US2847669A

US2847669A - Stacked coplanar antenna array

Info

Publication number: US2847669A
Application number: US433151A
Authority: US
Inventors: Joseph V Fisher
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-05-28
Filing date: 1954-05-28
Publication date: 1958-08-12
Anticipated expiration: 1975-08-12

Description

Aug. 12, 1958 J. v. FISHER 2,347,569

STACKED COPLANAR ANTENNA ARRAY Filed May 28, 1954 2 Sheets-Sheet 1 INVEN TOR. JOJ'EPH 14 /s/ree,

Unite This invention relates to antennas, and more particularly to a wide band antenna suitable for reception of all television channels and also suitable for FM reception.

A main object of the invention is to provide a novel and improved wide band antenna for television and FM, said antenna being simple in construction, involving a minimum of electrical and mechanical parts, and providing high gain over the entire spectrum employed for television and FM transmission.

A further object of the invention is to provide an improved high gain, wide band antenna which is inexpensive t fabricate, which is rugged in construction, which involves substantially no corrosive joints and which is easily adjustable, particularly with respect to ultra high frequency channels so that a desired sharpness of the ultra high frequency field pattern may be obtained by adjusting the antenna.

A still further object of the invention is to provide an improved high gain, wide band antenna array of the multiple bay type wherein the number of stacking harnesses is minimized.

A still further object of the invention is to provide an improved wide band, high gain antenna, suitable for reception of all television channels and for FM channels, said anntena being neat in appearance, being relatively light in weight, and being arranged so that only one transmission line is required over the entire spectrum received by the antenna.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

Figure l is a perspective view of an improved wide band antenna constructed in accordance with the present invention.

Figure 2 is a top plan view of one of the bays of the antenna array of Figure 1.

Figure 3 is a schematic diagram showing the equivalent electrical circuit of the antenna array of Figure 1 and indicating the direction of flow of current in the antenna elements.

Figure 4 is a schematic diagram of the antenna array of Figure 1 illustrating the dimensional relationships of the various elements of the antenna array, particularly with respect to the lower frequency portion of the television channel spectrum.

Figure 5 is a schematic diagram similar to Figure 1,

and illustrating the dimensional relationships of the rates Patent 0 in construction, and are separated by substantially equal vertical spacings.

Referring to Figure 2, the construction of the top bay 13 is illustrated, said top bay comprising a straight reflector bar 17 of conductive material, for example, of aluminum tubing, and a pair of dipole elements, designated at 18, 18, each dipole element comprising a conductive rod of aluminum or similar material, formed at an intermediate portion thereof with a Ushaped, relatively narrow loop of substantial length, shown at 19.

Respective insulators

20, 20 rigidly connect the bight portions of the

loops

19, 19 to the reflector bar 17, the loops 19 being symmetrically located on opposite sides of the mid point of the reflector bar 17. The mid point of the reflector bar 17 is connected by a rigid bracket rod 21 to an insulator 22, the inner ends of the

respective dipole elements

18, 18 being secured to the opposite ends of the insulator 22, as shown in Figure 2.

The outer portions of the

respective dipole elements

18, 18 are substantially \I-shaped, as shown at 23, 23, facing away from the reflector bar 17. Respective rigid connecting

rods

24, 24 connect the reflector bar 17 to insulators 25- secured to the bends of the \I-shaped portions 23 of the dipoles.

As is clearly shown in Figure 2, the inner portions 26 of the respective dipoles are inclined inwardly toward the reflector bars 17 and together define a V-shaped configuration similar to the configurations of the respective outer, V-

shaped dipole portions

23, 23.

All the elements thus far described, comprising the reflector bar 17, the

dipoles

18, 18, the

respective loops

19, 19, and the

bracket elements

24, 24 and 21 are in the same horizontal plane.

As shown in Figure 2, the reflector bar 17 is of a length substantially equal to one-half the wave length of the mid channel of the lower portion of the television spectrum, namely, the spectrum including channels 2 to 6. The distance between the outer ends of the

dipoles

18, 18 is substantially equal to the length of the reflector bar, namely, to one-half of the wave length of the mid channel of the lower portion of the television spectrum.

As is further shown in Figure 2, the lengths of the V-

shaped portions

23, 23 and the V element defined by the

inner ends

26, 26 of the dipoles are substantially equal and correspond to one-half the wave length of a frequency substantially in the middle of the upper V. H. F. television band, namely, the portion of the television spectrum including channels 7 to 13. Obviously, since the length of the V-

shaped portions

23, 23 and the V-shaped portion defined by the

inner portions

26, 26 of the dipoles are equal, each of the V-shaped elements thus defined has a length substantially one-third that of the reflector bar 17.

The spacing of the main portions of the

dipole elements

18, 18 from the reflector bar 17 is, of course, determined by the lengths of the bracket bars 24, 2 -1, 21 and the

loops

19, 19. In a typical embodiment of the invention, this length was approximately equal to a quarter wave length of a middle channel in the upper portion of the V. H. F. television spectrum, namely, that portion of the television spectrum including the channels 7 to 13.

Obviously, a considerable range of dimensions may be employed in choosing the proper lengths of the reflector bar 17 and the

dipole elements

13, 18. For example, the reflector bar 17 may be of a length equal to the length of one'half of the wave length for the lowest television channel of the spectrum to be covered and the lengths of the V-

shaped portions

23, 23, as well as the intermediate V-shaped portion defined by the

inner end elements

26, 26 of the dipoles may be in accordance with the wave length of a particular channel in the upper portion of the V. H. F. television band, namely, in the bandincluding channels 7 to 13, the spacing of the dipole elements from the reflector bar being similarly governed by the selected upper V. H. F. channel frequency and the spacing being one-quarter of the wave length of said selected frequency.

The inner ends of the dipoles of the

bays

13 and 14 are connected by a pair of

vertical harness conductors

27 and 28, and similarly, the inner ends of the dipoles of the

bays

15 and 16 are connected by a pair of

vertical harness conductors

29 and 3%

Suitable insulators

31 and 32 connect the intermediate portions of

harness conductors

27, 28 and 29, 3d. The intermediate portions of the harness conductors Z7 and 29 are interconnected by a vertically extending additional rigid harness conductor rod member 33, and similarly, the intermediate portions of the

harness conductors

23 and 30 are intenconnected by a vertically extending, rigid harness conductor rod member 34 extending parallel to the harness conductor rod member 33. The intermediate portions of the

harness conductor rods

33 and 34 are secured together by a terminal insulator 35 provided with respective terminals connected to the respective

harness conductor rods

33 and 34, to which the transmission line wires are connec ted, whereby the antenna array may be suitably connected to the terminals of a television receiver. The terminal insulator 35 is rigidly braced to the mast 12; by a horizontally extending bracket rod 36 connecting the intermediate portion of the insulator 35 to a suitable clamp bracket 37 secured on the mast 12.

Adjustably mounted on the respective vertically extending

harness conductor rods

33 and 34 are the respective pairs of ultra-high

frequency tuning loops

38, 39 and 4t), 4-1, said tuning loops being vertically movable and being provided with suitable means for securing the loops in adjusted positions on the

harness conductors

33 and 34. As shown in Figure 1, the

tuning loops

38, 39, tll and 41 extend in horizontal planes and are relatively small in diameter.

However, the U. H. F.

bow loop elements

38, 39, 4t) and 41 are angularly adjustable so that they can be set at any desired angle so as to adjust the sharpness of the U. H. F. field pattern of reception.

The bracket rods 21, extending perpendicularly from the mid point of the respective reflector rods 17 are electrically connected to said reflector rods, forming a part thereof, and serve to keep out side signals, making the antenna array sharply directional. Similarly, the

rod elements

24, 24 are electrically connected to the reflector bars 17, for the same purpose.

Referring now to Figure 3, it will be seen that the transmission line conductors, shown at 4-2 and 43 are connected to the intermediate portions of the respective harness

conductor rod elements

33 and 34 whereby respective circuits are completed between the television receiver input circuit and the ether. From this schematic diagram, the current can be considered as entering the antenna array at the right ends of the

dipoles

13, 14, 15 and 16, and circulating through the respective dipole elements in the directions indicated by the arrows. Thus, the currents in the right end portions of the

upper dipole elements

13 and 14 enter the top end of the harness condoctor 34- =and pass to the television receiver input circuit through the transmission line conductor 43, the current leaving the input circuit of the receiver through the transmission line conductor 42 and entering the harncss conductor 33. The currents leave the ends of the harness conductor 33 and pass through the left end portions of the dipole elements of the bays l3, l4, l and 16 and. discharge into the ether.

it will be noted that each structural element of the array has an electrical function, and that a minimum amount of mechanical parts are thus required in order to complete the antenna assembly. This not only reduces the cost of the assembly but also considerably lightens its weight, making it easier to erect the antenna and rotate theasame to obtain. the desired orientation The lightness.

of the antenna also makes it suitable for use with antenna rotating mechanisms of conventional type.

As shown in Figure 4, the vertical spacing between the

bays

13, 14, 15 and 16 is preferably such that with respect to the lower portion of the V. -H. F. television spectrum, the vertical spacing between the bays is equal to one-fifth of a wave length, for example, the mid wave length in this portion of the band, or, alternatively, onefifth of the lowest wave length in the band. Figure 5 illustrates the wave length distribution which may be employed in a typical antenna array according to the present invention, with reference to the television channels in the upper portion of the spectrum, namely, channels 7 to 83.

An important feature of the present invention is that the U-shaped elements 1) act not only as matching stubs but also take the place of the supporting rods and phasing harnesses employed in previously known antenna arrays.

While a specific embodiment of an improved broad band antenna has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

' 1. In a broad band antenna of the character described, a straight reflector bar, a pair of dipole elements, each dipole element comprising a conductor rod formed at an intermediate portion thereof with a U-shaped, relatively narrow loop of a length equal to one quarter of a wave length of an upper V. H. F. television frequency and having its bight portion located closely adjacent to said reflector bar, and respective insulators rigidly and supportingly connecting the bight portions of said loops to the reflector bar with the dipole elements and reflector bar disposed in the same horizontal plane and with the dipole elements spaced symmetrically relative to the mid point of said reflector bar, the arm portion of each dipole element located outwardly of its loop being substantially V-shaped and facing away from the reflector bar, said V-shaped outer arm portions being in the common horizontal plane of the loops and reflector bar.

2. In a broad band antenna of the character described, a straight reflector bar, a pair of dipole elements, each dipole element comprising a conductor rod formed at an intermediate portion thereof with a U-shaped, relatively narrow loop of a length equal to one quarter of a wave length of an upper V. H. F. television frequency and having its bight portion located closely adjacent to said reflector bar, and respective insulators rigidly and supportingly connecting the bight portions of said loops to.

the reflector bar with the dipole elements and reflector bar disposed in the same horizontal plane and with the dipole elements spaced symmetrically relative to the mid point of said reflector bar, the arm portion of each dipole element located outwardly of its loop being substantially V-shaped and facing away from the reflector bar, said V-shaped outer arm portions being in the common horizontal plane of the loops and reflector bar, the arm portion of each dipole element located inwardly of its loop being inclined inwardly toward the reflector bar and being in said common horizontal plane.

3. In a broad band antenna of the character described, a straight reflector bar, a pair of dipole elements, each dipole element comprising a conductor rod formed at an reflector bar, the arm portion of each dipole element located outwardly of its loop being substantially V-shaped and facing away from the reflector bar, said V-shaped outer arm portions being in the common horizontal plane of the loops and reflector bar, respective insulators connected to the bends of said V-shaped portions, the arm portion of each dipole element located inwardly of its loop being inclined inwardly toward the reflector bar and being in said common horizontal plane, an insulator rigidly connecting the ends of said last-named arm portions, and respective conductive support elements rigidly and supportingly connecting said last-named insulator and the insulators at the bends of the V-shaped outer arm portions of the dipole elements to the reflector bar and being electrically connected to said reflector bar.

4. In a broad band antenna of the character described, a vertical support, a pair of antenna bays stacked one above the other and secured to said support, each antenna bay comprising a straight reflector bar, a pair of dipole elements, each dipole element comprising a conductor rod formed at an intermediate portion thereof with a U- shaped, relatively narrow loop of a length equal to one quarter of a wave length of an upper V. H. F. television frequency and having its bight portion located closely adjacent to said reflector bar, respective insulators rigidly and supportingly connecting the bight portions of said loops to the reflector bar with the dipole elements and reflector bar disposed in the same horizontal plane and with the dipole elements spaced symmetrically relative to the mid point of said reflector bar, the arm portion of each dipole element located outwardly of its loop being substantially V-shaped and facing away from the reflector bar, said V-shaped outer arm portions being in the common horizontal plane of the loops and the reflector bar, the arm portion of each dipole element located inwardly of its loop being inclined inwardly toward the reflector bar and being in said common horizontal plane, an insulator rigidly connecting the ends of said last-named arm portions, and respective conductive support elements rigidly and supportingly connecting said last-named insulator and the bends of the V-shaped outer arm portions of the dipole elements to the reflector bar and being electrically connected thereto, and respective vertically extending harness conductors interconnecting the inner ends of the dipole elements.

5. In a broad band antenna of the character described, a vertical support, a pair of antenna bays stacked one above the other and secured to said support, each antenna bay comprising a straight reflector bar, a pair of dipole elements, each dipole element comprising a conductor rod formed at an intermediate portion thereof with a U-shaped, relatively narrow loop of a length equal to one quarter of a wave length of an upper V. H. F. television frequency and having its bight portion located closely adjacent to said reflector bar, respective insulators rigidly and supportingly connecting the bight portions of said loops to the reflector bar with the dipole elements and reflector bar disposed in the same horizontal plane and with the dipole elements spaced symmetrically relative to the mid point of said reflector bar, the arm portion of each dipole element located outwardly of its loop being substantially V-shaped and facing away from the reflector bar, said V-shaped outer arm portions being in the common horizontal plane of the loops and reflector bar, the arm portion of each dipole element located inwardly of its loop being inclined inwardly toward the reflector bar and being in said common horizontal plane, an insulator rigidly connecting the ends of said last-named arm portions, and respective conductive support elements rigidly and supportingly connectting said last-named insulators and the bends of the U-shaped outer arm portions of the dipole elements to the reflector bar and being electrically connected thereto, respective vertically extending harness conductors interconnecting the inner ends of the dipole elements, and relatively small, closed conductor loop elements adjustably mounted on the harness conductors.

6. In a broad band antenna of the character described, a vertical support, a plurality of antenna bays stacked one above the other and secured to said support, each antenna bay comprising a straight reflector bar, a pair of dipole elements, each dipole element comprising a conductor rod formed at an intermediate portion thereof with a U-shaped, relatively narrow loop of a length equal to one quarter of a wave length of an upper V. H. F. television frequency and having its bight portion located closely adajacent to said reflector bar, respective insulators rigidly and supportingly connectting the bight portions of said loops to the reflector bar with the dipole elements and reflector bar disposed in the samehorizontal plane and with the dipole elements spaced symmetrically relative to the mid point of said reflector bar, the arm portion of each dipole element located outwardly of its loop being substantially V-shaped and facing away from the reflector bar, said V-shaped outer arm portion being in the common horizontal plane of the loops and reflector bar, the arm portion of each dipole element. located inwardly of its loop being inclined inwardly toward the reflector bar and being in said common horizontal plane, an insulator rigidly connecting the ends of said last-named arm portions, and respective conductive support elements rigidly and supportingly connecting said last-named insulators and the bends of the V-shaped outer arm portions of the dipole elements to the reflector bar and being electrically connected thereto, respective, vertically extending harness conductors interconnecting the inner ends of the dipole elements, said antenna including four bays stacked one above each other, said harness conductors including vertical conductors connecting the inner ends of the dipoles of the adjacent top and bottom pairs of bays, respective additional vertically extending harness conductors connecting the mid point of the first-mentioned vertical conductors, and relatively small, closed conductive loop elements 'adjustably mounted on said additional vertically extending harness conductors.

References Cited in the file of this patent UNITED STATES PATENTS 1,934,182 Franklin Nov. 7, 1933 2,586,276 Umstead Feb. 19, 1952 2,655,599 Finneburgh' Oct. 13, 1953 OTHER REFERENCES Radio Electronics, page 67, November 1951. Radio Electronics, page 155, January 1953.