First demonstration of l-band high-power limiter with gan schottky barrier diodes (Sbds) based on steep-mesa technology

Gallium nitride (GaN) has attracted increased attention because of superior material properties, such as high electron saturation velocity and high electrical field strength, which are promising for high-power microwave applications. We report on a high-performance vertical GaN-based Schottky barrier diode (SBD) and its demonstration in a microwave power limiter for the first time. The fabricated SBD achieved a very low differential specific on-resistance (R_ON,sp) of 0.21 mΩ·cm², attributed to the steep-mesa technology, which assists in reducing the spacing between the edge of the anode and cathode to 2 µm. Meanwhile, a low leakage current of ~10⁻⁹ A/cm²@−10 V, a high forward current density of 9.4 kA/cm² at 3 V in DC, and an ideality factor of 1.04 were achieved. Scattering parameter measurements showed that the insertion loss (S₂₁ ) was lower than −3 dB until 3 GHz. In addition, a microwave power limiter circuit with two anti-parallel diodes was built and measured on an alumina substrate. The input power level reached 40 dBm (10 watts) in continuous-wave mode at 2 GHz, with a corresponding leakage power of 27.2 dBm (0.5 watts) at the output port of the limiter, exhibiting the great potential of GaN SBD in microwave power limiters.