Abstract:
The disclosed antenna is designed to work at GPS L1, GPS L2, GPS L5/GLONASS/BEIDOU frequencies. The antenna is fabricated on a flexible body and includes a meander line between a 50Ω RF feeding cable on the ground plane and a patch element. The resonant mechanism is excited by the meander line structure from 1170 Mhz to 1610 MHz and the Patch gives the wideband performance. Most configurations of the antenna have a low profile of about 0.15 mm.

Description:
CROSS-REFERENCE 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/281,009 filed Jan. 20, 2016, and U.S. Provisional Application No. 62/344,818 filed Jun. 2, 2016 which applications are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    Previously employed meander line antennas have low bandwidth and low radiation efficiency when the size of the antenna is reduced. While the meander line antenna has advantages due to its small size, low profile and simple structure, there are also disadvantages. The meander line antenna has a low radiation efficiency and when the size of the antenna is reduced, the radiation resistance is also reduced. This results in a decreased radiation efficiency. Additionally, meander line antenna typically have a low bandwidth (less than 5%). 
         [0003]    Global Positioning Systems (GPS) systems broadcast microwave signals which can be received by GPS receives on or near the earth&#39;s surface to determine location, velocity and time. Currently there are four GPS signals available for civilian use: L1 C/A, L2C, L5 and L1. GLONASS is a space-based satellite navigation system which is used by the Russian Aerospace Defense Forces and is an alternative to GPS. The BeiDou Navigation Satellite System consists of two separate satellite constellations and has been offering navigation services in China and neighboring regions. 
         [0004]    What is needed is a flexible antenna employing a meander line which provides stable performance across a plurality of bandwidths without compromising performance. 
       SUMMARY 
       [0005]    An antenna is disclosed which has a stable radiation performance across a plurality of bandwidths using a flexible body. A meander line is incorporated to get GPS L1/GPS L2/GPS L5/GLONASS/BeiDou resonances and a patch to increase the bandwidth from 1170 MHz to 1610 Mhz. The patch antenna has a low profile which can be mounted on a flat surface and includes a flat rectangular sheet of metal forming a microstrip transmission line. The flexible body of the antenna allows the antenna to conform to the shape of the surface, including a plurality of bends. The meander line is positioned between a patch element and a 50Ω feeding cable on the ground plane. The patch element is continuous to the meander line and enables an increase in the bandwidth. In at least some configurations, the patch element has a C shape which partially surrounds the meander line. By combining the meander line and the patch in a single antenna structure, the antenna can achieve GPS L1, GPS L2, GPS L5, GLONASS, and BeiDou frequency resonances. Additionally, a mini-coaxial cable can be used as a feeding technique on a ground plane of the antenna which is adjacent the patch and meander line. 
         [0006]    An aspect of the disclosure is directed to an antenna comprising: a patch element wherein the patch element has a flat rectangular transmission line; a meander line element which is continuous with the patch element; a 50Ω mini-coaxial feeding cable; and a ground plane, wherein the meander line element is positioned between the patch element and a 50Ω feeding cable on the ground plane. Additionally, the patch element can be a flat rectangular sheet of metal with a low profile. In at least some configurations, the patch element is flexible. The patch element can also be C-shaped and surrounds the meander line element on three sides. The patch element is configurable to be conformable to a mounting surface. In some configurations, the 50Ω mini-coaxial feeding cable has a center conductor at a first end that attaches to the patch element. Additionally, the 50Ω mini-coaxial feeding cable can have an outer conductor attached to the ground plane. Further, wherein the 50Ω mini-coaxial feeding cable has a second end with an SMA connector that attaches to an external electronic device. The ground plane can be positioned adjacent the patch element. Additionally, the ground plane can be rectangular. The ground can also be attached to the 50Ω mini-coaxial feeding cable via an outer conductor. 
         [0007]    Another aspect of the disclosure is directed to an antenna comprising: a patch element wherein the patch element has a flat rectangular transmission line; a meander line element which is continuous with the patch element and surrounded by the patch element on three sides; a 50Ω mini-coaxial feeding cable; and a ground plane. Additionally, the patch element can be a flat rectangular sheet of metal with a low profile. In at least some configurations, the patch element is flexible. The meander line element can also be positioned between the patch element and a 50Ω feeding cable on the ground plane. The patch element is configurable to be conformable to a mounting surface. In some configurations, the 50Ω mini-coaxial feeding cable has a center conductor at a first end that attaches to the patch element. Additionally, the 50Ω mini-coaxial feeding cable can have an outer conductor attached to the ground plane. Further, wherein the 50Ω mini-coaxial feeding cable has a second end with an SMA connector that attaches to an external electronic device. The ground plane can be positioned adjacent the patch element. Additionally, the ground plane can be rectangular. The ground can also be attached to the 50Ω mini-coaxial feeding cable via an outer conductor. 
         [0008]    Yet another aspect of the disclosure is directed to an antenna means comprising: a patch element means wherein the patch element means has a flat rectangular transmission line; a meander line element means which is continuous with the patch element means; a 50Ω mini-coaxial feeding cable means; and a ground plane means, wherein the meander line element means is positioned between the patch element means and a 50Ω feeding cable on the ground plane means. Additionally, the patch element means can be a flat rectangular sheet of metal with a low profile. In at least some configurations, the patch element means is flexible. The patch element means can also be C-shaped and surrounds the meander line element means on three sides. The patch element means is configurable to be conformable to a mounting surface. In some configurations, the 50Ω mini-coaxial feeding cable means has a center conductor at a first end that attaches to the patch element means. Additionally, the 50Ω mini-coaxial feeding cable means can have an outer conductor attached to the ground plane means. Further, wherein the 50Ω mini-coaxial feeding cable means has a second end with an SMA connector that attaches to an external electronic device. The ground plane means can be positioned adjacent the patch element means. Additionally, the ground plane means can be rectangular. The ground can also be attached to the 50Ω mini-coaxial feeding cable means via an outer conductor. 
         [0009]    Still another aspect of the disclosure is directed to an antenna means comprising: a patch element means wherein the patch element means has a flat rectangular transmission line; a meander line element means which is continuous with the patch element means and surrounded by the patch element means on three sides; a 50Ω mini-coaxial feeding cable means; and a ground plane means. Additionally, the patch element means can be a flat rectangular sheet of metal with a low profile. In at least some configurations, the patch element means is flexible. The meander line element means can also be positioned between the patch element means and a 50Ω feeding cable on the ground plane means. The patch element means is configurable to be conformable to a mounting surface. In some configurations, the 50Ω mini-coaxial feeding cable means has a center conductor at a first end that attaches to the patch element means. Additionally, the 50Ω mini-coaxial feeding cable means can have an outer conductor attached to the ground plane means. Further, wherein the 50Ω mini-coaxial feeding cable means has a second end with an SMA connector that attaches to an external electronic device. The ground plane means can be positioned adjacent the patch element means. Additionally, the ground plane means can be rectangular. The ground can also be attached to the 50Ω mini-coaxial feeding cable means via an outer conductor. 
       INCORPORATION BY REFERENCE 
       [0010]    All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. See, for example, WO 2002/060007A1 published Aug. 1, 2002, for Meander Line Loaded Tunable Patch Antenna; U.S. Pat. No. 6,404,391 B1 issued Jun. 11, 2002, for Meander Line Loaded Tunable Patch Antenna; U.S. Pat. No. 6,642,893 B1 issue Nov. 4, 2003 for Multi-Band Antenna System Including a Retractable Antenna and a Meander Antenna; U.S. Pat. No. 7,190,322 B2 issued Mar. 13, 2007 for Meander Line Antenna Coupler and Shielded Meander Line; U.S. Pat. No. 8,063,845 B2 issued Nov. 22, 2011 for Symmetrical Printer Meander Dipole Antenna; and U.S. Pat. No. 8,284,105 B2 issued Oct. 9, 2012, for Multi-Band Microstrip Meander-Line Antenna. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which: 
           [0012]      FIG. 1A  is a block diagram of an antenna design according to the disclosure; 
           [0013]      FIG. 1B  is a front view of an antenna design according to the disclosure; 
           [0014]      FIG. 2  is a graph illustrating the return loss of the antenna of  FIGS. 1A-B ; 
           [0015]      FIG. 3  is a graph illustrating an efficiency of the antenna of  FIGS. 1A-B ; and 
           [0016]      FIG. 4  is a graph illustrating a peak gain of the antenna of  FIGS. 1A-B . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      FIG. 1A  is a block diagram of an antenna  100 . The antenna  100  has a patch  112  and a meander line  150  with a ground  132 . A coaxial cable  160  is connected to the antenna  100  at a location adjacent the meander line  150 . 
         [0018]      FIG. 1B  is a front view of an antenna  100  having an antenna top surface  110 . The antenna  100  is planar and, as illustrated, has a first side  102 , a second side  104 , a third side  106  and a fourth side  108 , numbered clockwise when viewed from above. The sides can be situated at 90 degree angles so that the resulting surface forms a rectangle (or square) as illustrated. Note that although the depiction in  FIG. 1B  is planar, the antenna itself is sufficiently thin and flexible such that it can conform to non-planar surfaces. Thus, the installed antenna  100  need not be planar when installed. In the quadrant whose outside edges are defined by sides  104  and  106 , is a meander line  150 . This meander line  150  zigs-zags from its origin, roughly mid-way between sides  104  and  108 , to its terminus near the corner defined by the insertion of sides  104  and  106 . The zig-zag has long legs parallel to sides  104  and  108  and short legs perpendicular to sides  104  and parallel to  106 . Thus, the patch  112  surrounds the meander line  150  on three sides. The antenna  100  is fed by 50Ω coaxial cable  160 . An SMA connector  162  at one end of the coaxial cable  160  provides connection of the antenna  100  to external electronics. A center conductor  166  attaches to the patch  150  portion of antenna  100  near the corner defined by sides  104  and  106 , while an outer conductor  164  attaches to the ground plane  130 . The ground plane  130  is planar with a top surface  140 . It has a first side  132 , a second side  134 , a third side  136  and a fourth side  138 , numbered clockwise when viewed from above. The sides can be situated at 90 degree angles so that the resulting surface forms a rectangle (or square) as illustrated. 
         [0019]      FIG. 2  is a graph illustrating the return loss of the antenna of  FIGS. 1A-B . At 1176 MHz  210 , which corresponds to GPS L5, the return loss is approximately −27 dB. Through the GPS L2 range (1212 MHz  220 -1242 MHz  222 ), the return loss increases monotonically from approximately −22 dB at 1212 MHz to approximately −16 dB at 1242 MHz. Across the GPS L1 range (1560 MHz  230 -1590 MHz  232 ), the return loss decreases monotonically from approximately −12 dB at 1560 MHz  230  to approximately −13 dB at 1590 MHz  232 . Through the GLONNAS G1 range (1593 MHz  240 -1610 MHz  242 ), the return loss decreases monotonically from approximately −13 dB at 1593 MHz to approximately −14 dB at 1610 MHz. Across the BEIDOU range (1559 MHz  250 -1591 MHz  252 ), the return loss decreases monotonically from approximately −12 dB at 1559 MHz to approximately −13 dB at 1593 MHz  254 . 
         [0020]      FIG. 3  is a graph illustrating an efficiency of the antenna of  FIGS. 1A-B  at various frequencies between 1150 MHz and 1610 MHz. The efficiency is approximately 69% at 1176 MHz  310 , which corresponds to GPS L5. Efficiency through the GPS L2 range (1212 MHz  320 -1242 MHz  322 ) varies from approximately 74% at 1212 MHz  320  to 71% at 1242 MHz  322  with a peak value of approximately 76% at 1222 MHz  324 . Efficiency across the GPS L1 range (1560 MHz  320 -1590 MHz  332 ) varies from approximately 87% at 1560 MHz  330  to 94% at 1590 MHz  332  with a peak value of approximately 97% at 1578 MHz  334 . Efficiency through the GLONNAS G1 range (1593 MHz  340 -1610 MHz  342 ) is approximately 95% at either end of the range with a peak value of approximately 96% at 1606 MHz  344 . Efficiency across the BEIDOU range (1559 MHz  350 -1591 MHz  352 ) varies from approximately 86% at 1559 MHz  350  to 94% at 1591 MHz  352  with a peak value of approximately 97% at 1578 MHz  354 . 
         [0021]      FIG. 4  is a graph illustrating a peak gain of the antenna of  FIGS. 1A-B  at various frequencies between 1150 MHz and 1610 MHz. The peak gain is approximately 3.2 dB at 1176 MHz  410 , which corresponds to GPS L5. Peak gain through the GPS L2 range (1212 MHz-1242 MHz  422 ) varies from approximately 3.4 dB at 1212 MHz  420  to 2.8 dB at 1242 MHz  422  with a maximum value of approximately 3.4 dB at 1212 MHz  420  and 1222 MHz  424 . Peak gain across the GPS L1 range (1560 MHz  430 -1590 MHz  432 ) varies from approximately 3.5 dB at 1560 MHz to 3.8 dB at 1590 MHz  432  with a maximum value of approximately 4.1 dB at 1579 MHz  434 . Peak gain through the GLONNAS G1 range (1593 MHz  440 -1610 MHz  442 ) varies from approximately 3.9 dB at 1593 MHz  440  to 3.8 dB at 1610 MHz  442  with a maximum value of approximately 4.0 dB at 1601 MHz  444 . Peak gain across the BEIDOU range (1559 MHz  450 -1591 MHz  452 ) varies from approximately 3.5 dB at 1559 MHz  450  to 3.8 dB at 1591 MHz  452  with a maximum value of approximately 4.1 dB at 1579 MHz  454 . 
         [0022]    While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.