A 243 GHz LNA module based on mHEMT MMICs with integrated waveguide transitions

For use in a millimeter-wave direct detection radiometer for earth remote sensing, we have developed a low-noise amplifier (LNA) module with a small-signal gain of 19.5 dB at 243 GHz and a 3 dB bandwidth of 40 GHz. The implemented three-stage LNA MMIC has been manufactured using a 50 nm gate length metamorphic HEMT (mHEMT) technology on 50 m thick GaAs substrates. Each of the two on-chip integrated E-plane probe waveguide transitions offers a transmission loss of only 0.5 dB at 243 GHz including a 7.5 mm long WR-3.4 waveguide. Due to the low-loss packaging, the LNA module achieves a low noise figure of only 6.0 dB at room temperature.