A D-band SiGe Subharmonic Downconverter with Dynamic Conversion Gain and Fixed Input Compression

A fourth subharmonic downconverter operates with a bandwidth of 123-158 GHz and incorporates bias feedback to control the conversion gain over a large LO power range. A push-pull frequency multiplier achieves a high multiplication factor (X4) without sacrificing the additional area or power of a cascaded multiplier chain. Wide bandwidth is achieved by use of a sub-quarter-wavelength (SQWL) balun and an inductivelypeaked transimpedance amplifier (TIA). The downconverter is realized in a 90-nm SiGe BiCMOS technology and has a peak conversion gain 7.5 dB at 155 GHz with -5 dBm of LO power at 35 GHz while consuming a maximum 55 mW of DC power and 0.196 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of area. The minimum 1-dB input compression power (P1dB) at 155 GHz is -15 dBm. Compared to earlier work, this paper demonstrates a higher LO multiplication factor with lower LO power requirements and over 20 dB of dynamic gain control while having the same peak power consumption and a 1.9 dB/dB conversion gain to LO power trade-off.