Abstract: A wave detector circuit includes: a first transistor having its base and collector connected together, the first transistor receiving an AC signal and a reference voltage at its base and collector; a second transistor having its base connected to the base of the first transistor through a resistor, the second transistor outputting a detected voltage at its collector; and a diode-connected temperature compensation transistor connected between ground potential and the base and the collector of the first transistor.

Abstract: A power amplifier according to the present invention is operated by switching a main power amplifier and a subsidiary power amplifier. The idle current of the subsidiary power amplifier is smaller than the idle current of the main power amplifier. Each of the main power amplifier and the subsidiary power amplifier has a former amplification element for amplifying RF signals, a latter amplification element for amplifying output signals from the former amplification element, a former bias circuit for driving the former amplification elements, and a latter bias circuit for driving the latter amplification elements, respectively. The interval between the latter amplification element of the main power amplifier and the latter amplification element of the subsidiary power amplifier is not more than 100 ?m. The interval between the latter amplification element of the main power amplifier and the latter bias circuit of the subsidiary power amplifier is not less than 200 ?m.

Abstract: A voltage-controlled oscillator has an oscillation frequency controlled through a voltage applied across ends of a variable-capacitance element. The voltage-controlled oscillator has a frequency control bias circuit which applies to a first end of the variable-capacitance element a voltage for frequency control according to a control voltage, a first current source which generates a first current according to the control voltage, a second current source which generates a second current according to temperature, independent of the control voltage, a converting resistor which converts a current, obtained by adding together the first and second currents, into a voltage, and a temperature compensation bias circuit which applies to the second end of the variable-capacitance element a voltage for temperature compensation according to the voltage produced by the converting resistor.

Abstract: An amplifier element amplifies RF signals. An emitter follower unit drives the amplifier element at a constant voltage corresponding to a reference voltage supplied to a reference terminal from outside. A current injection unit drives the amplifier element at a constant current corresponding to the reference voltage. An analog control unit analogically controls the output voltage of the emitter follower unit in correspondence with the control voltage supplied to a control terminal from outside. A mode switching unit switches whether the emitter follower unit is operated or not in correspondence with the control voltage.

Abstract: An amplifier element amplifies RF signals. An emitter follower unit drives the amplifier element at a constant voltage corresponding to a reference voltage supplied to a reference terminal from outside. A current injection unit drives the amplifier element a constant current corresponding to the reference voltage. An analog control unit analogically controls the output voltage of the emitter follower unit in correspondence with the control voltage supplied to a control terminal from outside. A mode switching unit switches whether the emitter follower unit is operated or not in correspondence with the control voltage.

Abstract: A power amplifier according to the present invention is operated by switching a main power amplifier and a subsidiary power amplifier. The idle current of the subsidiary power amplifier is smaller than the idle current of the main power amplifier. Each of the main power amplifier and the subsidiary power amplifier has a former amplification element for amplifying RF signals, a latter amplification element for amplifying output signals from the former amplification element, a former bias circuit for driving the former amplification elements, and a latter bias circuit for driving the latter amplification elements, respectively. The interval between the latter amplification element of the main power amplifier and the latter amplification element of the subsidiary power amplifier is not more than 100 ?m. The interval between the latter amplification element of the main power amplifier and the latter bias circuit of the subsidiary power amplifier is not less than 200 ?m.

Abstract: A voltage-controlled oscillator has an oscillation frequency controlled through a voltage applied across ends of a variable-capacitance element. The voltage-controlled oscillator has a frequency control bias circuit which applies to a first end of the variable-capacitance element a voltage for frequency control according to a control voltage, a first current source which generates a first current according to the control voltage, a second current source which generates a second current according to temperature, independent of the control voltage, a converting resistor which converts a current, obtained by adding together the first and second currents, into a voltage, and a temperature compensation bias circuit which applies to the second end of the variable-capacitance element a voltage for temperature compensation according to the voltage produced by the converting resistor.

Abstract: A wave detector circuit includes: a first transistor having its base and collector connected together, the first transistor receiving an AC signal and a reference voltage at its base and collector; a second transistor having its base connected to the base of the first transistor through a resistance, the second transistor outputting a detected voltage at its collector; and a diode-connected temperature compensation transistor connected between ground potential and the base and the collector of the first transistor.

Abstract: A voltage-controlled oscillator including a voltage-controlled oscillation section, a frequency control bias circuit, a temperature compensation bias circuit, and a temperature compensation bias generation circuit. The temperature compensation bias generation circuit has a transistor having its collector or drain connected to the temperature compensation bias circuit, a first resistor having one end connected to the collector or drain of the transistor and having another end that is grounded, a second resistor having one end connected to the base or gate of the transistor, a base or gate bias application terminal connected to another end of the second resistor, a third resistor having one end connected to the emitter or source of the transistor, and an emitter or source bias application terminal connected to another end of the third resistor.

Abstract: Provided is a high-frequency oscillator whose output power increases without a change in physical size of the entire high-frequency oscillator and deterioration of a phase noise characteristic. The high-frequency oscillator for harmonic extraction includes: an active element (5); a fundamental reflection stub (9) provided on a signal line located on an output side of the active element (5); an output terminal (4); and a harmonic impedance converting circuit (3) interposed between the fundamental reflection stub (9) and the output terminal (4), for converting a harmonic output terminal side load impedance into an optimum value for maximizing harmonic output power, the optimum value being obtained in advance.

Abstract: A cascode circuit in which two field effect transistors (“FET”) are connected in cascode has a first FET having its source grounded, a second FET having its source connected to the drain of the first FET, and a Schottky barrier diode having an anode connected to the source of the first FET and a cathode connected to the gate of the second FET.

Abstract: A semiconductor device having an improved voltage control oscillator circuit is provided. The voltage control oscillator circuit includes, in combination, a variable-capacitance element and at least one bipolar transistor on a single semiconductor substrate. The variable-capacitance element includes reversely serially connected PN junctions, and junctions are formed by a single common collector layer and separated base layers on the common collector layer. The capacitance of the variable-capacitance element is generated between respective base layers of the PN junctions with the common collector layer, and varies in correspondence with the voltage applied to the common collector layer.

Abstract: A voltage-controlled oscillator including a voltage-controlled oscillation section, a frequency control bias circuit, a temperature compensation bias circuit, and a temperature compensation bias generation circuit. The temperature compensation bias generation circuit has a transistor having its collector or drain connected to the temperature compensation bias circuit, a first resistor having one end connected to the collector or drain of the transistor and having another end that is grounded, a second resistor having one end connected to the base or gate of the transistor, a base or gate bias application terminal connected to another end of the second resistor, a third resistor having one end connected to the emitter or source of the transistor, and an emitter or source bias application terminal connected to another end of the third resistor.

Abstract: A cascode circuit in which two field effect transistors “FET”) are connected in cascode has a first FET having its source grounded, a second FET having its source connected to the drain of the first FET, and a Schottky barrier diode having an anode connected to the source of the first FET and a cathode connected to the gate of the second FET.

Abstract: In an oscillator, a FET, an output matching circuit having a diode, an LC series resonant circuit having a capacitor and an inductor, a transmission line, and a source inductor are arranged on one surface of a substrate consisting of a semiconductor material. The source of the FET is grounded through a source inductor. The drain of the FET is connected to the anode of the diode of the output matching circuit through a transmission line. The FET amplifies a high-frequency signal input to the gate, and outputs the high-frequency signal from the drain to an output matching circuit. The diode regulates an oscillation power.

Abstract: A semiconductor device having an improved voltage control oscillator circuit is provided. The voltage control oscillator circuit includes, in combination, a variable-capacitance element and at least one bipolar transistor on a single semiconductor substrate. The variable-capacitance element includes reversely serially connected PN junctions, and junctions are formed by a single common collector layer and separated base layers on the common collector layer. The capacitance of the variable-capacitance element is generated between respective base layers of the PN junctions with the common collector layer, and varies in correspondence with the voltage applied to the common collector layer.

Abstract: A voltage controlled oscillating circuit operable to output a variable frequency, includes a variable capacitance element with the variable frequency varying with a variation in capacitance of the variable capacitance element. The variable capacitance element is provided by a bipolar transistor. The capacitance of the variable capacitance element is achieved by combining the capacitance by the PN junction between the emitter layer and the base layer and capacitance formed by the PN junction between the base layer and the collector layer in a bipolar transistor, and is controlled by a voltage applied between the emitter layer and the collector layer of the bipolar transistor.

Abstract: A voltage controlled oscillating circuit operable to output a variable frequency, includes a variable capacitance element with the variable frequency varying with a variation in capacitance of the variable capacitance element. The variable capacitance element is provided by a bipolar transistor. The capacitance of the variable capacitance element is achieved by combining capacitance formed by a PN junction between an emitter layer and a base layer and capacitance formed by a PN junction between the base layer and a collector layer in a bipolar transistor, and is controlled by a voltage applied between the emitter layer and the collector layer of the bipolar transistor.

Abstract: In an oscillator, on one major surface of a substrate consisting of a semiconductor material there are arranged a FET, an output matching circuit having a diode, an LC series resonant circuit having a capacitor and an inductor, a transmission line, and a source inductor. The source of the FET is grounded through a source inductor. The drain of the FET is connected to the anode of the diode constituting an output matching circuit through a transmission line. The FET amplifies a high-frequency signal input to the gate, and outputs the high-frequency signal from the drain to an output matching circuit. The diode regulates an oscillation power.

Abstract: A compact high-frequency circuit device including a signal distribution circuit and a signal combining circuit.