High-Power GaN SBD Limiter for Sub-6G With Fast Response and Recovery

In this letter, a multistage high-power RF limiter based on a thin-barrier AlGaN/GaN Schottky barrier diode (SBD) has been proposed and demonstrated in 2-6 GHz. By multifinger device layout design with increased total anode width, the on resistance of the diode reduces drastically and the maximum RF current can be increased, resulting in an increase of the power capacity of the limiter. In addition, benefiting from the thin-barrier epitaxial design and plasma-damage-free SBD device fabrication, the response time and recovery time of the limiter can be reduced, as well. By incorporating the fabricated devices with a well-designed matching circuit, the RF limiter obtains high incident power above 50 W in continuous wave (CW) mode, over 100 W in pulse mode, a fast recovery time of 35 ns, and spike leakage free at 4 GHz. The simulation and measurement results are well-agreed with each other. This demonstration shows that the GaN-SBD-based limiter is promising for future high-power and high-frequency applications.