Abstract: A radio frequency IC device includes a radio frequency IC chip arranged to process a transmitted/received signal, a printed circuit board on which the radio frequency IC chip is mounted, an electrode arrange on the circuit board, and a loop electrode that is arranged on the circuit board so that the loop electrode is electrically connected to the radio frequency IC chip and is coupled to the electrode by electromagnetic coupling. The electrode is coupled to the radio frequency IC chip via the loop electrode so as to transmit or receive a high-frequency signal. A power supply circuit board including a resonance circuit and/or a matching circuit may be disposed between the radio frequency IC chip and the loop electrode.

Abstract: A voltage controlled oscillation circuit includes a resonance circuit and an oscillation circuit. The oscillation circuit includes a capacitor, a variable capacitance diode, and a resonator composed of a strip line one end of which is grounded. The oscillation circuit includes an oscillation transistor, bias resistors, and, a Colpitts capacitor, a harmonic bypass capacitor, and a chip capacitor, one end of which is connected in series with a resistor and the other end of which is grounded. A node between the bias resistor and the chip capacitor connects the resonator composed of a strip line provided within the resonance circuit via a connection line, whereby the emitter of the oscillation transistor provided within the resonance circuit is grounded via the bias resistor and the resonator. In addition, a parallel resonance circuit is composed of the resonator and the chip capacitor.