MOBILE COMMUNICATION UNIT

摘要

A high-frequency amplifier used in the conventional mobile communication unit requires adjustments of an output matching circuit by priority of output power when the source voltage drops. With the source voltage being normal, therefore, the output voltage is over the rating, resulting in low efficiency. To solve this problem, a mobile communication unit comprises an antenna, a high-frequency amplifier, a receiving section, a control section, and a battery, wherein the high-frequency amplifier includes a plurality of stages of amplifier elements for amplifying high-frequency signals, an input matching circuit, an interstage matching circuit, and an output matching circuit having means for varying the output impedance matching condition depending on the source voltage level applied to the amplifier elements. This mobile communication unit achieves low power consumption (high efficiency) and can have a compact and lightweight structure.