Design and realisation of a pHEMT diode MMIC power limiter using 3D GaAs multilayer CPW technology

We report for the first time, the design and realization of a MMIC power limiter based on (0.5 × 200) μm² pHEMT Schottky diodes using an in-house 3D GaAs multilayer CPW technology. The system of three layers of conductor metals and two layers of sandwich polyimide as dielectric was employed. The limiter design consists of a 50Ω V-shaped coplanar waveguide transmission line connected to a pair of shunt GaAs pHEMT diodes. Measured on-wafer S-parameter data demonstrates a maximum small signal insertion loss of less than 2 dB from 50 MHz to 3 GHz and a return loss better than 7.5 dB.