Patent ID: 8358989

Claim:
A wireless communication apparatus comprising a receiving circuit which receives a reception signal via an antenna, a voltage detection circuit for detecting a level of signal power received by said receiving circuit, a variable-impedance matching circuit controllable for effecting impedance matching between said antenna and said receiving circuit, an oscillator circuit, a current limiting resistor, a first switch, controllable for connecting a selected one of said receiving circuit and said oscillator circuit to said matching circuit, a second switch, controllable for selectively connecting and disconnecting said current limiting resistor from between said antenna and said receiving circuit, said current limiting resistor serving to limit a level of current flowing between said antenna and said receiving circuit when connected between said antenna and said receiving circuit, a signal processing apparatus for processing an output received signal from said receiving circuit, when said first switch connects said receiving circuit to said matching circuit and said second switch disconnects said current limiting resistor from between said antenna and said receiving circuit, and a control circuit for controlling said connection and disconnection operations of said first switch and said second switch, and for controlling an impedance of said matching circuit to bring an output voltage value of said voltage detection circuit close to a predetermined reference voltage value, when said first switch connects said oscillator circuit to said matching circuit and said second switch connects said current limiting resistor between said antenna and said receiving circuit, with an output signal of said oscillator circuit thereby inducing resonance of said antenna.