Abstract:
An antenna is formed on a vest by providing a pair of conducting regions on the outer surface. A non-conducting gap separates the conducting regions. A front conducting strip provides an electrical connection between the first and second electrically conducting portions. A feed conductor is connected to a conducting patch that is connected to one of the conducting regions.

Description:
This application claims the benefit of U.S. Provisional Application Serial No. 60/244,952, filed on Oct. 30, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the invention 
     This invention is directed to an ultra-wideband man-portable radio antenna that operates in the 30 MHz to 500 MHz frequency range using a single antenna. 
     2. Description of the Prior Art 
     Most man-portable communications antennas are of the monopole type. A typical monopole antenna uses a metal wire, a thin surface-metalized rod, or a thin, narrow metal tape and operates against the radio enclosure. Although a monopole antenna is simple and inexpensive to manufacture, it has the following serious deficiencies: 
     1. Typical wire/rod/tape monopole antennas exhibit a narrow instantaneous bandwidth, on the order of one magnitude lower than the bandwidth of the vest antenna according to the present invention. 
     2. A monopole has a characteristic visual signature (extending above the operator&#39;s head) thus identifying the radio operator and disclosing the operator&#39;s location 
     3. Monopole antennas are vulnerable to entanglement in foliage and damage in urban environments. 
     4. To prevent the deficiencies listed above, many monopole antennas are deployed on a “need to use” basis meaning that they have to be assembled/set up (unfurled in case of metal tape or assembled out of several sections in case of metalized rods) prior to use and then disassembled for stowage after use, which increases the operator workload and precludes instantaneous establishment of radio communication at any arbitrary instant in time. 
     5. Multiple monopoles (a monopole set) is required to cover the frequency range of 30 MHz to 500 MHz, increasing the number of items/weight the soldier has to carry and restricting the radio operation to only one frequency band at a time (the one corresponding to the particular monopole selected as the antenna). 
     6. To reduce the monopole length and/or avoid the use of multiple monopoles for man-portable radios, an antenna tuner is used in conjunction with the monopole to increase the monopole&#39;s operational bandwidth but this limits the use of the radio to a “single channel” (narrowband) operation at a time. 
     SUMMARY OF THE INVENTION 
     The vest antenna according to the present invention overcomes the foregoing and other deficiencies of the prior art by providing a unique combination that no conventional man-portable antenna has been able to provide. The present invention provides a new approach to man-portable antennas by fully integrating the antenna with the combat wear of a soldier. The vest antenna according to the present invention enables radio operation over a very wide frequency range using an ultra-wideband antenna worn by the radio operator. 
     It is an object of the invention to provide a man-portable antenna that provides wideband operation capability to provide efficient operation in the entire 30 MHz to 500 MHz frequency range without an antenna tuner. 
     Another object of the invention is to provide a man-portable antenna that is non-obtrusive and that exhibits no visual signature. 
     It is an object of the invention to provide a man-portable antenna that is inexpensive to manufacture, operate, and maintain and that adds minimal weight to operator. 
     Still another object of the invention is to provide a man-portable antenna that provides safety from possible entanglements in high voltage overhead wires; 
     A further object of the invention is to provide a man-portable antenna that is wearable by the operator through integration with existing items of clothing; 
     Yet another object of the invention is to provide a man-portable antenna that is formed using existing combat equipment such as a flak vest or a load bearing vest that is used as a base for conducting cloth. 
     An object of the invention is to provide a man-portable antenna that has extensive application potential for both military and non-military uses. 
     An object of the invention is to provide a man-portable antenna that has a nearly omni-directional radiation pattern with vertical polarization. 
     Another object of the invention is to provide a man-portable antenna that requires no set-up for its usage and that is suitable for all-weather antenna operation. 
     Accordingly, in accordance with the present invention, a man-portable antenna assembly formed on a vest to be worn as an article of clothing comprises first and second electrically conducting portions connected to the vest. A non-conducting band is formed on the vest between the first and second electrically conducting portions. A first conducting strip is arranged in a first portion of the vest to provide an electrical connection between the first and second electrically conducting portions. A second conducting strip is placed in a second portion of the vest and connected to the first electrically conducting portion. A conducting patch is connected to the second electrically conducting portion, and a feed conductor is electrically connected to the conducting patch. 
     The first and second electrically conducting portions the vest preferably comprise metalized cloth arranged to substantially cover all of the vest except for the non-conducting band. 
     The first conducting strip preferably extends the full length of the front portion of the vest. 
     The feed conductor preferably comprises a coaxial cable having its center conductor connected to the conducting patch. 
     The second conducting strip and the conducting patch preferably are on a back portion of the vest and are separated by the non-conducting band. 
     The second conducting strip preferably extends between a lower edge portion of the vest and the non-conducting band and the coaxial cable has a shield that preferably is secured to the second conducting strip. 
     The non-conducting band preferably divides the vest so that the first and second conducting portions have substantially equal areas. 
     The non-conducting band preferably is formed to have a substantially uniform width of about 2.5 cm. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a rear elevation view of a vest antenna according to the present invention; 
     FIG. 2 is a front elevation view of the vest antenna of FIG. 1; 
     FIG. 3 graphically illustrates the real component of the impedance of the vest antenna as a function of frequency; 
     FIG. 4 graphically illustrates the voltage standing wave ratio of the vest antenna according to the present invention as a function of frequency; 
     FIG. 5 shows an alternate embodiment of a non-conducting band that is between two conducting portions of the vest antenna according to the present invention; 
     FIG. 6 shows a second alternate embodiment of the non-conducting band; and 
     FIG. 7 shows an alternate embodiment of a sleeve that may be included in the vest antenna according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 and 2, a vest antenna assembly  10  according to the present invention comprises an antenna structure  12  formed on a vest  14 . In a preferred embodiment of the invention. The vest  14  is a military “flak” vest. Military flak vests are well-known devices for protecting the torso of personnel in hazardous situations. A typical flak vest has a height of about 57.5 cm and a width of about 35 cm as viewed in FIGS. 1 and 2. The vest  14  may have curved shoulder regions  16  and  18  and curved side regions  20  and  22  that each have radii of curvature of about 12.5 cm. 
     The base material for the vest  14  is ordinary cotton duck cloth sewn to the flak vest. The vest antenna assembly  10  includes conducting regions formed of a metalized cloth. Such cloth formed of a copper coated polyester fabric is commercially available from Flectron Metalized Materials of St. Louis, Mo. Any reasonably conducting material can be substituted for the conducting cloth described herein. 
     A non-conducting band  24  divides the vest antenna assembly  10  into an upper portion  26  and a lower portion  28 . The upper portion  26  and the lower portion  28  preferably have equal surface areas to provide optimum electrical performance. The non-conducting band  24  defines a gap that is an integral part of the design. The embodiment of FIG. 1 preferably has a 2.5 cm horizontal gap at the center of the vest  14 . The geometry and width of the nonconducting band  24  affect the frequency response and impedance of the vest antenna assembly  10 . 
     Referring to FIG. 1, a conducting strip  30  extends from a central bottom edge portion  32  of the lower conducting half  28  upward to the non-conducting band  24 . The conducting strip  30  preferably has “sawtooth” shaped side edges  32  and  34 . The conducting strip  30  has a lower edge  36  that preferably has a width of about 15.24 cm. A portion  38  having substantially uniform width extends upward from the lower edge. The width of the portion  38  measured between corresponding “troughs” in the sawtooth configuration preferably is about 9.53 cm. The conducting strip  30  has an upper tapered portion  40  that has an upper edge  42  that preferably has a width of about 17.78 cm adjacent the non-conducting band  24 . 
     Still referring to FIG. 1, a conducting patch  44  is located just above the non-conducting band  24  above the upper edge  42  of the tapered portion  40  of the conducting strip  30 . The conducting patch  44  has a lower edge  46  that preferably has a width of 22.86 cm. The conducting patch  44  preferably is formed generally as half an oval having a sawtooth shaped outer edge  48 . The conducting patch preferably has an overall height of about 11.43 cm. The distance from the lower edge  46  to the bottom of the uppermost trough  50  in the outer edge  48  preferably is about 8.56 cm. The width between the troughs  52  and  54  that are closest to the lower edge  46  preferably is about 17.15 cm. 
     Still referring to FIG. 1, the antenna structure  12  includes a coaxial feed cable  56 . The coaxial feed cable  56  has a center conductor  58  that preferably is connected to the conducting patch  44  using solder or a conducting adhesive. The coaxial cable  56  has a shield  60  that is connected to the conducting strip  30  on the lower portion  28  of the vest  14 . FIG. 1 shows a plurality of solder connections  62  between the conducting strip  30  and the shield  60 . The plurality of connections aid in maintaining the integrity of the electrical connection between the feed cable  58  and the conducting patch  44 . Flexible coaxial cable is preferred to allow movement of a person wearing the vest  14  without damaging the feed connection. It should be noted that the feed cable may be connected to the conducting strip  30  instead of the patch  44 . Copper tape is preferably used to form the patch  44  that functions as a feed region. The copper tape preferably is sewn to the vest material to provide a sturdy, reliable electrical connection to the vest material. Copper tape expands the current from the feed region through a wide region of the conducting outer surface of the vest  14  and improves signal propagation. The copper tape is a generic item that is commercially available at plumbing hardware stores. 
     Referring to FIG. 2, the upper portion  26  and the lower portion  28  are connected in a front portion  64  of the vest  14  via a conducting strip  66 . The conducting strip  66  preferably passes from the lower front edge  68  of the vest to the neck opening  70 . A portion  72  of the conducting strip  66  passes over the non-conducting band  24 . 
     FIG. 3 graphically illustrates the real component of the impedance of the antenna structure  12  as a function of frequency. The solid line in FIG. 3 represents measured values of impedance. The dashed line represents impedance data obtained from a computer simulation. 
     FIG. 4 illustrates the voltage standing wave ratio (VSWR) of the antenna structure  12  as a function of frequency. The solid line in FIG. 4 represents measured values of VSWR. The dashed line represents VSWR data obtained from a computer simulation. 
     FIGS. 5 and 6 show alternate configurations for the non-conducting band between the upper and lower regions of the vest  14 . FIG. 5 shows a non-conducting band  74  formed in a generally “sawtooth” configuration. The non-conducting band  74  preferably has a width in the range of 2.5 to 5.0 cm. 
     FIG. 6 shows a non-conducting band  76  having alternating sharply pointed teeth  78  and flattened teeth  80 . The pointed teeth  78  may be formed as triangular projections, and the flattened teeth  80  may be formed as frustoconical projections. 
     FIG. 7 shows a vest sleeve  82  that has a rounded shoulder portion  84  and a straight portion  86  that extends between the shoulder portion  84  and an upper side portion  88 . 
     The vest antenna assembly  10  according to the present invention has the follow advantages and unique characteristics: 
     1. Wideband operation capability to provide efficient operation in the entire 30 MHz to 500 MHz frequency range without an antenna tuner 
     2. Non-obtrusive, exhibiting no visual signature; 
     3. Inexpensive to manufacture, operate, and maintain; 
     4. Adds minimal weight to operator; 
     5. Provides safety from possible entanglements in high voltage overhead wires; 
     6. Cannot become ensnared or entangled 
     7. Conducting cloth used as the antenna material; 
     8. Wearable design through integration with existing items of clothing; 
     9. Existing combat equipment such as the flak vest or load bearing vest can be used as a base for the conducting cloth; 
     10. Extensive application potential for both military and non-military uses; 
     11. Nearly omni-directional radiation pattern with vertical polarization; 
     12. No set-up required for using the antenna; and 
     13. All-weather antenna operation.