Method of adjusting a frequency response in a three-conductor type filter device

• US 5,075,653 A
• Filed: 05/01/1990
• Issued: 12/24/1991
• Est. Priority Date: 05/03/1989
• Status: Expired due to Term

• Current Assignee: NGK Spark PLUG Company Limited No 14-18 Takatsuji-Cho Mizuho-Ku Nagoya-Shi Aichi Japan
• Original Assignee: NGK Spark PLUG Company Limited
• Inventors: Ito, Kenji, Shimizu, Hiroyuki
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Ham, Senng
• Application Number:
  US07/517,330
• Time in Patent Office: 602 Days
• Field of Search: 333/202-205, 333/235, 333/246, 333/219
• US Class Current: 333/205
• CPC Class Codes: H01P 1/20336 Comb or interdigital filters

Abstract

A method of adjusting a frequency response in a filter device of a three-conductor type having a pair of stacked dielectric substrates with a plurality of strip-line resonator conductors being sandwiched therebetween, wherein the frequency adjusting of the filter is performed by partially removing the ground conducting layer provided on the peripheral portion of each dielectric substrate at regions corresponding to the open circuit ends, or to the open circuit ends and the short circuit ends of the resonator conducting layers.

Claims

1. A method of adjusting a frequency response of a filter device of a three-conductor structure type comprising a pair of dielectric substrates each having a peripheral and outer surfaces provided with an external ground conducting layer, and a plurality of stripline resonator conducting layers sandwiched between said dielectric substrates, each resonator conducting layer having a short circuit end connected to the ground conducting layer on one lateral surface of said each substrate and an open circuit end spaced from the ground conducting layer on the opposite lateral surface of said each substrate, wherein said method comprises the step of partially removing said external ground conducting layer on the peripheral surface of said each substrate at a portion which corresponds to the open circuit end of said each resonator conducting layer to tune filter device to a desired frequency response.

2. A method as claimed in claim 1, wherein said removing step is performed by using a cutting tool, a laser beam machining, or sand blasting.

3. A method of adjusting the frequency response of a filter device of a three-conductor structure comprising a pair of dielectric substrates each having a peripheral and outer surfaces provided with an external ground conducting layer, and a plurality of stripline resonator conducting layers sandwiched between said dielectric substrates, each resonator conducting layer having a short circuit end connected to said ground conducting layer on one lateral surface of said each substrate and an open circuit end spaced from said ground conducting layer on the opposite lateral surface of said each substrate, said method comprising a first step of partially removing said external ground conducting layer on the peripheral surface of said each substrate at a portion which corresponds to the open circuit end of said each resonator conducting layer so as to provide tuning of the filter device to a desired frequency response, and a further step of partially removing said external ground conducting layer on the peripheral surface of said each substrate at a portion which corresponds to the short circuit end of said each resonator conducting layer so as to compensate for any overshoot of the tuning provided by said first step.

4. A method as claimed in claim 3, wherein said each removing step is performed by using a cutting tool, laser beam machining, or sand blasting.

5. A method of adjusting a frequency response of a filter device of a three-conductor structure comprising a pair of dielectric substrates each having a peripheral surface provided with a pluraeity of recesses and an outer surface, an external ground conducting layer provided on the peripheral and outer surfaces of said each dielectric substrate, and a plurality of stripline resonator conducting layers sandwiched between said dielectric substrates, each resonator conducting layer having a short circuit end connected to the ground conducting layer on one lateral surface of said each substrate and an open circuit end spaced from the ground conducting layer on the opposite lateral surface of said each substrate, wherein said method comprises the step of partially removing said external ground conducting layer on the peripheral surface of each said substrate defining the recesses at a portion which corresponds to the open circuit end of said each resonator conducting layer so as to increase the response frequency of the filter device to a desired level.

6. A method as claimed in claim 5, wherein said each removing step is performed by using a cutting tool, laser beam machining, or sand blasting.

7. A filter device of a three-conductor structure type comprising a pair of dielectric substrates having a peripheral and outer surfaces;

an external ground conducting layer provided on the peripheral and outer surfaces of said each dielectric substrate;

a plurality of stripline resonator conducting layers sandwiched between said dielectric substrates, each resonator conducting layer having a short circuit end connected to said ground conducting layer on one lateral surface of said each substrate and an open circuit end spaced from said ground conducting layer on the opposite lateral surface of said each substrate, said external ground conducting layer provided on the peripheral surface of said each dielectric substrate having a portion removed for changing a capacitance between said ground conducting layer and each of said stripline resonator conducting layers sandwiched between said dielectric substrates; and

a casing for containing a filter assembly of said dielectric substrates and said resonator conducting layers, said casing having an inner height equal to the thickness of said filter assembly.