Resonant unit, voltage controlled oscillator (vco) implementing the same, and push-push oscillator implementing a pair of vcos

Patent metadata

Field	Value
Publication number	US-2016248142-A1
Application number	US-201615048427-A
Country	US
Kind code	A1
Filing date	Feb 19, 2016
Priority date	Feb 20, 2015
Publication date	Aug 25, 2016
Grant date	—

Abstract

A resonant circuit to be connected to a negative resistance unit is disclosed. The resonant circuit includes a pair of resonant transmission lines electrically coupled to each other and a coupling transmission line connecting the resonant transmission lines. The resonant transmission lines and the coupling transmission line are formed on a semiconductor substrate. The resonant transmission lines have a length corresponding to a quarter wavelength (λ/4) of twice of the resonant frequency attributed to the resonant circuit.

First claim

What is claimed is:

1 . A resonant circuit having a resonant frequency, comprising:
a semiconductor substrate; and a pair of resonant transmission lines electrically coupled to each other, one of the resonant transmission lines including an input port and a through port, an other of the resonant transmission lines including an isolation port and a coupling port, and a coupling transmission line connecting the input port of the one of the resonant transmission lines to the coupling port of the other of the resonant transmission lines, wherein the resonant transmission lines and the coupling transmission line are provided on the semiconductor substrate.

2 . The resonant circuit of claim 1 ,
wherein the resonant transmission lines each have a length corresponding to a quarter wavelength (λ/4) of twice of the resonant frequency, and wherein the coupling transmission line has a length shorter than the length of the resonant transmission lines.

3 . The resonant circuit of claim 1 ,
wherein the substrate is made of gallium arsenide (GaAs).

4 . The resonant circuit of claim 3 ,
wherein the substrate includes a dielectric film on a primary surface thereof, wherein the resonant transmission lines and the coupling transmission line are provided on the primary surface of the semiconductor substrate, the dielectric film covering the resonant transmission lines and the coupling transmission line, and wherein the dielectric film is covered with a ground metal.

5 . The resonant circuit of claim 1 ,
wherein the resonant transmission lines each have a width of 58 to 62 μm , with a gap of 5.8 to 6.2 μm, and the coupling transmission line has a width substantially same with the width of the resonant transmission lines.

6 . The resonant circuit of claim 1 ,
further including a variable capacitor connected between the through port of one of the resonant transmission lines and a ground, wherein the variable capacitor varies capacitance thereof by being supplied with a bias.

7 . A voltage controlled oscillator (VCO) that generates an oscillating signal at an oscillating frequency, comprising:
a resonant circuit including a semiconductor substrate, a pair of resonant transmission lines electrically coupled to each other, a coupling transmission line, wherein one of the resonant transmission lines includes an input port and a through port, an other of the resonant transmission lines includes an isolation port and a coupling port, the coupling transmission line being connected between the input port of the one of the resonant transmission lines and the coupling port of the other of the resonant transmission lines, the resonant transmission lines and the coupling transmission line being formed on the semiconductor substrate, and a variable capacitor connected to the through port of the one of the resonant transmission lines, the variable capacitor varying capacitance thereof depending on a bias supplied thereto; and a negative resistance unit including a transistor connected to the input port of the one of the resonant transmission lines, wherein the resonant circuit has impedance viewed from the negative resistance unit and the negative resistance unit has impedance viewed from the resonant circuit, the impedance of the resonant circuit in an imaginary part thereof added with the impedance of the negative resistance unit in an imaginary part thereof being substantially zero at the oscillating frequency, the impedance of the resonant circuit in a real part thereof added with the impedance of the negative resistance unit in a real part thereof being negative at the oscillating frequency.

8 . The voltage controlled oscillator of claim 7 ,
wherein the resonant transmission lines each have a length corresponding to a quarter wavelength (λ/4) of twice of the oscillating frequency, and wherein the coupling transmission line has a length shorter than the length of the resonant transmission lines.

9 . The voltage controlled oscillator of claim 7 ,
wherein the substrate is made of gallium arsenide (GaAs).

10 . The voltage controlled oscillator of claim 9 ,
wherein the substrate includes a dielectric film on a primary surface thereof, wherein the resonant transmission lines and the coupling transmission line are provided on a primary surface of the semiconductor substrate, the dielectric film covering the primary surface of the semiconductor substrate, the resonant transmission lines and the coupling transmission line, and wherein the dielectric film is covered with a ground metal.

11 . The voltage controlled oscillator of claim 7 ,
wherein the resonant transmission lines each have a width of 58 to 62 μm , with a gap of 5.8 to 6.2 μm, and the coupling transmission line has a width substantially same with the width of the resonant transmission lines.

12 . The voltage controlled oscillator of claim 7 ,
wherein the transistor is a type of a heterojunction bipolar transistor (HBT) containing InGaP.

13 . A push-push oscillator, comprising:
a pair of voltage controlled oscillators (VCOs) each having a resonant circuit and a negative resistance unit, wherein the resonant circuits each include a pair of resonant transmission lines electrically coupled to each other, a coupling transmission line connecting the resonant transmission lines, and a variable capacitor, one of the resonant transmission lines including an input port and a through port, an other of the resonant transmission lines including an isolation port and a coupling port, the resonant transmission lines and the coupling transmission line being provided on the semiconductor substrate, the variable capacitor being connected to the one of the resonant transmission lines, the variable capacitor varying capacitance thereof depending on a bias supplied thereto, wherein the resonant circuits have impedance viewed from the negative resistance units connected thereto and the negative resistance units have impedance viewed from the resonant circuits connected thereto, the impedance of the resonant circuits in an imaginary part thereof added with the impedance of the negative resistance units connected thereto in an imaginary part thereof being substantially zero at a fundamental oscillating frequency, the impedance of the resonant circuits in a real part thereof added with the impedance of the negative resistance units connected thereto in a real part thereof being negative at the fundamental oscillating frequency, wherein the negative resistance unit includes a transistor connected to the one of the resonant transmission lines and an output port thereof, wherein the output port of the negative resistance unit of the one of the VCOs is connected to the output port of the negative resistance unit of the other of the VCOs, and wherein the push-push oscillator generates oscillation signals of even modes of overtones of the fundamental oscillating frequency and substantially eliminates oscillation signals of odd modes of the overtones of the fundamental oscillating frequency.

14 . A push-push oscillator, comprising:
a pair of voltage controlled oscillators (VCOs) each having a resonant circuit and a negative resistance unit, wherein the resonant circuits each includes a semiconductor substrate, a pair of resonant transmission lines electrically coupled to each other, a coupling transmission line electrically connecting the resonant transmission lines, and a variable capacitor connected to the one of the resonant transmission lines, the resonant transmission lines and the coupling transmission line being provided on the semiconductor substrate, wherein the negat

Assignees

• Sumitomo Electric Industries

Inventors

• Kawasaki Takeshi
• Tokumitsu Tsuneo

Classifications

• H03B5/1847

  the active element in the amplifier being a semiconductor device · CPC title

• H03L7/08

  Details of the phase-locked loop · CPC title

• H03J3/20 Primary

  of single resonant circuit by varying inductance only or capacitance only · CPC title

• H03L3/00

  Starting of generators · CPC title

• H01P5/185

  Edge coupled lines · CPC title