Dual-band feed horn with common beam widths

• US 8,957,821 B1
• Filed: 08/15/2013
• Issued: 02/17/2015
• Est. Priority Date: 04/10/2009
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Hsu, Chih-Chien, Matyas, Gerard J., Rao, Sudhakar K.
• Primary Examiner(s): DINH, TRINH VO
• Application Number:
  US13/968,303
• Time in Patent Office: 551 Days
• 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 19/132 Horn reflector antennas; Off-set feeding
• CPC Class Codes: H01Q 19/19 comprising one main concave reflecting surface associated with an auxiliary reflecting surface
• CPC Class Codes: H01Q 5/357 using a single feed point
• CPC Class Codes: H01Q 5/55 for horn or waveguide antennas

Abstract

A dual-band feed horn having a connection surface configured for connection to a waveguide and a first surface coupled to the connection surface. The first surface has a cylindrical surface with a length and a first diameter chosen to propagate TE11 modes for both a low frequency band and a high frequency band. The horn has a bandwidth ratio of the high-frequency band to the low frequency band in the range of 1.6-4.0. The horn also has a substantially conical surface coupled to the first surface at a first slope discontinuity. The conical surface includes multiple surfaces each having a respective slope and coupled to adjacent surfaces by a respective plurality of slope discontinuities each having a respective diameter. The slopes and diameters are chosen to generate primarily TM1,m modes (m=1, 2, 3, etc.) in the high-frequency band and primarily higher order TE1,n modes (n=2, 3, etc.) in the low-frequency band such that the low frequency band and the high frequency band have approximately equal beam widths.

Claims

1. A dual-band feed horn comprising:

a connection surface configured for connection to a waveguide;

a first surface coupled to the connection surface, the first surface comprising a cylindrical surface having a length and a first diameter chosen to propagate TE11 modes for both a low-frequency band and a high-frequency band, wherein a bandwidth ratio of the high-frequency band to the low-frequency band is greater than 1.6 and less than or equal to 4.0;

a substantially conical surface coupled to the first surface at a first slope discontinuity and comprising a plurality of surfaces each having a respective slope and coupled to adjacent surfaces by a respective plurality of slope discontinuities each having a respective diameter; and

an aperture coupled to the conical surface;

wherein the slopes and diameters are chosen to generate primarily TM1,m modes (m=1, 2, 3, etc.) in the high-frequency band and primarily higher-order TE1,n modes (n=2, 3, etc.) in the low-frequency band such that the low-frequency band and the high-frequency band have approximately equal beam widths.

2. The dual-band feed horn of claim 1, wherein the slopes and diameters are chosen to provide a first efficiency in the low-frequency band and a second efficiency in the low-frequency band, wherein the second efficiency is lower than the first efficiency.

3. The dual-band feed horn of claim 2, wherein the first efficiency is greater than 60%.

4. The dual-band feed horn of claim 2, wherein the second efficiency is less than 12%.

5. The dual-band feed horn of claim 1, further comprising a peak gain that is greater than 19 dBi across all frequencies.

6. The dual-band feed horn of claim 1, further comprising a ratio of co-polar directivity to cross-polar directivity that is greater than 20 dB across a 3 dB beam width across all frequencies.

7. The dual-band feed horn of claim 1, further comprising an axial ratio across a 3 dB beam width that is less than 2 dB across all frequencies.

8. The dual-band feed horn of claim 1, further comprising an illumination angle having a phase variation of less than 90 degrees in the low-frequency band and greater than 360 degrees in the high-frequency band.