Wave transmission lines and networks – Coupling networks – Wave filters including long line elements
Reexamination Certificate
2000-09-21
2002-03-12
Pascal, Robert (Department: 2817)
Wave transmission lines and networks
Coupling networks
Wave filters including long line elements
C333S246000, C333S204000, C333S219000
Reexamination Certificate
active
06356168
ABSTRACT:
TECHNICAL FIELD
This invention relates to high-frequency, e.g., microwave, filters.
BACKGROUND OF THE INVENTION
The recent proliferation of, and resulting stiff competition among, wireless communications products have put price/performance demands on filter components that conventional technologies find difficult to deliver. This is primarily due to expensive manufacturing operations such as milling, hand-soldering, hand-tuning, and complex assembly.
SUMMARY OF THE INVENTION
This invention is directed to solving this and other problems and disadvantages of the prior art. According to the invention, a filter is made from a single sheet of electrically conductive material, e.g., metal, preferably by stamping. The sheet is preferably all metal, e.g., a metal plate or a stacked assembly of metal sheets, but it may also be a metal-laminated non-conductive substrate, e.g., a printed-circuit board. In the latter case, the filter may advantageously be made by etching. An electromagnetically conductive housing preferably encapsulates at least both faces of the sheet. The sheet of conductive material defines a frame, one or more resonator filter elements inside of the frame, and one or more supports attaching the resonators to the frame. At least one contact connected to the resonator filter element provides an electromagnetic contact thereto. Preferably, the contact is a flange on at least one of the resonators, also defined by the sheet of conductive material. Another flange or the frame itself serves as another contact to the filter. Illustratively, the flanged resonator is rectangular and the flange and the supports extend from a side of the rectangle, whereby the distance between the flange and an end of the rectangular resonator that lies on the same side of the supports as the flange primarily determines the input characteristics of the filter. The resonant frequency of the filter element is primarily determined by the length of the element (&lgr;/2). Other factors, such as the width, the thickness, the tap point (L), and the resonators proximity to other metal also determine the resonant frequency.
Major benefits of the invention include low manufacturing costs, narrow (illustratively about 1%) bandwidth filters requiring no tuning, and high Q, relative to conventional technology. These and other features and advantages of the invention will become more evident from the following description of an illustrative embodiment of the invention considered with the drawing.
REFERENCES:
patent: 2945195 (1960-07-01), Matthaei
patent: 3104362 (1963-09-01), Matthaei
patent: 3806844 (1974-04-01), Buckley et al.
patent: 4609892 (1986-09-01), Higgins, Jr.
patent: 5225799 (1993-07-01), West et al.
patent: 5235298 (1993-08-01), Banno et al.
patent: 5352996 (1994-10-01), Kawaguchi
patent: 6005455 (1999-12-01), Lindell et al.
patent: 0 766 333 (1996-09-01), None
Barnett Ron
Ma Zhengxiang
Manzione Louis Thomas
Schwartz Richard F.
Wu Hui
Avaya Technology Corp.
Jones Stephen E.
Pascal Robert
Volejnicek David
LandOfFree
Sheet-metal filter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sheet-metal filter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sheet-metal filter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2882544