A 18-23 GHz power amplifier design using approximate optimal impedance region approach for satellite downlink

摘要

This paper presents the design procedure of a K-band 0.1 μm GaAs pseudomorphichigh electron mobility transistors (pHEMT) monolithic microwaveintegrated circuit (MMIC) for satellite communication downlinks. The methodfocuses on the selection and design of the matching network (MN) by applyingthe Approximate Optimal Impedance Region (AOIR) approach which is acomposition of simple mathematical constraints. The AOIR approach overcomesthe drawbacks of traditional MN design method which cannot controlthe reflection coefficient trajectory of the MN precisely. The method formulatesthe constraints through symbolic-graphic combinations with integratedfunctions of computer-aided design (CAD) tools. The impedance transformationtrajectory of MN is combined to reduce the mismatch and the insertionloss using equations with multiple mathematical constraints to realize theautomatic selection of the MN's topology. The AOIR method fully considersthe underutilized characteristics of power amplifier (PA) and to maximize itsperformance in a balanced manner. The MMIC, was designed using the proposedtechnique, operates in 18 GHz-23 GHz with a gain of 27 dB and has anaverage P−1dB of 27 dBm and PAE of 38% under the continuous wave(CW) drive signal.