MULTITURN LOOP ANTENNA

• US 3,823,403 A
• Filed: 06/09/1971
• Issued: 07/09/1974
• Est. Priority Date: 06/09/1971
• Status: Expired due to Term

• Current Assignee: Benedikt A.A. Munk, Carlton H. Walter, Gary A. Thiele
• Original Assignee: Benedikt A.A. Munk, Carlton H. Walter, Gary A. Thiele
• Inventors: Walter, Carlton H., Munk, Benedikt AA., Thiele, Gary A.
• Primary Examiner(s): Lieberman, Eli
• Application Number:
  US05/151,228
• Time in Patent Office: 1,126 Days
• Field of Search: 343/705,708,895,908,867,718,744,745,787,846
• US Class Current: 343/708
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H01Q 1/286 substantially flush mounted with the skin of the craft
• CPC Class Codes: H01Q 19/09 wherein the primary active element is coated with or embedded in a dielectric or magnetic material protective material H01Q1/40, varying the electric or magnetic characteristics of refracting or diffracting devices H01Q3/44
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

The invention is a multiturn loop antenna of an efficient design suitable for use singly, in arrays, or for inductively exciting radiating currents on a structure - the surface and the elements radiating to achieve optimum system performance. The antenna may be fed balanced or unbalanced and its input impedance may be either capacitive or inductive. In a preferred embodiment for omnidirectional coverage the antenna is positioned in a dielectric or ferrite filled cavity; the antenna may be a single element for linear polarization or a pair of multiturn loops at right angles to each other and with 90* phasing to effect circular polarization.

Claims

1. An antenna comprising an electrically conducting surface, and a multiturn element having an overall length substantially at 1/4 wavelength or odd multiples thereof;

a capacitance means terminating one end of said multiturn element to said surface, and an unbalanced feed further comprising a matching capacitance.

2. An antenna system as set forth in claim 1 wherein said capacitor further comprises a capacitor in series with said multiturn element and said surface to finely adjust the apparent electrical length of said loops.

3. An antenna system as set forth in claim 1 wherein said capacitor further comprises a capacitor in parallel with said multiturn element and said surface to finely adjust the apparent electrical length of said loops.

4. An antenna system as set forth in claim 1 further comprises dielectric loading means of said multiturn element to lower the frequencies at which the resistance peaks of said elements occur.

5. The antenna of claim 1 wherein said multiturn loop is embedded in a ferrite material.

6. An antenna as set forth in claim 1 wherein said loop further comprises a discontinuity which varies the length of said loop as a function of said operating frequency.

7. An antenna of claim 1 wherein said multiturn loop is embedded in a dielectric material.

8. The antenna of claim 1 wherein said multiturn element comprises a first multiturn loop and a second multiturn loop to provide an omnidirectional radiation pattern.

9. The antenna of claim 1 wherein said first and second loops are positioned at right angles relative to one another.

10. An omnidirectional antenna of claim 8 wherein each of said multiturn loops is tuned to the same frequency.

11. An omnidirectional antenna of claim 8 wherein said first multiturn loop is tuned slightly lower and second multiturn loop tuned slightly higher than the operating frequency of said antenna.

12. An omnidirectional antenna of claim 9 wherein said right angle position comprises positioning said multiturn loops in a common plane.

13. An omnidirectional antenna of claim 9 wherein said right angle position comprises positioning said multiturn loops one above the other.

14. An omnidirectional antenna of claim 9 wherein said multiturn loops are intertwined one within the other.

15. An omnidirectional antenna of claim 9 wherein said conductive surface is a cavity and wherein said first and second right angle multiturn loops are positioned in said cavity.

16. An omnidirecTional antenna of claim 15 wherein said cavity is a single cavity and said loops are positioned in said single cavity.

17. An omnidirectional antenna of claim 15 wherein said cavity is a pair of cavities and said first multiturn loop is positioned in said first cavity and said second multiturn loop is positioned in said second cavity.

18. An omnidirectional antenna of claim 13 wherein said cavity further comprises material loading means for said loops to vary the resonant frequency of said loops.

19. An omnidirectional antenna of claim 16 wherein said material loading means is a dielectric.

20. An omnidirectional antenna of claim 16 wherein said material loading means is a ferrite.

21. An antenna system as set forth in claim 16 further comprises ferrite loading means of said loops to lower the frequencies at which the resistance peaks of said elements occur.