Magnetic hybrid-mode horn antenna

• US 5,126,750 A
• Filed: 09/21/1990
• Issued: 06/30/1992
• Est. Priority Date: 09/21/1990
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Tripp, Victor K., Wang, Johnson J. H.
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): LE, HOANGANH T
• Application Number:
  US07/588,636
• Time in Patent Office: 648 Days
• Field of Search: 343/786, 343/787
• US Class Current: 343/786
• CPC Class Codes: H01Q 13/0208 Corrugated horns waveguide mouth antenna with corrugated flange H01Q13/065; manufacturing details H01Q13/0283
• CPC Class Codes: H01Q 19/08 for modifying the radiation pattern of a radiating horn in which it is located corrugated horns H01Q13/0208; producing a circular polarisation H01Q13/0241

Abstract

A magnetic corrugated horn antenna system is disclosed. This system includes a magnetic hybrid-mode horn antenna composed of a circular waveguide and a corrugated horn antenna which has a thin magnetic coating on its inner wall. The corrugation of the conical horn helps it to produce equal E-plane and H-plane patterns with low sidelobes. The magnetic coating can enhance or duplicate the beneficial effects of the corrugation, while avoiding the high gain loss and poor patterns reported in prior art systems that relay only on corrugated horns.

Claims

1. A magnetic hybrid-mode antenna system comprising:

a waveguide which receives and conducts transverse electromagnetic radio frequency signals;

a corrugated horn antenna housing which has an inner wall, and which is fixed to said waveguide to receive said transverse electromagnetic radio frequency signals therefrom, said corrugated horn antenna housing radiating an electromagnetic waveform into space, said electromagnetic waveform having an E-plane pattern and an H-plane pattern; and

a thin magnetic coating fixed on the inner wall of said corrugated horn antenna housing to adjust the E-plane and H-plane patterns of said electromagnetic waveform so that they are approximately equal by inducing an excitation of HE₁₁ mode in the electromagnetic waveform to adjust said E-plane and H-plane patterns, wherein said thin magnetic coating has a thickness ranging between 30 and 60 mils, and wherein said thin magnetic coating has a complex relative permittivity of about 10.8-j0.4 and a complex relative permeability of about 0.8-j1.2.

2. A magnetic hybrid-mode horn antenna system comprising:

a waveguide which receives and conducts transverse electromagnetic radio frequency signals;

a tapered throat which is connected to said waveguide to receive said transverse electromagnetic radio frequency signals therefrom;

a hollow body which has an inner wall and which is fixed to said tapered throat and which expands with a flare angle as one proceeds away from said tapered throat, said flare angle permitting said hollow body to radiate said electromagnetic waveform in the direction of radiation into free space;

a serration mode converter element which is fixed in said hollow body, and which induces said excitation in said electromagnetic waveform to adjust said E-plane and H-plane patterns; and

a thin magnetic coating which is fixed to said inner wall of said hollow body, said magnetic coating interacting with said electromagnetic radio frequency signals so that said E-plane and H-plane patterns are adjusted as desired when said electromagnetic waveform is radiated into free space, wherein said thin magnetic coating has a thickness ranging between 30 and 60 mils said converter element having serrations of said magnetic coating.

3. A magnetic hybrid-mode antenna system, as defined in claim 2, wherein said thin magnetic coating has a complex relative permittivity of about 10.8-j0.4 and a complex relative permeability of about 0.8-j1.2.