Integrated high-gain active radar augmentor

• US 4,612,543 A
• Filed: 05/05/1983
• Issued: 09/16/1986
• Est. Priority Date: 05/05/1983
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: DeVries, James M.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Gregory, Bernarr Earl
• Application Number:
  US06/491,686
• Time in Patent Office: 1,230 Days
• Field of Search: 343/6.8 R, 343/5 R, 343/18 E, 343/856, 343/867, 343/872, 343/874, 343/875, 343/890, 343/700 MS, 343/18 B, 343/18 C, 343/16 M, 343/841, 343/885, 343/705, 455/7, 455/11
• US Class Current: 342/187
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26
• CPC Class Codes: H01Q 17/001 for modifying the directional characteristic of an aerial
• CPC Class Codes: H01Q 21/20 the units being spaced along or adjacent to a curvilinear path slotted waveguide arrays H01Q21/005; circularly or helically slotted waveguides H01Q21/0062

Abstract

A compact and integrated high-gain radar augmented system, including: a cylindrical microstrip receive antenna mounted on a cylinder for providing nominal omni-directional coverage, a transmit antenna similar to the receive antenna mounted on the same cylinder, isolating radio-frequency (RF) absorbing means located between the two antennas, and a high-gain amplifier located within the body of the cylinder and connected to the two antennas. The entire assembly can be covered by an RF radome for component protection.

Claims

1. An integrated and compact high-gain active radar augmentor for enhancing radar visibility, comprising:

a. An omni-directional receive antenna;

b. an omni-directional transmit antenna;

c. said omni-directional receive antenna and said omni-directional transmit antenna being axially oriented and integrally mounted about a metallic cylinder;

d. a cylindrical RF absorbing means having an inside diameter equal to the outside diameter of said metallic cylinder and being mounted on said metallic cylinder between said omni-directional receive antenna and said omni-directional transmit antenna for isolating said receive antenna from said transmit antenna such that required isolation between the two antennas is achieved by the strategic placement of said RF absorbing means between the two antennas;

e. a filter means housed within said metallic cylinder and connected to said receive antenna for selecting the band of input frequency to be processed;

f. a high-gain RF amplifier housed within said metallic cylinder and connected to the output of said filter means for amplifying the selected signal frequency band;

g. the isolation between said receive antenna and said transmit antenna being greater than the gain of said RF amplifier;

h. said transmit antenna being connected to the output of said Rf amplifier for re-radiating the amplified selected band of input frequency omni-directionally;

i. a directional coupler provided between said RF amplifier and said transmit antenna for allowing measurement of the amount of power being re-radiated via said transmit antenna;

j. said omni-directional receive antenna, said RF absorbing means, and said omni-directional transmit antenna being cylindrical in shape and connected to said filter means, said RF amplifier and related equipment which powers the augmentor which are housed within the metallic cylinder;

whereby simultaneous reception, amplification and retransmission of select radar signals is provided that enhance the radar visibility.

2. An active radar augmentor as in claim 1 wherein said receive antenna and said transmit antenna are each microstrip antennas cylindrically shaped to provide omni-directional coverage.

3. An active radar augmentor as in claim 2 wherein said cylinder is metallic and operates to provide a continuous ground plane beneath both the receive microstrip antenna and the transmit microstrip antenna for providing a higher isolation between the receive and transmit antennas by preventing diffraction which otherwise would occur between the two microstrip antennas.

4. An active radar augmentor as in claim 2 wherein said receive antenna and said transmit antenna are each microstrip antenna arrays of radiating elements including feed networks.

5. An active radar augmentor as in claim 1 wherein said RF absorbing means comprises a dielectric material loaded with carbon particles which operates to absorb incident microwave energy.

6. An active radar augmentor as in claim 5 wherein said dielectric material is polyurethane foam.

7. An active radar augmentor as in claim 5 wherein said dielectric material is a solid high-loss silicone rubber.

8. An active radar augmentor as in claim 1 wherein isolation between said receive antenna and said transmit antenna is greater than 60 decibels.

9. An active radar augmentor as in claim 1 wherein said RF absorbing means provides at least 20 decibels attenuation to incident signals.

10. An active radar augmentor as in claim 1 housed within the mast of a sea craft.

11. An active radar augmentor as in claim 1 wherein a radome is provided for protection of the components from the elements.

12. An active radar augmentor as in claim 1 wherein said RF absorbing means comprises a dielectric material loaded with ferrite particles which operates to absorb incident microwave energy.

13. An integrated and compact high-gain active radar augmentor for enhancing radar visibility, comprising:

a. An omni-directional receive microstrip antenna;

b. an omni-directional transmit microstrip antenna;

c. said omni-directional receive antenna and said omni-directional transmit antenna being axially oriented and integrally mounted about a single RF conducting metallic cylinder;

d. a cylindrical RF absorbing means having an inside diameter equal to the outside diameter of said metallic cylinder and being mounted on said metallic cylinder between said omni-directional receive antenna and said omni-directional transmit antenna for isolating said receive antenna from said transmit antenna such that required isolation between the two antennas is achieved by the strategic placement of said RF absorbing means between the two antennas;

e. a filter means housed within said metallic cylinder and connected to said receive antenna for selecting the band of input frequency to be processed;

f. a high-gain RF amplifier housed within said metallic cylinder and connected to the output of said filter means for amplifying the selected signal frequency band;

g. the isolation between said receive antenna and said transmit antenna being greater than the gain of said RF amplifier;

h. said transmit antenna being connected to the output of said RF amplifier for re-radiating the amplified selected band of input frequency omni-directionally;

i. said single RF conducting metallic cylinder on which said receive antenna, said RF absorbing means and said transmit antenna are axially mounted providing a continuous ground plane beneath both the omni-directional receive microstrip antenna and the omni-directional transmit microstrip antenna which produces a higher isolation between the receive and transmit antennas by preventing diffraction which otherwise would occur between the two microstrip antennas when mounted on separate ground planes;

whereby simultaneous reception, amplification and retransmission of select radar signals is provided that enhance the radar visibility.

14. An integrated and compact high-gain active radar augmentor for enhancing radar visibility, comprising:

a. An omni-directional receive antenna;

b. an omni-directional transmit antenna;

c. an RF absorbing means for isolating said receive antenna from said transmit antenna;

d. said receive antenna and said transmit antenna being integrally mounted on either side of said RF absorbing means such that required isolation between the two antennas is achieved by the strategic placement of said RF absorbing means between the two antennas;

e. a filter means connected to said receive antenna for selecting the band of input frequency to be processed;

f. a high-gain RF amplifier connected to the output of said filter means for amplifying the selected signal frequency band;

g. the isolation between said receive antenna and said transmit antenna being greater than the gain of said RF amplifier;

h. said transmit antenna being connected to the output of said RF amplifier for re-radiating the amplified selected band of input frequency omni-directionally, and means provided for measuring the power re-radiated by said transmit antenna;

i. said receive antenna, said RF absorbing means, and said transmit antenna being axially mounted on and about and forming a portion of an RF conducting housing which encloses said filter means, said RF amplifier and related equipment;

said RF conducting housing also operating to provide isolation between the two antenna;

whereby simultaneous reception, amplification and retransmission of select radar signals is provided that enhance the radar visibility.

15. An active radar augmentor as in claim 14 wherein said receive antenna and said transmit antenna are each microstrip antenna arrays of radiating elements including feed networks.

16. An active radar augmentor as in claim 14 wherein said RF absorbing means comprises high-loss silicone rubber material loaded with carbon particles which operates to absorb incident microwave energy.