Development of a 20 GHz to baseband MMIC direct downconverter for advanced SATCOM terminal applications

摘要

A monolithic microwave integrated circuit (MMIC) 20 GHz / baseband downconverter has been developed for implementation in a low cost EHF SATCOM terminal. This paper reports on the development aspects of the mixer and the PHEMT diode model. The mixer conversion loss was measured to be 9.6dB ± 0.4dB over the 50 MHz to 450 MHz IF frequency range. The 1dB compression point was 10dBm and the two-tone. 3rd order IM intercept point was 20dBm. The single sideband (SSB) noise figure was about 10.5dB between 50 MHz and 450 MHz and the RF/LO isolation was 26dB. Measured and predicted performances showed good agreement.