Switchable beamwidth monopulse method and system

US3965475A · kind A · utility

Assignee

• The United States of America as represented by the United States Administrator of the National Aeronautics and Space Administration · US

Inventors

• Leonard F. Deerkoski · Crofton, US
• Richard Schmidt · Kiel, DE

Key dates

• Filing date: May 30, 1975
• Grant date: Jun 22, 1976
• Expiry date: May 30, 1995

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01Q25/002
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In a switchable beamwidth monopulse method and system, an antenna comprising a curved reflector and a first set of monopulse feeds positioned in the effective region of the Airy disc of the antenna includes a second set of monopulse feeds. The second set of monopulse feeds is positioned outside the Airy disc in the region of first bright Airy ring. In narrow beamwidth monopulse operation, monopulse sum and difference channel patterns are obtained from the first set of feeds within the Airy disc. In wide beamwidth monopulse operation, the difference channel pattern is obtained from the second set of feeds in the Airy ring; the sum channel pattern is obtained by attenuation and phase shifting the sum channel signal obtained from the first set of feeds, and adding the resultant to the sum channel signal obtained from the second set of feeds. In a simplified form of the invention, the difference channel patterns for both narrow and wide beamwidth mode operation are obtained from the second set of feeds, while the sum channel patterns are obtained as described above.