Discontinuous mobile antenna

• US 4,940,991 A
• Filed: 01/09/1989
• Issued: 07/10/1990
• Est. Priority Date: 04/11/1988
• Status: Expired due to Fees

• Current Assignee: Modublox & Company Incorporated, SKY Probes, Inc.
• Original Assignee: Modublox & Company Incorporated
• Inventors: Sheriff, Jack W.
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): Wimer, Michael C.
• Application Number:
  US07/294,186
• Time in Patent Office: 547 Days
• Field of Search: 343/795, 343/828, 343/829, 343/846, 343/897, 343/899, 343/792.5, 343/872, 343/807, 343/905, 343/792
• US Class Current: 343/795
• CPC Class Codes: H01Q 9/28 Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00

Abstract

A discontinuous panel shaped element forms one of the radiating dipole members of a radio frequency mobile antenna fed by a coaxial cable. The discontinuous element decouples antenna currents in the coaxial cable placed at short to medium distances from the element, while maintaining matched element performance as a long distance transmitter. The radiating elements are surrounded by an insulating material which serves as a dielectric, further improving antenna performance and also serving as environmental protection. The radiating elements are made from readily available sheet stock materials aligned in a generally planar configuration. The discontinuous dipole member is attached to the shield and the other dipole member is connected to the center lead of the coaxial cable. A small section of the central cable conductor is stripped of insulation and shielding, to serve as a miniature loading coil for loading the first plate-type conductive element. The specific geometries tested produce antenna performance that is generally insensitive to dielectric variations of as much as 25%.

Claims

1. An antenna connectable to a radio communication device which consists of:

a first conductive panel-shaped, generally oblong element;

a second conductive panel-shaped, generally oblong element having a different geometry;

said elements being aligned in a same plane along their largest axes and defining a gap between two respective adjacent edges of said elements;

a coaxial cable, connectable at a distal end to the communication device and having a proximal end section running parallel to said largest axes along said first element and terminating within said gap;

a first conductor in the center of said cable being connected at said proximal end to the edge of the second element adjacent to the first element;

a second conductor of said cable forming a sleeve around said first conductor and being connected at said proximal end to the edge of the first element adjacent to the second element;

said first element having a discontinuous construction;

an oblong container completely enclosing said conductive elements and said end section of the cable, said container being made of a dielectric material having a dielectric strength greater than air.

2. The antenna as claimed in claim 1, wherein said second conductive element is a made of brass shim stock material having a thickness ranging from 0.13 mm to 0.25 mm and a maximum dimension of less than 6.5 cm.

3. The antenna as claimed in claim 2, wherein said first conductive element is made of brass shim stock material having perforations and notches along one edge, and a thickness ranging from 0.13 mm to 0.25 mm and a maximum dimension at least equal to said maximum dimension of said second planar element.

4. The antenna as claimed in claim 3, wherein the distance between said adjacent edges is generally equal to the external diameter of said coaxial cable within one order of magnitude.

5. The antenna as claimed in claim 4, wherein said perforated element and said second conductive element have generally symmetrical external shapes.

6. The antenna as claimed in claim 5, wherein said conductive elements are generally spaced with 0.32 cm of said dielectric material of said container.

7. The antenna as claimed in claim 6, wherein said diameter of said coaxial cable is approximately 0.64 cm.

8. The antenna as claimed in claim 1, wherein said discontinuous element is a mesh-type structure in a parallelepiped shape made of brass wire approximately 0.0254 cm in diameter woven in a 40×

40 mesh, having 40 openings per 2.54 cm vertically, 40 openings per 2.54 cm horizontally.

9. The antenna as claimed in claim 1, wherein said discontinuous first conductive element is a planar shape having a notched edge, wherein said notched edge forms a structural shape having a plurality of branches.

10. The antenna as claimed in claim 1, wherein said discontinuous first element is a planar shape having a saw toothed edge.

11. The antenna as claimed in claim 9, wherein said notched element also comprises interior perforations.