SERPENTINE ANTENNA MOUNTED ON A ROTATABLE CAPACITIVE COUPLER

• US 3,716,861 A
• Filed: 03/22/1971
• Issued: 02/13/1973
• Est. Priority Date: 03/22/1971
• Status: Expired due to Term

• Current Assignee: John J. Root
• Original Assignee: John J. Root
• Inventors: Root, John J.
• Primary Examiner(s): Lieberman, Eli
• Application Number:
  US05/126,448
• Time in Patent Office: 694 Days
• Field of Search: 343/741,744,748,802,806,866,908,882
• US Class Current: 343/741
• 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

This disclosure teaches an antenna including a conductor disposed in a serpentine arrangement defined by a plurality of undulations, wherein the amplitude or size of the undulations determines the directivity of the antenna, and wherein the undulations function to cancel mutual inductance parameters of the antenna while increasing the capacitive reactance thereof, to yield broadband characteristics. The antenna can take a variety of shapes, as for example the undulations may all fall entirely in a common plane and generally define a circle, a square, or an ellipse, etc.; or, such undulations may be arranged to form a ring or other three-dimensional object. The said shape of the antenna and its disposition with the earth'"'"''"'"'s surface also contribute to the directivity of the antenna.

Claims

1. A broadband transmit/receive antenna comprising:

an antenna element having two ends and having between said two ends a continuous serpentine configuration defined by a plurality of serially connected together loop portions each orientated relative to its immediate adjacent loop portions to effectively cancel out mutual inductance occurring therebetween during use of the antenna;

support means for rotatably supporting said antenna element;

a pair of terminals connected to said support means and connectable to devices for transmitting and receiving electromagnetic energy during use of the antenna; and

means at least partially disposed interiorly of said support means for capacitively connecting each end of said antenna element to respective ones of said terminals.

2. A broadband transmit/receive antenna as set forth in claim 1, in which said plurality of loop portions comprise means defining a direct relationship between the capacitive reactance of said antenna element and the number of said loop portions.

3. A broadband transmit/receive antenna as set forth in claim 1, in which all said loop portions lie in a common plane.

4. A broadband transmit/receive antenna as set forth in claim 3, in which said plurality of loop portions comprise means defining an antenna directivity extending normal to said common plane when said loop portions are of equal size and are equal to one wavelength of the lowest frequency to be applied to said antenna, and said directivity is in said common plane when said loop-portions are of equal size and are equal to one-half wavelength of said lowest frequency.

5. A broadband transmit/receive antenna as set forth in claim 1, in which each said loop portion has a peak portion and a valley portion, and wherein each said peak portion lies in a first plane and each said valley portion lies in a second plane extending parallel to said first plane.

6. A broadband transmit/receive antenna as set forth in claim 5, in which said plurality of loop portions comprise means defining an antenna directivity extending normal to said first and second planes when said loop portions are of equal size and are equal to one wavelength of the lowest frequency to be applied to said antenna, and said directivity is in a plane parallel to said first and second planes when said loop portions are of equal size and equal to one-half wavelength of said lowest frequency.

7. A broadband transmit/receive antenna as set forth in claim 5, in which said plurality of loop portions form a hollow truncated cone having major and minor diameters, wherein said first plane is disposed at the minor diameter of said truncated cone and said second plane is disposed at the major diameter of said truncated cone, and wherein said plurality of loop portions comprise means defining an antenna directivity which is in a direction projecting outward from said first plane.

8. A broadband transmit/receive antenna as set forth in Claim 1, wherein said support means comprises a base member, an insulative sleeve, first and second conductive sleeve portions fixed on said insulative sleeve in axially spaced-apart relationship, means rotationally interconnecting said insulative sleeve with said base member, conductive means for electrically interconnecting one end of said antenna element to said first conductive sleeve portion and the other end of said element to said second conductive sleeve portion, first and second conductive terminals fixedly interconnected with said base member, an insulative tubular member fixed to said base member and disposed coaxially within said insulative sleeve, first and second conductive tubuLar members mounted in axially spaced-apart relationship on said insulative tubular member and extending coaxially and in opposed facing relationship with said first and second sleeve portions, respectively, and means connecting said first and second conductive terminals to said first and second tubular members, respectively.

9. A broadband transmit/receive antenna as set forth in Claim 1;

wherein said support means comprises a base member having connected thereto said pair of terminals, an electrically insulated tube connected to and extending outwardly from said base member and having around the exterior thereof a pair of peripherally extending and axially spaced-apart electrically conductive portions, a support plate having means therein defining an opening through which said tube extends, means mounting said support plate for rotational movement around said tube, a hollow member coaxially disposed around and spaced from said tube and connected to said support plate to undergo rotational movement therewith around said tube and having a pair of electrically conductive portions peripherally extending thereover and axially spaced-apart therealong each in opposing spaced-apart relationship from respective ones of said electrically conductive portions of said tube, and means electrically connecting said two ends of said antenna element to respective ones of said electrically conductive portions of said hollow member and electrically connecting said pair of terminals to respective ones of said electrically conductive portions of said tube, whereby said antenna element may be angularly displaced to vary the antenna directivity.