INTERDIGITAL CAPACITOR, INDUCTOR, AND TRANSMISSION LINE AND COUPLER USING THEM

• US 20100039193A1
• Filed: 10/30/2007
• Published: 02/18/2010
• Est. Priority Date: 10/30/2006
• Status: Active Grant

• Current Assignee: Emw Co., Ltd.
• Original Assignee: Emw Co., Ltd.
• Inventors: Kim, Gi Ho, Sung, Won Mo, Ryou, Byung Hoon
• Granted Patent: US 8,717,125 B2
• Time in Patent Office: Days
• US Class Current: 333/219
• CPC Class Codes: H01P 3/081 Microstriplines
• CPC Class Codes: H01P 5/08 for linking dissimilar lines or devices H01P1/16, H01P5/04 take precedence; linking lines of the same kind but with different dimensions H01P5/02

Abstract

There is herein disclosed an interdigital capacitor, an inductor, and an LH transmission line and a coupler using the interdigital capacitor and the inductor. The interdigital capacitor comprises two finger sets which are substantially disposed in parallel with each other. Fingers of each finger set are overlapped at outer edges thereof with each other to thereby generate capacitance. The inductor is formed substantially spirally inside the transmission line, so that it can have a large inductance in a compact shape and can be used in a broad frequency band. The LH transmission line has a broad frequency band in a compact shape, which includes interdigital capacitors connected in series with each other and inductors connected in parallel with each other. In addition, the coupler employing the LH transmission line has an excellent couplability.

Claims

1. A capacitor comprising:

a first set of fingers including at least two fingers disposed spaced apart from each other and connected at one ends thereof to each other; and

a second set of fingers including at least two fingers disposed spaced apart from each other and connected at one ends thereof to each other, the second finger set being spaced apart from the first finger set by a predetermined interval in such a fashion as to be substantially in parallel with the first finger set.

2. The capacitor according to claim 1, wherein the capacitor further comprises a dielectric substrate disposed between the first finger set and the second finger set.

3. The capacitor according to claim 1, wherein the width of each finger of the first finger set is larger than that of each finger of the second finger set so that fingers of the first finger set are at least partially overlapped with fingers of the second finger.

4. An inductor which is connected at one end thereof to a transmission line and is connected at the other end thereof to a ground plane, the inductor being formed inside the transmission line in such a fashion as to have a substantially spiral shape.

5. The inductor according to claim 4, wherein the inductor is formed on a dielectric substrate, and is connected at the other end thereof to the ground plane through a via hole.

6. A transmission line having an LH characteristic, comprising:

a capacitor which comprises;

a first set of fingers including at least two fingers disposed spaced apart from each other and connected at one ends thereof to each other; and

a second set of fingers including at least two fingers disposed spaced apart from each other and connected at one ends thereof to each other, the second finger set being spaced apart from the first finger set by a predetermined interval in such a fashion as to be substantially in parallel with the first finger set; and

an inductor which is connected at one end thereof to the second finger set and is connected at the other end thereof to a ground plane.

7. The transmission line according to claim 6, wherein the capacitor further comprises a dielectric substrate disposed between the first finger set and the second finger set.

8. The transmission line according to claim 6, wherein the width of each finger of the first finger set is larger than that of each finger of the second finger set so that fingers of the first finger set are at least partially overlapped with fingers of the second finger.

9. The transmission line according to claim 6, wherein the inductor is connected to the second finger set through the transmission line, and wherein the inductor is connected at one end thereof to the transmission line and is connected at the other end thereof to a ground plane, the inductor being formed inside the transmission line in such a fashion as to have a substantially spiral shape.

10. The transmission line according to claim 9, wherein the inductor is formed on a dielectric substrate, and is connected at the other end thereof to the ground plane through a via hole.

11. A coupler comprising the transmission line having the LH characteristic according to claim 6.