Layered stripline filter including inductive coupling adjustment strip

• US 5,608,364 A
• Filed: 10/31/1994
• Issued: 03/04/1997
• Est. Priority Date: 11/02/1993
• Status: Expired due to Term

• Current Assignee: NGK Insulators Limited, Soshin Electric Company Limited (Walsin Technology Corporation)
• Original Assignee: NGK Insulators Limited, Soshin Electric Company Limited (Walsin Technology Corporation)
• Inventors: Hirai, Takami, Watanabe, Masahiko
• Primary Examiner(s): Lee, Benny Y.
• Assistant Examiner(s): Gambino, Darius
• Application Number:
  US08/332,390
• Time in Patent Office: 855 Days
• Field of Search: 333/202, 333/203, 333/204, 333/185, 333/219, 333/246
• US Class Current: 333/204
• CPC Class Codes: H01P 1/20345 Multilayer filters

Abstract

A layered stripline filter has input and output electrodes formed on a dielectric layer, two resonant elements disposed on the dielectric layer and having ends connected to a ground electrode, providing a quarter-wave stripline resonator, an inductive coupling adjustment electrode disposed on the dielectric layer intermediate between the two resonant elements and having opposite ends connected to the ground electrode, and a coupling electrode disposed on the dielectric layer in overlapping relationship to portions of the two resonant elements. The layered stripline filter is small in size and has a desired bandwidth achieved by adjusting the inductive coupling between the two resonant elements. The layered stripline filter has an attenuation peak spaced from the passband thereof, resulting improved attenuation and spurious characteristics.

Claims

1. A layered stripline filter comprising:

a first ground electrode;

a second ground electrode;

a dielectric layer disposed between said first ground electrode and said second ground electrode;

a first resonant element short-circuited at one side and disposed in said dielectric layer;

a second resonant element short-circuited at one side and disposed adjacent to said first resonant element in said dielectric layer;

a first electrode disposed in said dielectric layer in direct confronting relationship to a portion of said first resonant element and in direct confronting relationship to a portion of said second resonant element; and

a second electrode disposed in said dielectric layer between said first resonant element and said second resonant element, said second electrode being separated from said first electrode with a portion of said dielectric layer interposed between said first electrode and said second electrode, and said second electrode having opposite ends short-circuited to ground.

2. A layered stripline filter according to claim 1, wherein said second electrode is disposed in said dielectric layer in confronting relationship to a portion of said first electrode.