐bus to establish the potency of the suggested CQOCOA algorithm. The active power loss cost is also evaluated after the installation of hybrid PV/WT/BES system. Adjusting the growing load demand, 25% increased load and 10% decreased load is considered for load uncertainty modeling. In both (69‐bus and 94‐bus) systems, the placement of hybrid PV/WT/BES system using the CQOCOA method reduces the active power loss by 58.93%, 60.53%, 53.53%, and 62.19%, 65%, 62.99% for normal, 25% increased, and 10% decreased loading conditions, respectively. In yearly running cost of hybrid system design by CQOCOA method for 69‐bus at normal and 10% decreased load gives yearly savings of 25 364$, 31 951$, 88 951$ and 16 511$, 1527$, 25 608$ than COA, DAOA, and AOA methods. The comparative study of results revealed that the CQOCOA algorithm is better than several optimization algorithms.