Directional planar log-spiral slot antenna

• US 8,193,997 B2
• Filed: 08/20/2009
• Issued: 06/05/2012
• Est. Priority Date: 08/20/2009
• Status: Active Grant

• Current Assignee: AntennaSys, Inc.
• Original Assignee: AntennaSys, Inc.
• Inventors: Webb, Spencer
• Primary Examiner(s): Phan, Tho G
• Application Number:
  US12/544,838
• Publication Number:
  US 20110043414A1
• Time in Patent Office: 1,020 Days
• Field of Search: 343/767, 343/792.5, 343/895
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/02 Arrangements for de-icing; Arrangements for drying-out ; Arrangements for cooling; Arrangements for preventing corrosion
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 11/10 Logperiodic antennas H01Q11/08 takes precedence
• CPC Class Codes: H01Q 13/106 Microstrip slot antennas patch antenna elements H01Q9/0407
• CPC Class Codes: H01Q 13/18 the slot being backed by, or formed in boundary wall of, a resonant cavity longitudinally slotted cylinder H01Q13/12 ; Open cavity antennas
• CPC Class Codes: H01Q 17/001 for modifying the directional characteristic of an aerial
• CPC Class Codes: H01Q 9/27 Spiral antennas
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making
• CPC Class Codes: Y10T 29/49018 with other electrical component

Abstract

Directional wide band antenna that may be utilized to enhance cell phone coverage within a building, or for signals intelligence collection (SIGINT). Includes a log-spiral slot antenna with feed-point configured to transfer energy to/from the antenna. Includes an energy absorbent backing and an energy absorbent siding coupled with the log-spiral slot antenna. Includes a cavity behind the log-spiral slot antenna and in front of the energy absorbent backing. Includes a cable connector coupled to a tapered microstrip line coupled to the feed-point wherein the tapered microstrip line is configured to transform the input impedance to the antenna impedance. Housed in a container configured to hold the above listed components. Energy absorbent siding, cavity and energy absorbent backing greatly reduces back lobes. Another embodiment has log-spiral shaped slots at an outer portion of the log-spiral slot antenna overlap with the energy absorbent siding and wherein the feed-point overlaps the cavity.

Claims

1. A directional planar log-spiral slot antenna comprising:

a log-spiral slot antenna comprising

a feed-point configured to transfer energy to and from said log-spiral slot antenna,

log-spiral shaped slots that begin at said feed-point and spiral outward and away from said feed-point toward an outer portion of said log-spiral slot antenna,

an antenna impedance;

an energy absorbent backing;

an energy absorbent siding coupled with said energy absorbent backing and further coupled with said log-spiral slot antenna;

a cavity behind said log-spiral slot antenna and in front of a portion of said energy absorbent backing;

a cable connector having an input impedance wherein said cable connector is coupled to the feed-point; and

,

a container configured to hold said log-spiral slot antenna, said energy absorbent backing, said energy absorbent siding, said cavity, said cable connector.

2. The directional planar log-spiral slot antenna of claim 1 further comprising:

a transformer coupled between the cable connector and the feed-point and configured to transform the input impedance to the antenna impedance.

3. The directional planar log-spiral slot antenna of claim 1 further comprising:

a tapered microstrip line coupled between the cable connector and the feed-point and configured to transform the input impedance to the antenna impedance and provide a balanced output.

4. The directional planar log-spiral slot antenna of claim 1 wherein said log-spiral shaped slots at said outer portion of said log-spiral slot antenna overlap with said energy absorbent backing and wherein said feed-point overlaps said cavity.

5. The directional planar log-spiral slot antenna of claim 1 wherein said log-spiral slot antenna is coupled with a printed circuit board.

6. The directional planar log-spiral slot antenna of claim 1 wherein said energy absorbent backing and said energy absorbent siding is constructed from polyurethane impregnated with carbon.

7. The directional planar log-spiral slot antenna of claim 1 wherein said energy absorbent backing and energy absorbent siding has a net resistivity that is greater than zero Ohms/Square.

8. The directional planar log-spiral slot antenna of claim 1 wherein said energy absorbent backing and energy absorbent siding has a net resistivity of 200 to 400 Ohms/Square.

9. The directional planar log-spiral slot antenna of claim 1 wherein said antenna impedance is 150 Ohms.

10. The directional planar log-spiral slot antenna of claim 1 wherein said input impedance is 50 Ohms.

11. The directional planar log-spiral slot antenna of claim 1 wherein said container is conductive.

12. The directional planar log-spiral slot antenna of claim 1 wherein said container further comprises a gas vent.

13. The directional planar log-spiral slot antenna of claim 1 wherein said container further comprises a gas vent that is configured to block moisture from entering said container.

14. The directional planar log-spiral slot antenna of claim 1 further comprising a radome coupled with said container.

15. A method for constructing a directional planar log-spiral slot antenna comprising:

coupling a log-spiral slot antenna to a container wherein said log-spiral antenna comprises

a feed-point configured to transfer energy to and from said log-spiral slot antenna,

log-spiral shaped slots that begin at said feed-point and spiral outward and away from said feed-point toward an outer portion of said log-spiral slot antenna,

an antenna impedance;

coupling an energy absorbent backing to said container;

coupling an energy absorbent siding with said energy absorbent backing and with said log-spiral slot antenna;

configuring a cavity behind said log-spiral slot antenna and in front of said energy absorbent backing;

coupling a cable connector having an input impedance to said container; and

,

coupling the cable connector and the feed-point.

16. The method for constructing a directional planar log-spiral slot antenna of claim 15 further comprising:

coupling a transformer between the cable connector and the feed-point; and

,

transforming the input impedance to the antenna impedance.

17. The method for constructing a directional planar log-spiral slot antenna of claim 15 further comprising:

coupling a tapered microstrip line between the cable connector and the feed-point; and

,

transforming the input impedance to the antenna impedance and providing a balanced output.

18. The method for constructing a directional planar log-spiral slot antenna of claim 15 further comprising:

overlapping said log-spiral shaped slots at said outer portion of said log-spiral slot antenna with said energy absorbent siding; and

,

overlapping said feed-point with said cavity.

19. The method for constructing a directional planar log-spiral slot antenna of claim 15 further comprising:

coupling a gas vent with said container.

20. The method for constructing a directional planar log-spiral slot antenna of claim 15 further comprising:

coupling a radome with said container.