A 117–155-GHz SiGe HBT D-Band Subharmonic Mixer Utilizing a Novel 180° Hybrid Coupler

This letter presents a
${D}$
-band subharmonic downconversion mixer for next-generation communications and implemented in a 90-nm SiGe BiCMOS technology. The design consists of a cascoded push–push doubler and a wideband transimpedance amplifier (TIA), and it utilizes a novel, 180° hybrid coupler topology to achieve wide bandwidth, moderate conversion gain (CG), and power consumption. The subharmonic mixer achieves a peak in-band gain of 5.1 dB and a bandwidth of 38 GHz at a center frequency of 136 GHz. The subharmonic mixer utilizes a fixed local oscillator (LO) of 2 dBm at 57.5 GHz and consumes 50.8 mW of dc power. The core die area of the subharmonic mixer is
$0.9\times0.5$
mm2. This mixer achieves highly competitive performance in terms of CG, bandwidth, and power consumption with respect to
${D}$
-band subharmonic mixers demonstrated in silicon.