Resonator, filter, duplexer, and communication device

• US 6,486,754 B1
• Filed: 12/22/1999
• Issued: 11/26/2002
• Est. Priority Date: 12/22/1998
• Status: Expired due to Fees

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Hidaka, Seiji, Ishikawa, Yohei, Abe, Shin, Ota, Michiaki
• Primary Examiner(s): Pascal, Robert
• Assistant Examiner(s): Nguyen, Patricia T.
• Application Number:
  US09/470,182
• Time in Patent Office: 1,070 Days
• Field of Search: 333/219, 333/161, 333/202, 333/134, 333/204, 333/156, 333/236, 333/238, 333/245, 333/246
• US Class Current: 333/219
• CPC Class Codes: H01P 1/20381 Special shape resonators
• CPC Class Codes: H01P 1/2135 using strip line filters H01P1/2131 takes precedence
• CPC Class Codes: H01P 7/082 Microstripline resonators H01P7/088 takes precedence

Abstract

A resonator can provide good loss characteristics by effectively suppressing power losses due to an edge effect. In addition, a filter, a duplexer, and a communication device incorporating the resonator are formed. In the resonator, a plurality of spiral lines are disposed on a surface of a dielectric substrate in such a manner that the inner and outer ends of the lines are aligned respectively along an inner periphery and an outer periphery which are centered around a central point on the substrate so that the lines do not cross each other. With this arrangement, the edge effect in the spiral lines is substantially canceled, by which power losses due to the edge effect can be effectively suppressed.

Claims

1. A resonator comprising:

a substrate; and

a set of lines comprising a plurality of spiral lines;

wherein inner and outer ends of the spiral lines are distributed substantially along an inner periphery and an outer periphery of the set of lines respectively, the inner and outer peripheries being centered around a specified point on the substrate,

wherein the lines do not cross each other and

wherein the width of at least one of the lines is substantially equal to or narrower than the skin depth of a conductor material of the line at a resonant frequency of the resonator.

4. A resonator according to one of claims 1, 2, or 3, wherein an electrode is disposed on the substrate at the center of the set of lines, and the lines are connected to the electrodes.

5. A resonator according to one of claims 1, 2 or 3, wherein equipotential portions of the plurality of lines are mutually connected by a conductor member.

6. A resonator according to one of claims 1, 2 or 3, wherein at least one end portion of each of the plurality of lines is grounded to a ground electrode.

7. A resonator according to one of claims 1, 2 or 3, wherein each of the plurality of lines comprises a respective folded line.

8. A resonator according to one of claims 1, 2 or 3, wherein the widths of the plurality of lines and a distance between adjacent lines are substantially equal from one end portion of the lines to the other end portion thereof.

9. A resonator according to one of claims 1, 2 or 3, wherein the width of each of the plurality of lines is substantially equal to or narrower than the skin depth of a conductor material of the line at a resonant frequency of the resonator.

10. A resonator according to one of claims 1, 2 or 3, wherein each of the plurality of lines is a thin film multi-layer electrode comprising a lamination of a thin-film dielectric layer and a thin-film conductor layer.

11. A resonator according to one of claims 1, 2 or 3, wherein a dielectric material is filled in a space between adjacent lines of the plurality of lines.

12. A resonator according to one of claims 1, 2 or 3, wherein at least one of the plurality of lines is formed of a superconducting material.

13. A resonator according to one of claims 1, 2 or 3, further comprising a conductive cavity which shields said substrate and said set of lines.

14. A resonator according to one of claims 1, 2 or 3, wherein said plurality of lines comprises at least 24 lines.

15. A filter comprising the resonator in accordance with one of claims 1, 2 or 3, further comprising signal input and output conductors disposed adjacent to the resonator.

16. A duplexer comprising the filter in accordance with claim 13, the duplexer having a transmitting terminal, a receiving terminal, and an antenna terminal, said signal input and output conductors being connected respectively to a pair of said terminals, and further comprising a second filter having input and output conductors connected respectively to a second pair of said terminals.

17. A communication device comprising:

a transmitting circuit;

a receiving circuit; and

the duplexer in accordance with claim 16;

said transmitting circuit being connected to said transmitting terminal; and

said receiving circuit being connected to said receiving terminal.

18. A communication device comprising:

a transmitting circuit;

a receiving circuit; and

the filter in accordance with claim 15;

wherein at least one of said signal input and output said conductors is connected to at least one of said transmitting circuit and said receiving circuit.

2. A resonator comprising:

a substrate; and

a set of lines comprising a plurality of spiral lines;

wherein the spiral lines are disposed in rotation-symmetrical positions around a specified point on the substrate,

wherein the spiral lines do not cross each other, and

wherein the width of at least one of the lines is substantially equal to or narrower than the skin depth of a conductor material of the line at a resonant frequency of the resonator.

3. A resonator comprising:

a substrate; and

a set of lines comprising a plurality of lines formed thereon, each line being indicated by a monotonically increasing or decreasing line in a polar-coordinate expression with one axis representing angles and the other axis representing radius vectors;

wherein each line is arranged on the substrate in such a manner that a width of the line is within an angular width equal to or less than a value obtained by dividing 2π

radians by the number of the lines, and the width of the overall set of the lines is constantly within an angular width of 2π

radians or less at any arbitrary radius vector.