A 28-GHz Switchless, SiGe Bidirectional Amplifier Using Neutralized Common-Emitter Differential Pair

This letter presents a 28-GHz switchless, SiGe bidirectional amplifier (BDA) using a neutralized differential common-emitter amplifier core. On-chip transformer-based input-output baluns are included in the design for single-ended measurement and characterization. The BDA was implemented using GlobalFoundries 8HP 0.13-μm SiGe BiCMOS technology. The forward and backward gains are 10 and 8.6 dB, with noise figure of 3.9 and 4.2 dB, respectively, at 28 GHz. The input-referred 1-dB compression point at 28 GHz for forward and backward operations is -2.4 and -0.4 dBm, respectively. The BDA consumes 26.9 mW of power with a 1.6-V V
_CC
at a V
_BE
bias of 0.86 V. The circuit has dimensions of 0.71 × 0.90 mm
²
including bondpads.