A 219–266 GHz fully-integrated direct-conversion IQ receiver module in a SiGe HBT technology

This paper presents a fully-integrated direct-conversion fundamentally-operated mixer-first quadrature receiver chip working at 240 GHz. It has been implemented in a 0.13-μm SiGe HBT technology with fT/fmax of 350/550 GHz. The chip includes an LO path based on a x16 multiplier with a 3-stage PA, driven externally from the PCB at 14–18 GHz. The LO signal is split in quadrature by a broadband coupler. It drives two double-balanced fundamentally-operated mixers with their RF ports connected directly to a wideband lens-integrated linearly-polarized on-chip ring antenna. For low-cost packaging, the chip-on-lens assembly is wire-bonded onto a high-speed PCB, where an on-board 8-section step-impedance microstrip-line low-pass filter has been implemented to compensate the wire-bond inductance at the IF outputs. The 3-dB RF/LO operation BW (with fixed IF) is 47 GHz with peak CG of 7.8 dB, and minimum SSB NF of 11.3 dB, whereas a 3-dB IF bandwidth is at least 12 GHz. All measurement results have been taken at the board-level and include the implementation losses of both the antenna and the on-board high-speed interconnects. The receiver IQ amplitude imbalance is below 1.58 dB for the 210–280 GHz band. In combination with a 9-mm silicon lens, the receiver module provides a directivity of 25.2 to 27.04 dBi from 210 to 280 GHz.