Low sidelobe reflector antenna system employing a corrugated subreflector

• US 5,959,590 A
• Filed: 08/08/1996
• Issued: 09/28/1999
• Est. Priority Date: 08/08/1996
• Status: Expired due to Fees

• Current Assignee: Tripoint Global Microwave Inc.
• Original Assignee: Endgate Corp (Renesas Electronics Corporation)
• Inventors: Kishk, Ahmed A., Sanford, John R., Blasing, Raymond R.
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US08/695,286
• Time in Patent Office: 1,146 Days
• Field of Search: 343/781 P, 343/781 CA, 343/914, 343/779, 343/781 R, 343/782, 343/783
• US Class Current: 343/781.0CA
• CPC Class Codes: H01Q 19/021 Means for reducing undesirable effects
• CPC Class Codes: H01Q 19/134 Rear-feeds; Splash plate feeds

Abstract

An improved subreflector antenna with lower sidelobes than prior art subreflector antennas is disclosed herein. A tapered, anisotropic, corrugated subreflector is attached to a waveguide and located at the focus of a near-parabolic deep dish main reflector. The subreflector has corrugations of varying depth. The varying depths of the corrugations result in varying reactance, or reactance taper, of the subreflector. This taper is designed in such a manner to guide or steer the energy from the antenna feed to the main reflector in such a manner as to help assure sharply reduced sidelobes. Further, the subreflector is physically shaped so as to further steer or guide the energy in the desired direction. The deep geometry of the main reflector allows the reduced sized subreflector to be positioned within the rim of the main reflector such that the combination can be covered by a flat radome.

Claims

1. An antenna system comprising:

a nearly parabolic main reflector having a focus below its rim;

a waveguide having one end attached to said main reflector at an axis passing normally through substantially the center of said main reflector, the other end of said waveguide located near the focus of said main reflector; and

a symmetrically peaked corrugated subreflector with corrugations that vary in depth and with an additional corrugation located within its edge surface attached symmetrically to said other end of said waveguide, wherein said antenna system is operating at any sense of signal polarization.

2. An antenna system comprising:

a main reflector,

a waveguide having one end attached to said main reflector at an axis passing normally through substantially the center of said main reflector, the other end of said waveguide located near the focus of said main reflector; and

a corrugated, symmetrically non-planar subreflector having corrugations which vary in depth wherein the depth and placement of said corrugations guide energy from said waveguide in desired directions and wherein said subreflector has a corrugation within its edge surface, symmetrically attached to said other end of said waveguide.