RASTER SCAN ANTENNA

• US 3,766,558 A
• Filed: 09/17/1971
• Issued: 10/16/1973
• Est. Priority Date: 09/17/1971
• Status: Expired due to Term

• Current Assignee: ITT Corporation (ITT, Inc.)
• Original Assignee: John A. Kuechken
• Inventors: Kuechken, John A.
• Primary Examiner(s): Borchelt, Benjamin A.
• Assistant Examiner(s): Berger, Richard E.
• Application Number:
  US05/181,453
• Time in Patent Office: 760 Days
• Field of Search: 343/1SA,113R,854
• US Class Current: 342/375
• CPC Class Codes: H01Q 3/42 using frequency-mixing H01Q3/2676 takes precedence

Abstract

A broadside array antenna arrangement capable of scanning electronically in one or two planes, wherein the transmitted or received frequency remains fixed although beam steering is effected by progressive phase shifts introduced to the various array elements as provided by the expedient of frequency variations. A prime oscillator frequency fo is mixed with a variable steering oscillator frequency fs to produce sum and difference frequencies fo + fs and fo - fs. The latter is fed to a delay line having a plurality of taps spaced apart in accordance with the particular arrangement of array elements, the delay line providing in the frequency signal fo - fs progressive phase shifts from tap to tap. The individual tap outputs are separately mixed with the sum frequency signal fo + fs, wherein N separate outputs are simultaneously derived having the same frequency of 2fo but varying from one another progressively in phase. Variation of fs, which causes the phase relationship between the N outputs to change as they are fed to the radiators in one-to-one correspondence, thus provides a sweep of the beam in one plane. Raster type scanning is provided by introducing a multi-tapped secondary delay line at each tap of the primary delay line and mixing instead the tap outputs of each secondary delay line individually with fo + fs and applying the resultant 2fo outputs to individual ones of a corresponding element row of a two-dimensional array. The tapped spacings on each of the secondary delay lines relative to the tapped spacings of the primary delay line is such as to provide scanning of an order of magnitude more sensitive in one plane.

Claims

1. An antenna scanning arrangement comprising:

a. first means for generating from a fixed prime frequency signal fo and a variable steering frequency signal fs first and second frequencies of fo + fs and fo - fs;

b. second means operating on one of said first and second signal frequencies to provide N simultaneous signal portions thereof of the same frequency and each having a unique phase which varies progressively from one another in predetermined increments;

c. third means separately coupling each of said N simultaneous signal portions with the untreated other one of said first and second signal frequencies for providing N separate output signals each having the same harmonic frequency of fo and progressively varying in phase from one another in said predetermined increments; and

d. N radiating elements in an array of predetermined arrangement coupled to said third means for radiating signal energy responsive to said N separate output signals applied thereto in one-to-one correspondence, wherein said second means is comprised of a primary phase shifting device having a plurality of terminals for providing simultaneous outputs varying in phase from one another progressively in said predetermined manner, and a plurality of secondary phase shifting devices each having a plurality of terminals for providing simultaneous outputs varying in phase from one another progressively in a predetermined manner, said secondary phase shifting devices each being separately coupled between a terminal of said primary phase shifting device and said third means, and wherein said radiating elements are arranged in a two-dimensional array and said primary and secondary phase shift devices are comprised of delay lines having taps arranged periodically thereon.

2. The arrangement according to claim 1 wherein said first means includes a prime oscillator for producing said fixed prime frequency signal energy fo, a steering oscillator providing said variable steering frequency signal energy fs and a first mixer coupling said fo and fs signal energies for providing said fo + fs and fo - fs signal energies.

3. The arrangement according to claim 2 wherein when operation of the arrangement is in a receive mode, said first means further includes a second mixer coupled between said second means and the output of said steering oscillator wherein said steering frequency signal energy fs and the difference frequency fo - fs from said second means are coupled to provide the frequency output fo.