82 GHz direct up-converter mixer using double-balanced Gilbert cell with sensitivity analysis at mm-wave frequency

This paper presents a 82 GHz direct up-converter mixer fabricated in a 130 nm SiGe BiCMOS technology as a part of a complete 82 GHz transmitter operating at mm-wave frequency. The mixer is based on a double-balanced Gilbert cell topology. Two broadband baluns are employed to differentiate the single-ended input signals of the mixer: one on-chip balun operates at 82 GHz at the LO port, and one off-chip balun at the IF port operates at 0.5 GHz. With 2.2 V supply voltage, -5 dBm local oscillator pumping power, and -30 dBm IF power, the measured mixer achieves a double-sideband conversion gain of 9 dB over the RF frequency range from 76 to 84 GHz, consuming just 23 mW static DC power (including output buffer). Isolation between LO-RF signals and IF-RF signals at the RF output port is larger than 34 dB and 52 dB, respectively. The sensitivity of the relevant circuit figures of merit with respect to important transistor parameters has also been investigated.

I. Introduction

BiCMOS process technologies with Silicon-Germanium (SiGe) heterojunction bipolar transistors (HBT) have become an attractive option for realizing mm-wave systems on a chip [1]-[3]. Transceivers operating around 82 GHz offer significant advantages in terms of the available bandwidth and form factor. These advantages make them well-suited for various applications such as high data rate communications (including chip-to-chip), nondestructive material characterization and identification, and radar.