A direct carrier I/Q modulator for high-speed communication at D-band using 130nm SiGe BiCMOS technology

This paper presents a 110-170 GHz direct conversion I/Q modulator realized in 130 nm SiGe BiCMOS technology with ft/fmax values of 250 GHz/ 370 GHz. The design is based on double-balanced Gilbert mixer cells with on-chip quadrature LO phase shifter and RF balun. In single-sideband operation, the modulator exhibits up to 9.5 dB conversion gain and has measured 3 dB IF bandwidth of 12 GHz. The measured image rejection ratio and LO to RF isolation are as high as 20 dB and 31 dB respectively. Measured input P1dB is -17 dBm at 127 GHz output. The dc power consumption is 53 mW. The active chip area is 620 μm× 480 μm including the RF and LO baluns. The circuit is capable of transmitting more than 12 Gbit/s QPSK signal.