A Yield-Improvement Method for Millimeter-Wave GaN MMIC Power Amplifier Design Based on Load—Pull Analysis

Abstract

Process fluctuations can significantly affect the yield of millimeter-wave circuits based on submicrometer semiconductor processes. A yield-improvement design that incorporates passive circuits is well established. However, how to consider the process fluctuation in active circuit designs (e.g., power amplifiers) and improve yield is still a challenge. In this article, a yield-improvement load-pull design method, which can be used to find optimum load impedance accounting for high yield while maintaining good output performance, is presented. The yield-improvement load-pull theory is described using an analytical model of transistor large-signal performance considering the process fluctuation. A method of the yield-improvement load-pull for the practical microwave monolithic integrated circuit (MMIC) design is introduced in detail. For demonstration purposes, a high-performance Ka-band power amplifier MMIC is designed. The results show that with the proposed yield-improvement load-pull method, an obvious improvement of yield can be observed with only minimal sacrifice of the output power ( P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">out</sub> ) and the power added efficiency ( η <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">PAE</sub> ), respectively. As a result, the method of this article can be used to improve the yield of millimeter-wave/terahertz integrated circuits (ICs).