Monolithically Integrated Parametric Mixers With Time-Varying Transmission Lines (TVTLs)

Abstract

Mixers are frequency conversion devices that are widely used in radio applications. This article presents an in-depth theoretical study on the parametric mixing and amplification performance of the time-varying transmission lines (TVTLs) and utilizes the concept to design two TVTL parametric mixers on a commercially available InGaP HBT process. Unlike traditional passive mixers, these parametric mixers can provide a mild conversion gain and achieve a relatively low-noise figure. For the traveling-wave TVTL, the theory of the parametric mixing with the single-sideband condition is reviewed and compared with the double-sideband mixing case. The noise performance analysis shows that the noise figure of the TVTL can be made arbitrarily low to the quantum noise limit through the input reactive termination. The theory serves as a guideline for the design of MMIC parametric mixers. Measurement results have shown that the MMIC traveling-wave TVTL can achieve a maximum of 2.1-dB conversion gain. The mean noise figure was 2.7 dB within the measured frequency band. For the reflective TVTL parametric mixer, the conversion gain and the pump power consumption can be significantly improved. The noise figure, however, is degraded due to the multiple reflections created in the matching circuit. These conclusions are supported by theoretical analyses, ADS harmonic balance simulations, and experiments in this article.