RF Analog and Digital Circuit Technology as a Basis for Development of RFIC and PA for Mobile Phones

Abstract

During the period 1985-2022, I developed high-frequency circuits for mobile communications, especially radio frequency integrated circuits (RFICs) that integrate transceiver functions and power amplifiers (PAs) that amplify the transmitted signal, at various companies (Hitachi, Ltd., Renesas Electronics Corporation, and Murata Manufacturing Co., Ltd.). Looking back on the history of my own development, it can be divided into three periods : the early period when I was searching for applications until the emergence of cell phones as a killer application, the mid-period when I was developing RFIC and PA modules mainly for second-generation cell phones, and the late period when I was developing PA modules for smartphones. In the latter half of this period, I was developing PA modules for smart phones. In this paper, I describe the early stage of development during which I was searching for applications as my starting point, and how it led to the later stage of development.