Demonstration of high output power (3.75 W/mm) with 31.8% PAE in Ga-Polar AlGaN/GaN HEMTs on sapphire at 94 GHz

Ruixin Bai; Swarnav Mukhopadhyay; Michael Elliott; Ryan Gilbert; Surjava Sanyal; Darryl Shima; Jiahao Chen; Rafael A. Choudhury; Kyudong Kim; Yu-Chun Wang; Ganesh Balakrishnan; Ahmad E. Islam; Andrew J. Green; Shubhra S. Pasayat; Chirag Gupta

doi:10.1109/lmwt.2026.3736479

arXiv · 2610.36492

Demonstration of high output power (3.75 W/mm) with 31.8% PAE in Ga-Polar AlGaN/GaN HEMTs on sapphire at 94 GHz

Ruixin Bai·Swarnav Mukhopadhyay·Michael Elliott·Ryan Gilbert·Surjava Sanyal·Darryl Shima·Jiahao Chen·Rafael A. Choudhury·Kyudong Kim·Yu-Chun Wang·Ganesh Balakrishnan·Ahmad E. Islam·Andrew J. Green·Shubhra S. Pasayat·Chirag Gupta

View original source ↗Read source document ↗Export metadata ↓

Abstract

In this work, a recessed-gate Ga-polar AlGaN/GaN high-electron-mobility transistor (HEMT) on sapphire incorporating an AlGaN back-barrier for W-band operation is demonstrated. The device achieves a subthreshold slope of ~130 mV/dec, a peak transconductance of 0.75 S/mm, and an fmax exceeding 240 GHz. Continuous-wave load-pull measurements at 94 GHz show an output power of 3.75 W/mm with a power-added efficiency of 31.8%. This performance significantly exceeds the best previously reported Ga-polar devices on sapphire and approaches that of state-of-the-art Ga-polar devices on SiC, which provides a promising pathway toward high-performance W-band devices.

Explore related subjects

physics.app-ph

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Ruixin Bai, Swarnav Mukhopadhyay, Michael Elliott, Ryan Gilbert, Surjava Sanyal, Darryl Shima, Jiahao Chen, Rafael A. Choudhury, Kyudong Kim, Yu-Chun Wang, Ganesh Balakrishnan, Ahmad E. Islam, Andrew J. Green, Shubhra S. Pasayat, Chirag Gupta. 2026-10-27. Demonstration of high output power (3.75 W/mm) with 31.8% PAE in Ga-Polar AlGaN/GaN HEMTs on sapphire at 94 GHz. https://doi.org/10.1109/lmwt.2026.3736479

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Voltage-Dependent Photocurrent and Crossover Behavior in Crystalline Silicon Solar Cells

Contrary to the conventional assumption of voltage-independent photocurrent, we show that the photocurrent in monocrystalline silicon p-n junction solar cells depends explicitly on voltage. By applying physically realistic boundary conditions to the classical p-n junction solar-cell model, we derive an analytical expression for the photocurrent that incorporates both the built-in potential and the applied voltage. The model predicts a crossover point between the dark and illuminated $I-V$ characteristics, irrespective of illumination intensity. This prediction is experimentally validated by lock-in measurements on a commercial monocrystalline silicon solar cell. These results establish a more consistent understanding of the quantitative role of the built-in potential in the photovoltaic effect.

physics.app-ph↗

arXiv2026

A Stable, High-Order Time-Stepping Scheme for the Drift-Diffusion Model in Modern Solar Cell Simulation

This paper presents a one-dimensional transient drift-diffusion simulator for advanced solar cells, integrating a structure-preserving finite-volume spatial discretization with Scharfetter-Gummel-type fluxes and a high-order, L-stable implicit Runge-Kutta (Radau IIA) temporal integrator. The scheme ensures local charge conservation, handles sharp material interfaces, achieves second-order spatial and fifth-order temporal convergence, and exhibits excellent computational efficiency and numerical stability. Its accuracy is verified against the classical depletion approximation in p-n junction and validated against four independent software implementations for an organic photovoltaic device under a common protocol. The framework's extensibility is demonstrated by incorporating exciton kinetics in organic solar cells, capturing multi-timescale dynamics, and by modeling mobile ions in perovskite solar cells, reproducing characteristic J-V hysteresis without empirical parameters. This work provides a robust, high-order numerical foundation for simulating coupled charge, exciton, and ion transport in next-generation photovoltaic devices.

physics.app-ph↗

arXiv2026

Suppression of Sedimentation in Polystyrene Microsphere Suspensions via Femtosecond Laser Irradiation

Micrometer-sized particles denser than their medium settle out of suspension within hours, and Brownian motion is too weak to prevent it. We report that femtosecond laser irradiation at 1030 nm slows this settling in suspensions of 8 um polystyrene microspheres in water, without altering the particles themselves. Suspensions at three concentrations were treated for up to 3 h under weak acoustic agitation or vigorous magnetic stirring, each with and without simultaneous irradiation, and the particles remaining in the probe volume were quantified optically by angle-resolved Mie scattering. Under acoustic agitation, irradiation raised retention in eleven of twelve paired comparisons, at every concentration, by 0.17 on average against a measured aliquot-to-aliquot scatter of 0.02; the twelfth comparison lies within that scatter. Under stirring, which already keeps most particles suspended, it produces no resolvable change. The angular positions of the Mie maxima are unchanged to within about 1% over 3 h, so the particles are neither fragmented nor aggregated and the effect arises from particle transport rather than from changes in the particles. An order-of-magnitude analysis rules out optical forces, the optical Kerr effect, and transient photochemistry, and leaves laser-driven convection: the power absorbed by the water sustains flows orders of magnitude faster than the 1.8 um/s settling velocity. Femtosecond irradiation therefore acts as a non-contact, supplementary agitation source, most effective where mechanical mixing is weak.

physics.app-ph↗