Electronically scanned microstrip antenna array

• US 4,053,895 A
• Filed: 11/24/1976
• Issued: 10/11/1977
• Est. Priority Date: 11/24/1976
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Malagisi, Carmen S.
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Moore, David K.
• Application Number:
  US05/744,498
• Time in Patent Office: 321 Days
• Field of Search: 343/700 MS, 343/854, 343/769
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 3/247 by switching different parts of a primary active element
• CPC Class Codes: H01Q 3/44 varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40

Abstract

A microstrip electronically scannable antenna is realized by means of an array of disc elements that are separated from a common ground plane by a dielectric medium. The center of each disc element is electronically short circuited to the ground plane. At least two pairs of diametrically opposed short circuitry switches (diodes) are connected between certain locations on the peripheral edge of each disc element and the ground plane. The polarization and phase of the reflected energy of each disc element is controlled by certain combinations of open circuited and short circuited pairs of short circuiting switches. Electronic scanning is achieved by control of the short circuitry switches, specifically by digitally controlling the forward and reverse bias of the diodes.

Claims

1. An antenna element comprising:

a metallic disc in juxtaposition with a metallic ground plane member and separated therefrom by a dielectric medium,

an electrical short circuit connecting the center of said metallic disc and said ground plane member,

at least two pairs of diametrically opposed short circuiting switches connected between the edge of said disc and said ground plane member, and

a phase control circuit for actuating said short circuiting switches.

2. An antenna element as defined in claim 1 including means for coupling RF energy to said metallic disc.

3. An antenna element as defined in claim 1 including means for coupling circularly polarized RF energy to said metallic disc.

4. An antenna element as defined in claim 3 wherein said pairs of short circuiting switches comprise four diodes positioned around the periphery of said disc at 90°

increments, and said phase control circuit comprises means for selectively controlling the forward and reverse bias applied to discrete pairs of diodes.

5. An antenna element as defined in claim 4 wherein said pairs of short circuiting switches comprise eight diodes positioned around the periphery of said disc at 45°

increments.

6. An antenna element as defined in claim 4 wherein said pairs of short circuiting switches comprise twelve diodes positioned around the periphery of said disc at 30°

increments.

7. An antenna element as defined in claim 4 wherein said pairs of short circuiting switches comprise N diodes positioned around the periphery of said disc at 360°

/N increments, N being an even integer.

8. An electronically scanned antenna array comprising

a multiplicity of metallic discs in juxtaposition with a metallic ground plane member and separated therefrom by a dielectric medium,

an electrical short circuit connecting the center of each metallic disc and said ground plane member,

at least two pairs of diametrically opposed short circuiting switches connected between the edge of each said disc and said ground plane member,

a phase control circuit for activating said short circuiting switches, and

means for coupling RF energy to said metallic discs.

9. An electronically scanned antenna array as defined in claim 8 wherein for each said disc said pairs of short circuiting switches comprise N diodes positioned around the periphery of said disc at 360°

/N increments, N being an even integer, and said phase control circuit comprises means for selectively controlling the forward and reverse bias applied to discrete pairs of diodes.

10. An electronically scanned antenna array as defined in claim 9 wherein said discs, dielectric medium and metallic ground plane are fabricated of microstrip.