Switched steerable multiple beam antenna system

• US 4,772,893 A
• Filed: 06/10/1987
• Issued: 09/20/1988
• Est. Priority Date: 06/10/1987
• Status: Expired due to Fees

• Current Assignee: National Aeronautics and Space Administration (Government of the United States of America)
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Iwasaki, Richard S.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Le, Hoanganh
• Application Number:
  US07/060,196
• Time in Patent Office: 468 Days
• Field of Search: 343/776, 343/777, 343/778, 343/779, 343/781 R, 343/785, 343/783, 343/756, 343/786, 342/374, 342/373, 342/377, 342/375
• US Class Current: 343/779
• CPC Class Codes: H01Q 19/027 for compensating or reducing aperture blockage offset feeding H01Q19/132, H01Q19/192
• CPC Class Codes: H01Q 25/005 providing two patterns of opposite direction; back to back antennas H01Q25/004 takes precedence
• CPC Class Codes: H01Q 25/007 using two or more primary active elements in the focal region of a focusing device for operation on different wavebands H01Q5/22
• CPC Class Codes: H01Q 3/2658 Phased-array fed focussing structure
• CPC Class Codes: H01Q 3/2682 Time delay steered arrays

Abstract

A steerable multibeam five element cross-feed cluster antenna (16) system. The feed power is divided into five branches. Each branch includes a switching network (12A-12E) comprised of a plurality of time delay elements (90A; 92A) each individually controlled by a respective electromagnetic latching switch (56A,B; 58A,B; 60A,B; 62A,B; 46A,B). Frequency independent individual two-dimensional beam steering at IF scanning frequencies is thereby provided wherein discrete incremental time delays are introduced by the switching networks into each branch and the signals recombined thereafter to form each beam. The electromagnetic latched switching reduces power consumption and permits higher power switching and reciprocal coincident transmit and receive operation. Frequency independence due to incremental time delay switching permits coincident reciprocal operation and steering for transmit-receive signal paths carrying different transmit-receive frequencies. Diagonal quarter wave plates (30B-38B) in the wave guides (30-38) alter polarization from circular to orthogonal linear to provide transmitter-receiver isolation.

Claims

1. Apparatus for use in a multiple beam antenna system, comprising:

time delay switching network means for providing a plurality of pairs of bi-directional signal paths, each having a discrete time delay of selectably variable magnitude, and wherein each said pair of signal paths comprises a first and second signal path, and wherein said switching network means includes a switching means for adding and subtracting time delays having magnitudes preselected from a plurality of time delays to said first signal path and from said second signal path, respectively.

2. The apparatus of claim 1 wherein said magnitudes are equal.

3. The apparatus of claim 2 wherein said switching means comprises:

a first plurality of switches and discrete incremental time delay elements interconnected in series in said first signal path; and

a second plurality of switches and discrete incremental time delay elements interconnected in series in said second signal path.

4. The apparatus of claim 3 wherein said switches are double pole double throw latching switches.

5. The apparatus of claim 4 wherein said switches are electromagnetically actuated.