Design of high-power, high-efficiency 60-GHz MMICs using an improved nonlinear PHEMT model

Abstract

This work describes the design and nonlinear modeling of two V-band monolithic microwave integrated circuit (MMIC) power amplifiers using a nonlinear high electron mobility transistor (HEMT) model developed specifically for very short gate length pseudomorphic HEMTs (PHEMTs). Both circuits advance the state-of-the-art of V-band power MMIC performance. The first, a single-ended design, produced 293 mW of output power with a record 26% power-added efficiency (PAE) and 9.9 dB of power gain at 62.5 GHz when measured on-wafer. The second MMIC, a balanced design with on-chip input and output Lange couplers for power combining, generated a record 564 mW of output power (27.5 dBm) with 21% PAE and 9.8 dB power gain. The MMIC's are passivated, thinned to 2 mils, and down-biased to 4.5 V for high reliability space applications. These excellent first-pass MMIC results are attributed to the use of an optimized 0.1-//spl mu/m PHEMT cell structure and a design based on millimeter-wave on-wafer device characterization, together with a new and very accurate large signal analytical FET model developed for 0.1-//spl mu/m PHEMTs.