Patent Publication Number: US-6906669-B2

Title: Multifunction antenna

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a Continuation Application of U.S. patent application Ser. No. 10/084,576, titled Multifunction Antenna for Wireless and Telematic Applications, filed Feb. 27, 2002 now U.S. Pat. No. 6,664,932, which is a Continuation-in-Part Application of U.S. patent application Ser. No. 09/758,955, titled Low Cost Compact Omni-Directional Printed Antenna, filed Jan. 11, 2001 now U.S. Pat. No. 6,480,162, which claims the benefit of U.S. Provisional Application No. 60/175,790, titled Low Cost Compact Omni-Directional Printed Antenna, filed Jan. 12, 2000. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates generally to a multifunction printed antenna and, more particularly, to a multifunction printed antenna for wireless and telematic applications, including GPS, satellite radio, AMPS, PCS, GSM, etc., where multiple antenna elements are printed on a common circuit board. 
   2. Discussion of the Related Art 
   There is a growing demand for wireless communications services, such as cellular telephone, personal communications systems (PCS), global positioning systems (GPS), satellite radio, etc. With this demand comes a need for low-cost miniaturized planar antennas. The multitude of wireless services requires multiple antennas to cover the different frequency bands and functions. Also, the demand for dual-band phones is ever growing, as people increasingly tend to use both analog and digital communications services. Further, both cellular phone and PCS antennas require an omni-directional pattern. 
   Additionally, it is desirable that the size of the communication apparatus and the transmitting or receiving antennas be small. This becomes even more of a necessity when multiple antennas have to be mounted in a limited area. In military applications, a small antenna size is critical for low radar visibility, and to increase system survivability. In commercial applications, small size alleviates problems with styling, vandalism and aerodynamic performance. Size reduction is especially useful in low frequency applications in the HF, VHF, UHF and L frequency bands ranging from 30 to 3000 MHz. The wavelengths in these bands range from 10 m to 10 cm. Considering the fact that a resonant dipole is about a half-wavelength long, the motivation behind size reduction is obvious. 
   For low frequency applications, low-profile printed antennas include printed microstrip dipole and printed slot antennas. Printed antennas essentially comprise a printed circuit board with a trace layout. The trace layouts can be made using chemical etching, milling or other known methods. These antennas enjoy a host of advantages including ease of manufacture, low cost, low profile, conformality, etc. 
   FIGS.  1 ( a ) and  1 ( b ) show a known printed slot antenna  10  including a metallized ground plane  16  and a microstrip feed line  12  printed on opposite sides of a printed circuit board (PCB)  14 . A linear slot element  18  is cut out of the ground plane  16  by a suitable etching step or the like. The microstrip line  12  is connected to the ground plane  16  at the edge of the slot element  18  by a shorting pin  20  extending through the PCB  14 . 
   Various techniques are known in the art to reduce the size of a printed slot antenna of the type shown in FIGS.  1 ( a ) and  1 ( b ). For example, it is known to use dielectric lenses to reduce the size of a printed antenna. U.S. Pat. No. 6,081,239 issued Jun. 27, 2000 to Sabet et al. discloses a planar printed antenna that employs a high dielectric superstrate lens having a plurality of air voids that set the effective dielectric constant of the material of the lens to reduce resonant waves in the lens, thus reducing power loss in the antenna. The superstrate with air voids allows the size of the dipoles or slots to be reduced for any particular frequency band. 
   It is also possible to reduce the area occupied by a linear antenna element by bending or winding the antenna element into a curved or twisted shape. FIGS.  2 ( a ) and  2 ( b ) show a linear slot element  22  being wound to illustrate this technique. However, bending the antenna element  22  immediately results in a sharp reduction of its bandwidth. This can be verified by numerical modeling and computer simulation. 
     FIG. 3  shows the effect of gradually bending a slot antenna element  24  and how it affects the antenna bandwidth, near field, and vertical and horizontal polarization. This simulation shows that more windings result in a more omni-directional antenna pattern, but the bandwidth of the antenna element  24  is reduced. 
   A wound slot antenna element has to be fed at a location close to its end because the input impedance at its center is very high. The antenna element can be fed using a microstrip line printed on the other side of the substrate with a matching extension or a shorted via hole, as shown in FIGS.  1 ( a ) and  1 ( b ). A coaxial cable can also be used, where its outer conductor is connected to the ground area of the slot antenna and its inner conductor is shorted through the slot. 
   One of the current design challenges for making multifunction antennas includes providing a plurality of different antenna elements in a single compact structure. One particular application where multiple antennas are needed in a compact and low cost design is for a vehicle antenna that is used for all of GPS, satellite radio, advance mobile phone service (AMPS), PCS and group special mobile (GSM) systems. Combining so many antennas in a single structure provides various design challenges that have heretofore not been met in the art. One design challenge includes making some of the antennas, such as the GPS and the satellite radio antennas, circularly polarized with an upward looking beam to accommodate signals from satellites. Other antennas, such as the AMPS, PCS and GSM antennas, require omni-directional and vertically polarized radiation patterns to receive and transmit terrestrial signals. Thus, there is a need to provide all of the antennas on a common structure and still satisfy these needs. 
   SUMMARY OF THE INVENTION 
   In accordance with the teachings of the present invention, a multifunction printed antenna is disclosed including antenna elements for wireless and telematic applications, including, but not limited to, GPS, satellite radio, terrestrial radio, AMPS, PCS and GSM frequencies. In one embodiment, the GPS and satellite antenna elements are patch antenna elements printed on one side of a printed circuit board, and the AMPS, PCS and GSM antenna elements are slot antenna elements etched in a ground plane on an opposite side of the same printed circuit board. The circuit board is mounted at an angle relative to the horizon so that the patch antenna elements for the GPS and satellite radio frequencies are at least partially horizontally oriented relative to the horizon, and the slot antenna elements for the terrestrial radio, AMPS, PCS and GSM frequencies are at least partially vertically oriented relative to the horizon to provide radiation patterns in the desired direction. The patch antenna elements can be corner fed or edge fed to be circularly polarized. 
   Low noise amplifiers (LNAs) can be mounted on the GPS and satellite radio printed circuit board. Further, diplexers, duplexers, filters, amplifiers and other circuit components can be mounted on the terrestrial radio, AMPS, PCS and GSM printed circuit board to provide component integration, reduce system hardware and conserve space. 
   Additional advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS.  1 ( a ) and  1 ( b ) is a top view and a cross-sectional view, respectively, of a conventional printed slot antenna having a microstrip feed line; 
     FIGS.  2 ( a ) and  2 ( b ) show bending a printed antenna element to reduce the antenna size; 
       FIG. 3  shows a series of slot antennas that depict the effect of bending the antennas on the reduction of bandwidth; 
       FIG. 4  is a plan view of a multi-trace antenna design, according to an embodiment of the present invention; 
     FIGS.  5 ( a ) and  5 ( b ) are a top view and a cross-sectional view, respectively, of a multiple slot antenna and its feed, according to the invention; 
     FIGS.  6 ( a ) and  6 ( b ) are two graphs showing the input impedance behavior of a multi-slot antenna of the invention; 
       FIG. 7  is a graph showing an omni-directional radiation pattern of a printed slot antenna according to the various embodiments of the present invention; 
       FIG. 8  is a compact UHF antenna, according to the invention, that is tuned at 390 MHz with a bandwidth of 1 MHz; 
       FIG. 9  is a graph showing the return loss of the antenna shown in  FIG. 8 ; 
       FIG. 10  is a plan view of a dual band antenna design, according to an embodiment of the present invention, that covers the AMPS band and the PCS band; 
       FIG. 11  is a graph showing the return loss of the antenna shown in  FIG. 10 ; 
       FIG. 12  is a perspective view of a sticker antenna design, according to an embodiment of the present invention; 
       FIG. 13  is a front view of an integrated, multifunction GPS/cellular/PCS/GSM antenna, according to an embodiment of the present invention; 
       FIG. 14  is a front view of a multifunction, integrated spiral slot antenna, according to another embodiment of the present invention, that employs a CPW balanced feed; 
       FIG. 15  is a front view of a multifunction antenna for wireless and telematic applications, according to an embodiment of the present invention; 
       FIG. 16  is a back view of the antenna shown in  FIG. 15 ; 
     FIGS.  17 ( a ) and  17 ( b ) are plan views of edge fed patch antennas for the GPS and satellite radio antenna elements shown in  FIG. 15 ; 
       FIG. 18  is a perspective view of a multifunction antenna for wireless and telematic applications, where GPS and satellite radio patch antenna elements are configured on one printed circuit board and terrestrial radio, AMPS, GSM, PCS antenna elements are configured on an orthogonal printed circuit board as part of a common structure, according to another embodiment of the present invention; 
       FIG. 19  is a perspective view of a variation of the antenna shown in  FIG. 18  where the terrestrial radio, AMPS, GSM, PCS printed circuit board is curved relative to the GPS and satellite radio printed circuit board; 
       FIG. 20  is a front view of the terrestrial radio, AMPS, GSM and PCS printed circuit board of the antenna shown in  FIGS. 18 and 19 , where an edge of the printed circuit board has a saw tooth pattern to reduce edge currents; 
       FIG. 21  is a front view of the GPS and satellite radio printed circuit board including low noise amplifiers, according to an embodiment of the present invention; 
       FIG. 22  is a schematic diagram of an antenna and diplexer configured on a common printed circuit board, according to an embodiment of the present invention; and 
       FIG. 23  is a schematic diagram of a receiver/transmitter amplifier circuit for a common printed circuit board, according to another embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE EMBODIMENTS 
   The following discussion of the embodiments of the invention directed to a multifunction antenna for wireless and telematic applications is merely exemplary in nature, and is in no way intended to limit the invention or its applications or uses. 
   To overcome the limitations of reduced bandwidth for a curved or wound antenna design, the present invention proposes a multi-trace antenna design consisting of two or more slot antenna elements of different lengths configured in a relatively parallel orientation.  FIG. 4  is a plan view of a printed antenna  30  having such a design, where the printed circuit board is removed for clarity. The antenna  30  includes two wound, resonating slot antenna elements  32  and  34  that represent slots etched in a ground plane, such as the ground plane  16 , formed on a printed circuit board, such as the printed circuit board  14 . A feed line  36 , that is a conductive microstrip patterned on an opposite surface of the printed circuit board, includes a feed stub  38  that feeds the element  32  and a feed stub  40  that feeds the element  34 . The feed stub  38  is connected to a shorting via  42  that extends through the printed circuit board and is shorted to the ground plane on the opposite side of the printed circuit board proximate to the element  32 , as shown. Likewise, the feed stub  40  is connected to a shorting via  44  that extends through the printed circuit board and is shorted to the ground plane proximate to the element  34 , as shown. 
   As will be discussed in greater detail below, the resonating elements  32  and  34  are coupled to produce a desired wide bandwidth. In alternate embodiments, more than two wound slot antenna elements can be coupled together within the scope of the present invention. 
   Each slot element  32  and  34  resonates at its resonant frequency proportional to its physical length, but with limited bandwidth. However, the overall antenna  30  exhibits a multi-resonant response from the combination of the resonant frequencies for both elements  32  and  34 . Because of electromagnetic coupling between the adjacent slot elements  32  and  34 , the overall response of the multi-trace antenna  30  is not a simple superposition of the individual responses. By properly adjusting the spacing between the elements  32  and  34 , their physical lengths and the feed location of each, it is possible to achieve different multi-band frequency responses with distinct resonant peaks. This can be done through a computer simulation and optimization. For a wide-band operation, the electromagnetic coupling between the neighboring slot elements can be exploited to fill the gaps between the resonant peaks, and thus broaden the bandwidth. 
   FIGS.  5 ( a ) and  5 ( b ) provide further support of the invention as to how tightly coupled slot elements can increase the antenna&#39;s effective bandwidth. FIGS.  5 ( a ) and  5 ( b ) show an antenna  50  that is a modification of the dipole antenna  10  discussed above having four slot elements  52 ,  54 ,  56  and  58 . The antenna  50  includes a small ground plane  60  patterned on one side of a printed circuit board  62 , and a microstrip feed line  64  patterned on an opposite surface of the printed circuit board  62 . The slot elements  52 ,  54 ,  56  and  58  are etched out of the ground plane  60 . The microstrip feed line  64  is connected to a vertical via  66  that extends through the printed circuit board  62  and is shorted to the ground plane  60  proximate the slot element  52 . 
   In this configuration, the microstrip line  64  feeds the slot elements  52 ,  54 ,  56  and  58 . Each slot element resonates at its own resonant frequency, which depends on the length of the element. Due to the tight coupling between the four elements, the overall bandwidth of the printed antenna  50  is increased. The length of the elements  52 ,  54 ,  56  and  58 , the feed location of the vertical via  66  and the spacing between the slot elements  52 ,  54 ,  56  and  58  are selectively controlled to control the bandwidth as well as the resulting radiation pattern. 
   FIG.  6 ( a ) is a graph with frequency on the horizontal axis and input reactance on the vertical axis, and FIG.  6 ( b ) is a graph with frequency on the horizontal axis and input resistance on the vertical axis showing the bandwidth performance of the antenna  50  for various combinations of the elements  52 - 58 . Particularly, graph line  82  is for the antenna  50  with only the slot element  52  present, graph line  84  is for the antenna  50  with the slot elements  52  and  54  present, graph line  86  is for the antenna  50  with the slot elements  52 ,  54  and  56  present, and graph line  88  is for the antenna  50  with all four of the slot elements  52 - 58  present. As is apparent, improved bandwidth performance is achieved by tightly coupling more slot elements of different lengths. 
   Printed slot antennas on thin substrates or printed circuit boards radiate almost equally into both sides of the antenna. In order to have a vertically polarized omni-directional radiation pattern as normally required by most ground-based wireless services, the multi-band antenna described above is printed on a thin vertical PCB card with a small-size ground plane. In this case, due to the finiteness of the antenna, it will exhibit an omni-directional pattern in the azimuth plane.  FIG. 7  is a graph showing the radiation pattern for an 840 MHz printed slot antenna of the type being described herein. As is apparent, these printed slot antennas provide a substantially omni-directional radiation pattern. There might be a slight degradation of the pattern at the edges of the PCB card. However, the nulls normally seen at the edges of large ground planes are not present in this design. For this purpose, the size of the ground plane should be comparable to the wavelength. 
   It should be noted that the use of coupled parasitic elements for bandwidth enhancement has been proposed and utilized in the past, particularly, in Yagi-Uda arrays. In this type of design, the active and parasitic elements together form an array to achieve a directional radiation pattern. The spacing between the elements, however, is about a half wavelength to achieve the desired directionality. Moreover, the elements are usually linear dipoles with lengths around a half wavelength. 
   Single trace wound slot antenna elements are inherently narrow-band. Winding them several turns can make them omni-directional. In certain applications, such as for garage door openers or keyless remote entry devices, it is desirable to have a very narrow band, but compact, antenna that is highly omni-directional. A tightly wound slot dipole antenna vertically mounted relative to the horizon provides such an antenna. 
     FIG. 8  is a top front view of a compact UHF antenna  90  tuned at 390 MHz with a bandwidth of 1 MHz. The antenna  90  includes a ground plane  92  patterned on a printed circuit board  94 , where a wound slot element  96  is configured in the ground plane  92 . The wound slot element  96  can be fed either by a coaxial feed line  98  on the same side of the printed circuit board  94  as the slot element  96  or by a microstrip feed line printed on the other side of the printed circuit board  94 , as described above. The antenna  90  is not a wound spiral antenna of the type known in the art because it is fed proximate an outer end of the element  96 . Further, in this embodiment, the ground plane  92  is limited (small in size), and adds to the compact size of the antenna  90 . The length of the element  96  determines the resonant frequency of the antenna  90 . In this embodiment, the ground plane  92  is square and has side dimensions less than one-half the wavelength of the resonant frequency of the element  96 . For a resonant frequency of 390 MHz, the ground plane  92  is about a 4 inch by 4 inch square in this embodiment. 
   The narrow-band antenna  90  is suitable for remote control systems, such as garage door openers and remote keyless entry devices. The sharp resonance of the antenna  90  eliminates the need for additional noise rejection band-pass filters.  FIG. 9  is a graph with frequency on the horizontal axis and return loss on the vertical axis depicting the narrow band resonant frequency of the antenna  90 . 
     FIG. 10  is a top view of a dual band cellular phone antenna  110  including four wound slot elements  112 - 118  that are etched into a ground plane  120  on a printed circuit board  122 , according to another embodiment of the present invention. The elements  112 - 118  resonate at different frequencies that cover the AMPS band (824 MHz-894 MHz) and the PCS band (1850 MHz-1990 MHz). The dual band antenna  110  has a single cable  126  that is connected to the ground plane  120  and feeds all of the elements  112 - 118 . The cable  126  consists of a power distribution network printed on the back of the circuit board. In this design, the two outer slot elements  112  and  114  correspond to AMPS cellular phone operation while the two inner slot elements  116  and  118  correspond to PCS operation. 
     FIG. 11  is a graph with frequency on the horizontal axis and return loss on the vertical axis showing the resonant frequencies of the elements  112 - 118 . The combination of the resonant peaks  128  and  130  provide a wide bandwidth for the AMPS antenna applications, and the combination of the peaks  132  and  134  provide a wide bandwidth for the PCS antenna applications. 
   Conformality is one of the major advantages planar antennas have to offer. When these antennas are printed on thin substrates, they can conform to the contour of the application surface. In commercial applications, the antenna can be embedded on the surface of a vehicle body or into the surface of a system enclosure, such as a telephone handset, a garage door opener housing, or a personal digital assistant or laptop computer cover. In military applications, the antenna can be hidden inside a platform or stretched on its surface to minimize radar visibility. 
   Slot antenna designs based on this invention can be realized by stamping their layout pattern on copper tape to create a “sticker” antenna. The copper tape can then be readily mounted on a glass platform or any other surface. To depict this embodiment of the present invention,  FIG. 12  shows a perspective view of an antenna  140  including a copper tape  142  adhered to a glass surface or substrate  144 . A wound slot element  146  is formed in the copper tape  142 , and is fed by a coaxial feed cable  148 . In this case, the dielectric properties of the mounting surface have to be taken into account in the design of the trace layout. 
   It is possible to print the slot antenna designs discussed above on an existing non-metallic platform, such as glass or a low-loss plastic or ceramic slab. This can be done in the form of a conductive coating or metallization deposit, or using adhesive pre-stamped metallic foils over the non-metallic surface. In particular, by using a high permittivity ceramic slab, the overall size of the antenna can be reduced drastically. In either case, a major requirement is to be able to feed the different antenna elements all from one side of the structure because a platform occupies the other side. According to another embodiment of the present invention, a co-planar waveguide (CPW) feed network is employed in conjunction with multifunction slot antennas. In this case, the entire antenna structure can be realized using metallization on one side of a non-metallic platform. 
   As discussed above, printed antennas provide low-cost, low-profile, integrated solutions for many antenna applications. By printing different types of planar antennas on the same substrate, an integrated multifunction antenna can be achieved. According to another embodiment of the present invention, a multifunction, integrated GPS/cellular/PCS/GSM antenna is disclosed. A broad band slot spiral is used for the circularly polarized GPS antenna, which can also receive other satellite signals of the same polarization within its band. The cellular AMPS/PCS/GSM antenna is based on the compact multi-band omni-directional design discussed above, and is accommodated on the same aperture with proper spacing and topology. 
     FIG. 13  is a front view of a multifunction, integrated GPS/cellular/PCS/GSM antenna  152  of this type. The antenna  152  includes the antenna  110  discussed above having the four slot elements  112 - 116  tuned to the desirably frequency band. However, in this embodiment, the ground plane  120  has been extended so that a printed GPS antenna  154  can be provided in combination with the antenna  110 . In this embodiment, the GPS antenna  154  includes a spiral slot element  156  that is tuned to a particular resonant frequency band for GPS operation. The GPS antenna  154  is fed by a feed line  158  electrically connected to the ground plane  120  as shown. 
   Cirius and XM satellite radio systems require an antenna that not only receives circularly polarized (CP) satellite signals, but is also able to receive vertically polarized signals from ground-based stations. Therefore, an antenna for this application should have both a directional upward-looking CP radiation pattern with some gain and a vertically polarized omni-directional pattern. In accordance with the teachings of another embodiment of the present invention, the antenna design consists of a spiral slot antenna with a CP operation combined with a compact omni-directional printed antenna for the linear polarization of the type discussed above. The two antenna elements share a common aperture and are printed on the same printed circuit board. The PCB card should be oriented upright at a small angle from zenith (about 30 degrees). In this case, the vertical polarization performance will be satisfactory, while the CP antenna will exhibit a good performance due to its broad beamwidth. 
   In the above-mentioned multifunction integrated antenna designs, the spiral slot antenna can be replaced with any other planar antenna that provides a CP operation. One example is a cross-slot antenna that is fed near the ends of two adjacent arms of the cross with proper phase difference. In particular, when a uniplanar multifunction antenna is desired, which has to be printed entirely on one side of a non-metallic platform, the present invention proposes a CPW balanced feed for the broadband spiral antenna design that is fit between the two arms of the dual-arm spiral. A CPW feed network is also designed for the omni-directional antenna for the cellular/PCS/GSM operation. 
     FIG. 14  is a front view of a CPW-fed, printed spiral slot antenna  162  employing this design. The antenna  162  includes a ground plane  164  formed on one side of a PCB. A spiral slot element  166  is etched in the ground plane  164 , and is of the same type as the slot element  156  discussed above. A CPW feed network  168  is provided where a spiral slot element  170  is formed in the ground plane  164  parallel to the slot element  166 , as shown. A center conductor  172  is formed in the slot element  170 , and is connected to an inner conductor of a coaxial connector  174 , as shown. The outer conductor of the coaxial connector  174  is electrically connected to the ground plane  164 . The slot element  170  and the center conductor  172  together form a balanced coplanar waveguide feed for the spiral slot element  166 . 
     FIG. 15  is a front view and  FIG. 16  is a back view of a multifunction antenna  200  for wireless and telematic applications, according to another embodiment of the present invention. In this embodiment, the antenna  200  is a five-band or five function antenna that includes resonating antenna elements providing the desired resonant frequency for each of GPS, satellite radio, AMPS, PCS, GSM and terrestrial radio, as will be discussed below. In this discussion, the satellite radio and the terrestrial radio are part of the same satellite digital audio radio service (SDARS) and combine to provide a single function. All of the antenna elements are formed on a common PCB  202  including a dielectric substrate  204 . In one embodiment, the substrate  204  has a high permativity (&gt;10) that makes the overall size of the antenna  200  smaller. Other techniques can be employed to make the antenna  200  smaller, such as dielectric lenses and the like, well known to those skilled in the art. In one embodiment, the antenna  200  has a particular application for use in a vehicle. The antenna  200  can be mounted to any suitable location on the vehicle, such on the vehicle glass, windshield, instrument panel, duck bill (extension of headliner), rear shelf package, inside spoiler, bumper, etc. 
   The antenna  200  includes a GPS patch antenna element  206  and an SDARS satellite radio antenna element  208 . As is known in the art, patch antenna elements are formed by a planar metal structure, here square patches, having the desirable shape and size for the particular frequency band of interest. The antenna element  206  is corner fed by a microstrip feed line  210  coupled to an electrical connector  212  to provide circular polarization for satellite signals. Likewise, the antenna element  208  is corner fed by a microstrip feed line  214  coupled to an electrical connector  216  to provide circular polarization. Another microstrip feed line  218  is patterned on this side of the substrate  204  to feed the AMPS, PCS, GSM and terrestrial radio antenna elements discussed below. The feed line  218  is coupled to an electrical connector  220 . The patch antenna elements  206  and  208  and the microstrip feed lines  210 ,  214  and  218  are formed by etching a metal layer, such as copper, deposited on this side of the substrate  204  by a deposition and etching process well known to those skilled in the art. 
   The other side of the substrate  204  includes a metallized ground plane  222  in which is formed a series of slot antenna elements for the AMPS, PCS, GSM and terrestrial radio frequencies. Particularly, an AMPS slot element  224 , a PCS slot element  226 , a GSM slot element  228  and an SDARS terrestrial radio slot element  230  are etched in the ground plane  222  to receive and transmit the appropriate frequency signals. As is apparent, the slot antenna elements  224 - 230  are curved slot elements to reduce the size of the antenna  200 . The elements  224 - 230  have the appropriate length for the frequency band of interest and generally follow the same contour. As will be appreciated by those skilled in the art, the position and shape of the elements  224 - 230  can be changed within the scope of the present invention. 
   As discussed above, winding slot antenna elements reduces the bandwidth. However, it is sometimes desirable to have a narrow bandwidth for a particular application. Further, the elements  224 - 230  couple together, as discussed above, to provide a wide bandwidth. The slot antenna elements  224 - 230  are fed by the microstrip feed line  218 . The feed line  218  is electrically coupled to shorting vias  232  and  234  that extend through the substrate  204  and are electrically coupled to the ground plane  222  proximate the slot antenna elements  224 - 230 . 
   Because the antenna  200  is used for satellite and terrestrial based applications, the orientation of the radiation patterns of the patch and slot elements  206 ,  208  and  224 - 230  must be proper to receive and/or transmit the desired signals. As is known in the art, satellite signals are circularly polarized and terrestrial signals are vertically polarized. Therefore, it is typically desirable to provide satellite antennas oriented horizontally and directed towards the sky to receive the satellite signals. However, it is also desirable that the terrestrial based antenna elements be linearly polarized where the antenna is oriented vertically relative to the horizon and is omni-directional. In one embodiment, the antenna  200  is mounted at an angle relative to the horizon to provide at least a partial vertical orientation for the terrestrial antenna elements (PCS, AMPS, GSM) and at least a partial horizontal orientation for the satellite antenna elements (GPS, satellite radio). Thus, all of the antenna elements  206 ,  208  and  224 - 230  are able to receive the signals. 
   As discussed above, the patch antenna elements  206  and  208  are corner fed to provide the desired circular polarization. In an alternate embodiment, the patch antenna elements  206  and  208  can be edge fed and still provide circular polarization. FIGS.  17 ( a ) and  17 ( b ) are plan views of patch antenna elements  240  and  242 , respectively, that are edge fed and provide circular polarization. Particularly, the antenna element  240  is fed by a microstrip feed line  244  that is separated into feed branches  246  and  248  coupled to orthogonal edges  250  and  252 , respectively, of the element  240 . By feeding orthogonal edges of the element  240 , the resulting radiation pattern provides circular polarization. Orthogonal edges  254  and  256  of the patch element  242  are fed by a microstrip feed line  258  separated into branches  260  and  262 , as shown. The length of the feed branches  246 ,  248 ,  260  and  262  provide the correct phasing for circular polarization. 
     FIG. 18  is a perspective view of a multifunction antenna  270  for wireless and telematic applications, according to another embodiment of the present invention. The antenna  270  includes a first PCB  272  and a second PCB  274  mounted orthogonal to each other, as shown, by any suitable technique. The PCB  272  includes a substrate  276  on which is deposited a metallized ground plane  278 . As above, slot antenna elements are etched in the ground plane  278  and include an AMPS slot element  280 , a PCS slot element  282 , a GSM slot antenna element  284  and a terrestrial radio slot element  286 . The elements  280 - 286  are fed in the same manner discussed above for the antenna  200 , where a feed line is patterned on an opposite side of the substrate  276  and is coupled to electrical connectors  290  and  292 . 
   Further, as discussed above, the PCB  274  includes a substrate  296  including a GPS patch antenna element  298  and a satellite radio patch antenna element  300 . The antenna element  298  is corner fed by a microstrip feed line  302  coupled to an electrical connector  304 , and the antenna element  300  is corner fed by a microstrip feed line  306  coupled to an electrical connector  308 . In this embodiment, the antenna  270  is mounted to the support structure so that the orientation of the PCB  272  provides the radiation patterns for terrestrial signals and the PCB  274  is oriented in the proper direction for satellite signals. The PCBs  272  and  274  can be “sticker” type PCBs, discussed above, to be stuck to the corner of a support structure to provide the desired orientation. 
     FIG. 19  is a perspective view of a multifunction antenna  310  similar to the antenna  270 , where like components are identified by the same reference numeral. In this embodiment, the printed circuit board  272  is replaced with a printed circuit board  312  that is curved in a vertical direction. By slightly bending the PCB  312  in this manner, nulls along the edges of the PCB  312  are reduced, and a more omni-directional radiation pattern is achieved. 
     FIG. 20  is a front view of a PCB  316  similar to the PCBs  272  and  312  where like reference numerals identify like components. In this embodiment, an edge  318  of the PCB  316  that would be mounted to the PCB  274  has a saw tooth pattern on the conductor to reduce edge currents between the PCBs  316  and  274 . Reduction in edge currents minimizes adverse effects of the PCB  316  on the circular polarization of the patch elements  298  and  300 . 
     FIG. 21  is a front view of an antenna  322  including a PCB  324  on which is formed patch antenna elements  326  and  328  of the type discussed above. In this embodiment, a low noise amplifier (LNA)  330  is provided in a microstrip feed line  332  that feeds the antenna element  326 . Further, an LNA  334  is provided in a microstrip feed line  336  that feeds the antenna element  328 . Providing the LNAs  330  and  334  on the same circuit board as the antenna elements  326  and  328  provides better integration, lower cost and better performance. Low noise amplifiers can be configured on a common printed circuit board with the antenna elements  280 - 286 , discussed above. 
   Because the various antenna elements are printed on a printed circuit board, the present invention proposes providing some of the necessary circuit elements on the circuit board to provide increased component integration, size reduction and noise performance.  FIG. 22  is a schematic diagram of an antenna circuit  342  including an antenna  344  that is intended to represent each of the various AMPS, GSM and PCS slot antenna elements discussed herein. A diplexer  346  is mounted on a PCB  338 , such as the same PCB as each of the AMPS, GSM and PCS slot antenna elements, for the purposes described herein. The diplexer  346  is coupled to a common feed line  348  or a feed distribution network that feeds all of the slot antenna elements. As is known in the art, the diplexer  346  acts as a filter to separate the received signals into the appropriate frequency band for AMPS, GSM and PCS signals. Also, because these services also require transmit functions, the diplexer  346  couples each of the AMPS, GSM and PCS signals onto the feed line  348  or a feed distribution network connected to the antennas. 
   Other antenna circuit components can also be provided on the printed circuit board with the antenna elements. As discussed above, each of the AMPS, PCS and GSM signals require both transmit and receive signals. Because the transmit signals have much higher power levels than the receive signals, the receive and transmit circuits require components that handle different power levels, and so the signals must be separated.  FIG. 23  is a schematic diagram of a receive/transmit amplifier circuit  350  formed on a printed circuit board  340  for this purpose. A separate receive/transmit circuit will be provided for each of the signals separated by the diplexer  346  discussed above. According to the invention, the rear bracket  34  includes a spring assembly  94  mounted to a rear surface  92  of the side plate  32  by a nut and bolt  96 . As will be discussed in more detail below, the spring assembly  94  includes a pair of flat metal spring elements  98  and  100  that are positioned side by side and against each other, as shown. As is apparent, the spring element  100  is slightly longer than the spring element  98 . The spring elements  98  and  100  extend relative to an opening  102  between the side plate  32  and the mounting portion  40 . Thus, the spring elements  98  and  100  can flex in a direction perpendicular to the plane of the side plate  32  relative to the opening  102 . 
   The receive signal from the diplexer  346  is sent to a duplexer  352 . The duplexer  352  is a directional coupler that directs the signal into a particular path depending on its direction. The duplexer  352  couples the receive signal into a receive signal path  354  to be amplified by an amplifier  356 . Filters  358  and  360  are provided in the path  354  to filter the signals that are not in the frequency band of interest to improve the signal-to-noise ratio. Signals to be transmitted by the antennas are sent to a duplexer  362  that couples the transmit signals into a transmit signal path  364 . The signals in the transmit path  364  are amplified by a amplifier  366  and filtered by suitable filters  368  and  370 . The amplification discussed herein is sometimes needed where the antenna is mounted interior to a platform, such as a vehicle interior. In this case, the signals are usually attenuated due to multi-path reflection or absorption in the surrounding environment. 
   The foregoing discussion discloses and describes merely exemplary embodiments of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims, that various changes, modifications and variations can be made therein without departing from the spirit and scope of the invention as defined in the following claims.