Abstract:
An oriented PIFA-type apparatus for reducing hearing aid radio frequency (RF) interference including a directional multi-band and/or single band antenna for use with PWDs such as digital cellphones is disclosed. The apparatus greatly reduces or eliminates the audio noise induced in hearing aids by the PWDs and allows operation of a hearing aid during PWD operation. In operation, the apparatus may be provided on the PWD side away from the user&#39;s head. The apparatus may be integrated into the PWB during its manufacture or provided as an after market assembly for a PWD that has a port for connection of an external antenna. The apparatus provides for improved front-to-back ratio as compared to antennas currently in use on PWD&#39;s, and therefore also reduces SAR (specific absorption rate), the level of RF energy received into the head by a PWD.

Description:
This is a continuation-in-part application of application Ser. No. 10/262,447, filed Sep. 30, 2002 now U.S. Pat. No. 6,639,564, which claims benefit of provisional Application No. 60/357,162, filed Feb. 13, 2002. 
    
    
     RELATED APPLICATIONS 
     
         
         PCT Patent Application US/03/04230, filed Feb. 12, 2003, 
         U.S. patent application Ser. No. 10/262,447, filed Sep. 30, 2002, and 
         U.S. Patent Application Ser. No. 60/357,162, filed Feb. 13, 2002. 
       
    
     FIELD OF THE INVENTION 
     The present invention relates to a portable wireless communications device. More particularly, the present invention relates to an oriented PIFA assembly and ground conductor for reducing the specific absorption rate (SAR) of the associated device during operation. 
     BACKGROUND 
     SAR (specific absorption rate) for users of portable wireless devices (PWDs) is a matter of increasing concern. RF radiation to the user&#39;s head results from the free-space generally omnidirectional radiation pattern of typical current PWD antennae. When PWDs equipped with such an antenna are placed near the user&#39;s head, the antenna radiation pattern is no longer omnidirectional as radiation in a large segment of the azimuth around the user is blocked by the absorption/reflection of the user&#39;s head and hand. An antenna system for PWDs that greatly reduces radiation to the body and redirects it in a useful direction is also desirable. 
     Prior art antennas for PWDs may cause audio noise in a hearing aid of the user. Referring to  FIG. 16 , a diagrammatic view of a prior art PWD  400  (in the form of a cellphone) used in the vicinity of a hearing aid  402  is illustrated. Cellphone  400  has a speaker on the keyboard surface near the top of the phone, which is normally aligned with the center of the user&#39;s ear  404  during use. Hearing aid  402  may be any type, including in-ear and behind-ear variations. Hearing aid  402  has an amplified audio output port  406 , which is inserted into the ear canal of the ear  404 . During operation, an electromagnetic field  408  is generated around cellphone  400  by omnidirectional antenna  440 . In operation, electromagnetic field  408  illuminates the hearing aid  402 , user&#39;s ear  404 , and the user&#39;s head. RF noise is induced in the hearing aid by the field  408 , resulting in excessive audio noise being presented to the user. 
     The planar inverted F antenna or PIFA is characterized by many distinguishing properties such as relative lightweight, ease of adaptation and integration into the device chassis, moderate range of bandwidth, omni directional radiation patterns in orthogonal principal planes for vertical polarization, versatility for optimization, and multiple potential approaches for size reduction. Its sensitivity to both vertical and horizontal polarization is of practical importance in mobile cellular/RF data communication applications because of the absence of the fixed antenna orientation as well as the multi-path propagation conditions. 
     To assist in the understanding of a conventional PIFA, a conventional single band PIFA assembly is illustrated in  FIG. 17 .  FIG. 17  illustrates a prior art single-band PIFA antenna  440  located on the rear side  442  of a personal wireless device  444 . PIFA  440  consists of a radiating element  446 , a ground plane  448 , a feed conductor  450 , and a grounding conductor  452 . PIFA  440  is typically positioned near an upper edge of ground plane  448  with the free end of radiating element  446  being closer to a user&#39;s hand than the feed conductor  450  and grounding conductor  452 . The feed conductor  450  serves as a feed path for radio frequency (RF) power to the radiating element  446 . The feed conductor  450  is electrically insulated from the ground plane  448 . The grounding conductor  452  serves as a short circuit between the radiating element  446  and the ground plane  448 . The resonant frequency of the PIFA  440  is determined by the length (L) and width (W) of the radiating element  446  and is slightly affected by the locations of the feed conductor  450  and the grounding conductor  452 . The impedance match of the PIFA  440  is achieved by adjusting the dimensions of the conductors  450 ,  452 , and by adjusting the separation distance between the conductors  450 ,  452 . In operation, ground plane  448  radiates RF energy which is absorbed by a user&#39;s hand. Antenna  440  can be configured to reduce the SAR value to 1.6 mw/g with the PWD  444  transmitting at the 0.5 watt cw level. However, even at this level audio noise may be generated in a user&#39;s hearing aid by operation of PWD  444 . Another limitation of the PIFA is its relatively low front-to-back ratio. Front-to-back ratios of typically PIFAs range from 0 to 2 dB. A 5 dB front-to-back ratio may be achieved by substantially increasing the distance between radiating element  446  and ground plane  448 . A need exists for an antenna exhibiting substantially greater front-to-back ratios. 
       FIG. 18  illustrates a prior art dual-band PIFA antenna  462 , which is located on the rear of a personal wireless device  464 , and electrically connected to ground plane  466  at one end and capacitively coupled to ground plane  466  at another end. PWD  464  further includes a battery pack  470  positioned away from antenna  462 . In normal operation, PWD  464  is oriented in an upright manner so that end  472  is generally above end  474 . Ground plane  466  is provided by the ground traces of the printed wiring board (PWB). The portion of antenna  462  indicated by numeral  476  resonates over a higher frequency band, while the entire portion  476 ,  478  of antenna  462  resonates over a lower frequency band. PIFA antenna  462  is grounded at its upper end at location indicated as numeral  480  to ground plane  466 . PIFA antenna  462  is capacitively coupled at pad  482  in a direction away from upper end  472  of PWD. This type of antenna provides some reduction in SAR, but has limited ability to reduce hearing aid noise from a digital PWD. 
     Despite all of the desirable properties of a PIFA, the PIFA has the limitation of a rather large physical size for practical application. A conventional PIFA should have the semi-perimeter (sum of the length and the width) of its radiating element equal to one-quarter of a wavelength at the desired frequency. With the rapidly advancing size miniaturization of the radio communication devices, the space requirement of a conventional PIFA is a severe limitation for its practical utility. 
     SUMMARY OF THE INVENTION 
     The device of the present invention greatly reduces radiation directed toward a user&#39;s hand and head during device operation. As a result, the device promotes a reduction of the SAR for a PWD. Other benefits include longer transmit/receive range, lower transmit power, and longer battery life. Yet another benefit is the reduction in PWD generated noise in a user&#39;s hearing aid. 
     A device according to the present invention may include a PWD implemented for operation over single or multiple frequency-band. An antenna may be incorporated within a PWD at the time of manufacture, or may be provided as an accessory or after market item to be added to existing PWDs having an external antenna port. The latter feature is particularly useful, in that existing PWDs can be retrofitted to achieve the benefits of the antenna of the present invention, including elimination of hearing aid noise and very low SAR. The antenna of the present invention is suitable for high-volume, low cost manufacturing. The antenna/PWD combination, whether an aftermarket or original equipment item, may be placed in a leather or plastic case, such that the antenna side of the PWD is facing away from the body. This provides a further advantage with respect to SAR, when the PWD is stored via a belt clip when in receive-only mode. 
     Other objects of the present invention include: 
     the provision of an antenna exhibiting high gain and a front-to-back ratio which is substantially greater than known antenna devices; 
     the elimination (or substantial reduction) of audio noise in hearing aids caused by close proximity to transmitting PWDs, particularly PWDs operating in one or more frequency bands, enabling use of hearing aids in close proximity to such PWDs; 
     the reduction in SAR due to operation of a single or multi-band PWD near the user&#39;s head; 
     the provision of an antenna suitable for integration within or upon a PWD; 
     the provision of an antenna having wide bandwidth in one or more frequency bands; 
     the provision of an antenna having one or more active elements and one or more passive elements, each resonant on one or more frequency bands; 
     the provision of an antenna which radiates RF energy from a PWD preferentially away from a user thereof; 
     the provision of an antenna promoting increased PWD battery life by reducing commanded RF power; 
     the provision of an antenna having a reduction in the amount of RF energy being absorbed by a user&#39;s hand and head during operation; and 
     the provision of an antenna with the one or more active element(s) connected to a PWDs transmit/receive port. 
     These and further objects of the present invention will become apparent to those skilled in the art with reference to the accompanying drawings and detailed description of preferred embodiments, wherein like numerals refer to like parts throughout. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a first embodiment of a device according to the present invention. 
         FIG. 2  is a perspective view of a second dual band embodiment of a device according to the present invention. 
         FIG. 3  is a perspective view of a third embodiment of a device according to the present invention. 
         FIG. 4  is a perspective view of another embodiment of a device according to the present invention. 
         FIG. 5  is a top plan view of the device embodiment of  FIG. 4 . 
         FIG. 6  is a side view of the device embodiment of  FIGS. 4 and 5 . 
         FIG. 7  is a perspective partial view of another embodiment of the present invention. 
         FIG. 8  is a perspective view of yet another embodiment of a device according to the present invention. 
         FIG. 9  is a perspective partial view of another embodiment of the present invention. 
         FIG. 10  is a perspective view of yet another embodiment of a device according to the present invention. 
         FIG. 11  is a top plan view of the device embodiment of a single-band embodiment of the present invention. 
         FIG. 12  is a side view of the device embodiment of  FIG. 11 . 
         FIG. 13  is yet another embodiment of an antenna according to the present invention. 
         FIG. 14  is yet another embodiment of an antenna according to the present invention. 
         FIG. 15  is yet another embodiment of an antenna according to the present invention. 
         FIG. 16  is a diagrammatic view of a prior art device in operation. 
         FIG. 17  is a perspective view of a prior art device. 
         FIG. 18  is a perspective view of another prior art device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 through 3 , a device according to one embodiment of the present invention is indicated as numeral  2 . Device  2  includes a portable wireless device “PWD”  4  and a PIFA antenna structure  6 . Relative to a user, in operation PWD  4  includes a front side  8  which is nearer to the user than a back side  10 . PWD  4  has a top  12  and a bottom  14 . In operation, bottom  14  is between top  12  and the ground surface upon which the user is positioned. PWD  4  is generally aligned in operation so that its top  12  is above a user&#39;s hand which grasps the PWD. PWD  4  includes a ground plane  16 , typically a conductive plane within a printed wiring board upon which electronic components are secured. 
     Antenna structure  6  includes a ground plane conductor element  18  and a configured conductive radiating element  20 . Element  20  may include a plurality of planar surfaces or may be configured to have some curvature or other shape. Element  20  may be formed as a metal part or may be a plating or conductive layer disposed upon a support element. 
       FIG. 1  illustrates a single-band version of a device according to the present invention. Element  20  is an upwardly directed conductor having a free end  22  of conductor  24 , a leg conductor  26 , and a leg conductor  28 . Leg conductor  26  is connected to ground plane  18  at an opposite end as indicated by numeral  30  on leg  26 . A feedpoint  32 , having a desired impedance, is defined upon leg conductor  28 . Conductors  24 ,  26 ,  28  may be provided with differing widths and/or thicknesses. A coax line or a microstrip or other type of transmission line may be used to couple the feedpoint to signal electronics of PWD  4 . In operation, free end  22  is above leg elements  26 ,  28  relative to the ground surface upon which the user is positioned. 
     In the illustrated embodiment, ground plane element  18  is a separate conductor from ground plane  16  of PWD  4 . Element  18  may optionally be electrically connected to ground plane  16 . A portion  34  of element  18  overlaps a portion of ground plane  16  of PWD  4 . Element  18  is illustrated with a tapered end  36 . In alternative embodiments, element  18  may assume various other shapes. Element  18  may have holes, slots or other openings (not shown). Element  18  may be curved or configured to reduce its overall length, i.e., element  18  need not be a planar element. For example, the free end of element  18  may be bent toward or away from front side  8  of PWD  4 . Element  18  may be provided within an accessory item for a PWD  4 . Alternatively, element  18 , may be incorporated within the overall housing of a PWD  4 . Element  18  may be extendible relative to PWD  4 . The width “W 1 ” of element  18  is preferably equal to the width “W 2 ” of PWD ground plane  16 . A distance “D 1 ” between the grounding conductor  26  and the edge of ground conductor  18  is between ⅛ th  to 1 inch. A particular preferred D 1  distance is approximately ¼ inch. The overall length “L 1 ” of ground conductor  18  is between 1.5 to 3 inches. Ground plane element  18  preferably has an electrical length in the range of 0.25 to 0.6 wavelength for a frequency within the band of operation. A particular preferred L 1  distance is approximately 0.4 wavelength. The length “L 2 ” represents the portion of ground plane  18  away from conductors  24 ,  26 ,  28 . In comparison to prior art PIFA devices, L 2  is substantially greater than L 3  of  FIG. 17 . As a result, L 1  is substantially smaller than typical ground plane lengths of prior art functional PIFA antennas. L 1  is approximately 50% shorter than typical lengths of ground planes associated with prior art PIFA antennas. 
     In operation, element  18  may be selectively extendible away from the body of PWD  4 . A sliding coupling between element  18  and PWD  4  is envisioned, though alternative couplings would be appreciated by those of ordinary skill in the art, e.g., element  18  may be pivotally connected to PWD and rotate into position during operation. Element  18  may manually or automatically transition between an operational position (as shown in  FIG. 1 ) and a non-operational position (not shown). Element  18  may be automatically extended into its operational position upon receipt of an RF signal. A PWD  4  according to the present invention displays a substantially higher gain and front-to-back ratio as compared to known PIFA devices. A front-to-back ratio of 30 dB may be achieved by the present invention. In comparison, known PIFA devices exhibit 0 to 2 db front-to-back ratio. 
       FIG. 2  is a dual band version of an embodiment of the present invention. In the drawings, like numbers reference like elements. Element  40  includes a conductor  42  having a free end  44 , conductor  46 , leg conductor  48 , a leg conductor  50 , a leg conductor  52 , and a foot conductor  54 . Element  40  includes a slot  56 . Leg conductor  48  is connected to ground plane  18  as indicated by numeral  58 . Foot conductor  54  is not conductively coupled to ground plane  18 . A feedpoint  60 , having a desired impedance, is defined upon leg conductor  50 . Conductors  42 ,  46 ,  48 ,  50 ,  52 ,  54  may be provided with differing widths and/or thicknesses. A coax line or a microstrip or other type of transmission line may be used to couple the feedpoint  60  to signal electronics of PWD  4 . In operation, free end  44  is above leg elements  48 ,  50  relative to the ground surface upon which the user is positioned. Slot  56  may assume various shapes or configurations, e.g., serpentine, curved, etc. Leg elements  52  and foot element  54  are optional. 
       FIG. 3  illustrates another dual band embodiment of the present invention. A dielectric element  61  is positioned between PIFA conductor  62  and ground plane  63 . Ground plane  63  is movable relative to ground plane  16  including ground traces of the printed wiring board of the PWD. Ground plane  63  of  FIG. 3  may be disposed upon a printed circuit board—type dielectric material by known circuit printing technology. Alternatively, ground plane  63  may be a conductive sheet attached to a support structure. Dielectric  61  may be solid or hollow. PIFA conductor  62  may be a plated surface of dielectric  61 , or may be a separate formed metal element positioned relative to dielectric  61 . PIFA conductor  62  is conductively coupled to ground plane  63  at location  64 . A feedpoint  66  is defined upon a leg conductor  68 . A slot  70  is defined on conductor  62 . 
     Referring to  FIGS. 4 through 6 , an antenna device according to one embodiment of the present invention is indicated as numeral  70 . Device  70  comprises an external assembly which may be provided as an aftermarket device to improve PWD  4  performance. Device  70  has an RF port  72  which connects into an external antenna port  74  of the PWD  4 . In alternative embodiments, device  70  may be connected via a coaxial cable or other type of transmission line. 
     Device  70  includes a conductor element  76  and a pair of configured conductive radiating elements  78 ,  80 . Element  76  may be a planar conductive element, or may be configured to have some curvature or other shape. Element  76  preferably has an electrical length in the range of 0.3 to 0.8 wavelength for a frequency within the band of operation. Element  76  may be formed as a metal part or may be a plating or conductive layer disposed upon a support element, such as a housing, etc. Further, at least a portion of element  76  may be provided by the ground traces of the printed wiring board of a PWD within or upon which antenna  70  is located. 
     Each of the conductors  78 ,  80  has a free end and is conductively connected to element  76  at an opposite end as indicated by numeral  82  in  FIGS. 5 and 6 . A feedpoint  84 , having a desired impedance, is defined along conductor  78 . A short conductor  86  is attached at feedpoint  84 . Conductor  86  is connected to the center conductor of a coaxial line  90 . An outer shield of line  90  connects to conductor element  76  at location  92 . In alternative embodiments, coax line  90  may be replaced by a microstrip or other type of transmission line. 
     In the embodiment of  FIGS. 4–6 , transmission line  90  connects to RF connector  72 , which is selected to match the connector used for the external antenna port  74  on WCD  4 . Although connector  72  is shown exiting the back side of element  76 , it may take any other route as required to plug into the WCD&#39;s external antenna port. Antenna device  70  may also be incorporated into a WCD at the time of manufacture, in which case transmission line  90  would directly connect to the RF input/output point of the WCD&#39;s transceiver. 
     Elements  78 ,  80  are designed to resonant over one or more frequency bands. As an example, conductor  78 , which is a fed element, may be resonant at a higher frequency band, with inductor  100  and conductor  102  acting as a “trap” or electrical stop for said higher frequency band. The term “LC trap” as used herein is defined to mean either a inductor/capacitance trap or an inductive trap. Coil  100  and conductor  16  may be selected so as to cause the combination of elements  78 ,  100 , and  102  to resonate at a lower frequency band, thus providing a dual-band element having one feedpoint. 
     Element  80 , which is not directly connected to feedline  90 , may have its length adjusted to resonate over the same or nearly the same frequency bands as  78 . Inductor  104  and conductor  106  may be selected to act as a “trap” or stop for the said higher frequency band, and the combination of elements  80 ,  104 , and  106  may be selected to resonate at a lower frequency band, which may be the same or nearly the same as that of elements  78 ,  100 , and  102 . Again, a greater bandwidth in a lower frequency band is attained with two adjacent elements ( 78 ,  100 ,  102 ) and ( 00 ,  104 ,  106 ) than with a single element. The higher frequency band may be 1850–1990 MHz, and the lower frequency band may be 824–894 MHz. A range and preferred values of dimensions for these frequency bands are as follows; 
     
       
         
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                   
               
               
                   
                 Dimension 
                    Range 
                 Preferred Dimension 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 W1 
                 0.25–1.525 
                 in. 
                 0.75 in. 
               
               
                   
                 W2 
                 1–6 
                 in. 
                  1.6 in. 
               
               
                   
                 H1 
                 0.3–2 
                 in. 
                 0.75 in. 
               
               
                   
                 H2 
                 0.001–0.5 
                 in. 
                 0.02 in. 
               
               
                   
                 L1 
                 1.5–4 
                 in. 
                 2.75 in. 
               
               
                   
                 L2 
                 0.5–4 
                 in. 
                   1 in. 
               
               
                   
                 L3 
                 4–8 
                 in. 
                 5.25 in. 
               
               
                   
                   
               
             
          
         
       
     
     Conductors  78 ,  80  may have any cross section, including round and rectangular. One preferred cross section is 0.05 in diameter round wire. 
     Conductor  76  length, L 3 , is greater than the length of elements  78  and  80 . Conductor  76  may be defined by a plurality of conductive trace elements on a dielectric board, such as a printed wiring board. Through additional experimentation by those skilled in the relevant arts, the traces may assume a variety of configurations. 
     Element  78  and  80  are oriented upon conductor  76  so that the free ends of the elements  78 ,  80  are above the connection ends  82  during device operation. In other words, during device operation, elements  78 ,  80  are upwardly directed. In a typical operation of PWD  4 , elements  78 ,  80  would be more or less perpendicular to the floor or ground surface upon which the operator is positioned. For an embodiment of antenna  70  which is integrated within a PWD  4 , elements  78 ,  80  are secured at first ends to conductor  76  and have free ends extending in a direction toward the top  12  of PWD  4 . 
       FIG. 7  shows another embodiment of the element  78  and trap inductor  100 . Inductor  100  is a wire element having windings which may be uniformly spaced or which may be non-uniformly spaced. In this particular embodiment, inductor windings  100  are more closely spaced proximate to element  78  than proximate to the conductor element  76 , i.e., the “pitch” of the wire winding varies across its length. The resonant frequency of the combination  78  and  100  may be adjusted by varying height “h”. 
       FIG. 8  illustrates features of another embodiment of an antenna device  70  according to the present invention. Radiating elements  110 ,  112  are coupled at a position relative far away from the top  38  of the PWD  4 , and the open ends  114  of elements  110 ,  112  are in a direction toward the top of the PWD  4 , e.g. during normal operation open ends  114  of elements  110 ,  112  are upwardly directed (e.g., away from a floor surface). 
     The ground plane required for the antenna system  70  may be provided separately from that within the PWD  4 , by conductive segments  120 ,  122  and  124 . Segments  120 ,  122  may be capacitively coupled within the overlap region “O”. Segments  124 ,  120  are electronically connected, and segment  124  may slide in and out relative to  120  to reduce size, when the PWD  4  is not in use. Segment  124  may be manually retracted as during PWD  4  operation. In alternative embodiments, segment  124  may be automatically extended during operation, such as via a small solenoid, motor and gearing, etc. 
     Referring to  FIG. 9 , an alternative embodiment of a driven element  136  of the antenna  70  of the present invention is shown. In this embodiment, PWB (printed wiring board) technology is utilized to facilitate close dimensional tolerances for the antenna. A dielectric printed wiring board  134 , which may have a dielectric constant in the range 2–30, is used to support the element conductors  131 ,  132 ,  135 . The feed point is indicated as numeral  84 . Connection point to coax line  90  is indicated as numeral  133 . Meander line inductor  132  corresponds to inductor  100  from  FIGS. 4–6 . Although meander line inductor  132  is shown as a meander line on one surface of the PWB  134 , one skilled in the art would recognize that it could also be implemented as traces occupying both sides of PWB  134 , with plated-through holes (“vias”) connected the line segments. Although the driven elements  131 ,  132 ,  135  alone are depicted in  FIG. 9 , the same construction may be used to fabricate the non-driven element as well. 
     Referring to  FIG. 10 , another embodiment of the antenna  70  of the present invention is shown in perspective view. The various conductive elements consisting of leg elements  200  and  204  (which are generally perpendicular relative to conductive element  206 ), elements  208  and  210  (which are generally parallel to conductive element  206 ), feed conductor  220 , and crossbar conductor  222  all of which may be formed as a single stamped metal part. The bottom ends of legs  200 ,  202  are inserted into slots  224  in element  206 , and may be soldered or otherwise captured mechanically. 
     Element leg  204  and element  210  may preferably be wider than corresponding leg element  200  and element  208 . Inductors  230 ,  232  may have extensions  240  leading to an additional turn or turns  242 ,  244 . This construction of the inductor  230 ,  232  eliminates a separate conductor plate  102 ,  106  at the end of the coils,  100 ,  104  as shown in  FIG. 5 . 
     Elements  28  and/or  210  may be supported by dielectric post  250  and a dielectric clamp (not shown) at location  252 , respectively. 
     Referring to  FIGS. 11 and 12 , yet another embodiment of a device according to the present invention is illustrated. Antenna  70  in this embodiment is a single band antenna assembly. In comparison to the dual-band embodiment of  FIGS. 4–6 , this embodiment of antenna  70  does not require the trap tuning elements, e.g., elements  100 ,  102 ,  104 , and  106  of  FIGS. 5 and 6 . 
       FIG. 13  shows a single band embodiment of the antenna  300  of the present invention. Antenna  300  is located near the top  38  of PWD  4 . The radiating element has three segments  302 ,  304 ,  306 . A microstrip feed section  310  is shown connected to the rf input/output port of the PWD at  312 . A ground plane  320 , separate from the internal ground plane of PWD  4 , is used. Segment  306  is electrically connected to  320  at location  330 . Ground plane  320  may extend beyond the top of PWD  4 , and it may be a sliding type as shown in  FIG. 8 . Ground plane  320  may be provided, at least in part, by the ground traces of the printed wiring board of PWD  4 , particularly in an application where antenna  300  is integrated within the PWD  4 . 
     Antenna  300  may function as a single band antenna suitable for operation over the range of 1710–1990 MHz, for example. In one embodiment the dimensions: for ground plane  320  are 1.41 in. by 2.72 in; for segment  306  are 0.57 in. (width) by 0.5 in. (height); and for segment  302  are 0.57 in (width) by 1.46 in. (length). Thickness of all conductors may be in the range of 0.001–0.10 inch, with 0.020 being a preferred thickness. The length of ground plane  320  extending beyond end  38  may be in the range of 0 to 1 inch, with 0.7 in being a preferred dimension. In an embodiment of antenna  300  being incorporated within a PWD  4 , ground plane  320  may not extend outside of the PWD  4  housing. 
     Referring to  FIG. 14 , another antenna embodiment  70  with a configured ground plane conductor  76  is shown. The length L 1  of conductor  76  of  FIG. 6  is replaced by the combination of L 1 ′, L 1 ″ and L 1 ′″. Generally, this combination of segments will have a length equal to or somewhat longer than L 1  of  FIG. 6 , depending on the ratio of L 1 ″ to L 1 ′″. The function of this feature is to reduce the overall length of conductor  76  from  FIG. 6 . 
     Referring to  FIG. 15 , yet another antenna embodiment  70  with a differently configured ground plane conductor  76  is shown. Here conductor  341  and inductor  342  are closely spaced from element  76  and electrically connected to element  76  at location  343 . Again, the purpose of this embodiment is to reduce the length of  76 . 
     The above described embodiments of the invention are merely descriptive of its principles and are not to be considered limiting. Further modifications of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention.