US2489287A - Antenna - Google Patents

Description

Nov. 29, 1949 P. A. GUARINO ET AL 2,489,287

ANTENNA Filed March 26, 1946 2 Sheets-Sheet 1 mmvroas EANTHONY GUARINO DAvD WILLIAMS ATTORNEY Nov. 29, 1949 P. A. GUARINO ET AL 8 ANTENNA Filed March 26, 1946 2 Sheets-Sheet 2 INVENTORS P. ANTHONY GUARINO DAVID WILLIAMS ATTORNEY IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII Patented Nov. 29, 1949 ANTENNA Pasquale Anthony Guarino, Cleveland, Ohio, and David Williams, Washington, D. 0.

Application March 26, 1946, Serial No. 657,311

6 Claims. (Cl. 250---33..65)

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) This invention relates to antenna systems and more particularly, to a single antenna structure to provide omni-directional, non-polarized recep tion of radiant energy over a broad band of frequencies.

In a radio search receiver it is desirable for many purposes to receive any transmission of radiant energy without limitations because of its frequency, type of polarization, or position of source relative to the receiving antenna. To attempt this coverage with ordinary means would require numerous antennas: different antennas for each small change of frequency, additional antennas in each frequency band for different types of polarization, and additional antennas in each of these two classes to permit reception through 360. To accomplish this purpose with a single antenna structure provides a great economy of space, material, and expense, and will permit installations hitherto prohibited by insufiicient space.

An object of this invention is to provide an antenna system of simple construction capable of omni-directional, non-polarized reception over a wide band of frequencies.

Another object of this invention is to provide an antenna system of simple construction capable of omni-directional, non-polarized reception over a wide band of frequencies while maintaining satisfactory standing wave ratio and resistance characteristics (and more particularly, maintaining a standing wave ratio of less than two to one over a major portion of its frequency range).

Another object of this invention is to provide an antenna system of simple construction capable of omni-directional, non-polarized reception over a wide band of frequencies, which although designed for receiving purposes, meets the usual requirements for transmitting antennas.

Another object of this invention is to provide an antenna system of simple construction capable of omnidirectional, non-polarized reception over a wide band of frequencies, directly connectable by a transmission line to an unbalanced receiver means without requiring matching transformers or other balancing devices.

Another object of this invention is to provide an antenna ground pla which may combined with a suitable radi... W element so as to constitute an Omani-directional, non-polarized, antenna system.

Another object of this invention is to provide an antenna ground wh may be so incorporated with a suitable radiating element as to constitute a wide-band, omni-directional, nonpolarized antenna system.

Another object of this invention is to provide an antenna ground plane which may be so incorporated with a suitable radiating element as to constitute a wide-band, non-polarized antenna system.

Other objects and features of novelty of the invention will be made apparent by the following description and the annexed drawings, it being understood that such description and drawings are merely illustrative of the invention and impose no limitations thereon.

In the drawings:

Figs. 1 and 2 are side and top elevational views respectively of one typical embodiment of the invention;

Fig. 4 is a cross-sectional view taken thru line 44 of Fig. 3 and showing the antenna radiating element and the support therefor, and

Fig. 3 is an underside view of the antenna ground plane.

Briefly, the omni-directional, non-polarized, wide band antenna provided by this invention comprises a ground plane in combination with a suitable radiating element. The ground plane is tilted at an angle something less than with respect to the vertical and the radiating element is supported with respect to the ground plane in such a manner that its axis makes an angle of something less than 90 relative to the ground plane.

Referring, now, in particular to Figs. 1 and 2 of the drawings, it is seen that the ground plane comprises a series of co-planar, equal angularly disposed reflecting rods ll through I! radiating from a vertex. These reflecting rods are electrically secured to a suitable metallic base-plate member indicated at 5, Fig. 2, and are supported in a plane tilted at an angle 23 with respect to the vertical by cylindrical member 9. This departure from the vertical is necessary to accomplish nonpolarized operation. For purposes of permitting omni-directional reception or transmission, the reflecting rods Ii through ii are disposed about the vertex through some angle less than For the same reason, the base plate 5 is cut away as indicated at 25 in Fig. 2.

The radiating element as shown in Figs. 1 and 2 comprises in its preferred form, a conical shaped metallic member 6 which is terminated at its base in a hemispherical section 26. The conical radiating element 5 is so disposed with respect to the reflecting rods ll through l1 that its axis 20 intersects the vertex of the reflecting rods and lies in a plane perpendicular to both the plane of the reflecting rods and the plane which bisects the angle between the end reflecting rods II and I1. Additionally, it is tilted in this plane so that its axis 20 makes an angle therein (shown as angle 22 in Fig. 4) of something less than 90 with respect tothe plane of the reflecting rods.

Referring to Fig. 4, the apex of the cone is terminated in the center conductor of a connector 1 for the coaxial transmission line shown at 21 in Fig. 1. The connection for the outer contact of this connector is shown at'8', and is electrically joined to the ground plane through the conical conductor shown at 48 and. the base plate 5.-

This coaxial cable serves to connect the antenna system to a transmitter or receiver means and may be directly connected without the necessity of matching or balancing devices.

None of the physical dimensions of this invention is especially critical. Except in respect to back pick up; the size of the ground plane constitutes a limiting factor only at the lower extremity of the frequency range. It should have a radial dimension greater than one-quarter wave length for the low end of the frequency band to be covered. For electri al purposes the ground plane becomes larger as the frequency increases. For this reason even the base plate 5 will become large enough to interfere with back pick up at the higher frequencies. The cone is of a length approximating something greater than one-eighth wave length at the low end of its frequency range and approximating three halves wave length at its high end. Supporting the conical radiating element midway between its base and its apex such as by the cylindrical insulating shell is extends its frequency range to a higher limit than otherwise possible.

In a specialized case an antenna constructed according to the following specification was found to operate very satisfactorily over a frequency band extending from 300 Inc. to 3000 me.

With reference to Fig. 4, the radius of curvature of the hemispherical section 26 of the control radiating element was set at 6%". The diameter of the cone base was set at 6.8". The cone was tilted. at an. angle 22 of 60 to the ground plane and is affixed thereto by a nonconducting member l9 supporting it about its center to prevent irregularities with the dielectric constant about the apex. For the same reason the supporting plugs shown at Zia and 2 lb are made of insulation with a dielectric constant approaching that of air.

With reference to Fig. 4, the base plate 5 has for its larger dimension a radius of 3" and for its smaller dimension, a radius of 1 inches. The reflecting rods llll are in length and aflixed' (brazed for example) to the periphery of the larger dimension of the base plate, establishing an overall distance of 18" from the vertex to the ends of the reflecting rods.

The displacement of the ground plane from the vertical as shown by the angle 23 in Fig. 1 is 45. The antenna system was connected by a 50 ohm coaxial transmission line shown at 21 in Fig. 1 to the input of an unbalanced receiver.

Although we have shown and described only a limited and specific embodiment of the present invention we are fully aware of the many modificationsv possible thereof. Therefore this invention is not to be limited except insofar as is necessitated by the spirit of the prior art and the scope of the appended claims.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1.. An antenna, comprising a radiating element and a ground plane reflector surface, said ground plane reflector surface comprising a series of radially extending reflecting rods lying in a plane which is tilted at an angle less than with respect to the vertical, and said radiating element being. sotil'ted with respect to said ground plane reflector surface that it makes an angle of something less than 90 therewith.

2. An antenna, comprising a radiating element symmetrically arranged about a longitudinal axis and a ground plane reflector surface, said ground plane reflector surface comprising a series of reflecting rods extending radially from a vertex and lying in a plane which is tilted at an angle less. than 90 with respect to the vertical, said reflecting rods being so arranged that the angle between the extreme end rods of said series is less than 180, and said radiating element being so disposed that its axis intersects the vertex of said reflecting rods and so tilted in a plane whichv is perpendicular to. both the plane of the reflector rods and. aplane which bisects the angle between the said end reflecting rods that its axis. makes an angle therein of something less than 90 with respect to the plane of the reflector rods.

, 3. An antenna, comprising a radiating element symmetrically arranged. about a longitudinal axis and a ground plane reflector surface, said ground plane reflector surface comprising a series of reflecting rods extending radially from a vertex and lying in a plane which is tilted at an angle of 45 with respect to the vertical, said reflecting rods being so arranged that the angle between the extreme end rods of said series is and said radiating element being. so disposed that its axis intersects the vertex of. said reflecting rods and so tilted. in a plane which is perpendicular to both the plane of the reflector rods and a plane which bisects the angle between the said end reflecting rods that its axis makes an angle of 60 therein with respect to the plane of the reflector rods.

4. An antenna, comprising a conical radiating element and a ground plane reflector surface, said ground plane reflector surface comprising a series of radially extending reflecting rods the plane of which is tilted at an angle less than 90 with respect to the vertical, and said radiating element being so tilted with respect to said ground plane reflector. surface that it makes an angle something less than 90 therewith.

5. An antenna, comprising a conical radiating element symmetrically arranged about a longitudinal axis and a ground plane reflector surface, said ground plane reflector surface comprising a series of reflecting rods extending radially from a vertex and lying in a plane which is tilted at an angle less than 90 with respect to the vertical, said reflecting rods being so arranged that the angle between the extreme end rods of said series is less than and said radiating element being so disposed that its axis intersects the vertex of said reflecting rods and so tilted in a plane which is perpendicular to both the plane of the reflecting rods and a plane which bisects the angle between the said end reflecting rods that its axis makes an angle something less than 90 with respect to the plane of the reflector rods.

an angle of 45 with respect to the vertical, said reflecting rods being so arranged that the angle between the extreme end rods of said series is 150, and said radiating element being so disposed that its axis intersects the vertex of said reflecting rods and. so tilted in a plane which is perpendicular to both the reflector rods and a plane which bisects the angle between the said end REFERENCES CITED The following references are of record in the file of this patent:

Niunber reflecting rods that its axis makes an angle of 15 60 therein with respect to the plane of the reflector rods.

P. ANTHONY GUARINO. DAVID WILLIAMS.

Number 5 UNITED STATES PATENTS Name Date Fessenden Mar. 8, 1904 Ludenia Mar. 27, 1934 Ponte Jan. 7, 1936 Hooven Oct. 25, 1938 Buschbeck Mar. 19, 1940 Aubert Dec. 30,1941 Granquist Dec. 21, 1943 FOREIGN PATENTS Country Date Germany July 7, 1937

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