Parametric Downconverter for Mixer-First Receiver Front Ends

Abstract

In this article, we present a parametric downconverter that may be used in a mixer-first receiver front end. In such a receiver, the first mixer should offer a satisfactory low-noise figure (NF), high conversion gain (CG) to suppress the noise contribution of the next stages, and high linearity to avoid receiver saturation in the presence of interferences. Parametric mixers are known to offer parametric CG for frequency upconversion with no fundamental noise penalty due to its parametric amplification nature. This work is the first experimental demonstration of a parametric downconverter that achieves positive gain and low NF. The proof-of-concept mixer with a center input frequency of 1.9 GHz and an output frequency of 1.45GHz is designed and implemented on PCB. The mixer achieves a measured peak CG of 10 dB and a 1-dB compression point of +7 dBm. Furthermore, the fabricated mixer achieves a minimum NF of 2.8 dB over its bandwidth.