Multiple phase center feedhorn for reflector antenna

• US 7,180,459 B2
• Filed: 06/18/2004
• Issued: 02/20/2007
• Est. Priority Date: 06/24/2003
• Status: Expired due to Fees

• Current Assignee: Her Majesty The Queen In Right of Canada As Represented By The Minister of National Defence, Informagnetic Technologies Corporation
• Original Assignee: Her Majesty The Queen In Right of Canada As Represented By The Minister of National Defence
• Inventors: Shafai, Lotfollah, Sharma, Satish, Damini, Anthony, Haslam, George E., Balaji, Bhashyam
• Primary Examiner(s): Ho; Tan
• Assistant Examiner(s): AL NAZER, LEITH A
• Application Number:
  US10/869,844
• Publication Number:
  US 20050007287A1
• Time in Patent Office: 977 Days
• Field of Search: 343/772, 343/781.R, 343/786
• US Class Current: 343/786
• CPC Class Codes: H01Q 13/025 Multimode horn antennas; Horns using higher mode of propagation H01Q13/0241 takes precedence; multiple beam H01Q25/04
• CPC Class Codes: H01Q 19/12 wherein the surfaces are concave H01Q19/18 takes precedence
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00

Abstract

A feedhorn driving method and apparatus allows the establishment of multiple phase centers using only a single multimode feedhorn. At least two higher-order modes are extracted from the feedhorn and weighted in amplitude and phase. The phase center separation is established in accordance with an assigned weights. The feedhorn has application in i.a. moving target indication systems.

Claims

1. A feedhorn for a multiple phase center reflector antenna, the feedhorn comprising:

a horn section for receiving a beam;

at least two ports coupled to the horn section, each port for extracting a different mode; and

a controller for receiving the different modes from said at least two ports and for combining the different modes using a pre-determined complex weighting so as to produce at least two different separated phase centers, said at least two ports comprising a TE₁₁ port for coupling a TE₁₁ mode and a TE₂₁ port for coupling a TE₂₁ mode.

2. A feedhorn according to claim 1, wherein the feedhorn is responsive to a polarization that is orthogonal to the direction of the phase center separation.

3. A feedhorn according to claim 1, wherein the TE₁₁ port is a circular waveguide dimensioned such that only the TE₁₁ mode propagates therein.

4. A feedhorn according to claim 1, wherein the TE₂₁ port comprises a pair of opposing rectangular waveguides transversely located on the horn section, each of the rectangular guides being dimensioned to propagate the TE₂₁ mode therein.

5. A feedhorn according to claim 1, wherein the horn section is dimensioned such that only the TE₁₁ and the TE₂₁ modes are able to propagate therein.