Reflected power suppression circuit

摘要

An amplifier (3) amplifies a transmission signal, and outputs the amplified signal to an antenna. A directional coupler (6) causes a portion of power passing through a first path connecting the amplifier (3) and the antenna to branch to a second path. A detection section (7) detects an electrical parameter changing with a change in the intensity of power reflected from the antenna to the amplifier (3), thereby detecting the intensity of the reflected power. A control circuit (8) changes a proportion of power caused to branch to the second path by the directional coupler (6), based on the electrical parameter detected by the detection circuit (7). Thus, it is possible to provide a reflected power suppression circuit capable of facilitating size reduction and preventing a power amplifier from being damaged due to breakage of an antenna, while minimizing a power loss at the time of signal transmission. <IMAGE>