Dielectric filter

• US 4,800,347 A
• Filed: 09/03/1987
• Issued: 01/24/1989
• Est. Priority Date: 09/04/1986
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Hiroshima, Motoharu, Yorita, Tadahiro
• Primary Examiner(s): Nussbaum, Marvin L.
• Application Number:
  US07/092,769
• Time in Patent Office: 509 Days
• Field of Search: 333/202, 333/206, 333/207, 333/208, 333/209, 333/210, 333/212, 333/219, 333/222, 333/223, 333/235, 333/203
• US Class Current: 333/202
• CPC Class Codes: H01P 1/2056 Comb filters or interdigital filters with metallised resonator holes in a dielectric block

Abstract

A dielectric filter includes a single block made of dielectric material having three or more through holes, in each of which an inner conductor is deposited, to define three or more dielectric resonators coupled in a cascade manner. Coupling holes are each formed between a pair of neighboring dielectric resonators. A bypass circuit, having a reactance component, is provided for connecting between two or more coupling holes; or for connecting the through hole of the dielectric resonator and a coupling hole; or for connecting the input terminal and one or more through holes of the dielectric resonators or the coupling holes. By selecting the holes to be interconnected and the value of the reactance of the bypass circuit, it is possible to provide a filter having a frequency characteristic in a desired format, including at least one pole at a selected point in an attenuation region thereof, without any increase in the number of dielectric resonator stages of the dielectric filter.

Claims

1. A dielectric filter comprising:

at least three dielectric resonators coupled in a cascade manner, said resonators being arranged in a unit defined by a single block made of dielectric material having at least three first-type through holes extending into a main face thereof, an inner conductor deposited on an inner face of each said first-type through hole, and an outer conductor deposited at least on an outer face of said block other than said main face thereof, each dielectric resonator being defined by one said inner conductor, by said dielectric material provided therearound, and by said outer conductor;

at least two coupling means, each formed between a pair of neighboring dielectric resonators wherein each said coupling means is defined by a second-typehole formed extending into said main face between a respective pair of said first-type through holes; and

at least one bypass circuit means separate from said coupling means, having a reactance component, connected between at least two of said second-type holes.

2. A dielectric filter comprising:

at least three dielectric resonators coupled in a cascade manner, said resonators being arranged in a unit defined by a single block made of dielectric material having at least three first-type through holes extending into a main face thereof, an inner conductor deposited on an inner face of each said first-type through hole, and an outer conductor deposited at least on an outer face of said block other than said main face thereof, each dielectric resonator being defined by one said inner conductor, by said dielectric material provided therearound, and by said outer conductor;

at least two coupling means, each formed between a pair of neighboring dielectric resonators; and

at least one bypass circuit means, having a reactance component, connected between at least two of said coupling means;

wherein each said coupling means is defined by a second-type hole formed extending into said main face between a respective pair of said first-type through holes; and

wherein said bypass circuit means comprises;

first and second bushings made of electrically nonconductive material inserted into said second-type holes, respectively;

metallic pins having portions thereof inserted into said first and second busings, respectively; and

printed circuit means with an elongated electrode for electrically connecting said metallic pins.

3. A dielectric filter comprising:

at least three dielectric resonators coupled in a cascade manner, said resonators being arranged in a unit defined by a single block made of dielectric material having at least three first-type through holes extending into a main face thereof, an inner conductor deposited on an inner face of each said first-type through hole, and an outer conductor deposited at least on an outer face of said block other than said main face thereof, each dielectric resonator being defined by one said inner conductor, by said dielectric material provided therearound, and by said outer conductor;

at least two coupling means, each formed between a pair of neighboring dielectric resonators wherein each said coupling means is defined by a second-type hole formed extending into said main face between a respective pair of said first-type through holes; and

at least one bypass circuit means separate from said coupling means, having a reactance component, connected between at least one second-type hole and at least one dielectric resonator which is other than one of said pair of neighboring dielectric rsonators located immediately adjacent said at least one second-type hole.

4. A dielectric filter comprising:

at least three dielectric resonators coupled in a cascade manner, said resonators being arranged in a unit defined by a single block made of dielectric material having at least three first-type through holes extending into a main face thereof, an inner conductor deposited on an inner face of each said first-type through hole, and an outer conductor deposited at least on an outer face of said block other than said main face thereof, each dielectric resonator being defined by one said inner conductor, by said dielectric material provided therearound, and by said outer conductor;

at least two coupling means, each formed between a pair of neighboring dielectric resonators; and

at least one bypass circuit means, having a reactance component, connected between at least one coupling means and at least one dielectric resonator which is other than one of said pair of neighboring dielectric resonators located immediately adjacent said at least one coupling means;

wherein each said coupling means is defined by a second-type hole formed extending into said main face between a respective pair of said first-type through holes; and

wherein said bypass circuit means comprises;

first and second bushings made of electrically non-conductive material inserted into said second-type hole and first-type through hole, respectively;

metallic pins having portions thereof inserted into said first and second bushings, respectively; and

printed circuit means with an elongated electrode for electrically connecting said metallic pins.

5. A dielectric filter as claimed in claim 4, wherein said printed circuit means has capacitors formed therein.

6. A dielectric filter comprising:

at least three dielectric resonators coupled in a cascade manner, said resonators being arranged in a unit defined by a single block made of dielectric material having at least three first-type through holes extending into a main face thereof, an inner conductor deposited on an inner face of each said first-type through hole, and an outer conductor deposited at least on an outer face of said block other than said main face thereof, each dielectric resonator being defined by one said inner conductor, by said dielectric material provided therearound, and by said outer conductor;

at least two coupling means, each formed between a pair of neighboring dielectric resonators wherein each said coupling means is defined by a second-type hole formed extending into said main face between a respective pair of said first-type through holes;

first terminal means connected through a coupling capacitor to a first one of said dielectric resonators;

second terminal means connected through a coupling capacitor to a last one of said dielectric resonators; and

at least one bypass circuit means separate from said coupling means, having a reactance component, connected between said first terminal means and at least one of;

one said second-type hole, and a dielectric resonator which is other than said first and said last dielectric resonators.

8. A dielectric filter as claimed in claim 6, further comprising at least one bypass circuit means separate from said coupling means, having a reactance component, connected between said second terminal means and at least one of:

one said second-type hole, and a dielectric resonator which is other than said first and said last dielectric resonators.

7. A dielectric filter comprising:

at least three dielectric resonators coupled in a cascade manner, said resonators being arranged in a unit defined by a single block made of dielectric material having at least three first-type through holes extending into a main face thereof, an inner conductor deposited on an inner face of each said first-type through hole, and an outer conductor deposited at least on an outer face of said block other than said main face thereof, each dielectric resonator being defined by one said inner conductor, by said dielectric material provided therearound, and by said outer conductor;

at least two coupling means, each formed between a pair of neighboring dielectric resonators;

first terminal means connected through a coupling capacitor to a first one of said dielectric resonators;

second terminal means connected through a coupling capacitor to a last one of said dielectric resonators; and

at least one bypass circuit means, having a reactance component, connected between said first terminal means and at least one of;

one said coupling means, and a dielectric resonator which is other than said first and said last dielectric resonators;

wherein each said coupling means is defined by a second-type hole formed extending into said main face between a respective pair of said first-type through holes; and

wherein said bypass circuit means comprises;

first and second bushings made of electrically nonconductive material inserted, respectively, into said first-type through hole of said first one of said dielectric resonators, and at least one of;

said second-type hole of said one coupling means, and said first-type through hole of said dielectric resonator which is other than said first and said last dielectric resonators;

metallic pins having portions thereof inserted into said first and second bushings, respectively; and

printed circuit means with an elongated electrode for electrically connecting said metallic pins.