Abstract: There is provided a voltage controlled oscillator that is compact and can be manufactured at low cost. The voltage controlled oscillator is structured to include: a resonance part including a variable capacitance element and an inductance element, the variable capacitance element having a capacitance that varies according to a control voltage for frequency control input from an external part, and a series resonant frequency of the resonance part being adjusted according to the capacitance; an amplifying part amplifying a frequency signal from the resonance part; and a feedback part including a capacitance element for feedback and feeding the frequency signal amplified by the amplifying part back to the resonance part to form an oscillation loop together with the amplifying part and the resonance part, wherein the amplifying part is provided in an integrated circuit chip, and the resonance part and the capacitance element for feedback are formed as circuit components separate from the integrated circuit chip.

Abstract: To provide a voltage controlled oscillator capable of being treated as a lumped constant circuit, having small size and capable of obtaining an oscillation frequency in a high frequency band. A resonance part in a voltage controlled oscillator has variable capacitance elements whose electrostatic capacitance varies in accordance with a control voltage for frequency control input from the outside and an inductance element, an amplifying part amplifies a frequency signal from the resonance part, and a feedback part, having feedback capacitance elements, forms an oscillation loop together with the amplifying part and the resonance part by making the frequency signal amplified in the amplifying part to be fed back to the resonance part. Further, the resonance part and the feedback part are provided on a quartz-crystal substrate.

Abstract: There is provided a voltage controlled oscillator using a Colpitts circuit capable of suppressing deterioration (decrease) in variable range (adjustable range) of an output frequency due to the influence of an inductance component on a conductive line, which connects a connection point between two capacitors of a feedback part and an emitter of a transistor. In a VCO using a Colpitts circuit, with respect to capacitors 22, 23 of a feedback part 2, a first feedback capacitance element (capacitor) 22 is disposed so as to directly couple a terminal for base (connection part 7) and a terminal for emitter on a base substrate 5, to which a terminal part 8 (T1) extending from a base of a transistor 21 and a terminal part 8 (T2) extending from an emitter of the transistor 21 are fitted, respectively, and a second feedback capacitance element (capacitor) 23 is disposed so as to directly couple the terminal for emitter and the terminal for grounding (ground electrode 51).

Abstract: There is provided a voltage controlled oscillator that is compact and can be manufactured at low cost. The voltage controlled oscillator is structured to include: a resonance part including a variable capacitance element and an inductance element, the variable capacitance element having a capacitance that varies according to a control voltage for frequency control input from an external part, and a series resonant frequency of the resonance part being adjusted according to the capacitance; an amplifying part amplifying a frequency signal from the resonance part; and a feedback part including a capacitance element for feedback and feeding the frequency signal amplified by the amplifying part back to the resonance part to form an oscillation loop together with the amplifying part and the resonance part, wherein the amplifying part is provided in an integrated circuit chip, and the resonance part and the capacitance element for feedback are formed as circuit components separate from the integrated circuit chip.

Abstract: There is provided a voltage controlled oscillator using a Colpitts circuit capable of suppressing deterioration (decrease) in variable range (adjustable range) of an output frequency due to the influence of an inductance component on a conductive line, which connects a connection point between two capacitors of a feedback part and an emitter of a transistor. In a VCO using a Colpitts circuit, with respect to capacitors 22, 23 of a feedback part 2, a first feedback capacitance element (capacitor) 22 is disposed so as to directly couple a terminal for base (connection part 7) and a terminal for emitter on a base substrate 5, to which a terminal part 8 (T1) extending from a base of a transistor 21 and a terminal part 8 (T2) extending from an emitter of the transistor 21 are fitted, respectively, and a second feedback capacitance element (capacitor) 23 is disposed so as to directly couple the terminal for emitter and the terminal for grounding (ground electrode 51).

Abstract: To provide a voltage controlled oscillator capable of being treated as a lumped constant circuit, having small size and capable of obtaining an oscillation frequency in a high frequency band. A resonance part 1 in a voltage controlled oscillator has variable capacitance elements 13, 14 whose electrostatic capacitance varies in accordance with a control voltage for frequency control input from the outside and an inductance element 11, an amplifying part 21 amplifies a frequency signal from the resonance part 1, and a feedback part 2, having feedback capacitance elements 22, 23, forms an oscillation loop together with the amplifying part 21 and the resonance part 1 by making the frequency signal amplified in the amplifying part 21 to be fed back to the resonance part 1. Further, the resonance part 1 and the feedback part 2 are provided on a quartz-crystal substrate 5.

Abstract: A harmonic oscillator comprises a transmission line resonator in which an oscillation frequency depends on an electrical length of a transmission line and both ends of the transmission line are electrical open ends; an active element for oscillation as a negative resistance connecting to the transmission line resonator; an output line connected to a midpoint portion of the transmission line resonator; and electrical and/or physical suppressing means for suppressing a voltage displacement distribution of second harmonic among the even-order harmonics. The suppressing means is provided at a position which is at least a minimum voltage displacement portion for the second harmonic between the midpoint portion and either ends of the transmission line resonator.

Abstract: A high-frequency filter includes a substrate; a ground conductor disposed on one main surface of the substrate and having an opening; a center conductor making up a coplanar line resonator together with the substrate and the ground conductor; and an input line and an output line each of which has a microstrip line structure and is disposed on the other main surface of the substrate to electromagnetically couple with the center conductor. At least one of the input line and the output line has a closed loop line portion surrounding a corresponding end of the center conductor and crossing the center conductor transversely through the substrate. On the other main surface of the substrate, a stub overlapping with the center conductor is arranged from a transverse position where the closed loop line portion crosses the center conductor.

Abstract: In a balun for mutually converting an unbalanced line for unbalanced input/output and a balanced line for balanced input/output, the unbalanced line and the balanced line are microstrip lines including a signal line arranged on one main surface of a substrate and a ground conductor arranged on the other main surface of the substrate. The balun further includes a slot line formed by a aperture line arranged in the ground conductor in the other main surface. The microstrip line as the unbalanced line includes one end portion used as an input/output end and the other end portion that traverses the slot line, electromagnetically couples to the slot line, and functions as an electric short-circuited end. The central portion of the microstrip line as the balanced line traverses the slot line and electromagnetically couples to the slot line. Both ends of this microstrip line serves as the input/output ends.

Abstract: A harmonic oscillator comprises a transmission line resonator in which an oscillation frequency depends on an electrical length of a transmission line and both ends of the transmission line are electrical open ends; an active element for oscillation as a negative resistance connecting to the transmission line resonator; an output line connected to a midpoint portion of the transmission line resonator; and electrical and/or physical suppressing means for suppressing a voltage displacement distribution of second harmonic among the even-order harmonics. The suppressing means is provided at a position which is at least a minimum voltage displacement portion for the second harmonic between the midpoint portion and either ends of the transmission line resonator.

Abstract: In a balun for mutually converting an unbalanced line for unbalanced input/output and a balanced line for balanced input/output, the unbalanced line and the balanced line are microstrip lines including a signal line arranged on one main surface of a substrate and a ground conductor arranged on the other main surface of the substrate. The balun further includes a slot line formed by a aperture line arranged in the ground conductor in the other main surface. The microstrip line as the unbalanced line includes one end portion used as an input/output end and the other end portion that traverses the slot line, electromagnetically couples to the slot line, and functions as an electric short-circuited end. The central portion of the microstrip line as the balanced line traverses the slot line and electromagnetically couples to the slot line. Both ends of this microstrip line serves as the input/output ends.

Abstract: A high-frequency filter includes a substrate; a ground conductor disposed on one main surface of the substrate and having an opening; a center conductor making up a coplanar line resonator together with the substrate and the ground conductor; and an input line and an output line each of which has a microstrip line structure and is disposed on the other main surface of the substrate to electromagnetically couple with the center conductor. At least one of the input line and the output line has a closed loop line portion surrounding a corresponding end of the center conductor and crossing the center conductor transversely through the substrate. On the other main surface of the substrate, a stub overlapping with the center conductor is arranged from a transverse position where the closed loop line portion crosses the center conductor.

Abstract: A high-frequency oscillator includes: a substrate composed of a dielectric material; a first transmission line of coplanar structure which is arranged on one principal surface of the substrate; an amplifier having an input terminal and an output terminal and which is inserted into the first transmission line such that the input terminal and output terminal connect to the first transmission line; and a second transmission line which is provided on the other principal surface of the substrate, which electromagnetically couples with the first transmission line, and which constitutes a feedback circuit with respect to the amplifier. The first transmission line is typically a coplanar line of finite length, and the second transmission line is typically a microstrip line.

Abstract: A high-frequency oscillator includes: a substrate composed of a dielectric material; a first transmission line of coplanar structure which is arranged on one principal surface of the substrate; an amplifier having an input terminal and an output terminal and which is inserted into the first transmission line such that the input terminal and output terminal connect to the first transmission line; and a second transmission line which is provided on the other principal surface of the substrate, which electromagnetically couples with the first transmission line, and which constitutes a feedback circuit with respect to the amplifier. The first transmission line is typically a coplanar line of finite length, and the second transmission line is typically a microstrip line.