Integrated down converter and interdigital filter apparatus and method for construction thereof

• US 5,020,149 A
• Filed: 10/24/1988
• Issued: 05/28/1991
• Est. Priority Date: 09/30/1987
• Status: Expired due to Term

• Current Assignee: Conifer Corporation
• Original Assignee: Conifer Corporation
• Inventors: Hemmie, Dale L.
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): Lee, Benny T.
• Application Number:
  US07/261,557
• Time in Patent Office: 946 Days
• Field of Search: 333/203, 174/52.1, 174/52.3, 361/394, 361/395, 361/399, 361/424, 455/318, 455/319, 455/325, 455/323, 455/347
• US Class Current: 455/325
• CPC Class Codes: H01P 1/205 Comb or interdigital filters; Cascaded coaxial cavities H01P1/203 takes precedence

Abstract

An integrated down converter and interdigital filter apparatus having a down converter and a number of interdigital filters mounted on the same printed circuit board and installed in the watertight housing. The housing of each interdigital filter is cut from sheet metal, with a conductive surface on the printed circuit board as one side. A method for construction of the interdigital filter is also set forth.

Claims

1. An integrated down converter interdigital filter apparatus receptive of a microwave signal for producing an electrical output signal in a predetermined band corresponding to said microwave signal comprising:

a planar surface,

a down converter located on said planar surface having an electrical signal input and an electrical signal output,

an interdigital filter also located on said planar surface, said interdigital filter comprising;

(a) a ground plane conductive surface formed on said planar surface,

(b) a conductive rectangular housing having an interior and an open bottom, said housing having said open bottom affixed to said conductive surface in order to fully enclose the interior of said housing,

(c) a plurality of conductive elements spatially located in said housing for filtering said microwave signal in said predetermined band,

(d) means connected through said housing for interconnecting said microwave signal with one of said elements,

means connected through said housing and connected to another one of said elements for interconnecting the filtered signal in said band from said interdigital filter to the input of said down converter, and

means connected to the output of said down converter for delivering said electrical signal output from said down converter.

2. The integrated down converter interdigital filter apparatus of claim 1, wherein the planar surface is a printed circuit board.

3. An integrated down converter interdigital filter apparatus receptive of a microwave signal for producing an electrical output signal in a predetermined band corresponding to said microwave signal input comprising:

an apparatus housing having one end open,

a jack plate for engaging said open end of said housing to provide a seal for said housing,

a printed circuit board within said apparatus housing having a first end and a second end,

a down converter located on said first end of said board,

an interdigital filter located on the second end of said board, said interdigital filter comprising;

(a) a ground plane conductive surface formed on said second end of said printed circuit board,

(b) a conductive rectangular filter housing having an interior, an end, anD an open bottom, said housing having said open bottom soldered to said conductive surface in order to fully enclose the interior of said housing in a conductive envelope, said end of said filter housing being connected to said jack plate,

(c) a plurality of conductive elements spatially located in said filter housing for filtering said microwave signal in said predetermined band, with one of said elements being nearest to said jack plate and another of said elements being farthest from said jack plate, and

(d) means connected to said jack plate and to said end of said filter housing for interconnecting said microwave signal with the element nearest said jack plate,

means connected through said filter housing and connected to the element farthest from said jack plate for interconnected said filtered signal to the input of said down converter, and

means connected to the output of said down converter and to said jack plate for delivering said electrical signal output from said apparatus housing.

4. An integrated down converter apparatus having a number of interdigital filters receptive of a corresponding number of microwave signal bands for producing an electrical output signal in a number of predetermined bands, each filter corresponding to one of said microwave signal bands, comprising:

a printed circuit board,

a down converter located on said board having a electrical signal input and an electrical signal output,

a number of interdigital filters also located on said board, each of said interdigital filters comprising;

(a) a ground plane conductive surface formed on said board,

(b) a conductive rectangular housing having an interior and an open bottom, said housing having said open bottom affixed to said conductive surface in order to fully enclose the interior of said housing,

(c) a plurality of conductive elements spatially located in said housing for filtering said microwave signal in one of said predetermined bands,

(d) means connected through said housing for interconnecting said corresponding microwave signal band with one of said elements, and

(e) means connected through said housing and connected to another of said elements for interconnecting the filtered signal in said corresponding band from said interdigital filter to the input of said down converter, and

means connected to the output of said down converter for delivering said electrical signal output said down converter.

5. The integrated down converter apparatus of claim 4 further comprising:

(a) a housing enclosing the integrated down converter apparatus having one end open, and

(b) means for engaging said open end of said housing to provide a watertight seal.

6. An integrated down converter apparatus having a number of interdigital filters receptive of a corresponding number of microwave signal bands for producing an electrical output signal in a number of predetermined bands, each filter corresponding to one of said microwave signal bands, comprising:

an apparatus housing comprising;

(a) an apparatus housing having one end open,

(b) means for sealing said opening, and

(c) means for engaging said sealing means and said open end of said housing to provide a seal,

a printed circuit board within said apparatus housing,

a down converter located on said board having an electrical signal input and electrical signal output,

a number of interdigital filters also located on said board, each of said interdigital filters comprising;

(a) a ground plane conductive surface formed on said board,

(b) a conductive rectangular filter housing having an interior and an open bottom, said filter housing having said open bottom affixed to said conductive surface in order to fully enclose the interior of said filter housing,

(c) one end of said filter housing being connected to said engaging means,

(d) a plurality of conductive elements spatially located in said filter housing for filtering said microwave signal in one of said predetermined bands, with one of said elements being nearest to said engaging means and another of said elements being farthest from said engaging means,

(e) means connected to said engaging means and to said connected end of said filter housing for interconnecting said microwave signal with the element nearest said engaging means, and

(f) means connected through said filter housing and connected to the element farthest from said engaging means for interconnecting said filtered signal to the input of said down converter, and

means connected to the output of said down converter for delivering said electrical signal output from said down convertor.

7. An integrated down converter apparatus having a member of interdigital filters receptive of a corresponding number of microwave signal bands for producing an electrical output signal in a number of predetermined bands, each filter corresponding to one of said microwave signal bands, comprising:

an apparatus housing comprising;

(a) a housing having one end open,

(b) a gasket for sealing around said opening, and

(c) a jack plate for engaging said gasket and said open end of said housing to provide a seal for said apparatus housing,

a printed circuit board within said apparatus housing having a first end and a second end,

a down converter located on said first end of said board having an electrical signal input and an electrical signal output,

a plurality of interdigital filters located on the second end of said board, each of said interdigital filters comprising;

(a) a ground plane conductive surface formed on said second end of said printed circuit board,

(b) a conductive rectangular filter housing having an interior, an end, and an open bottom, said filter housing having said open bottom soldered to said conductive surface in order to fully enclose the interior of said filter housing in a conductive envelope, said end of said filter housing being connected to said jack plate,

(c) a plurality of conductive elements spatially located in said filter housing for filtering said microwave signal in one of said predetermined bands, with one of said elements being nearest to said jack plate and another of said elements being farthest from said jack plate,

(d) means connected to said jack plate and to said end of said filter housing for interconnecting said microwave signal with the element nearest said jack plate, and

(e) means connected through said filter housing and connected to the element farthest from said jack plate for interconnecting said filtered signal to the input of said down converter, and

means connected to the output of said down converter and to said jack plate for delivering said electrical signal output from said apparatus housing.

8. An integrated down converter apparatus having two interdigital filters receptive of two microwave signal bands for producing an electrical output signal in two predetermined bands, each filter corresponding to one of said microwave signal bands, comprising:

a printed circuit board,

a down converter located on said board having an electrical signal input and an electrical signal output,

two interdigital filters also located on said board, both of said interdigital filters comprising;

(a) a ground plane conductive surface formed on said board,

(b) a conductive rectangular housing having an interior and an open bottom, said housing having said open bottom affixed to said conductive surface in order to fully enclose the interior of said housing,

(c) a plurality of conductive elements spatially located in said housing for filtering said microwave signal in a corresponding one of said predetermined bands;

input signal connector means having two branches in parallel, connecting said microwave signal with one of said elements in both housings, each of said branches having a low impedance in the microwave signal band passed by the respective interdigital filter to which the branch is connected, but having a higher impedance in the microwave signal band passed by the other interdigital filter;

means connected through said housings and connected to another of said elements in both interdigital filters for interconnecting the filtered signals in both bands from said interdigital filters to the input of said down converter, and

means connected to the output of said down converter for delivering said electrical signal output said down converter.