Abstract: In a mounting structure of an antenna switching circuit, a first switching diode is connected between a first conductor pattern and a second conductor pattern, an inductor is connected between the first conductor pattern and a third conductor pattern, a first capacitor is connected between the third conductor pattern and a fourth conductor pattern, and a second switching diode is implemented by a bare chip. The bare chip is mounted on the fourth conductor pattern, a cathode thereof being connected to the fourth conductor pattern and an anode thereof being connected to the third conductor pattern via a bonding wire.

Abstract: A plane patch antenna has a dielectric substrate formed by calcining ceramic powder press-molded in a desired shape. On one surface of the dielectric substrate, a concave groove is continuously formed along the inside of its outer edge, and on an entire surface within a region partitioned by this concave groove, a patch electrode is thick-film printed.

Abstract: In a mounting structure of an antenna switching circuit, a first switching diode is connected between a first conductor pattern and a second conductor pattern, an inductor is connected between the first conductor pattern and a third conductor pattern, a first capacitor is connected between the third conductor pattern and a fourth conductor pattern, and a second switching diode is implemented by a bare chip. The bare chip is mounted on the fourth conductor pattern, a cathode thereof being connected to the fourth conductor pattern and an anode thereof being connected to the third conductor pattern via a bonding wire.

Abstract: The frequency-characteristic switchable buffer circuit includes an amplifying stage, a parallel resonance circuit which serves as an output load of the amplifying stage, a frequency trap circuit electrically connected between the input of the amplifying stage and a reference potential point, and a frequency switching voltage generator for selectively generating a first switching voltage or a second switching voltage. The parallel resonance circuit parallel-resonates at a first frequency when the first switching voltage is supplied thereto. When the second switching voltage is supplied thereto, the parallel resonance circuit parallel-resonates at a second frequency. The frequency trap circuit comprises a series circuit made up of a diode and a capacitor. When the first switching voltage is supplied to the frequency trap circuit, the frequency trap circuit series-resonates at a frequency lower than the first frequency.

Abstract: There will be provided a plane patch antenna through which a desired resonance frequency can be obtained with stability without requiring any troublesome frequency adjusting operation. On one surface of a dielectric substrate to be obtained by calcining ceramic powder press-molded in a desired shape, a concave groove is continuously formed along the inside of its outer edge, and on an entire surface within a region partitioned by this concave groove, a patch electrode is thick-film printed.

Abstract: A selectable oscillation circuit includes a first oscillation circuit, a second oscillation circuit, and a selector circuit. The selector circuit selectively switches on and off the first oscillation circuit and the second oscillation circuit, in accordance with the provision of a selector signal, to selectively switch between two communicating modes, with low-power consumption.

Abstract: A connecting structure for connecting two oscillator circuits to an amplifier. The oscillator circuits are provided on one surface of a printed circuit board and include two dielectric resonators. The amplifier circuit is provided on the other surface of the printed circuit board for selectively amplifying oscillatory outputs from the oscillator circuits. The dielectric resonators are fixed to a metal plate mounted on the printed circuit board, and the amplifier circuit is located at a position opposite to the metal plate.

Abstract: A voltage-controlled-oscillator with a modulator, comprising a first variable capacitance diode and a second variable capacitance diode. The first variable capacitance diode is connected in series with the second variable capacitance diode to form a resonance device, wherein capacitance of the first variable capacitance diode is controlled by applying a reverse bias voltage and an oscillation frequency control voltage to both ends of the first variable capacitance diode, and capacitance of the second variable capacitance diode is controlled in a reverse direction to changes in the capacitance of the first variable capacitance diode with respect to the oscillation frequency control voltage by applying the oscillation frequency control voltage and a modulation signal to both ends of the second variable capacitance diode to thereby provide a frequency modulated wave.