Interdigital filter apparatus and method for construction

DETAILED DESCRIPTION a.
General Description In FIG.
1, the integrated down converter and interdigital filter of the present invention 10 is shown to include a waterproof housing 20, a single circuit board 30 containing a portion of the down converter section 40 and the interdigital filter section 50.
A jack plate 70 is shown which interconnects to the waterproof housing 20 by means of screws 72.
The microwave signal coming into the down converter from the antenna, not shown, is received through the N-connector 80 for delivery into the interdigital filter housing 90 which is then filtered in a predetermined bandwidth such as 2500-2686 MHz by the interdigital filter and delivered to lead 100 for processing by the down converter section 40.
The resulting electrical output signals from the down converter which corresponds to the filtered microwave signals are then delivered to the output connectors 120.
A portion of the interdigital filter 90 is the ground plane 130.
Under the teachings of the present invention, the interdigital filter section 50 is incorporated onto the printed circuit board carrying the conventionally available down converter section 40 and is mounted into the waterproof housing 20.
The jack plate 70 mounts over the jack plate gasket 140 which is preferably a closed-cell light density neoprene material.
When screws 72 are connected, the combined down converter and interdigital filter is securely protected within the waterproof housing 20.
In FIG.
2, the down converter printed circuit board 30 is shown.
This circuit board is preferably manufactured from 1/16th inch double-clad fiberglass epoxy board.
The silver cladding on board 30 is etched away to define the rectangular ground pad 130.
The ground plane conductive surface or pad 130 has a plurality of holes 200 formed around the outer periphery thereof which provides conductive paths to the opposite side of board 30, designated 210 in FIG.
3.
The opposite side of board 30, as shown in FIG.
3, also has a ground pad 210 etched to remain in place directly under surface 130