SCHWARZCHILD RADAR ANTENNA UTILIZING A RING SWITCH FOR GENERATING A SECTOR SCAN

• US 3,798,655 A
• Filed: 02/26/1973
• Issued: 03/19/1974
• Est. Priority Date: 02/26/1973
• Status: Expired due to Term

• Current Assignee: Clarence F. Ravilious, James M. Meek, Whilden G. Heinard
• Original Assignee: Clarence F. Ravilious, James M. Meek, Whilden G. Heinard
• Inventors: Meek, James M., Ravilious, Clarence F., Heinard, Whilden G.
• Primary Examiner(s): Lawrence, James W.
• Assistant Examiner(s): Nussbaum, Marvin
• Application Number:
  US05/335,876
• Time in Patent Office: 386 Days
• Field of Search: 343/754,755,761,779,781,837
• US Class Current: 343/754
• CPC Class Codes: H01Q 19/18 having two or more spaced reflecting surfaces H01Q19/20 takes precedence
• CPC Class Codes: H01Q 19/191 wherein the primary active element uses one or more deflecting surfaces, e.g. beam waveguide feeds
• CPC Class Codes: H01Q 3/14 for varying the relative position of primary active element and a refracting or diffracting device

Abstract

A Schwarzschild Antenna has main and subreflectors. A ring switch disposed behind the aperture in the main reflector generates a unidirectional sector scan beam that is collimated and transmitted to the far field, via the reflectors. The ring switch is comprised of two ring-shaped waveguide halves one of which rotates with respect to the other. Feed horns are mounted to one of the rings and are directed radially inwardly. Microwave energy from a transmitter is communicated to the horns, via the ring switch. Microwave energy emanating from the horns is directed by a lens to a rotatable mirror reflector that in turn reflects the resultant sector scan energy to the main and subreflectors of the antenna. The mirror reflector can be rapidly repositioned to allow the direct communication of a separately generated conical scan to the main and subreflectors of the antenna.

Claims

1. A Schwarzschild Antenna having main and subreflectors, the antenna being capable of generating a high-gain, unidirectional sector-scanning beam by apparatus comprising:

a stationary ring having a microwave energy input therein;

waveguide means formed in the stationary ring for transmitting microwave energy to a mating rotating ring that has waveguide means formed therein;

horn means mounted to the rotating ring for directing communicated microwave energy from the waveguide means of the rotating ring along a radially inward spacial direction during traversal of the horn means through a preselected arc thereby generating a unidirectional sector scan beam; and

means for reflecting the generated unidirectional sector scan beam to the far field via the main and subreflectors, during transmission.

2. The subject matter of claim 1 together with means for generating a conical scan beam when the sector scanner microwave propagation is de-energized, and further wherein the reflecting means is rotationally repositioned to permit direct microwave energy communication from the conical scanner means to the far field, via the main and subreflectors.

3. The subject matter of claim 1 together with means for driving the rotating ring in rotation about an axis concentric with the center of the stationary ring.

4. The subject matter of claim 1 wherein both mentioned waveguide means include cooperating miter means therein to direct input energy through the horn means only when the horn means traverses the preselected arc.

5. The subject matter of claim 4 wherein the miter means comprises a first miter that is stationarily positioned in the waveguide means of the stationary ring;

and further wherein the miter means includes at least one miter stationarily positioned in the waveguide means formed in the rotating means;

the miters of the stationary and rotating rings having means formed therein to allow the miter in the rotating ring to freely pass the miter in the stationary ring as the former rotates.

6. The structure of claim 5 wherein the miters are comb-like structures with offset teeth that permit said free passage.

7. The subject matter of claim 5 wherein the horn means comprises two or more feed horns;

each feed horn having a miter associated therewith, the associated miter being positioned in the waveguide means of the rotating ring at a point adjacent a communicating connection point of a respective horn.

8. The structure defined in claim 1 together with a microwave lens positioned along the preselected arc to provide the directivity of the primary energy of the produced sector scan.

9. The structure set forth in claim 2 wherein the reflecting means is pivotally mounted to the antenna to permit its rotational switching between the positions respectively associated with the unidirectional sector scan and the conical scan.

10. The apparatus defined in claim 1 wherein the horn means are characterized by an output flare that is pyramidal in shape.