Dielectric resonator having a frequency tuning element extending into the resonator hole

• US 5,550,519 A
• Filed: 01/18/1995
• Issued: 08/27/1996
• Est. Priority Date: 01/18/1994
• Status: Expired due to Fees

• Current Assignee: LK Products Oy (Yageo Corporation)
• Original Assignee: LK Products Oy (Yageo Corporation)
• Inventors: Korpela, Juha
• Primary Examiner(s): Lee, Benny
• Assistant Examiner(s): Bettendorf, Justin P.
• Application Number:
  US08/373,859
• Time in Patent Office: 587 Days
• Field of Search: 333/202, 333/206, 333/222, 333/207, 333/223, 333/224
• US Class Current: 333/207
• CPC Class Codes: H01P 1/2056 Comb filters or interdigital filters with metallised resonator holes in a dielectric block
• CPC Class Codes: H01P 7/04 Coaxial resonators

Abstract

The invention relates to a dielectric resonator comprising a block (2) of dielectric material, having upper (9), lower and side surfaces and in which there is a hole (3a) extending from the upper surface to the lower surface. The hole (3a) and the lower surface as well as at least part of the side surfaces are coated with an electrically conductive material and at least the upper surface (9) is uncoated so that the hole (3a) thus forms a transmission line resonator. The uncoated surfaces are covered with a lid (5) of an electrically conductive material, whereby the dielectric block is substantially surrounded by an electrically conductive material. The resonator hole (3a) is composed of two portions, a straight portion (3a) beginning from the lower surface of the dielectric block as well as a wider portion (10) that is formed above the straight portion and opens into the upper surface (9) of the dielectric block. Both portions are covered with an electrically conductive material and the coatings of both portions form a juncture. Formed above the resonator hole is a frequency tuning element (11), the first end of which is earthed, the other end being at a distance from the surface of the resonator hole, thus forming a capacitance between the earth plane and the upper end of the transmission line resonator.

Claims

1. A dielectric resonator comprising:

a dielectric block having opposed surfaces and a hole extending between the opposed surfaces, one of which surfaces is coated with an electrically conductive material and the other of which is uncoated, the hole having an electrically coated bore forming a transmission line resonator capable of generating an electric field therein, the bore having a wider section adjacent the uncoated surface than adjacent the coated surface, and

an electrically conductive frequency tuning element grounded at one end and having a structure such that an opposing end is bent into the wider section in the bore of the transmission line resonator so as to frequency tune the dielectric resonator by affecting the field present in the wider section and providing a capacitance between the transmission line resonator and ground.

2. A dielectric resonator according to claim 1, wherein the wider portion of the resonator hole widens smoothly towards the uncoated surface of the dielectric block.

3. A dielectric resonator according to claim 1, wherein the wider portion of the resonator hole widens in a stepped arrangement towards the uncoated surface of the dielectric block.

4. A dielectric resonator according to claim 1, wherein the wider portion of the resonator hole widens symmetrically towards the uncoated surface of the dielectric block along the axis of the resonator hole.

5. A dielectric resonator according to claim 1, wherein the wider portion of the resonator hole widens asymmetrically towards the uncoated surface of the dielectric block along the axis of the resonator hole.

6. A dielectric resonator according to claim 1, further including a lid covering the uncoated surface of the dielectric block wherein the frequency tuning element is formed in the lid as a bendable tab.

7. A dielectric resonator according to claim 1, further including a lid covering a side surface of the dielectric block wherein the frequency tuning element is formed in the lid as a bendable tab.

8. A dielectric resonator comprising:

a dielectric block which has an upper surface and a lower surface and side surfaces said block defining a hole extending from the upper surface to the lower surface, the hole and lower surface as well as at least a portion of the side surfaces being coated with an electrically conductive material, at least a portion of the upper surface adjacent the hole remaining uncoated, the hole forming a transmission line resonator adapted to generate an electric field therein;

a lid formed of an electrically conductive material over the upper surface of the dielectric block, whereby the dielectric block is substantially surrounded by an the electrically conductive material, the resonator hole includes a straight portion extending from the lower surface of the dielectric block and a wider portion that is formed above the straight portion and opens onto the upper surface of the dielectric block under the lid, both the straight and wide portions of the hole being coated with an electrically conductive material; and

a frequency tuning element having first and second ends formed above the hole with the first end being grounded and having a structure such that the second end is bent into at least the wide portion of the hole from the surface of the transmission line resonator so as to frequency tune the dielectric resonator by affecting the electric field present in the resonator hole and providing a capacitance between the ground and the transmission line resonator.

9. A dielectric filter comprising:

a first dielectric resonator; and

at least one other dielectric resonator including;

(i) a dielectric block having opposed surfaces and a hole extending between the opposed surfaces, one of said surfaces being coated with an electrically conductive material, the hole having an electrically coated bore forming a transmission line resonator capable of generating electric field therein, the bore having a wider section adjacent the uncoated surface than adjacent the coated surface; and

(ii) an electrically conductive frequency tuning element grounded at one end and having a structure such that an opposing end is bent into the wider section in the bore of the transmission line resonator so as to frequency tune the dielectric resonator by affecting the electric field therein and providing a capacitance between the transmission line resonator and ground.