| 摘要 |
PURPOSE: A circuit for tracing impedance in an adaptive tuning antenna circuit is provided to precisely control impedance by finally controlling the impedance through a tuner. CONSTITUTION: A coupler(310) outputs a signal received through an antenna(360) at the same power level through an output terminal. An impedance tracer(320) traces the impedance of the signal transmitting and receiving coupled power outputted from the coupler through an antenna. A power detector(330) detects reflected power outputted through a reflected power output terminal of the coupler. A tuner(350) controls the impedance of the signal transmitted and received through the antenna. A controller(340) varies the impedance of the impedance tracer. The controller controls the level of the reflected power, detected through the power detector, to be lowest. The controller controls combined impedance of the antenna and the tuner by controlling the tuner. |
