Temperature Compensated D-Band SiGe LNA with Supply Current Monitoring for Self-Healing Radiometers

In this work we present a SiGe D-Band Low Noise Amplifier (LNA) for radiometric applications near the water absorption line at 183 GHz. The LNA covers the frequency range near 188 GHz with a peak gain of 23 dB and a minimum noise figure of 10.5 dB. Space hardening techniques are also presented in order to mitigate the LNA performance variation due to orbital changes and therefore, to achieve a more stable and constant sensitivity, NETD, of the radiometer. First, a current sensor is designed for bias changes monitoring caused by radiation. The reference voltages of the bias circuits are left as tuning-knobs to compensate the effect of radiation. Furthermore, this bias circuit also compensates the temperature dependence of the LNA. The gain variation is reduced from 11 dB to 2 dB and the NETD is keeped below 0.4. Thanks to these techniques a complete self-healing system could be implemented if they were extended with a processing block.