Circuit Technology tor Mobile/Personal Communications

This paper reviews the microwave circuit technology recently developed by NTT Mobile Communications Network Inc. (NTT DoCoMo) for mobile/personal communication systems. The circuit construction techniques of highly efficient power amplifiers and high speed frequency synthesizers, which are the keys to achieve new sophisticated systems, are focused on. They include the high efficiency Harmonic-Reaction-Amplifier (HRA), the Harmonic-Matching and Reflection-Amplifier (MHRA), and the Linearized-Saturation-Amplifier with Bidirectional-Control (LSA-BC) for portable radio units, the very low distortion Self-Adjusting-Feed-Forward amplifier (SAFF) for radio base stations, and the high-speed frequency changeable Twin-Counter-Digital-Loop-Preset-Synthesizer (TC-DLPS) for digital portable radio units.