Wideband GaN FET based limiter MMICs

The design and performance of wideband FET limiter MMICs utilizing GaN on SiC technology are presented. Two different single pole single throw (SPST) switch based circuit architectures are investigated, both of which are designed to cover the 1-6 GHz frequency range. Measured on-wafer s-parameter data demonstrates a maximum insertion loss of 0.6 dB and minimum return loss of 14 dB for both design variants. Continuous wave (CW) power data measured from 2-4 GHz shows a linear transfer characteristic until about 16 dBm input power. The feedback limiter exhibited less than 25 dBm of flat leakage for a 40 W input signal level while the feedforward design demonstrated less than 22 dBm of leakage for a 50 W CW input.