Omni-directional Antenna Mounted In Circular Radome

Abstract

There is disclosed a method for manufacturing a television antenna, as well as a television antenna which is manufactured according to the preferred method. The television antenna of the preferred embodiment comprises a layer of flexible non-conductive material, such as mylar, on top of which is affixed a plurality of strips of flexible conductive material. Electrical leads are connected to the flexible strips of conductive material and the entire flexible structure is then placed on a rigid housing. In the preferred embodiment, the rigid housing comprises a circular non-conductive shell. The flexible layer of laminated conductive and non-conductive material is placed circumferentially around the interior of the circular shell, thereby forming an omni-directional antenna which is completely impervious to corrosive elements.

Description

BACKGROUND OF THE INVENTION

The present invention relates to antennas and more particularly, to an improved omni-directional antenna for use with television receivers and/or FM receivers.

In the field of antennas, it has been the general practice to employ dipole antennas. These dipole antennas have not proved entirely satisfactory and subsequently, Yagi-type antenna arrays were developed. The Yagi-type array usually employed an active or radiator element, in combination with one or more directors and/or reflectors. The use of these several elements widen the frequency response of the antenna when compared with a simple dipole antenna. Because these antennas were directional in nature, certain difficulties arose since they would only pick up signals from the direction in which the antenna was oriented. In an attempt to overcome these difficulties, omni-directional antennas have been developed.

SUMMARY OF THE INVENTION

The general purpose of this invention is to provide an improved, omni-directional antenna which provides a greater signal to noise ratio then previous omni-directional antennas and is less expensive to manufacture or fabricate. To attain this, the present invention contemplates a unique arrangement wherein all conductive elements of the antenna are constructed from a flexible conductive material which is laminated to a flexible strip of non-conductive material such as mylar. The conductive elements which are laminated to the mylar material are arranged in a preselected pattern and, in the preferred embodiment, comprise 11 uniform strips of flexible copper foil which are placed adjacent to each other in parallel arrangement and a preselected number of these strips are then electrically connected together by a suitable connecting means. The laminated structure is then attached to the interior of a rigid non-conductive housing in a circular arrangement, thereby forming the omni-directional antenna.

Therefore, an object of the present invention is to provide an improved, omni-directional antenna which is capable of 360.degree. reception and which provides a high signal to low noise ratio.

Another object is to provide an omni-directional antenna which utilizes flexible active elements.

A further object of the invention is to provide an omni-directional antenna which is impervious to metallically corrosive elements.

Still another object is to provide an omni-directional antenna which is extremely simple and inexpensive to fabricate and at the same time easy to install and maintain.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood with reference to the following detailed description when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a flexible antenna segment which constitutes a preferred embodiment of the invention.

FIG. 2 is a section of the flexible antenna segment taken on the lines 2--2 of FIG. 1.

FIG. 3 is a section of the flexible antenna segment taken on the lines 3--3 of FIG. 1.

FIG. 4 is a diagram which schematically shows the method for manufacturing the flexible antenna segment shown in FIG. 1.

FIG. 5 is an exploded view of a flexible antenna segment of FIG. 1 in combination with a rigid housing.

FIG. 6 is a perspective view, with a portion removed, of an alternative housing which may be used in combination with the flexible antenna segment of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a flexible antenna segment 10. Referring now to FIGS. 1, 2 and 3, it can be seen that the flexible antenna segment 10 is a laminated structure comprising a flexible non-conductive layer 12 and a flexible layer of conductive material 14. The layer of flexible conductive material 14 comprises a plurality of strips of flexible conductive material 16 which are arranged in a preselected pattern on the flexible non-conductive layer 12 and, as will be explained below, the strips of flexible conductive material 16 are permanently affixed to the flexible non-conductive layer 12. In the preferred embodiment, eleven strips of flexible conductive material are arranged so as to be parallel to each other and spaced apart an equal distance from each other, thereby forming eleven parallel spaced apart strips of flexible conductive material 16a through 16k.

The flexible antenna segment 10 is of preselected length having a first end 17 and a second end 19. In the preferred embodiment, its length in inches is equal to one quarter wave length of channel 2 or 64 1/2 inches.

As can be seen in FIG. 1, a conductor 18 electrically connects to each other four of the strips of flexible conductive material, while the remaining seven strips of flexible conductive material 16 are electrically connected together by a conductor 20. In addition, the strip of flexible conductive material 16a is segmented at its center by an aperture 22, thus forming two individual flexible conducted strips 24 and 26. The flexible conductive strip 26 is electrically connected to the conductor 20 while the flexible conductive strip 24 is electrically connected to the strip of flexible conductive material 16b by another conductor 28. Lastly, as best shown in FIGS. 1 and 2, a conventional antenna lead 30 is connected to the flexible antenna segment 10 by any suitable fastening means. In the preferred embodiment, a pair of snap fasteners 46 and 48 are employed. The antenna lead 30 may be conventional twin lead wire wherein the first lead wire 30a is electrically connected to the conductor 18 while the second lead wire 30b is electrically connected to the conductor 20. In this manner, all eleven of the strips of flexible conductive material 16a through 16k are electrically connected to the antenna lead 30. The antenna lead 30 may then be utilized to connect the flexible antenna segment 10 to a utilization device such as a television set or other similar device.

Referring now to FIG. 4, the method of fabricating the flexible antenna segment 10 will be described. To manufacture the flexible antenna segment 10, any conventional roll feeding machine that is adapted to feed rolls of continuous material to a receiving station may be utilized. In this regard, a roll 32 of flexible non-conductive material 12 is mounted on a feed roller means 33 and is fed to a receiving station 34. The flexible non-conductive material is treated with a heat resealable polyester adhesive. This heat resealable polyester adhesive may be applied to the flexible non-conductive material 12 as it is traveling to the receiving station 34 by any suitable means or the roll 32 of the flexible non-conductive material 12 may already have been treated by the manufacturer of the flexible non-conductive material with a heat resealable polyester adhesive. One such material which may be readily purchased and which contains the heat resealable polyester adhesive is Mylar and is manufactured by E. I. DuPont. In the preferred embodiment, the Mylar has a thickness of two mils and the adhesive contained on the surface of the Mylar has a thickness of 1 1/2 mils. The width of the roll 32 is designed so as to be the same width as the desired width of the flexible antenna segment 10. In the preferred embodiment, the roll 32 has a width of seven inches.

Continuous lengths of flexible conductive material 16 are also fed to the receiving station 34. These continuous lengths of flexible conductive material 16 are fed from a plurality of rolls 36 of preselected width which are mounted on a feed roller means 37. As can be seen in FIG. 2, the roll 36 of flexible conductive material 16 are located directly above the roll 32 of flexible nonconductive material 12 and as the flexible conductive material 16 is fed towards the receiving station 34, they are superposed above the flexible non-conductive material 12. As mentioned previously with reference to FIG. 1, the flexible antenna segment 10 comprises in the preferred embodiment, eleven strips of flexible conductive material 16a through 16k. Therefore, it is necessary to utilize 11 rolls 36 of flexible conductive material 16. It will be recognized, however, that if it is desired to utilize fewer than eleven strips, then fewer rolls 36 will be required and, likewise, if a greater number of strips were desired, then a greater number of rolls 36 will be required.

Each of the rolls 36 are then fed through an alignment apparatus 38. The alignment apparatus 38 insures that each of the flexible strips 16 are maintained at a preselected spaced distance from each other. The desired spacing may be determined empirically and, in the preferred embodiment, it is desired to maintain a spacing of 0.125 inches between the strips. Each of the strips of flexible conductive material 16 in the proposed embodiment are each one-half inch wide and the rolls 36 of this width may be obtained by slitting a larger roll of flexible conductive material into individual rolls one-half inch wide. In the preferred embodiment, the flexible conductive material 16 comprises a soft rolled copper foil which may be purchased commercially from many sources.

The plurality of strips of flexible conductive material 16 and the strip of flexible non-conductive material 12 are continuously fed to the receiving station 34. At the receiving station 34, each of the strips of flexible conductive material 16 are bonded or affixed to the upper surface 13 of the flexible non-conductive material 12. As described above, the upper surface 13 of the flexible non-conductive layer 12 has been treated with the heat resealable polyester adhesive. At the receiving station 34, a conventional set of hot rollers applies both pressure and heat to each of the strips of flexible conductive material 16, thereby sealing or affixing each of the flexible conductive strips 16 to the upper surface 13 of the flexible non-conductive material 12, thereby forming a continuous laminated flexible conductive material 40. The continuous laminated flexible material 40 may then be formed into a roll 42.

After obtaining the roll 42 of the continuous laminated flexible material 40, the flexible antenna segment 10 may be manufactured by merely cutting the continuous laminated flexible material 40 into segments 10 of proper length. In the preferred embodiment, the flexible antenna segments 10 are cut to a length of 64 1/2 inches. 64 1/2 inches represents one quarter wave length, in inches, of television channel 2. After obtaining this proper length, it is then necessary to electrically connect together a preselected plurality of the adjacent flexible conductors 16. As mentioned previously in connection with FIGS. 1 through 3, the strips of flexible conductive material 16a, 16b, 16c, 16d, 16e, 16f, and 16g are electrically connected together by a conductor 20. In the preferred embodiment, the conductor 20 may comprise a copper conductor which is welded to the layer of flexible non-conductive material 12 and to the strips of flexible conductive 16a through 16g. Similarly, the strips of flexible conductive material 16h through 16k are also electrically connected in the similar manner by the conductor 18. As also mentioned previously, the segment 24 of the flexible conductor 16a is electrically connected by a conductor 28 to the strip of flexible conductive material 16b. As can clearly be seen in FIG. 3, this connection is only made on the upper surface 13 of the flexible non-conductive layer 12. However, if it is desired, a two-sided connection may be utilized.

The segments 24 and 26 are shown to be of equal length in the preferred embodiment. To accomplish this, the aperture 22 is placed exactly in the center of the strip of flexible conductive material 16a. This positioning was determined empirically and it has been found that the best reception is obtained when the aperture 22 is positioned a good distance from each end of the strip of flexible conductive material 16a. However, other placements may be utilized.

As mentioned previously, the antenna lead 30 is electrically connected to the conductors 18 and 20 by any suitable fastening means. In the preferred embodiment, the snap fasteners 46 and 48 are inserted into the flexible, non-conductive layer 12 and the flexible conductive layer 14, as well as contacting each of the conductors 20 and 18, as shown in FIGS. 1 and 2. The snap fasteners 46 and 48 are identical. The snap fastener 46 comprises a male portion 45 and a female portion 47. The upper part 45a male portion 45 is in electrical contact with the conductor 18 while the female portion 47 is in electrical contact with the antenna lead 30a or 30b. By utilizing snap fasteners 46 and 48, a very secure, as well as inexpensive, fastening of the antenna lead 30 may be accomplished.

After fabricating the flexible antenna segment 10, this antenna segment may then be coated with a protective non-conducting coating. Any suitable protective coating, such as plastic, may be utilized. If it is desired, rather than utilizing plastic coating, a secodn layer of Mylar can be placed over the layer of flexible conductive material 16, thereby forming a three-layer flexible antenna segment having the layer of flexible conductive material 16 sandwiched in between two layers of flexible non-conductive Mylar 12.

After fabricating the flexible antenna segment 10, as described above, the flexible antenna segment 10 is then affixed or bonded to a rigid housing. In the preferred embodiment, it is desired to make the antenna omni-directional and, therefore, the housing must be circularly shaped. Referring now to FIG. 5, a preferred housing 50 is shown. The housing 50 comprises an upper segment 52 and a lower segment 54. The upper segment 52 is generally circularly shaped and has a circular rim 56 from which downwardly protrudes a cylindrically shaped extension 58. The dimensions of the cylindrically shaped extension are such that the flexible antenna segment 10 is wrapped around the outer surface 60 of the cylindrically shaped extension 58. When wrapped in this manner, and affixed or bonded to the housing, a space 15 is formed between the first end 17 and the second end 19 of the flexible antenna segment 10. The flexible antenna segment 10 may be bonded to the rigid housing by any suitable means such as a cement or by heat. After the flexible antenna segment 10 has been affixed to the downwardly protruding cylindrically shaped extension 58, the lower segment 54 of the housing 50 is again mated with the upper segment. As can be seen in FIG. 5, the upper segment acts as a male member and the lower segment 54 acts as a female member thereby forming a compact circular donut-shaped housing wherein the flexible antenna segment 10 is completely protected from any corrosive elements. For mounting purposes, a support bar 62 may then be placed across the opening in the housing 50 and a shaft (not shown) may then be connected to the support 62 to mount the antenna in a conventional manner.

Referring now to FIG. 6, an alternative housing 70 is disclosed. The housing 70 is generally shaped in the form of a hemisphere. The upper portion 72 of the hemisphere, however, comprises a vertically shaped segment 74 which is adapted to receive the flexible antenna segment 10. The width of this vertically shaped segment 74 is made slightly greater than the width of the flexible antenna segment 19 and, in the preferred embodiment, is 7 1/4 inches tall. The circumference of the housing 70 is slightly larger than the length of the flexible antenna segment 10. As can be seen in FIG. 6, the flexible antenna segment 10 is bonded or attached to the interior surface of the vertical segment 74. After the flexible antenna segment 10 has been affixed in this manner, a cover (not shown) may be affixed to the lower open end of the housing 70, thereby closing the housing and thereby making the antenna completely impervious to corrosive elements.

It will be recognized by one skilled in the art that it is immaterial to the practice of this invention whether housing 50 is utilized or housing 70 is utilized and, furthermore, any otehr similar housing may be employed without departing from the spirit and the scope of the invention.

As shown in FIG. 1, the preferred embodiment utilizes eleven strips of flexible conductive material connected together in several groups. The actual connections and dimensiosn of this antenna have been found empirically and provide the best television reception over channels 2 through 13 as well as the UHF channels. The dimensions of this antenna are provided below; however, it is to be recognized that these dimensions are merely illustrative of the invention, and various modifications may be made without departing from the spirit and the scope of the invention. The flexible non-conductive material utilized in the preferred embodiment is mylar an it two mills thick. An adhesive coating 1 1/2 mills thick is applied to one surface of the mylar. The flexible conductive material utilized is rolled copper foil which is 0.0014 inches thick and is 1/2 inch wide. The purity of the copper is rolled 99.9 percent. The resistivity of one ounce of this copper is 0.15940 ohm-gram meter at 20.degree. centigrade. The tensile strength is equal to 50. The connectors 18 and 20 are manufactured from a copper alloy and are one inch wide. The strips of flexible conductive material 16 are affixed to the mylar at the receiving station 34. The receiving station 34 applies a pressure of 30 psi at 325.degree. F. to each of the strips of flexible conductive material 16 thereby bonding the strips of flexible conductive material 16 to the flexible non-conductive layer 12. The space between each adjacent strip of flexible conductive material 16 is approximately 0.125 inches.

While specific dimensions and components have been described, it will be recognized that these dimensions and components are only exemplary and that if the antenna were to be used with other frequencies than the television frequency, different lengths and different spacings may be utilized and obviously, many modifications and alterations may be made herein without departing from the spirit and the scope of the invention as set forth in the appended claims.

Claims

What is claimed is:

1. An omni-directional television receiving antenna comprising:

a layer of flexible non-conductive material;

a plurality of parallel strips of flexible conductive material having a preselected substantially equal length wherein each of said strips of flexible conductive material includes a first end and a second end and wherein each of said strips of flexible conductive material are affixed to said layer of flexible non-conductive material;

first means for electrically connecting said strips of flexible conductive material to a utilization device; and

a rigid non-conductive circular housing wherein said layer of flexible non-conductive material is affixed to the interior of said housing whereby said first end of each of said conductive strips is placed adjacent to its respective second end of said conductive strips thereby forming a plurality of substantially circularly shaped conductive elements.

2. The omni-directional antenna of claim 1 further comprising:

second means for electrically connecting a preselected number of said parallel conductive strips to each other.

3. The omni-directional antenna of claim 2 wherein said second means comprises a strip of conductive material affixed to said first ends of each of said preselected parallel conductive strips.

4. The omni-directional antenna of claim 1 wherein said antenna comprises 11 parallel strips of flexible conductive material affixed to said non-conductive material.

5. The omni-directional antenna of claim 4 further comprising:

second means for electrically connecting together the first ends of four of said conducting strips thereby forming a first group of conductive elements; and

third means for electrically connecting together the first ends of the remaining seven of said conducting strips thereby forming a second group of conductive elements.

6. The omni-directional antenna of claim 5 further comprising:

a means for electrically bisecting one of said strips of conductive material of said second group of conductive elements whereby one of said bisected segments remains electrically connected to said third means; and

fourth means for electrically connecting the other of said bisected segments to another of said strips of conductive material in said second group of conductive elements.

7. The omni-directional antenna of claim 6 wherein said flexible non-conductive material comprises mylar and wherein said flexible strips of conductive material each comprise copper foil.

8. The omni-directional antenna of claim 7 wherein said circular housing completely encloses said layer of flexible non-conductive material thereby making said antenna impervious to corrosive elements.

9. The omni-directional antenna of claim 8 wherein said first means comprises a twin lead wire and wherein one of said leads is electrically connected to said first group of conductive elements and wherein the other of said leads is electrically connected to said second group of conductive elements.

10. The omni-directional antenna of claim 9 wherein each of said leads are electrically connected to said conductive elements by a snap fastening means.

11. The omni-directional antenna of claim 3 wherein said first means is electrically connected to said strips of flexible conductive material by a snap fastening means.