A monolithic DC temperature compensation bias scheme for multistage HEMT integrated circuits

This work benchmarks the first demonstration of a multistage monolithic HEMT IC design which incorporates a DC temperature compensated current-mirror bias scheme. This is believed to be the first demonstrated monolithic HEMT bias scheme of its kind. The active bias approach has been applied to a 2-18 GHz five-section low noise HEMT distributed amplifier which achieves a nominal gain of 12.5 dB and a noise figure <2.5 dB across a 2-18 GHz band, The regulated current-mirror scheme achieves better than 0.2% current regulation over a 0-125/spl deg/C temperature range, The RF gain response was also measured over the same temperature range and showed less than 0.75 dB gain degradation. This results in a -0.006 dB//spl deg/C temperature coefficient which is strictly due to HEMT device G/sub m/ variation with temperature. The regulated current-mirror circuit can be employed as a stand-alone V/sub gs/-voltage reference circuit which fan be monolithically applied to the gate bias terminal of existing HEMT ICs for providing temperature compensated performance, This monolithic bias approach provides a practical solution to DC bias regulation and temperature compensation for HEMT MMICs which can improve the performance, reliability, and cost of integrated microwave assemblies (IMAs) used in space-flight military applications.