Helix resonator filter with a coupling aperture extending from a side wall

• US 5,508,668 A
• Filed: 04/08/1994
• Issued: 04/16/1996
• Est. Priority Date: 04/08/1993
• Status: Expired due to Fees

• Current Assignee: LK Products Oy (Yageo Corporation)
• Original Assignee: LK Products Oy (Yageo Corporation)
• Inventors: Prokkola, Risto
• Primary Examiner(s): Lee, Benny
• Assistant Examiner(s): Bettendorf, Justin P.
• Application Number:
  US08/225,378
• Time in Patent Office: 739 Days
• Field of Search: 333/202, 333/208, 333/212, 333/227, 333/230, 333/239, 333/248, 333/219, 29/600
• US Class Current: 333/202
• CPC Class Codes: H01P 11/007 Manufacturing frequency-selective devices resonators H01P11/008

Abstract

In the housing of a filter realized with helix resonators, it is known to locate a coupling aperture in the partition between the resonators. According to the invention, the aperture in the partition is made so that outside the housing a milling cutter (33) is positioned at the point of the wall (31) of the housing where the partition (32) joins the wall of the housing. The longitudinal axis of the cutter extends in the plane of the partition. Then the cutter (33) is forced into the housing to a desired depth (H), whereby the cutter cuts an aperture in the partition open end at the housing surface, the aperture having a width equal to the width of the cutter and a height equal to the distance (H) the cutter was pushed. In this way it is easy to make coupling apertures also in extremely small sized filters, which are lower than 5 mm.

Claims

1. A radio frequency filter comprising

a housing having at least one partition for dividing the housing into compartments, the partition extending between outer walls of the housing, and

a respective helix resonator disposed in each of the compartments,

the partition having a coupling aperture that has a height and a width for coupling adjacent helix resonators to each other through the aperture, the coupling aperture having an open end at one of the outer walls of the housing and having two side edges and a bottom edge, the height of the coupling aperture being defined by the distance from the bottom edge to said one outer wall of the housing, and the width of the coupling aperture being defined by the distance between the two side edges, said aperture having smooth side edges extending along an entirety of the height, said one outer wall having an opening to the coupling aperture.

2. A radio frequency filter according to claim 1 wherein the opening in the outer wall of the housing is substantially circular.

3. A radio frequency filter according to claim 1, wherein the housing comprises as outer walls an upper face and first and second side faces transverse thereto the partition extending therebetween, the opening being located in the upper face and the coupling aperture opening to the upper face.