High-Power Microwave Limiters Using Recess-Free AlGaN/GaN Schottky Barrier Diodes

Abstract

In this letter, a thin-barrier AlGaN/GaN Schottky barrier diode (SBD) is proposed and implemented in a three-stage high-power RF limiter module. Benefited from the thin-barrier epitaxy, a recess-free process in the Schottky region is allowed to avoid the plasma damage, resulting in low ON-resistance of 5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> and high withstand voltage characteristics. In addition, the proposed SBDs have achieved a low junction capacitance of 0.35 pF at 0 V bias and a turn-on voltage of 0.5 V. With the optimized SBD and well-designed matching circuits, the limiter has reached a high power capacity of over 10 W in continuous wave (CW), 20 W in pulse mode, and a fast recovery time of 30 ns at a frequency of 3.5 GHz, exhibiting better characteristics than traditional limiters. Both simulation and measured results agree with each other. It indicates that the AlGaN/GaN-based SBD is promising for high-power and high-frequency limiters.