Coupling structure, resonator excitation structure and filter for coplanar-waveguide circuit

• US 20060193559A1
• Filed: 02/09/2006
• Published: 08/31/2006
• Est. Priority Date: 02/09/2005
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Koizumi, Daisuke, Narahashi, Shoichi, Satoh, Kei
• Granted Patent: US 7,397,331 B2
• Time in Patent Office: Days
• US Class Current: 385/39
• CPC Class Codes: H01P 1/2013 Coplanar line filters
• CPC Class Codes: H01P 1/213 combining or separating two or more different frequencies H01P1/215 takes precedence

Abstract

A coupling structure for coupling to a circuit portion (6) in a coplanar-waveguide circuit (1) having ground conductors (2, 3) at both sides is disclosed. A signal input/output line (4) is provided at the center of the coplanar-waveguide circuit; and an inductive coupling portion (5) having an end of the signal input/output line short-circuited to one of the ground conductors and facing a part of the circuit portion via a first gap is also provided.

Claims

1. A coupling structure for coupling to a circuit portion in a coplanar-waveguide circuit having ground conductors at both sides, comprising:

a signal input/output line provided at the center of the coplanar-waveguide circuit; and

an inductive coupling portion having an end of the signal input/output line short-circuited to one of the ground conductors and facing a part of the circuit portion via a first gap.

2. The coupling structure in the coplanar-waveguide circuit as claimed in claim 1, further comprising:

a second gap between a part of the ground conductor and the end of the signal input/output line at the opposite side from the circuit portion;

wherein the part of the ground conductor is removed to widen the second gap and adjust an external coupling strength.

3. The coupling structure in the coplanar-waveguide circuit as claimed in claim 1, wherein:

the inductive coupling portion is formed by folding the end of the signal input/output line to connect the end to the one of the ground conductors.

4. The coupling structure in the coplanar-waveguide circuit as claimed in claim 3, wherein:

a corner of the folded portion of the inductive coupling portion is chamfered or rounded.

5. The coupling structure in the coplanar-waveguide circuit as claimed in claim 3, wherein:

the folded portion includes a folded-back portion extending in the opposite direction from the short-circuited portion.

6. The coupling structure in the coplanar-waveguide circuit as claimed in claim 3, further comprising:

a surrounding-portion between the folded portion and the short-circuited portion of the inductive coupling portion, the surrounding portion partly surrounding a part of the circuit portion.

7. A coupling structure for coupling to a circuit portion in a coplanar-waveguide circuit having ground conductors at both sides, comprising:

a signal input/output line provided at the center of the coplanar-waveguide circuit; and

a capacitive coupling portion having a surrounding portion at an end of the signal input/output line, the surrounding portion partly surrounding and facing a part of the circuit portion via a first gap.

8. A resonator excitation structure for exciting a resonator in a coplanar-waveguide circuit having ground conductors at both sides, comprising:

an exciting line provided at the center of the coplanar-waveguide circuit; and

an excitation portion having an end of the exciting line short-circuited to one of the ground conductors and facing a part of the resonator via a first gap.

9. The resonator excitation structure as claimed in claim 8, wherein:

the resonator is one of a quarter-wavelength spiral resonator, a quarter-wavelength lumped-parameter type meander resonator and a half-wavelength resonator.

10. A filter having one or more resonators in a coplanar-waveguide circuit having ground conductors at both sides, comprising:

an exciting line provided at the center of the coplanar-waveguide circuit; and

an excitation portion having an end of the exciting line short-circuited to one of the ground conductors and facing a part of the first or last one of the resonators via a first gap.