Coaxial dielectric resonator having a groove therein and method of producing such coaxial dielectric resonator

• US 5,109,207 A
• Filed: 12/04/1990
• Issued: 04/28/1992
• Est. Priority Date: 12/19/1989
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kita, Masaki, Aizawa, Kimio
• Primary Examiner(s): Laroche, Eugene R.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/621,812
• Time in Patent Office: 511 Days
• Field of Search: 333/202, 333/206, 333/207, 333/219, 333/219.1, 333/222, 333/223, 29/600, 204/38.4, 427/126.2
• US Class Current: 333/222
• CPC Class Codes: H01P 1/2056 Comb filters or interdigital filters with metallised resonator holes in a dielectric block
• CPC Class Codes: H01P 11/007 Manufacturing frequency-selective devices resonators H01P11/008
• CPC Class Codes: H01P 7/04 Coaxial resonators

Abstract

A dielectric resonator includes a resonator body having a groove formed in its upper surface adjacent to an outer periphery of a through hole formed through the body. An electrically-conductive film on the inner surface of the groove is electrically connected to an electrically-conductive film formed on the inner peripheral surface of the through hole, via an electrically-conductive film formed on a portion of the upper surface of the body lying between the groove and the through hole. The groove having the electrically-conductive film formed on its inner surface enables the length of the body to be reduced and the overall resonator to have a reduced size.

Claims

1. A dielectric resonator comprising:

a dielectric body having a through hole extending therethrough from an upper and a lower surface of said body, said body having a groove formed in said upper surface of said body adjacent to an outer periphery of said through hole;

a first electrically-conductive film formed on an outer peripheral surface of said body, said lower surface of said body and an inner peripheral surface of said through hole;

a second electrically-conductive film formed on an inner surface of said groove; and

a third electrically-conductive film formed on a portion of said upper surface of said body lying between said through hole and said groove, said first electrically-conductive film being electrically connected to said second electrically-conductive film by said third electrically-conductive film.

2. A dielectric resonator according to claim 1, in which a bottom surface of said groove is concavely curved.

3. A dielectric resonator according to claim 1, in which an inner side surface of said groove disposed close to said through hole is inclined upwardly toward said through hole.

4. A dielectric resonator according to claim 2, in which an inner side surface of said groove disposed close to said through hole is inclined upwardly toward said through hole.

5. A dielectric resonator according to claim 1, in which part of a lead terminal is inserted in said groove.

6. A dielectric resonator according to claim 1, in which a depth of said groove is 20% to 30% of a height of said body.

7. A filter device comprising said dielectric resonator as claimed in claim 1, and an input terminal and an output terminal each connected to said dielectric resonator via a coupling capacitor.

8. A dielectric resonator comprising:

a dielectric body having a through hole extending therethrough form an upper and a lower surface of said body, said body having an annular groove formed in said upper surface of said body in surrounding relation to said through hole;

a first electrically-conductive film formed on an outer peripheral surface of said body, said lower surface of said body and an inner peripheral surface of said through hole;

a second electrically-conductive film formed on an inner surface of said groove; and

a third electrically-conductive film formed on a portion of said upper surface of said body lying between said through hole and said groove, said first electrically-conductive film being electrically connected to said second electrically-conductive film by said third electrically-conductive film.

9. A dielectric resonator according to claim 8, in which a bottom surface of said groove is concavely curved.

10. A dielectric resonator according to claim 8, in which an inner side surface of said groove disposed close to said through hole is inclined upwardly toward said through hole.

11. A dielectric resonator according to claim 9, in which an inner side surface of said groove disposed close to said through hole is inclined upwardly toward said through hole.

12. A dielectric resonator according to claim 8, in which part of a leader terminal is inserted in said groove.

13. A dielectric resonator according to claim 8, in which a depth of said groove is 20% to 30% of a height of said body.

14. A filter device comprising said dielectric resonator as claimed in claim 8, and an input terminal and an output terminal each connected to said dielectric resonator via a coupling capacitor.

15. A dielectric filter comprising:

a dielectric body having a plurality of through holes extending therethrough from an upper and a lower surface of said body, said body having a plurality of grooves which are formed in said upper surface of said body and are disposed adjacent respectively to outer peripheries of said plurality of through holes;

a first electrically-conductive film formed on an outer peripheral surface of said body, said lower surface of said body and inner peripheral surfaces of said plurality of through holes;

second electrically-conductive films formed respectively on inner surfaces of said plurality of grooves; and

third electrically-conductive films formed respectively on those portions of said upper surface of said body each lying between a respective one of said through holes and a corresponding one of said grooves disposed adjacent thereto, said first electrically-conductive film being electrically connected to each of said second electrically-conductive films by a respective one of said third electrically-conductive films.

16. A dielectric resonator according to claim 15, in which a bottom surface of each of said grooves is concavely curved.

17. A dielectric resonator according to claim 15, in which an inner side surface of each of said grooves disposed close to a corresponding one of said through holes is inclined upwardly toward said through hole.

18. A dielectric resonator according to claim 16, in which an inner side surface of each of said grooves disposed close to a corresponding one of said through holes is inclined upwardly toward said through hole.

19. A dielectric resonator according to claim 15, in which part of a lead terminal is inserted in each of said grooves.

20. A method of producing a dielectric resonator, comprising the steps of:

preparing a dielectric body of a columnar shape having a through hole extending therethrough from an upper and a lower surface of said body, said body having a groove formed in said upper surface of said body adjacent to an outer periphery of said through hole, and a portion of said upper surface of said body lying between said through hole and said groove being lower in height than a portion of said upper surface of said body disposed outwardly of said groove;

subsequently forming an electrically-conductive film on an entire surface of said body; and

subsequently removing said portion of said upper surface of said body disposed outwardly of said groove.