Radio frequency transmitting-receiving integrated electronic circuit for mobile telephone, has detector detecting reflected and transmitted power, and selection circuit selecting resonant frequency of antenna based on ratio of power

摘要

The circuit (5) has a terminal end (521) for receiving and transmitting a signal, and a plane antenna (51) with an adjustable resonant frequency. A primary line of a bidirectional coupler (52) is intercalated between the terminal end and the antenna, and a secondary line of the coupler comprises terminal ends (523, 524) providing respective information representing primary line side reflected and transmitted power. Detectors (53, 54) detect the power, and an integrated selection circuit (56) selects the antenna frequency based on ratio of the power.