Heterogeneously Integrated W-Band Downconverter

We report a heterogeneously integrated W-band downconverter, consisting of a low noise amplifier (LNA) and a star mixer. An LNA is realized in a 0.1-μm InP highelectron-mobility transistor (HEMT) technology and features the noise figure of ~2.5 dB and gain ≥25 dB at W-band. Star mixer is realized in four-layer interconnect InP heterojunction bipolar transistor (HBT) and diode process. A novel design eliminates electrically large diode ring by utilizing a multimetal configuration. Mixer chiplet is integrated into the LNA carrier wafer using heterogeneous integration, which offers electrically short connection between two technologies. Heterogeneously integrated interconnect or transition has measured a loss of ~0.8 dB up to 96 GHz. Integrated W-band downconverter has measured the conversion gain ≥0 dB from 87 to 100 GHz. This is a first reported integration of InP HBT chiplets into the InP HEMT wafer using heterogeneous integration, as well as first reported a W-band heterogeneously integrated downconverter.