94 GHz bidirectional variable gain amplifier in 0.13-µm SiGe BiCMOS for phased array transmit and receive (T/R) applications

This paper presents a bidirectional variable gain amplifier (VGA) for W-band phased array transmit and receive (T/R) application. The VGA is based on cascode topology and employs T-type matching networks combined with load inductor and transistor parasitics to serve for both input and output matching when establishing directional signal flow. The VGA is implemented in a 0.13 μm SiGe BiCMOS technology. Measurement results show -1~5.7 dB of gain control range, 9.5 dB NF, and -8.5 dBm IP_-1dB at 94 GHz at the expense of 9.9 m W of power dissipation. The reverse isolation is better than -18 dB at 94 GHz. Chip size is 0.56×56 mm² including pads.