DUAL WAVEGUIDE HORN ANTENNA

• US 3,611,396 A
• Filed: 06/18/1970
• Issued: 10/05/1971
• Est. Priority Date: 06/18/1970
• Status: Expired due to Term

• Current Assignee: Howard S. Jones Jr
• Original Assignee: Howard S. Jones Jr
• Inventors: Jones, Howard S. Jr.
• Primary Examiner(s): Lieberman, Eli
• Application Number:
  US05/047,504
• Time in Patent Office: 474 Days
• Field of Search: 343/776,783,784,785,786
• US Class Current: 343/776
• CPC Class Codes: H01Q 13/0291 for corrugated horns

Abstract

A dual waveguide horn antenna is provided with a rigid foam having a dielectric constant approximately equal to that of air and tapered to conform to the shape of a conventional horn antenna. Two tapered walls are corrugated and all four walls are covered with a thin metallic coating of sufficient thickness to carry the RF current produced by the propogation of an electromagnetic wave through the dielectric. A metallic septum divides the dielectric into first and second waveguide sections and individual coaxial inputs are provided to each of the sections. Energy coupling between the two sections of the waveguide are significantly reduced by means of a microwave resistive material secured to the septum at the enlarged end of the dielectric. The resistive strip may comprise a carbonized substrate or an insulating material coated with the resistive film. Additionally, a thin film of paint may be applied directly to the metallic septum by various techniques including vacuum deposition.

Claims

1. A dual waveguide horn antenna comprising:

a. a rigid foam dielectric material having a dielectric constant approximately equal to that of air and having tapered walls to conform to the shape of a conventional horn antenna;

b. a thin metallic coating covering the walls of the dielectric, said coating having sufficient thickness to carry the RF current produced by the propagation of an electromagnetic wave through said dielectric;

c. a metallic septum for dividing said dielectric into first and second waveguide sections;

d. an electromagnetic window located at the enlarged end of said tapered dielectric foam; and

e. means for applying electromagnetic energy to the tapered end of said dielectric.

2. The antenna of claim 1 wherein two of said tapered walls are corrugated to provide a slow wave structure.

3. The antenna of claim 1 wherein said thin metallic coating and said metallic septum comprise copper plating.

4. The antenna of claim 1 further comprising means for reducing energy coupling between said first and second waveguide sections.

5. The antenna of claim 4 wherein said means for reducing energy coupling comprises a microwave resistive material secured to said septum and located at the enlarged end of said dielectric.

6. The antenna of claim 5 wherein said resistive strip comprises a thin film resistive material secured to the surface of said septum by vacuum deposition.

7. The antenna of claim 5 wherein said resistive strip comprises a thin film paint on the surface of said septum.

8. The antenna of claim 5 wherein said resistive strip comprises a carbonized substrate.

9. The antenna of claim 5 wherein said resistive strip comprises an insulating strip secured to the edge of said septum and a microwave resistive coating on said insulating strip.

10. The antenna of claim 1 wherein said metallic septum equally divides said upper and lower waveguide sections.