Patent ID: 6603359
Filing Date: 2003-08-05
Classification: H03F

Abstract:
A high-frequency power amplifying apparatus, comprising:a plurality of amplifiers including at least first- and final-stage amplifiers and connected in series with one another in increasing order of saturation power; an input terminal connected to said first-stage amplifier; an output terminal connected to said final-stage amplifier; a power controller for selectively supplying said output terminal with an output from a desired one of the plurality of amplifiers in accordance with an externally demanded output power and for causing one or more amplifiers downstream of the desired one amplifier to be in a cutoff state when the desired one amplifier is not the final-stage amplifier; and an output delay line connected between said output terminal and said final-stage amplifier and having a line length thereof providing the final-stage amplifier with a high impedance as viewed from said output terminal when the final-stage amplifier is in a cutoff state.