Body effect up- and down-conversion mixer circuits for low-voltage ultra-wideband operation

This article presents fully differential up- and down-conversion mixer circuits manufactured in a triple well 45 nm CMOS process for low-voltage Ultra-Wideband transmitter and receiver applications. The proposed circuits both employ the transistor bulk terminal for signal injection. While the down-conversion mixer uses the bulk for switching via threshold voltage modulation, the up-conversion mixer applies the baseband signal to the bulk, thereby implicitly incorporating the back-gate controlled current source of the MOS transistor. Both circuits offer resistive on-chip termination and DC coupled output buffering for measurement purposes. The down-conversion mixer features an input-referred compression point of −13.2 dBm and a maximum conversion gain of 9.4 dB at 2.5 GHz with the 3-dB corner frequency being beyond 10 GHz. The implemented up-conversion mixer offers a maximum conversion gain of −8.8 dB at 5.8 GHz together with an output-referred compression point of −9.7 dBm. The operational bandwidth ranges from 4.5 to 6.7 GHz. Both circuits operate at a low supply voltage of 1.1 V.