A 28-/60-GHz Band-Switchable Bidirectional Amplifier for Reconfigurable mm-Wave Transceivers

Performance limits and design techniques for millimeter-wave amplifiers employing switches for multiband operation are presented in this article. A bidirectional dual-band amplifier is designed in a 130-nm silicon-germanium (SiGe) process. The amplifier can shift its operational frequency between 28 or 60 GHz and can operate in low-noise receive or high-power transmit mode. The frequency shift and transmit-receive (T/R) mode change has been realized using shunt switches based on SiGe HBTs. The switches are co-optimized and integrated with amplifiers to reduce the die area and improve performance. An analysis of switch loss reduction and associated tradeoffs is provided. The designed shunt switch, for band-switching operation, achieves the simulated ON-loss of as low as 1 dB at 60 GHz and OFF-loss of 0.7 dB at 28 GHz. By using these low-loss switches and a codesign approach, the proposed T/R amplifier surpasses the state-of-the-art performance in terms of mm-wave multiband amplifiers.