US2761140A - Antenna - Google Patents

Description

Aug- 28, 1956 G. B. ASHTON 2,761,140

ANTENNA Filed April 23, 1952 2 SheetsSheet l Aug. 28., 1956 G. B. ASHTON ANTENNA 2 Sheets-Sheet 2 Filed April 23, 1952 @Warn/e A United States Patent O M ANTENNA George B. Ashton, Riverside, lll. Application April 23, 1952, Serial No. 283,961

10 Claims. (Cl. 343-803) This invention relates to an antenna structure and more particularly'to an improved antenna of the folded dipole type.

One object of this invention is to provide an improved antenna of the folded dipole type which is simple in construction and cheap to manufacture. Another object is to provide such an antenna in which two folded dipoles are arranged in an opposed V-configuration with the effective ends of the dipoles adjacent the vertices of the Vs. A further object is to provide such an antenna which is readily adapted for transmitting or receiving radio waves which are either horizontally or vertically polarized.

Yet another object is to provide such an antenna which is equipped with reflector elements. And yet a further object is to provide such an antenna which is designed to operate efficiently on more than one band of frequencies and in which the reflector elements are spaced apart from each other to prevent interaction therebetween.

Further obects and advantages of my invention will appear from the specification and from the drawings in which:

Fig. 1 is a perspective view of one form of my invention;

Fig. 2 is a schematic drawing showing a circuit in which the antenna of Fig. 1 is used;

Fig. 3 is a perspective View of a modified form of my invention; Q

Fig. 4 is a schematic drawing showing a circuit in which the antenna of Fig. 3 is used; and

Fig. 5 is a schematic drawing showing another modification of my invention.

During the course of my description, I may refer to the antenna of my invention as either a transmitting or a receiving antenna. It is to be understood that no unnecessary limitation is to be inferred therefrom. My invention may be incorporated in either a transmitting or a receiving system unless there is a specific limitation to the contrary.

The form of my invention shown in Fig. l isI particularly adapted for use either alternately or simultaneously with horizontally and vertically polarized radio waves. In Fig. 1 a mast 10 is shown attached to a wall 11 by means of the bands 12 preferably so as to allow for direction-adjusting rotational movement of the mast when desired. A cross-arm 13 is attached to the top of the mast 10. An antenna fitting 14 is provided at one end of the cross-arm while a reflector fitting 15 is at the other end. These f1ttings are preferably of a suitable non-conducting material such as Lucite. t

The antenna indicated generally as 16 is supported by the four connectors 17, 13, 19 and 20 which serve the dual purposes of furnishing mechanical support to the antenna and providing means for making electrical connections thereto, as shall appear more fully later. The antenna 16 is preferably constructed of elongated electrically and mechanically continuons means, such as the length of rod or tube 21, formed or bent into two folded dipoles in opposed V-conguration as shown. In this form of my invention, each of the four legs or elements 2,761,140 Patented Aug. 28,1956

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`quency at which it is desired to operate the antenna.

Furthermore, the four legs or elements are preferably coplanar. The legs could, of course, be manufactured in sections and bolted together. i

The connectors 17, 18, 19 and 20 are electrically and mechanically connected to the antenna 16 at the vertices of the Vs, which are numbered, respectively, 26, 27, 28 and 29. These vertices are adjacent the common point or center of symmetry previously referred to, which lies preferably at or near the intersection of the projection of the axis of the cross-bar 13 and the common plane of the legs 23, 24, 25 and 26. The entire structure is preferably mounted so that the mast 10 is vertical and the'plane of the antenna is at right angles to the surface of the earth.

As previously mentioned, electrical connection may be made to the antenna at each of the vertices by means of the connectors 17, 18, `19 and 20. Consider first the sitnation if the antenna is energized at the points 27 and 29 as by the connection of a transmission line to the connectors 18 and 20. When the antenna is so energized the legs or elements 22 and 23 function as a first folded dipole, and the legs 24 and 25 function as a second folded dipole, the dipoles being in an opposed V-configuration. Radiation from the antenna would be essentially horizontally polarized. This antenna, of course, is not limited to use as a transmitting element but may be used in a receiving system, and if the input circuit of a receiver were connected to the vertices 27 and 29, the system would be adapted to receive the horizontally polarized component of a signal. The V-conguration of the dipoles gives the antenna a broad band pass characteristic.

`If, however, the antenna is energized at the points 26 and 28, the legs 22 and 25 will form one folded dipole, while 23 and 24 form a second folded dipole, the dipoles again being in opposed V-configuration. Radiation from the antenna will now be essentially vertically polarized.

By providing two transmission lines 30 and 31, one connected to the connectors 17 and 19 and the other to con nectors 18 and 20 as shown in Fig. 2, the antenna is adapted to be used to transmit or receive either horizontally or vertically polarized waves. A switch 32 may be provided to select the type of signal desired. Furthermore, if the antenna is energized by meansI of both transmission lines simultaneously, the radiated wave will be both horizontally and vertically polarized.

It is well known in the art that fading in a radio signal does not generally occur in both the horizontally and vertically polarized components of the wave at the same time. The antenna of my invention can be used with a standard receiver and switch 32 as shown in Fig. 2 to `malte available for instant use either component of the wave desired. My antenna also can be used advantageously with a diversity receiver which has two signal input channels, one connected to receive the horizontally polarized component of the signal and the other to receive the vertically polarized component, and only one output circuit. With such a receiver the effects of fading are minimized and by using my antenna, the necessity of spaced antennae is eliminated. My invention provides a single antenna which may be employed to provide both the horizontally and the vertically polarized signal components simultaneously, or either one individually, if desired.

lf unidirectional characteristics are desired `in the an-` tenna, reflector elements 33 and 34 may be attached to the rellector fitting 15. Reflector element 33 is in a subl` and` 25. and 24'. Reliectorelement 34 is in a substantially verticaLpositionand` cooperateswithwthe vertically polarized elements 22 and 25, and 23 and 24.

Figs. 3 and 4 show a modied form of my invention. PartsA inthesefigures`` corresponding to like parts in Fig.- ures; l and y2 willrbe given reference, numerals l0() higher than zthereferencenumeral given in Figs. l and 2. Again, a mast 111.0 is preferably secured to thev support 111 by means ofi the bands 112, while the upper end of the mast carriesfa cross-bar H3. Attached to one` endA of the cross-barV is an antennatitting 114, preferably of a nonconducting material. Connectors 40 and 41 `are electrically and mechanically connected to antenna 42, again providing a support means and means for making electrical connections thereto. The antenna 42 is preferably constructed of. elongated electrically and mechanically continuousmeans such` as a lengthof rod or tube 43 bent or; formed into twofolded dipoles in ,opposed V-coniiguration. The legs. or elements 44 and 45 form one dipole, while the legs 46 and 47 form a second dipole. The first dipole is designed to operate eiciently over one band of frequencies; while the second dipole operates efficiently over a second band of frequencies. The legs 44 and 45 of the rst dipole are of substantially the same length, preferably approximately one-fourth of a wave length at' the first frequency desired. The legs 46 and 47 are also. of substantially the same length, preferably onefourth of a wave length at the second frequency desired. A" transmission line 4S is electrically connected to the connectors 4t) and 4f. and is used to couple the antenna to the receiver or transmitter.

Reflector elements 49 and 5t) are provided, the element 494 being operatively associated with the upper dipole composed of legs 44 and 45, while element Sil is associated withthe lower dipole, legs 46 and 47. These reflector elements aresupported by, but electrically insulated from, the cross-bar 113 'as by the rods 51 and 52. The reector elements are spaced from each other both horizontally and vertically, whereby any interaction between them is prevented.

The length of elements 44, 4S, d6 and 47 may be designed, of course, so that the antenna responds to two adjacent bands of frequencies or, if desired, to two widely separated bands of frequencies. This antenna is particularly useful with present day television receivers, as tele* vision'broadcasts are on two widely vspaced frequency bands. Thus, a very versatile antenna is provided with which only one transmission line is needed to connect it to the'receiver or transmitter and in which reector elements provide unidirectional characteristics, but are spaced from each other thereby preventing interaction.

I have found that in designing an antenna for reception under adverse conditions, as for television reception in the so-called fringe areas, it is desirable to make use of both the horizontally and the vertically polarized components of the signal while employing only one transmission linefbetween the antenna and the receiver. Figure shows schematically a modil'ication of my invention which accomplishes this.

The antenna 60 is composed of four elements or legs 61, 62, 63 and 64 which are of substantially the same length and preferablysymmetrically arranged and equally spaced about a common point as in Figures l and 2. A

transmission line 65 is connected to one pair of opposed vertices 66 and 67. A length `oftransmission line68, one quarterwave length long, is connected between the first pair of opposed vertices 66 and 67 and the second pair of opposed- vertices 69 and 70. With this arrangement both the-horizontally and thevertically polarized components offthesignal are receivedrand fed in properly additive relation into a receiver (not shown) by means of the single transmission line 65.

WhilefI have shown and described certain embodiments ofemyinvention, itY is -to be understood that it is capable off-many'vmodications; Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scopey asdisclosed in the appended claims.

l claim:

l. A radio antenna of the character described, comprising: elongated electrically-continuous means formed in four elements each extending outwardly from and arranged symmetrically with respect to a common point to form a pair of folded dipoles in opposed V-conguration, with the vertices of said Vs being-.adjacent said common point; means for connecting a first transmission line to one pair of opposing vertices of said Vs; and means for connecting a second transmission line to the second pair of opposing vertices of said Vs.

2. A radio antenna system of the character described, comprising: elongated electrically-continuous means formed in four elements or" equal length each extending outwardly from and arranged symmetrically with respect to a common point to form a pair of folded dipoles in opposed V-coniiguration, with the vertices of said Vs being adjacent said common point; reflector elements operatively associated with said dipoles; a rst transmission line connected to one pair` of Opposing vertices of said Vs; and a second transmission line connected to the second pair of opposing vertices of said Vs.

3. A. radio antenna system of the character described, comprising: elongated electrically-continuous means formed in four elements of equal length each extending outwardly from and equally spaced about a common point to form a pair of folded dipoles in opposed V-coniiguration, with the vertices of saidfVs being adjacent said common point; reiiector elements operatively associated with said dipoles; a first transmission line connected to one r pair of opposing vertices of said Vs; and a second transgated member bent to form four elements of equal lengthA each extending outwardly from and arranged symmetrically with respect to a common point to form a pair offolded dipoles in opposed V-coniguration, with the vertices of said Vs being adjacent said common point; a first transmission line connected to one pair of opposing vertlces of said Vs; and a second transmission line con-vk nected to the second 'pair of kopposingvertices of said Vs.

5. A radio antenna-of thecharacter described, cornprising: an electrically and mechanically-continuous -conducting member bent to form four elements of equal length each extending outwardly from and equally spaced about a common point to form a pair of folded dipoles in opposed V-coniiguration, with the vertices of said Vsy common point; reliector elements operatively associatedl with said dipoles; a first transmission line connectedy to one pair of opposingvvertices of said Vs; and a second transmission line connected to the second pair ofA opposing vertices of said Vs.

l7. A radio antenna of the character described, comprising: an electricaliyand mechanically-continuous elongated'conducting member bent to form four elements of equal length each` extending outwardly fromand equally spaced about a common point to form a pair of-folded dipoles in opposed V-coniiguration, with the vertices-of said Vs being adjacent said common point; reflector elements operatively associated with said dipoles; a first transmission line connected tot one pair of opposing vertices of said Vs; and a second transmission line connected to the second pair of opposing vertices of said Vs.

8. A radio antenna of the character described, comprising: elongated electrically-continuous means formed in four elements each extending outwardly from and arranged symmetrically with respect to a common point to form a pair of folded dipoles in opposed V-conguration, with the vertices of said Vs being adjacent said common point; means for connecting a transmission line to one pair of opposing vertices of said Vs; and a quarter wave length section of transmission line connected between said one pair of opposing vertices and the second pair of opposing vertices of said Vs.

9. A radio antenna of the character described, comprising: an electrically and mechanically-continuous elon gated conducting member bent to form four elements of equal length each extending outwardly from and equally spaced about a common point to form a pair of folded dipoles in opposed Vconguration, with the vertices of said Vs being adjacent said common point; reector elements operatively associated with said dipoles; a transmission line connected to one pair of opposing vertices of said Vs; and a quarter wave length section of transmission line connected between said one pair of opposing vertices of said Vs and the second pair of opposing vertices of said Vs. l

10. A radio antenna of the character described, comprising: elongated electrically-continuous means formed in four elements each extending outwardly from and arranged symmetrically with respect to a cornrnon point to form a pair of folded dipoles in opposed v-conguration, with the vertices of said Vs being adjacent said common point; means for connecting a transmission line to one pair of opposing vertices of said Vs; and a section of transmission line connected between said one pair of opposing vertices and the second pair of opposing vertices of said Vs.

References Cited in the file of this patent UNITED STATES PATENTS 2,268,664 Landon Jan. 6, 1942 2,486,872 Parker Nov. l, 1949 2,531,035 Epstein Nov. 21, 1950 2,533,529 Spindler Dec. 12, 1950 2,572,166 Lorusso Oct. 23, 1951 2,585,636 Dome Feb. 12, 1952 2,609,503 Middlemark Sept. 2, 1952 2,613,349 Kandoian Oct. 7, 1952 2,617,935 Best Nov. 11, 1952 OTHER REFERENCES Radio and Television Retailing, March 1948 edition, page 25.

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