Antenna Structures

Abstract

There is disclosed an antenna structure utilizing a loop having an annular ring coupled thereto and lying in a substantially horizontal plane transverse to the plane of the loop. The ring has reflector and director elements mounted thereon, and on opposite sides of the ring to offer increased directivity to the structure. A pair of dipoles are also utilized in the antenna structure. The dipoles are mounted on a first rotatable base assembly and the loop is mounted on a second rotatable base assembly. These base assemblies are rotatable with respect to a fixed base member and are controlled in rotation by means of a knob to permit azimuth orientation of the antennas.

Description

The present invention relates to an antenna system and, more particularly, to a UHF-VHF receiving antenna.

Presently, there exist a plurality of various antenna designs, all of which are adapted to be used indoors. Such indoor antennas have relatively limited responses in both the UHF and VHF range. This is so because of the fact that the antenna elements have to be made relatively compact in order to assure that the assembly is not too large so as to interfere with the aesthetic preferences of the consumer.

Due to the fact that indoor antennas have to be capable of receiving the entire VHF and/or UHF bands, such antennas have conventionally been adjustable. For example, typical VHF antennas utilize a dipole system whereby the consumer can increase the length and adjust the angle of the dipoles which are fabricated in a telescopic structure, to receive the various channels and to achieve optimum signal strength.

It is known that when the consumer is adjusting the dipoles, his body capacitance and the consequent loading presented by his body, when he is accessing these elements, serves to change the effective response of the antenna.

It is therefore an object of this invention to provide an improved VHF and UHF indoor antenna system.

Another object is to provide an improved VHF-UHF antenna, the elements of which can be varied or rotated without making physical contact with the same.

According to an embodiment of the present invention, a UHF antenna structure comprises a loop of a given configuration, an annular ring is coupled to said loop and lies in a plane transverse to the plane containing the loop, the annular ring has mounted thereon at least one beam shaping element to afford increased directivity for the structure.

A UHF-VHF structure employs the loop and ring structure together with a pair of extendible dipoles. The dipoles and the loop are rotated in opposite directions by means of a pulley or gear arrangement under control of a single knob. The consumer can therefore achieve antenna azimuth adjustment without manually accessing the antenna structure.

Other objects, features and advantages of this invention will become fully apparent from the following detailed description taken in conjunction with the accompanying figures, in which:

FIG. 1 is a front view of a UHF-VHF indoor antenna according to this invention;

FIG. 2 is a top view of the antenna shown in FIG. 1;

FIG. 3 is a top view of an alternate embodiment of an antenna;

FIG. 4 is a partial front view of another embodiment of a UHF antenna according to this invention;

FIG. 5 is a top view of a rotatable support assembly for an antenna according to this invention;

FIG. 6 is a side cross-sectional view of the pulley mechanism necessary to provide rotation of such antennas;

FIG. 7 is a schematic diagram of a threading arrangement and a pulley assembly useful in explaining and accomplishing the rotation operation according to this invention;

FIG. 8 is a perspective view of an antenna employing two tilted annular rings;

FIG. 9 is a side view of the antenna of FIG. 8.

Referring to FIG. 1, there is shown a UHF-VHF antenna according to this invention. The VHF portion of the antenna comprises two dipoles 10 which are adjustable in length by means of a telescopic arrangement as is well known in the art. The UHF portion of the antenna includes a loop 11 which has located about its equatorial plane a director/reflector ring 12.

The UHF loop 11 is mounted on a rotatable base assembly 14, while the VHF dipoles 10 are mounted on a rotatable base assembly 15. The base assemblies 14 and 15 rotate with respect to a fixed base member 17 and are controlled in rotation by means of a knob 18.

Briefly, the director/reflector ring 12 rotates with the UHF loop 11 in any direction for a full 360.degree.. This flexibility assures a relatively efficient reception of all color and black and white UHF signals. The VHF dipoles 10 are chrome plated, five-section telescopic dipole devices which rotate 180.degree. to assure efficient pick-up of VHF signals. For example, due to the telescopic nature of the VHF dipoles, they can be extended to a typical length of about 46 inches. The dipoles 10 rotate in the opposite direction to that of the UHF antenna assembly. The consumer can counterrotate the VHF and UHF structures to obtain antenna pattern orientation suitable for the particular environment.

The antenna is also capable of receiving FM signals as well, which signals are in the center of the VHF TV band. The FM and VHF reception is further enhanced by two axial inductors 16 associated with each of the VHF dipole elements 10.

As indicated, there is no need to rotate the VHF and UHF elements by hand. These elements are counterrotatable simultaneously by the single rotator knob 18. The exact nature of the drive assembly and coupling of the knob 18 will be described subsequently.

Referring to FIG. 2, there is shown a top view of the UHF assembly. The UHF loop 11 is surrounded at its equatorial central plane by a director/reflector element 12. The element 12 is an annular disc, fabricated from a suitable plastic material and has deposited thereon a reflector assembly 20 and a director assembly 21. The reflector 20 and the director 21 assemblies are typically fabricated from a suitable conducting material such as aluminum or copper.

The reflector assembly 20 comprises a square wave type of pattern which serves to give an increase in the effective length of the reflector, thus permitting one to obtain a greater effective length in a smaller area. This permits one to obtain greater antenna directivity for the UHF band in a relatively small area. It is noted that the reflector assembly 20 could be sinusoidal or some other suitable configuration. The director assembly 21 is a curved metallic strip of an arcuate configuration. A plurality of apertures or windows 22 are located on the surface of director 21 and serve to enhance the aesthetic properties of the entire assembly. It is apparent that the electrical characteristics of the director will be provided by a single continuous arcuate structure having no apertures.

As indicated, the ring 12 is located approximately at the equatorial axis or central axis of the loop 11. The UHF antenna 11 and associated assembly is a relatively unidirectional type antenna because of the reflector 20 and the director 21 which are coupled to the UHF loop.

In the normal mode of coupling a director and a reflector to a UHF loop or to an antenna, a relatively short element would be placed in front of the loop to serve as the director assembly. On the other hand, a relatively long element would be placed behind the loop to serve as the reflector assembly. This configuration provides a relatively bulky structure which would occupy or define a relatively wide antenna area pattern when rotated.

In the configuration shown the reflector 20 is curved. Furthermore, the reflector is also of a zigzag type of configuration so that it is relatively long and yet consumes a relatively small amount of space. Due to the fact that the reflector and the director are mounted to the UHF loop element 11 in the equatorial plane of the loop, this affords a fairly substantial savings in space consumed by the antenna which is critical to indoor antenna structures. As will further be explained, all three elements, namely, the loop 11, the reflector 20 and the director 21 are rotated simultaneously.

The UHF antenna configuration shown utilizes a conventional circular loop 11 which is approximately 7 inches in diameter. It is known that rotation of such a circular loop sweeps out a spherical volume. In order to minimize size, it would be desirable to incorporate unidirectivity inside the swept sphere. As indicated above, a parasitic director would afford to do this and would actually present no problem, since for the UHF band it will be short enough to lie along the equator of the swept sphere. However, a reflector which would be tuned for the low end of a UHF band would be too long to lie along the equator. Hence, in the manner described above, a reflector 20 may be shortened effectively by giving it a zigzag or sinuous form, and it is further curved around the surface of the annular ring which affords a further reduction in the area occupied, thus providing a structure capable of providing a low swept volume. The low swept volume concept is particularly useful when the antenna is used in the same assembly with the VHF dipoles 10, since this particular configuration tends to minimize the required dipole spacing.

Referring to FIG. 3, there is again shown the circular UHF loop antenna 11 with the director/reflector ring 12. However, in FIG. 3, a sinusoidal configuration reflector element curved about the surface of the ring 12 is used which again serves to reduce the effective length of the reflector assembly, while affording increased directivity for the UHF antenna assembly.

FIG. 4 shows a UHF loop antenna 30 with a director/reflector ring as shown in FIGS. 2 and 3 mounted on an inclined axis with respect to the equatorial axis. This particular configuration will operate to afford increased selectivity as the configuration shown in FIG. 1 with certain aesthetic advantages. Alternatively, two rings may be utilized. One ring would be tilted up and one ring would be tilted down with respect to the equatorial plane. Each of these rings would carry both a reflector element and a director element. This combination would afford to offer some stacking gain for the entire antenna assembly. This configuration will be explained subsequently with reference to FIGS. 8 and 9.

Referring to FIG. 5, there is shown the mounting plates 14 and 15. The cross-hatched areas 32 and 33 on the mounting plate 15 show the location of the VHF dipoles such as 10 of FIG. 1, while the darkened areas on the mounting plate 14 show the location of the ends of the UHF loop. The arrows on each of the rotatable plates 14 and 15 indicate the direction of rotation of these plates with respect to each other. It can therefore be seen that the plates 14 and 15 rotate counter to each other.

Referring to FIG. 6, there is shown a cross-sectional view of the plates 14 and 15 and mechanical assemblies which may be coupled to a suitable driving arrangement to afford such rotation. A partial UHF loop 11 is shown mounted to a plate 14. The plate 14 has a central aperture 35. The mounting portion of the plate 14 is also coupled to a bottom pulley assembly portion 36, which has a wire or thread accommodating groove 38 around the periphery thereof.

The VHF plate 15 is circular in nature and is relatively symmetrically located about the central aperture 35 of the UHF plate 14. The VHF plate 15 is also contiguous with a bottom pulley assembly 39 having a thread accommodating groove 40 located about the periphery thereof.

Both the assemblies 14 and 15 rotate with respect to a fixed top portion 42 of the antenna assembly. The top portion 42 would be analogous to the top surface of the base member 17 of the antenna shown in FIG. 1.

Referring to FIG. 7, there is shown the UHF pulley 36 and the VHF pulley 39 which are offset one from the other in order to gain a clear explanation of the mechanical operation. Member 18 references the control knob 18 of FIG. 1, which actually is a control knob coupled to a pulley assembly. Member 43 references a roller or idler used as part of the mechanical path to accommodate a loop of thread to aid in affording rotation of the antenna assembly.

As indicated, member 36 represents the UHF drive pulley while member 39 represents the VHF drive pulley. These have been shown with their central axes offset in order to clarify the mode of operation, but as can be seen from FIG. 6, the two assemblies may actually be concentric to one another.

The threading assembly is as follows. A thread 50, which may be a wire or a cord, is directed as follows. The exact direction and threading arrangement will be clearer if reference is made to the associated arrows drawn at specified intervals along the assembly.

The thread 50 passes about the pulley associated with the control knob 18 and thence to a groove in the idler 43. The thread 50 is directed about the idler 43 and then on to the groove associated with the VHF drive gear 39. The thread 50 wraps about the VHF drive gear 39 for almost 360.degree. and then comes off the VHF drive gear to encircle a fixed or another idler member 51. The cord 50 is wrapped about member 51 for approximately 180.degree. and is then directed within the groove of the UHF drive pulley 36, where it encircles the same for approximately 180.degree. and is thence directed from the drive pulley 36 back into the groove of the control knob 18 and hence to the starting point.

It can be seen that if the control knob 18 is rotated in the counterclockwise direction, the drive gear 39 will rotate in the clockwise direction while drive pulley 36, because of the translation via member 51, will rotate in the counterclockwise direction. Therefore, the control knob and associated pulley 18 will cause the VHF turntable or gear drive pulley to rotate clockwise, while the UHF drive pulley 36 will rotate counterclockwise or in the same direction as the knob 18.

Rotation of the antennas by the knob 18 has the advantage of keeping the user's hands away from the antenna and, as indicated, this substantially reduces body coupling effects. It can be seen that, since the VHF dipoles are bidirectional, the VHF antenna needs only 180.degree. rotation. On the other hand, the UHF loop is not bidirectional and requires a 360.degree. loop rotation. The desired 360.degree. loop rotation and the 180.degree. VHF dipole rotation can easily be accomplished by rotating the UHF loop twice as fast as the VHF dipoles. This requires a half size pulley or drive gear for the UHF loop 11 and the relationship is well known to those skilled in the art.

Referring to FIGS. 8 and 9, there is shown a UHF loop 60 with two annular rings 61 and 62 mounted inclined with respect to each other and at an angle of approximately 45.degree. with loop 60. Each annular ring has a reflector and a director element mounted thereon with the reflector of one element disposed above the reflector of the other. Similarly, the directors are also stacked in the vertical plane. The configuration serves to assure that the reflector/director assembly couples with the major current carrying portions of the loop 60 which lie mainly on the upper and lower segments of the loop 60.

Increased performance in terms of directivity and gain can be achieved by this configuration because of the addition of the extra reflector/director structures.

Claims

What is claimed is:

1. An antenna structure, comprising:

a. a loop of a given configuration,

b. an annular ring coupled to said loop and lying in a substantially horizontal plane transverse to the plane containing said loop, and

c. at least one beam shaping element mounted on said annular ring and extending along a portion of the surface thereof to provide increased directivity for said antenna.

2. The antenna according to claim 1 wherein said beam shaping element is of a serpentine configuration fabricated from a conducting metal.

3. The antenna according to claim 1 wherein said beam shaping element is of an arcuate configuration fabricated from a conducting metal located on a surface thereof.

4. The antenna according to claim 1 wherein said loop is of a circular configuration.

5. The antenna according to claim 1 further comprising:

a. means coupled to said loop for rotating the same.

6. An antenna structure for responding to UHF and VHF signal transmissions, comprising:

a. first and second rotatable base assembly members having a common central axis about which either can be rotated,

b. a pair of extendible dipoles mounted on said first base assembly, said dipoles of a length sufficient to accommodate VHF signals,

c. a loop of a given configuration mounted on said second base assembly, said loop of a diameter sufficient to accommodate UHF signals, and

d. means coupled to said first and second base assemblies for rotating the same to thereby provide for directivity pattern orientation of each of said VHF and UHF antennas.

7. An antenna structure for responding to UHF and VHF signal transmissions, comprising:

a. first and second rotatable base assembly members having a common central axis about which either can be rotated,

b. a pair of extendible dipoles mounted on said first base assembly, said dipoles of a length sufficient to accommodate VHF signals,

c. a loop of a given configuration mounted on said second base assembly, said loop of a diameter sufficient to accommodate UHF signals,

d. an annular ring coupled to said loop and lying in a substantially horizontal plane transverse to the plane containing said loop,

e. at least one beam shaping element mounted on said annular ring and extending along a portion of the surface thereof to provide increased sensitivity for said antenna, and

f. means coupled to said first and second base assemblies for rotating the same to thereby provide for directivity pattern orientation of each of said VHF and UHF antennas.

8. An antenna structure, comprising:

a. a loop of a given configuration,

b. an annular ring coupled to said loop and lying in a substantially horizontal plane transverse to the plane containing said loop,

c. a reflector of a serpentine configuration mounted along a first portion of said annular ring for providing increased directivity to said antenna structure, and

d. a director of an arcuate configuration located thereon, mounted on a second different portion of said annular ring to provide a further increase of directivity for said antenna structure.