Low-noise Ku-band MMIC balanced P-HEMT upconverter

摘要

An enhanced design methodology for a low-noise Ku-band monolithicnbalanced high electron mobility transistor (HEMT) upconverter and itsnperformance are presented in this paper. The mixer topology consists ofna common source/common gate HEMT pair that performs the mixing and balunnfunctions. A detailed study has been done to establish the role of thentransistor model elements in the performance of the mixer. Based on thisnstudy, a new analysis is proposed to optimize the operating point of thenmixer in order to get a tradeoff between conversion gain and portnisolations. To combine the LO and intermediate-frequency (IF) signals,nactive circuits were used, as well as a high-pass filter in order tonimprove the isolations. The circuit size, including the filter and thencombiners, is 3 mm2. On-wafer measurements show a conversionngain over 2.5 dB, with only 3 dBm of LO power. A LO/RF isolation over 27ndB was measured in the whole LO band. The LO/IF isolation is over 27 dBnthanks to the low reverse gain of the combiner HEMT's. A single sidebandnnoise figure of 7.3 dB has been obtained