Miniature phased array antenna system

• US 6,246,369 B1
• Filed: 09/14/1999
• Issued: 06/12/2001
• Est. Priority Date: 09/14/1999
• Status: Expired due to Fees

• Current Assignee: Navsys Corporation
• Original Assignee: Navsys Corporation
• Inventors: Brown, Peter K., Norgard, John D., Matini, Amir H., Brown, Alison K.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): TRAN, CHUC
• Application Number:
  US09/395,550
• Time in Patent Office: 637 Days
• Field of Search: 343/753, 343/755, 343/700.MS, 343/911.R, 343/911.L, 343/872, 343/701, 343/786, 343/840, 343/754
• US Class Current: 343/700.0MS
• CPC Class Codes: G01S 19/21 Interference related issues ; Issues related to cross-correlation, spoofing or other methods of denial of service
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: H01Q 1/40 Radiating elements coated with or embedded in protective material
• CPC Class Codes: H01Q 19/062 for focusing
• CPC Class Codes: H01Q 19/065 Zone plate type antennas
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence

Abstract

A miniature phased array antenna system employs a substrate having a high dielectric constant. A plurality of antenna elements are located on a surface of the substrate, and a superstrate having a high dielectric constant covers the antenna elements. The dielectric constant, thickness, and shape of the superstrate enable it to act as a dielectric lens for controlling the phase relationship of a signal received by the antenna elements. The design of the superstrate dielectric lens permits a reduction in the physical spacing between the antenna elements while maintaining spatial diversity in phase between signals arriving from different directions. Thus, the antenna array may be significantly smaller than conventional phased array antennas while maintaining a similar phase relationship to that achieved using conventional phased array antennas. Electronic circuitry coupled to each of the plurality of antenna elements applies complex weights to received signals prior to a summation thereof in order to reconstruct a desired signal and to deconstruct an undesired signal. SAW filters employed in the electronic circuitry are temperature controlled to maintain group-delay and phase-offset stability.

Claims

1. A miniature phased array antenna system comprising:

a dielectric substrate having a plurality of antenna elements formed on a first surface thereof and having a metallic ground plane formed on a second surface thereof; and

a superstrate covering the plurality of antenna elements, said superstrate forming a dielectric lens;

the dielectric constant of the substrate being higher than the dielectric constant of the superstrate.

2. A miniature phased array antenna system as in claim 1 wherein said dielectric substrate is of uniform thickness.

3. A miniature phased array antenna system as in claim 1 wherein the size of said antenna elements is inversely proportional to the square root of the dielectric constant of said substrate.

4. A miniature phased array antenna system as in claim 1 wherein a separation between said plurality of antenna elements is inversely proportional to the square root of the dielectric constant of said superstrate.

5. A miniature phased array antenna system as in claim 3 wherein a separation between said plurality of antenna elements is inversely proportional to the square root of the dielectric constant of said superstrate.

6. A miniature phased array antenna system as in claim 1 wherein said superstrate is formed to preserve a free space phase relationship between said plurality of antenna elements over a design field of view.

7. A miniature phased array antenna system as in claim 1 wherein said superstrate is formed in the shape of a hemisphere.

8. A miniature phased array antenna system as in claim 1 wherein said superstrate comprises a material having a uniform dielectric constant.

9. A miniature phased array antenna system as in claim 1 wherein said superstrate comprises a material having a uniform dielectric constant.

10. A miniature phased array antenna system as in claim 1 wherein a width of each of said plurality of antenna elements is substantially equal to one-half wavelength at the design frequency in the substrate.

11. A miniature phased array antenna system as in claim 1 wherein a separation between centers of said plurality of antenna elements is substantially equal to one-half wavelength of a received signal divided by the square root of the dielectric constant of said superstrate.

12. A miniature phased array antenna system as in claim 1 wherein said superstrate comprises a Fresnel lens having a non-uniform dielectric constant.

13. A miniature phased array antenna system as in claim 1 wherein said superstrate comprises a refractive lens.

14. A miniature phased array antenna system as in claim 1 further comprising analog electronic circuitry coupled to each one of said plurality of antenna elements for applying complex weights to incoming antenna signals prior to a summation thereof in order to reconstruct a desired signal and to deconstruct an undesired signal.

15. A miniature phased array antenna electronics module comprising digital electronic circuitry coupled to each one of a plurality of antenna elements for digitizing incoming antenna signals and for applying digital complex weights to the digitized antenna signals prior to a summation thereof in order to reconstruct a desired signal and to deconstruct an undesired signal.

16. A miniature phased array antenna electronics module as in claim 15, wherein said digital electronic circuitry comprises one or more filter elements and temperature control means for maintaining said one or more filter elements at a constant desired temperature.

17. A miniature phased array antenna electronics module as in claim 16, wherein said filter elements comprise surface acoustic wave (SAW) filters.

18. A miniature phased array antenna electronics module as in claim 15, wherein said digital electronic circuitry comprises a digital front end unit for digitizing said incoming antenna signals and temperature control means for maintaining said digital front end unit at a constant desired temperature.

19. A miniature phased array antenna electronics module as in claim 15, wherein said temperature control means comprises one or more temperature controlled ovens, each of which encloses a respective one of said one or more filter elements.