Millimeter-Wave SiGe Radiometer Front End With Transformer-Based Dicke Switch and On-Chip Calibration Noise Source

Abstract

We present a co-designed Dicke switch and low-noise amplifier (LNA) in which the switch incorporates a transformer-based topology and serves as the input matching network of the LNA. This topology is configured to minimize the amplifier gain mismatch between the two switching states caused by process variations while providing a low noise figure (NF). The circuit is implemented in a 0.13- μm SiGe BiCMOS technology, and it achieves more than 20-dB gain and minimum NF values of 4.5 and 0.58 dB at 300 and 20 K, respectively. It consumes a dc power of 15 mW. The front-end switch presents a peak isolation of 17 dB, and the input return loss is better than 15 dB across 45-70 GHz. A noise source is also coupled to the front-end circuitry to enable on-chip calibration. The noise performance and reliability of several on-chip p-n junctions were characterized, and the one with the highest excess noise ratio was coupled to the front-end circuitry. To the best of our knowledge, the lowest NF of an integrated switch and LNA at V-band frequencies is achieved in the present work, along with the first reliability study of on-chip noise sources in a SiGe BiCMOS technology.