-Band Dual-Polarization Phased-Array Transceiver Front-End in SiGe BiCMOS

This paper discusses the design and implementation of a 94-GHz phased-array transceiver front-end in SiGe BiCMOS that is capable of receiving concurrently in both vertical (V) and horizontal (H) polarizations and time-duplexed transmission in either polarization. The compact front-end is implemented in $hbox{1.3 mm}times hbox{ 1.45 mm}$ of silicon area to ensure compatibility with a scalable phased-array tile approach with $lambda/2~(sim hbox{1.6 mm})$ spacing between elements. Each transceiver front-end includes variable transmitter (TX) and receiver (RX) gain and 360$^{circ}$ variable phase shift in TX and RX. Co-integration of the transmit-receive (T/R) switch with the power amplifier (PA) and low-noise amplifier (LNA) matching network minimizes switch impact on RX noise figure (NF). A varactor-based passive reflection-type phase shifter (RTPS) is shared between the TX and RX to reduce area. Analysis of loss mechanisms in on-chip RTPS leads to a novel RTPS load that minimizes RTPS loss while ensuring that the amplitude variation across phase shift is $ $2-dBm saturated output power and $> $0-dBm output-referred 1-dB compression point (OP1dB) in V and H polarizations (time-duplexed), 30-dB gain, and 8-GHz bandwidth (89–97 GHz). The 94-GHz phase shifters achieve full 360 $^{circ}$ variable phase shift with 5-bit phase resolution (11.25$^{circ}$ resolution) and $<3^{circ}~hbox{rms}$ error and $< $1-dB rms gain error at 94 GHz. The front-end consumes 160 mW in RX mode for dual-polarization concurrent reception/phase-shifting and 116 mW in TX mode for time-duplexed V and H output in the $W$-band.