US3434145A - Double loop antenna array with loops perpendicularly and symmetrically arranged with respect to feed lines - Google Patents

Description

March 18, 1969 D. H. WELLS 3,434,145

DOUBLE LOOP ANTENNA ARRAY WITH LOOPS PERPENDICULARLY AND SYMMETRICALLY ARRANGED WITH RESPECT TO FEED LINES Filed Aug. 1, 1966 Sheet or s FIG.I

INVENTOR. DONALD H. WELLS ATTORNEY March 18, 1969 D. H. WELLS 3,434,145

DOUBLE LOOP ANTENNA ARRAY WITH LOOPS PERPENDICULARLY AND SYMMETRICALLY ARRANGED WITH RESPECT TO FEED LINES Filed Aug. 1, 1966 Sheet of 5 I r \7 4 U {f J lOl 95' FIG. 2

33 35 IO6\ f 53 80 8| l/a 80\67a/8| S 51 67 55 57 -4| INVENTOR.

-39 1.09 DONALD H. WELLS FIG. 3 [-16.4 I ATTORNEY March 18, 1969 0. H. WELLS 3,434,145

DOUBLE LOOP ANTENNA ARRAY WITH LOOPS PERPENDICULARLY AND SYMMETRICALLY ARRANGED WITH RESPECT TO FEED LINES Filed Aug. 1, 1966 7 Sheet 3 of 5 I 114 LOOP I69 LOOP 219 i'iLi L ii- M 9O' 2 I8 |93 86 2 I8 e i 1! l8// 7 92/; 1/ 73 I8" 64 l 2n n 64" 2o" 59 I/ 54" 2o" 223 (:ZZI

64 2u 22/1 33 22 20' 209 I95 I97 1 30 8 l u 221/ 4 ZIO 115 811 4/! j: 5" 24" 5 INVENTOR. DONALD H. WELLS ATTORNEY March 18, 1969 0. H. WELLS 3,434,145

DDUBLE LOOP ANTENNA ARRAY WITH LOOPS PEHPENDICULARLY AND SYMMETRICALLY ARRANGED WITH RESPECT TO FEED LINES Filed Aug. 1, 1966 Sheet 4 of 5 WWW 1 i Q FIG. 9

' [g INVENTOR. DONALD H. WELLS March 18, 1969 o. H. WELLS 3,434,145

DOUBLE LOOP ANTENNA ARRAY WITH LOOPS PERPENDICULARLY AND SYMMETRICALLY ARRANGED WITH RESPECT TO FEED LINES Filed Aug. 1, 1966 Sheet 5 of 5 FIG. IO

INVENTOR.

ATTORNEY DONALD H. WELLS United States Patent F 17 Claims ABSTRACT OF THE DISCLOSURE This invention relates to an open loop antenna and the means of electrically connecting it to a pair of lead conductors, which means may include a specific dielectric support connection therefor. More particularly, it deals with an array of such loop antennas capactively and/ or integrally coupled together to form one or more figure 8 configurations so as to produce a high gain over a wide frequency band.

BACKGROUND OF INVENTION The increased use of the UHF in television broadcasting has created a need for an efficient antenna which will give a high gain over a broad band of frequencies and continue to do so even after a prolonged period of exposure to the weather. A high gain is achieved over a broad band generally by connecting a plurality of antenna elements together in an antenna array. Up to the present time the known style of the antenna elements and the method of stacking and coupling antenna elements together via feed or transmission lines has greatly restricted the number of elements which may be effectively coupled together in an array. One of the problems involved in producing a high gain 'broad band antenna is the fact that ultra high frequency (UHF) wave energy is readily lost, attenuated or otherwise altered at the antenna. This is particularly true at points in the antenna where the wave energy is transferred to or from feed lines through electrical contacts which may become corroded and partially or completely open during use. A change in the conductive properties of such electrial contacts after the antenna is put into operation, will cause the precisely established phase relationships between coupled antenna elements to be altered, which change will cause a reduction of the antennas original efficiency.

DESCRIPTION OF INVENTION Objects and advantages It is an object of this invention to produce an antenna which will provide a high gain over a frequency band having a ratio of about 2:1 between high and low frequencies.

Another object of this invention is to produce a directional antenna which has narrow horizontal and vertical response patterns.

Another object is to produce an antenna which retains its original performance efliciency even after prolonged exposure to the weather.

Another object is to produce a unidirectional antenna array having a non-resonant reflector and/or a loading means to provide a high front to back ratio.

Still another object of this invention is to produce an antenna array in which a large number of antenna elements may be coupled together by a pair of lead conductors which are sufficiently isolated from the antenna elements to avoid one element of the array from attenuating another element in the array, so that each element will maintain its Q without becoming de-tuned.

It is another object to produce an array of open loop antennas in which pairs of loop antenna elements are 3,434,145 Patented Mar. 18, 1969 connected together at their high impedance points either directly or through a capacitance and also connected through a capacitance to a pair of lead conductors, so that some of the energy in one loop is radiated to another loop.

It is another objet to produce an antenna having a foldable open loop antenna element, the ends of which are each supported and capactively coupled to a pair of parallel feed conductors by a unique dielectric connecting means.

Still a further object of this invention is to produce a UHF open loop antenna array which may be coupled in combination with very high frequency (VHF) and/or (FM) frequency modulation radio antennas.

Still a further object of this invention is to produce a loop antenna of an improved mechanical design which has a novel appearance, encompasses a maximum frontal area with a limited peripheral length, is compact, easy to assemble, mechanically rugged and has little wind resistance.

Brief description of the views The above mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be understood best by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view looking upwardly from the right of one embodiment of this invention comprising two equal length generally circular open loop antennas disposed a common plane and rigidly held in a spaced relationship with respect to each other and with respect to an intermediate pair of lead conductors by a dielectric bracket;

FIGS. 1a, lb, and 1c are electrical wave diagrams for the relative values of the current, voltage, and impedance, respectively, in an antenna for one, three halves, and two wave lengths of applied radio energy;

FIG. 2 is a front elevational view of a double loop antenna with a part broken away, of another embodiment of this invention, similar to that of FIG. 1, but with generally square loops which are fo-ldably held by a resilient dielectric bracket;

FIG. 2a is a side elevational view of the antenna of FIG. 2 showing additional details of the resilient bracket;

-FIG. 3 is a front elevation view on a reduced scale of a double loop antenna of a further embodiment of this invention, also similar to FIGS. 1 and 2, but with the loops joined together rather than spaced apart, and having a conductive support connected between low impedance points of each loop;

FIG. 4 is a front elevation view of a double loop antenna of still a further embodiment, similar to the antenna of FIG. 3, but with a folded quarter wave length supporting stub integrally connected between the high impedance ends of the loops;

FIG. 5 is a front elevation view on a reduced scale of an array of three double loop antennas similar to FIG. 1 vertically disposed in a vertical plane on a mast with the inner double loop antenna capacitively coupled to a pair of lead conductors and inductively coupled to the outer double loop antennas;

FIG. 6 is a side elevation view on a reduced scale of an array of three double loop antennas similar to the antenna of FIG. 1 spaced apart one quarter of the mean applied wave length, in a horizontal row and capacitively coupled to a pair of parallel lead conductors;

FIG. 7 is a front elevation view on a reduced scale of a unidirectional array having an antenna similar to FIG. 1 disposed in front of a grid type reflector;

FIG. 8 is a perspective view of an array embodying the present invention, of a row of three double coplanar loops integrally connected to each other and to a pair of parallel lead conductors with the double loops at one end shunted to produce a reflector;

FIG. 9 is a perspective view of a broad band unidirectional UHF array with a plurality of groups of double loop antennas similar to FIG. 2 parallelly disposed and horizontally spaced apart about one quarter of the mean wave length of the applied radio band, and having a nonresonant reflector at one end;

FIG 9a is an enlarged underside view of the mast and mast clamp of the array shown in FIG. 9 showing the oil?- set lead conductors and their insulative support;

FIG. 9b is a schematic electrical diagram of the array in FIG. 9 showing the spacing, loop lengths, a loading means between the ends of the lead conductors at the front end of the array, and feed line terminals and reflector at the opposite end;

FIG. 10 is a perspective view of a combination VHF (very high frequency) and FM (frequency modulation) dipole antenna and UHF antenna array of double loop antennas similar to FIG. 2, having common lead conductors with insulating coils substantially between the VHF and UHF sections of the array; and

FIG. 10a is a schematic electrical diagram of the antenna of FIG. 10 showing also the cross phasing between the VHF antenna dipole elements, the parallel phasing between UHF loop antennas, and a high impedance quarter wave length stub capacitively coupled between the open ends of the lead conductors adjacent the UHF loop antennas.

Detailed description FORMS The characteristic geometry of the individual planar loop elements of this invention is important because the effectiveness of an antenna element is dependent upon the planar area it encompasses, just as the gain of an antenna array is dependent upon the volumetric displacement of the array.

FIGS. 1 and 8 show coplanar double loop antenna assemblies and 22 comprising generally circular symmetric loop open elements 24 and 24', and 26 and 26, respectively, each loop of which encompasses a maximum area for a limited peripheral length. The otherwise circu- Iar loops 24 and 24 may each have straight foot sections 28 and 30, and 28' and 30', respectively, adjacent their openings.

FIGS. 2, 3 and 4 show similar coplanar double loop antenna assemblies 31, 33 and 35 comprising generally square open loops 37 and 37, 39 and 39, and 41 and 41' respectively, each loop of which encompasses an area satisfactorily near a maximum for a limited peripheral length, but deviates slightly from a maximum for the sake of manufacturing expediency or for other practical reasons. The generally square open loops 37 and 37 shown in FIG. 2 have slightly arcuate sides and rounded corners with a pair of parallel continuations or supporting legs 43 and 45, and 43 and 45' extending outwardly symmetrically from the opening of the loops 37 and 37'. Each of the legs 43 and 45, and 43' and 45 may terminate, respectively, in a perpendicular foot section 47 and 49, and 47' and 49.

The generally square loops of antenna assemblies 33 and 35 each have jointly shared sections 51 and 53, and 55 and 57 adjacent their respective loop openings which sections may be made of a single wire or rod as shown in FIGS. 3 and 4 or they may be made of two closely adjacent parallel wires or rods.

The characteristic geometry of these double loop antenna assemblies 20, 22, 31, 33 and 35 is a figure 8 configuration with a discontinuity at the cross-over. Each such assembly comprises two open loop antennas symmetrically disposed in a plane closely adjacent each other with their open ends facing each other. The discontinuity may comprise a lateral opening in the cross-over section of the figure 8 as shown in FIGS. 3 and 4 where the spacing between loops 39 and 39', and 41 and 41 is zero and the ends of one open loop are integrally joined with the ends of the other loop forming the jointly shared sections 51 and 53, 55 and 57, respectively. The double loop antenna assembly 22 in FIG. 8 also has a lateral opening in the cross-over region of the figure 8, but the loops 26 and 26 are spaced apart, with the open ends of loop 26 being joined to adjacent ends of loop 26' by means of integrally connected short spanning bars 60 and 62. The discontinuity may be a longitudinal opening in the figure 8 such as shown in FIGS. 1 and 2 where the open loops 24 and 24', and 37 and 37, are spaced from each other a short distance and not conductively connected. In all cases the discontinuity or longitudinal opening between the ends of an individual loop, exceeds the lateral spacing between the two coplanar loops of the double loop antenna assembly, which latter spacing may be small or zero.

The open loop antennas are made from a conductive material, such as an aluminum tube or wire rod having a diameter of about Ms" and with a length which resonates at about the mean wavelength of the frequency it is to detect.

THEORY FIGS. 1a, 1b and 1c are diagrams showing respectively the current, voltage and impedance along a conductive dipole or any radio antenna, as it responds to frequencies having wave lengths of 7\, 3M2 and 2x. For these three wavelengths, the magnitude of the impedance reaches a peak at the outboard ends of the dipole and this impedance condition makes the outboard ends of the dipole an ideal feed point, especially in a broad frequency band application where the ratio between high and low frequencies is two to one.

The voltage distribution along a loop antenna having a length corresponding to X, 3M2 and 2A is not adversely changed by bending but remains substantially the same as that along a straight antenna of the same length.

The horizontal directional radiation or response pattern for a straight dipole at frequencies producing standing waves A, 3M2 and 27\ has a poor directional radiation pattern with four equally spaced major lobes each disposed at an angle of 45 to the dipole element. However, when the dipole is bent in a vertical plane to form an open loop, such as the circular open loops 24 and 26 shown in FIGS. 1 and 8 or the generally square open loops 37, 39 and 41 shown in FIGS. 2, 3 and 4, the directional radiation or response pattern comprises two major lobes each perpendicular to the plane of the loop which pattern signifies a substantial increase in the directionality of the wave propagation. The response pattern of such a single loop antenna may be sharpened or made narrower in the vertical plane by the addition of another symmetrical loop antenna disposed in the same vertical plane as that of the first loop and forming an antenna assembly, such as the above described figure 8 antenna assemblies. Thus radiated waves are polarized in a plane tangent to the open ends of the loops, and radiate perpendicular to the plane of the double loop assembly.

Since the electrical properties of both loops of the double loop assembly are the same, the ends of the one or top loop may be coupled to the corresponding adjacent ends of the other or bottom loop (see FIGS. 3, 4 and 8) and/or to a transmission line. Even substantial portions adjacent the corresponding ends of the top and bottom loops may be conductively joined together or may be made as a single member as shown in FIGS. 3 and 4.

COUPLING The high impedance ends of each loop antenna may be capactively (see FIGS. 1, 2, 3, 4) or conductively (see FIG. 8) coupled to a pair of lead conductors. Capacitive coupling may be accomplished by a dielectric support bracket 64 or 65 (see FIGS. 1 and 2) having means for supporting and holding each loop end a fixed small dis tance of about one eighth of an inch from its respective lead conductor. This spacing provides a capacitance between the line and the loop end of the antenna of about 0.5 of a micromicrofarad. The dielectric brackets 64 and 65 may be molded in the form of a generally rectangular cross-piece from a plastic material having a dielectric constant preferably near 3.8 (dry air having a dielectric constant of 1.0). The bracket 65 may be fitted partially around a supporting member 67 or boom and be held in a fixed position thereon by a fastening means such as a rivet 69. The ends 72 and 74, and 75 and 77 of each bracket 64 and 65, respectively, may extend outwardly a substantial distance on either side of a support and may contain seats, apertures, grooves, or holes for the loop ends, and transverse grooves, holes or slots spaced between them for one of each of a pair of phasing lines or lead conductors 80 and 81.

The bracket 64 shown in FIG. 1 may be made of a relatively rigid plastic having seats or fixed holes 84, 84 86, 86 capable of holding the antenna loops 24 and 24' in a planar relationship with respect to each other by finmly gripping their inturned ends or feet 28, 28', 30 and 30.

The dielectric bracket 65 shown in FIG. 2 may be made of a resilient plastic and have a means for contain ing, retaining or seating the ends of feet 47, 47', 49 and 49' of the pair of loops 37 and 37 so they may be pivoted into a vertical or operating position shown in full lines in FIG. 2a from a horizontal, folded or parallel to boom position shown in dashed lines. This foldability facilitates packaging and shipping of antenna arrays such as shown in FIG. 9 comprising a substantial plurality of such loop antennas. The pivot means may include a pair of horizontally aligned spaced apart open ended trough or slots 87 and 89, and 87 and 89 adjacent the top and bottom of the bracket 65 into which slots the ends or capacitive feet 47 and 49, and 47 and 49 may be readily inserted by squeezing the ends of the loop toward each other, aligning them with their respective slots, and releasing them to spring into the open ends of the slots Where they are retained in part by the outward inherent spring force of the loops themselves. A vertical abutment means 91 and 93, and 91' and 93' may be located adjacent the open end of each slot along with a cooperating resilient latch finger 95 and 97, 9'5 and 97 Which has an inclined contact surface 99, 99 for being engaged by the legs 43 and 45, and 43' and 45' of the loops 37 and 3-7. The rotation of the loops from the folded position towards the operating position causes the legs of the loop to contact the inclined surfaces 99 and 99' (see FIG. Zn) on the spring latches 'which are wedged inwardly until the loop element contacts the abutment means at which point a detent section 101 and 101' (see FIGS. 2 and 2a) in each spring latch falls behind its respective leg of the loop element to hold the loop in the vertical or operating position.

The troughs 87 and '89 may be vertically spaced apart from troughs 87' and 89' a sufficient distance to accommodate a lead conductor 80 or 81 between each pair of adjacent loop ends, such that a fixed capacitance of about 0.5 micromicrofarad is established between each loop end and its respective lead conductor. A clothespin type gap means 103 and 105 opening towards the outer ends of the bracket 65 may be provided so that each of a pair of lead conductors 80 and 81 may be snapped into place and firmly held in the bracket. This structure promotes ease of assembly and economy especially when a large number of double loop assemblies are stacked in a columnar array. A rigid lead conductor made of about A3 aluminum rod was found to be well suited for this purpose and also provides some additional rigidity to the array.

The support for the double loops in FIG. 3 comprises a conductive rod or bar 106 integrally connected to midpoints of loops 39 and 39, i.e. bet-ween their low i-rnpedance portions, which bar 106 may be directly and fixedly connected to the boom 67. The common free ends 51 and 53 of the loops 39 and 39 may be capacitively or conductively coupled to the lead conductors and 81, respectively, and spaced from the boom -67 and bar 106.

The support bracket for the double loop assembly 35 shown in FIG. 4 may comprise a folded conductive U- shaped stub section 109 M4 in length with its ends integrally connected to the free ends of sections 55 and 57 of the loop assembly and its base portion integrally connected to the boom 67. The inner ends of sections 55 and 57 may be insulatively supported or capacitively joined to a pair of lead conductors 80 and 81.

ARRAYS The double loop planar antennas shown in FIGS. 1, 2, 3 and 4 are bi-directional. A substantial gain may be realized by stacking such antennas in a vertical plane or in a horizontal column.

FIG. 5 shows a vertical array 108 comprising three double loop antenna assemblies 110, 112 and 114 like the antenna assembly 20 shown in FIG. 1. The center antenna 112 may be capacitively coupled to a pair of lead conductors, while the outer antennas and 114 are only inductively connected to the center antenna 112. Similar arrays with more elements such as with five or seven antennas are also practical.

FIG. 6 shows a bi-directional array 116 of three double loop antennas 118, 120 and 122, like antenna 20, which are stacked in a horizontal column with each antenna capacitively coupled to the same pair of lead conductors 80, 81.

Antenna arrays may be made unidirectional by the addition of a nonresonant reflector, such as shown in FIG. 7, where a capacitively coupled double loop antenna 124 is disposed about M 4 (one quarter wavelength at the mean frequency) in front of a semi-grid type inductance or reflector 126.

FIG. 8 shows a unidirectional array 128 comprising two integrally connected double loop antennas 22 and 130 in front of a reflector 132, all in an aligned row spaced )\/4 from each other. The reflector may have the same outside configuration as the other antennas 22 and 130, but also having centrally located horizontal shunts 134 and 134' across each of its loops. A pair of conductor rods 136 and 138 may be integrally connected, one on each side of the central section of each double loop antenna 22 and 130 and similarly to the shunted reflector 132. The array may be supported by a mast clamp 140 integrally connected, such as by welding, to the rear side of the reflector 132 adjacent the ends of conductor rods 136 and 138, so that the sections of rods 136 and 138 between the antenna 130 and reflector 132 together with the clamp 140 across the ends of these sections, forms a U-shaped quarter mean wave length shunt from the center double loop 130. Terminals 142 and 144 for connecting lead-in wires may be integrally attached at the junctions of lead conductors connected to the center antenna 130.

The tapered unidirectional array 147 shown in FIG. 9 has a plurality of groups of double loop antennas spaced along a horizontal boom 67 and capacitively coupled to a pair of parallel phasing lines or lead conductors 80 and 81. The front end of the array may contain a group of six small equal size double loop antenna assemblies 149, like the one 31 shown in FIG. 2, having a loop length corresponding to the wave length of the highest frequency to be detected in the operational frequency band, for example, about 25% more length than shown in FIG. 9b. Then the second, third and fourth groups 151, 153, each may comprise four similar double loop antennas having loop lengths corresponding respectively to the remaining successive quarter segments in the operational frequency band, for example in FIG. 9b, up to about 25% less than the lowest operational frequency to be detected. Thus, the lengths of the loops along the boom 67 in this specific array, having a frequency band width of about 2:1, may vary from about one to three halves of the mean wave length of the applied frequency band. The double loop antenna assemblies may be horizontally spaced along the boom 67 at approximately one fourth of their wave length, such as is shown schematically in FIG. 9b. The loops of each group are the same size to facilitate manufacturing but a more smoothly tapered array could be produced if the loops were made sequen tially larger, going from the front to the back of the array. Similar tapered arrays but with fewer double loops may also be used to produce substantial gain.

In this and other arrays of this invention a deliberate mismatch is provided between each loop antenna and the lead conductors so only a portion of the electrical energy in an antenna loop is transmitted through the capacitance to the lead conductors, while a substantial portion of the energy is radiated back into space in phase to the adjacent antenna loops. Thus the signal is reinforced as it travels along the array. Also the lead conductors are sufliciently isolated by their capacitive couplings through the supporting brackets 65, to reduce or prevent an attenuating interaction between them, which interaction has been a serious problem in the past in lengthy arrays.

The front to back ratio of the array is improved by a non-resonant reflector assembly 157 provided at the back of the array 147 spaced approximately one-fourth of a wave length from the last double loop antenna. The nonresonant reflector may have an odd number of horizontal reflector bars 161 spaced vertically apart and attached to a short mast 163 by means of a pivotal bracket 165 having a pair of spring tabs for embracing opposite sides of the mast 163 and holding the bars 161 in operating position. The reflector assembly 157 may be removably attached to the rear end of the boom 67 by a bracket means 167 located adjacent the center reflector bar.

The front to back ratio may be further improved in lengthy arrays such as shown in FIG. 9, by providing a resistive load 169 (see FIG. 9b) across the end of the lead conductors 80 and 81 opposite the feed line terminals 173 and 175 which are located adjacent the reflector 157 (see FIG. 9b). The resistive load may comprise a 270300 ohm to /2 watt deposited carbon resistor which gives the array 147 a front to back ratio of about 17:1.

The array feedline may be supported by stand-off insulators 177 and 179 attached to the boom 67 and may extend forward through the lower row of antenna loops to a point adjacent the center of balance of the antenna where a mast clamp 181 may be provided to attach the horizontal boom 67 to a vertical mast 183. The lead conductors 80 and 81 may be symmetrically offset supported by an insulator 184 towards each other adjacent the mast clamp 181 (see FIG. 9a) when necessary to clear the vertical mast.

The array 147 shown in FIG. 9 will produce a 14 decibel gain as compared to a reference dipole, and will operate over a frequency band having a ratio between high and low frequencies of 2:1. It has a high Q and produces a high gain relative to its volumetric displacement.

FIGS. and 10a show a combination UHF and VHF antenna array 191 having the UHF portion 193 of the array compatibly connected to the VHF and/or FM portion 195 of the array by means of a pair of phasing bars or lead conductors 197 and 199 having intermediate coiled sections 201, 203, 205 and 207 for isolating the UHF wave energy in portion 193 from the VHF wave energy in portion 195. The UHF portion 193 may comprise a plurality, such as three, of double loop antennas like antenna 31 in FIG. 2 disposed in a horizontal column at the front end of the array and spaced M4 apart. The VHF and/or FM portion 195 may be located at the back end of the array 191 and may comprise a plurality of dipoles 209, 210 and 211 of various lengths arranged in conjunction with a plurality of parasitic elements 213 and 215. One or more parasitic elements 215 may be arranged in front of the isolating coils 201, 203, 205 and 207. The intermediate dipole 210 may have a tuning stub 217 conductivity connected to its inboard ends. The VHF dipoles may be alternately cross connected by criss-crossing the lead conductors 197 and 199 but the lead conductors 197 and 199 may be parallel through the UI-[F portion 193, because the double loop antennas do not require criss-cross phasing. The spaced apart lead conductors 197 and 199 may have a capacitively coupled high impedance stub section 219 at the front end of the array 191 and a pair of lead line terminals 221 and 222 intermediate the UHF portion 193 and the VHF portion 195 of the array.

While there is described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of this invention.

What is claimed is:

1. An antenna comprising:

(A) a pair of lead conductors (80, 81),

(B) a pair of open loop elements (20, 31) disposed in a common plane perpendicular to the direction of wave propagation and forming a figure 8 configuration with the open ends of said loops at the center of said configuration, and

(C) means (64, 65) for capacitively coupling the corresponding adjacent ends of each loop element of said pair together and to a correspondingly one of said lead conductors.

2. An antenna array comprising:

(A) a pair of parallel lead conductors (80, 81) disposed parallel to the direction of wave propagation,

(B) a plurality of coplanar double open loop antennas (20, 31) each disposed perpendicular to the direction of wave propagation, and

(C) means (64, 65, 136-138) for coupling said antennas to said conductors.

3. An antenna array according to claim 2 wherein said coupling means is a capacitive coupling (64, 65) having a capacitance of about 0.5 micromicrofarad between the ends of said loops and said conductors.

4. An antenna array according to claim 2 wherein said coupling means is a conductive coupling (136, 138) through integrally joined components.

5. An antenna array according to claim 2 wherein said coupling means electrically mismatches said loop antennas with respect to said lead conductors.

6. An antenna array according to claim 2 wherein the range of loop lengths corresponds to between about one and 3/ 2 of the mean wavelength of the applied frequency band.

7. An antenna array according to claim 2 wherein said loops have a geometric configuration which encompasses a near maximum area for a limited peripheral loop length.

8. An antenna array according to claim 2 wherein said double loop antennas are spaced apart one quarter wavelength along said conductors.

9. An antenna array according to claim 2 including a non-resonant reflector (132, 157, 211) means at the rearward end of said pair of conductors.

10. An antenna array according to claim 2 including a resistance load (169) having a value equal to the impedance of said pair of conductors and located opposite the feed end of said array.

11. A unidirectional high gain broad band receiving antenna array (147, 191) comprising:

(A) a pair of parallel lead conductors (80, 81) having a pair of feed line terminals (173, adjacent one end,

(B) a plurality of coplanar double loop antennas (20, 31) each having a length corresponding to between about one and three halves of the mean wavelength of the applied frequency band,

(C) dielectric bracket means (64, 65) capacitively coupling said loop antennas to said conductors, whereby each double loop antenna is disposed perpendicular to the direction of wave propagation and spaced substantially one quarter Wavelength apart in a row which is parallel to the direction of wave propagation,

(D) a non-resonant reflector means (157) at the rearward end of said array, and

(E) a loading means (169, 219) between the lead conductors at an end remote from said terminals.

12. An antenna array according to claim 11 wherein said dielectric bracket means maintains a fixed capacitance between the respective ends of said loops and said lead conductors of about five-tenths micromicrofarad.

13. An antenna array according to claim 11 wherein said dielectric bracket means has a means for unfolding said loop elements from a substantially coplanar position with respect to each other and to said lead conductors.

14. An antenna array according to claim 13 wherein said dielectric bracket comprises:

(A) means for rotatingly mounting and spacing adjacent ends of said loop elements,

(B) resilient arms for holding said loop elements in one of two limiting rotatable positions in said mounting and spacing means, and

(C) a pair of snap groove means adjacent said n1ounting and spacing means for retaining said lead conductors capacitively coupled to said ends of said loop elements.

15. An antenna array according to claim 11 wherein said loading means substantially matches the load of the associated feed lines.

16. A resilient dielectric capacitive coupling member (65 for a loop antenna (31) and a pair of lead conductors (80, 81) on a support (67), comprising:

(A) means (69) for anchoring the central portion of said member to said support,

(B) means (87, 89, 87', 89) for rotatingly mounting and spacing adjacent ends of said antenna,

(C) resilient arms (95, 97, 97) for holding said antenna in one of two limiting rotatable positions in said mounting and spacing means, and

(D) a pair of snap groove means (75, 77, 103,

adjacent said mounting and spacing means for retaining said conductors capacitively coupled to said ends of said antenna.

17. A combination UHF and VHF receiving antenna array (191) comprising:

(A) a UHF portion (193) having a plurality of open loop antennas (20, 31) disposed at the front of said array,

(B) a VHF portion (195) located rearward of said array and having a plurality of dipole antennas (209, 210),

(C) a pair of lead conductors (197, 199) coupling said UHF loop antennas and said VHF dipole antennas together, said lead conductors having a plurality of isolating coils (201, 203, 205, 207) intermediate said UHF and VHF portions, and

(D) a pair of feedline terminals (221, 223) conductively connected to said lead conductors adjacent said UHF portion.

References Cited UNITED STATES PATENTS r ELI LIEBERMAN, Primary Examiner.

US. Cl. X.R. 343-742, 792.5

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