Subharmonic 220- and 320-GHz SiGe HBT Receiver Front-Ends

Monolithically integrated 220- and 320-GHz receiver front-ends manufactured in an engineering version of anf_T/f_max=280/435-GHz SiGe technology are presented. Subharmonic mixing is provided by a Gilbert cell with stacked switching quads fed by quadrature 110/160-GHz local oscillator (LO) signals. The 220-GHz version of the front-end is equipped with an integrated LNA with a measured 15-dB gain and 28-GHz bandwidth. This front-end yields a conversion gain of 16 dB, an 18-dB single-sideband (SSB) noise figure (NF), and a 30-GHz bandwidth when pumped with a 0-dBm 110-GHz LO signal. The 320-GHz version of the front-end omits the low-noise amplifier and features an integrated × 9 LO multiplier chain to facilitate operation and characterization. A conversion gain of -14 dB and a 36-dB SSB NF is obtained over the 313-to-328-GHz frequency range. The presented circuits demonstrate that a fully integrated receiver front-end can be implemented up to submillimeter-wave frequencies in an SiGe HBT technology.