A 71–86-GHz Switchless Asymmetric Bidirectional Transceiver in a 90-nm SiGe BiCMOS

Abstract

An $E$ -band (71–86-GHz) bidirectional transceiver is presented in this paper. The time-division duplex architecture avoids transmit (TX)/receive (RX) switches through the use of transistor biasing in the signal path to minimize high-frequency loss. The low-noise amplifier (LNA) and power amplifier (PA) are combined into a wideband PA/LNA circuit, which alleviates the parasitic loading of each circuit through a wideband power combiner. The bidirectional transceiver circuit is implemented in 90-nm SiGe BiCMOS process. In TX mode, the bidirectional transceiver transmits a maximum saturated power of 11 dBm at 78 GHz with a 3-dB bandwidth from 71 to 86 GHz. In RX mode, the maximum 30.6-dB conversion gain and the minimum 6.6-dB noise figure are measured at 73 GHz. The whole RF frontend chip consumes 350.2- and 137.7-mW dc power in TX and RX modes, respectively, including all the RF, IF, and local oscillator amplifiers. The overall chip size is $1.5~\text {mm}\times 0.9$ mm including pads.