Very Low-Intermodulation GaAs Mixers with Negative Feedback

Abstract

A novel circuit configuration for GaAs FET mixers is proposed. An RC negative feedback technique on the drain LO injection GaAs FET mixer brings about substantial improvement in the 3rd-order intermodulation distortion property without conversion gain falloff. This effect is still more remarkable with higher LO power at the drain. Measured performance of a fabricated 1.9-GHz-band MMIC GaAs FET mixer shows more than an 8-dB improvement in the 3rd-order intermodulation intercept point over a conventional GaAs FET mixer with increased conversion gain.