A Compact 6–18 GHz RF Limiter Using Schottky Barrier Diodes in GaAs pHEMT Process

This paper presents a compact, wideband radio frequency (RF) limiter designed and fabricated using conventional Schottky barrier diodes (SBDs) in the 0.1μm GaAs D-mode pHEMT process. The number of stages is selected through a parametric trade-off analysis across one- to seven-stage configurations, balancing large-signal limiting capability and small-signal insertion loss. The inter-stage transmission lines are implemented as compact meander structures, with their physical dimensions determined through parametric simulation. This reduces the core area without requiring additional matching networks. On-wafer measurements demonstrate a small-signal insertion loss of less than 1.01 dB. Furthermore, large-signal continuous-wave (CW) measurements validate the wideband limiting performance. At an input power of 23 dBm, the limiter exhibits a flat leakage power of below 14.2 dBm, consistent with the simulated results. The recovery time, measured using a two-tone technique with CW signals from 6 to 12 GHz and an 18 GHz pulsed interfering signal, does not exceed 43.2 ns. The proposed limiter achieves compact integration while operating across a broad bandwidth of 6–18 GHz.