Sheet antenna with tapered resistivity

• US 5,959,586 A
• Filed: 07/18/1997
• Issued: 09/28/1999
• Est. Priority Date: 02/06/1995
• Status: Expired due to Term

• Current Assignee: MegaWave Corporation
• Original Assignee: MegaWave Corporation
• Inventors: Benham, John R., Cross, Marshall W., Benham, Glynda O.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): Ho, Tan
• Application Number:
  US08/896,896
• Time in Patent Office: 802 Days
• Field of Search: 343/713, 343/700 MS, 343/846, 343/848, 343/895
• US Class Current: 343/713
• CPC Class Codes: H01Q 1/1271 for mounting on windscreens
• CPC Class Codes: H01Q 9/40 Element having extended radiating surface

Abstract

An antenna exhibiting a wide bandwidth, a low standing wave ratio, and a substantially omnidirectional radiation pattern. The antenna includes a sheet-like antenna element having a feedpoint, and an electromagnetic characteristic having non-uniform variation with distance across the element from the feedpoint. One use of the antenna is on a windshield.

Claims

1. An antenna exhibiting a wide bandwidth, a low standing wave ratio, and an essentially omnidirectional radiation pattern, the antenna comprising

an antenna element in the form of a sheet having

a feedpoint, and

a resistance per unit length having non-uniform variation with distance along the element from the feedpoint, the variation in resistance per unit length being achieved by a pattern of voids and non-voids along the element.

2. The antenna of claim 1 in which the element is generally rectangular.

3. The antenna of claim 1 in which the element is generally triangular.

4. The antenna of claim 1 in which there are multiple antenna elements each in the form of a sheet connected to the feedpoint.

5. The antenna of claim 4 in which the elements are in the form of fingers.

6. The antenna of claim 4 in which the elements radiate in a cone from the feedpoint.

7. The antenna of claim 1 in which the element is in the form of a monopole.

8. The antenna of claim 7 in which the monopole has more than two elements.

9. The antenna of claim 1 in which the element is formed as a loop.

10. The antenna of claim 1 in which the element is generally planar.

11. The antenna of claim 1 in which the non-uniform variation comprises a monotonically increasing value with distance from the feedpoint.

12. The antenna of claim 1 in which the element has a thickness profile that varies along the element.

13. The antenna of claim 1 in which the shape of the element is visually camouflaged.

14. The antenna of claim 1 in which the element has a width profile that varies along the length.

15. The antenna of claim 1 in which the width profile varies randomly.

16. The antenna of claim 1 in which the element is effectively transparent.

17. The antenna of claim 1 also comprising

a device for attaching the element to a transparent support layer.

18. The antenna of claim 1 also comprising a rigid transparent support.

19. The antenna of claim 18 in which the antenna element is incorporated as a safety laminate between layers of glass.

20. The antenna of claim 18 in which the transparent support comprises a window.

21. The antenna of claim 1 also comprising a sheet-like ground available in the vicinity of the feedpoint.

22. A window and antenna combination, comprising

a rigid transparent support, and

an antenna element in the form of a sheet attached to the rigid transparent support, the element having

a feedpoint, and

a resistance per unit length having non-uniform variation with distance along the element from the feedpoint.

23. A method of forming an antenna comprising

applying, to a substrate, an antenna element in the form of a sheet, the element having

a feedpoint, and

a resistance per unit length having non-uniform variation with distance along the element from the feedpoint, the variation in resistance per unit length being achieved by a pattern of voids and non-voids along the element.

24. The method of claim 23 wherein the substrate is rigid.

25. The method of claim 23 wherein the substrate is flexible.