Abstract:
A 5 dBi embedded dual-band WiFi circular polarized 50 mm patch antenna with an SMA(f) connector is described. The antenna features a high efficiency dual-band WiFi 2.4 GHz/5˜6 GHz right hand circular polarization (RHCP). The antennas improve upon the previously developed antennas by simplifying the construction and simplifying the feed, while retaining circular polarization across two widely-separated bands. In order to integrate prior antennas into a system with simple coaxial connections, additional components and devices were required. The antennas simplifies the integration whilst retaining the circular polarization and dual frequency operation. The ratio between the two frequency bands can be adjusted by changing the middle patch and the V-shaped slot size of the top layer. The V-shaped slots improve the axial ratio bandwidth and assist with setting the frequency ration between the two bands.

Description:
CROSS-REFERENCE 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/265,784, filed Dec. 10, 2015, entitled DUAL-FREQUENCY PATCH ANTENNA, and U.S. Provisional Application No. 62/341,346, filed May 25, 2016, entitled DUAL-FREQUENCY PATCH ANTENNA which applications are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    Field 
         [0003]    The present disclosure relates in general to an antenna and, in particular, to a patch antenna. 
         [0004]    Background 
         [0005]    Circularly-polarized patch antennas are commonplace, with well-understood properties. These antennas are usually single-resonance, limiting the circular polarization bandwidth. Dual-frequency circularly-polarized patch antennas have in the past required dual or multiple pin feeds, complicating the design by requiring additional system components (see U.S. Pat. No. 5,815,119 A). Other designs involve shorting elements (U.S. Pat. No. 4,218,682 A), or, the dual resonances are near together in frequency. These elements either complicate the feed subsystem design or complicate the construction. Additionally, modifying the design of a dual-band circularly polarized antenna can be difficult, or the frequencies of the bands are limited to those that are harmonically related. 
         [0006]    What is needed is an integrated circularly-polarized antenna with dual frequency operation which is easily integratable into a system using a coaxial connection without the limitations previously observed. 
       SUMMARY 
       [0007]    Disclosed is a 5 dBi embedded dual-band WiFi circular polarized 50 mm patch antenna with an SMA(f) connector. The antenna features a high efficiency dual-band WiFi 2.4 GHz/5˜6 GHz right hand circular polarization (RHCP). The disclosed antennas improve upon the previously developed antennas by simplifying the construction and simplifying the feed, while retaining circular polarization across two widely-separated bands. In order to integrate prior antennas into a system with simple coaxial connections, additional components and devices were required. This disclosed antennas simplify the integration whilst retaining the circular polarization and dual frequency operation. The ratio between the two frequency bands can be adjusted by changing the middle patch and the V-shaped slot size of the top layer. The V-shaped slots improve the axial ratio bandwidth and assist with setting the frequency ratio between the two bands. 
         [0008]    The antenna consists of an advanced composite dielectric structure which improves performance at great distances and for a broader band frequency range. The antenna can be used for unmanned systems, such as unmanned aerial/ground vehicles (UAVs/UGVs), robotics and ground controller/stations. The antenna uses a glass microfiber reinforced polytetrafluoroethylene (PTFE) substrate to minimize signal transmission loss to achieve high efficiency and performs with high efficiencies at WiFi bands from 2400 to ˜2500 MHz and 5150 to ˜5850 MHz of 74% and 67%, and with peak gains of 5.5 dBi and 7.3 dBi, respectively. As will be appreciated by those skilled in the art, materials other than PTFE can be used without departing from the scope of the disclosure. Other suitable materials include phenylene ether co-polymer (PPE). 
         [0009]    An aspect of the disclosure is directed to a planar dual patch antenna. Planar dual patch antennas according to the disclosure comprise: a first planar substrate having a first patch antenna and a v-shaped slot therein; a second planar substrate formed from a composite material with dielectric properties and a square aperture centrally positioned therein; a third planar substrate having a ground layer adhered to one surface and a second patch antenna on an opposing surface; a single-pin feed; and a coupling between the first patch antenna on the first planar substrate and the second patch antenna on the third planar substrate. In some configurations, the first planar substrate is rectangular. Additionally, the first planar substrate can have two truncated corners. Where there are truncated corners, a first truncated corner can have a first length and a second truncated corner can have a second length and the first length does not need to be equal to the second length. The v-shaped slot can have a first slot arm and a second slot arm, and further wherein a length of the first slot arm and a width of a second slot arm is proportional to a length of the second slot arm and a width of the second slot arm. Additionally, the first slot arm can have a dimension that is ⅛ a dimension of the second slot arm. The planar dual patch antenna can also be square or rectangular. The second substrate can have a connector aperture. 
         [0010]    Another aspect of the disclosure is directed to a planar dual patch antenna. Planar dual patch antennas according to the disclosure comprise: a first planar substrate means having a first patch antenna means and a v-shaped slot therein; a second planar substrate means formed from a composite material with dielectric properties and a square aperture centrally positioned therein; a third planar substrate means having a ground layer means adhered to one surface and a second patch antenna on an opposing surface; a single-pin feed; and a coupling means between the first patch antenna means on the first planar substrate means and the second patch antenna on the third planar substrate means. In some configurations, the first planar substrate means is rectangular. Additionally, the first planar substrate means can have two truncated corners. Where there are truncated corners, a first truncated corner can have a first length and a second truncated corner can have a second length and the first length does not need to be equal to the second length. The v-shaped slot can have a first slot arm and a second slot arm, and further wherein a length of the first slot arm and a width of a second slot arm is proportional to a length of the second slot arm and a width of the second slot arm. Additionally, the first slot arm can have a dimension that is ⅛ a dimension of the second slot arm. The planar dual patch antenna can also be square or rectangular. The second substrate can have a connector aperture. 
         [0011]    Yet another aspect of the disclosure is directed to an antenna kit. Suitable antenna kits comprise one or more dual patch antennas comprising a first planar substrate having a first patch antenna and a v-shaped slot therein, a second planar substrate formed from a composite material with dielectric properties and a square aperture centrally positioned therein, a third planar substrate having a ground layer adhered to one surface and a second patch antenna on an opposing surface, a single-pin feed, and a coupling between the first patch antenna on the first planar substrate and the second patch antenna on the third planar substrate. 
       INCORPORATION BY REFERENCE 
       [0012]    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. References include, for example: U.S. Pat. No. 4,218,682 A issued Aug. 19, 1980 for Multiple band circularly polarized microstrip antenna; U.S. Pat. No. 5,815,119 A issued Sep. 29, 1998 for Integrated stacked patch antenna polarizer circularly polarized integrated stacked dual-band patch antenna; U.S. Pat. No. 6,091,364 A published Jul. 18, 2000 for Antenna capable of tilting beams in a desired direction by a single feeder circuit, connection device therefor, coupler, and substrate laminating method; U.S. Pat. No. 6,266,016 B1 published Jul. 24, 2001 for Microstrip arrangement; U.S. Pat. No. 6,281,845 B1 published Aug. 28, 2001 for Dielectric loaded microstrip patch antenna; U.S. Pat. No. 6,791,496 B1 published Sep. 14, 2004 for High efficiency slot fed microstrip antenna having an improved stub; U.S. Pat. No. 7,471,248 B2 published Dec. 30, 2008 for Planar multiband antenna; U.S. Pat. No. 8,077,103 B1 published Dec. 13, 2011 for Cup waveguide antenna with integrated polarizer and OMT; U.S. Pat. No. 8,350,771 B1 published, Jan. 8, 2001 for Dual-band dual-orthogonal-polarization antenna element; US 2009/0153404 A1 published Jun. 18, 2009 for Single layer dual band antenna with circular polarization and single fee point; US 2011/0163921 A1 published Jul. 7, 2011 for UHF RFID internal antenna for handheld terminals; US 2012/0242553 A1 published Sep. 27, 2012 for Elliptically or circularly polarized dielectric block antenna; US 2012/0280877 A1 published Nov. 8, 2012 for Antenna having an embedded radio device; CN203415687U published Jan. 29, 2014 for Substrate integration circular polarization double-frequency band antenna; and CN104201463A published Dec. 10, 2014 for Dual-band circular polarization dielectric antenna. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    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: 
           [0014]      FIG. 1A  is a table of exemplar specification ranges for electrical, mechanical and environmental features for an antenna according to the disclosure;  FIGS. 1B-C  illustrate a front view and a back view of a suitable antenna; 
           [0015]      FIG. 2  illustrates a view of an antenna; 
           [0016]      FIGS. 3A-I  illustrate a top view, side view, bottom view, and enlarged views for antennas and layers according to the disclosure; 
           [0017]      FIGS. 4-5  illustrate a suitable installation method; 
           [0018]      FIGS. 6A-E  illustrates antenna components according to the disclosure; 
           [0019]      FIGS. 7A-C  illustrates antenna components according to the disclosure; 
           [0020]      FIGS. 8A-E  illustrates antenna components according to the disclosure; 
           [0021]      FIG. 9  illustrates a return loss over a range of 2000-6000 MHz of an antenna according to the disclosure; 
           [0022]      FIG. 10  illustrates a return loss in free space and centered on three different size metal planes over a range of 2300-6000 MHz for an antenna according to the disclosure; 
           [0023]      FIG. 11  illustrates a percent efficiency over a range of 2000-6000 MHz for an antenna according to the disclosure; 
           [0024]      FIG. 12  illustrates a percent efficiency in free space and centered on three different size metal ground planes over a range of 2000-6000 MHz for an antenna according to the disclosure; 
           [0025]      FIG. 13  illustrates a peak gain over a range of 2000-6000 MHz for an antenna according to the disclosure; 
           [0026]      FIG. 14  illustrates a peak gain in free space and centered on three different size metal ground planes over a range of 2000-6000 MHz for an antenna according to the disclosure; 
           [0027]      FIG. 15  illustrates an average gain over a range of 2000-6000 MHz for an antenna according to the disclosure; 
           [0028]      FIGS. 16A-C  illustrate an axial ratio over a range of 2000-6000 MHz for an antenna according to the disclosure; 
           [0029]      FIGS. 17A-C  illustrate two-dimensional (2D) radiation patterns in an X-Y plane, an X-Z plane, and a Y-Z plane for the disclosed antennas; and 
           [0030]      FIGS. 18A-B  illustrate a three-dimensional (3D) radiation pattern at 2450 MHz and 5550 MHz for the disclosed antennas. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    Antenna configurations are disclosed. An antenna with subminiature version A female connector (SMA(F)) is provided, attached to the SMA(F) connector is a circular polarized dual-band Wi-Fi antenna which can be formed from a composite dielectric structure. Composite dielectric structures can provide improved performance at greater distances and a broader band frequency range in small package. In some configurations, military grade substrates and components can be used. Additionally, the antenna is suitable for use with unmanned systems, such as unmanned aerial/ground vehicles (UAVs/UGVs), robotics, and ground controllers/stations, applicable in different sectors from civilian, to law enforcement, to defense. As shown in  FIG. 1A , the antennas of the disclosure are configurable to have specification ranges for electrical, mechanical and environmental features for an antenna according to the disclosure. Details include exemplar electrical, mechanical and environmental parameters including frequency range, return loss (dB), efficiency (%), peak gain (dBi), polarization, axial ratio, impedance (Ohm), input power, dimensions (with and without connector), antenna patch material, connector type, weight (g), operation temperature, and storage temperature. 
         [0032]      FIGS. 1B-C  illustrate a front view and a back view of a suitable antenna.  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. A plurality of anchor apertures are provided, illustrated a first anchor aperture  142 , a second anchor aperture  144 , a third anchor aperture  146 , and a fourth anchor aperture  148 . The plurality of anchor apertures are sized and shaped to receive a securement device therethrough. As shown, the plurality of apertures have a circular cross-section. As illustrated, the plurality of anchor apertures are positioned at the corners of the rectangular (or square) antenna form factor. The plurality of anchor apertures allow attachment of the antenna to a mounting surface via, for instance, suitable threaded fasteners. The plurality of anchor apertures are positionable to facilitate securement of the antenna to a structure. The upper patch  120  of the antenna can be situated centrally on the top surface, as illustrated, but may be positioned in other locations without departing from the scope of the disclosure. 
         [0033]    The antenna bottom surface  112  shown in  FIG. 1C  has a first side  102 , a second side  104 , a third side  106  and a fourth side  108 , as illustrated, and a plurality of anchor apertures (e.g., first anchor aperture  142 , second anchor aperture  144 , third anchor aperture  146 , and fourth anchor aperture  148 ). A connector  160  is provided on one surface of the antenna  100 , shown extending from the bottom side of the antenna, which is typically a type subminiature version A female connector (SMA(F) connector with a screw type coupling mechanism). The connector  160  can be centrally located (but not necessarily centered) on the bottom surface as illustrated. The connector  160  provides a connection to external electronics and a probe feed to the upper patch  120  shown in  FIG. 1B . 
         [0034]      FIG. 2  is a mounting plate  250  shown in more detail in  FIGS. 4-5 . The mounting plate  250  has a top side and a bottom side and a plurality of apertures (e.g., first anchor aperture  242 , second anchor aperture  244 , third anchor aperture  246 , fourth anchor aperture  248 , and connector aperture  258 ) to receive the anchors and connector. The distance between the center of the first aperture  242  and the second aperture  244  (center to center) is about 44.0 mm. The width of the connector aperture  258  is about 18.0 mm. The height of the connector aperture  250  is about 8.0 mm and it can be positioned such that the center of the connector aperture  258  is positioned 9.0 mm from a cross-section of the mounting plate  250  taken midway between the second aperture  244  and the third aperture  246 . 
         [0035]      FIGS. 3A-F  illustrates additional detail for an embodiment of the antenna  300 .  FIG. 3A  is a top view of antenna  300  from the antenna upper surface  310 . The antenna has a first side  302 , a second side  304 , a third side  306  and a fourth side  308 , numbered clockwise when viewed from above. As illustrated, the sides are situated at 90 degree angles so that the resulting surface forms a rectangle (or square) form factor. Other shapes can be used without departing from the scope of the disclosure. Additionally, there are a plurality of securement or anchor apertures, illustrated as four apertures having a circular cross-section (first anchor aperture  342 , second anchor aperture  344 , third anchor aperture  346 , and fourth anchor aperture  348 ). As illustrated the plurality of securement or anchor apertures are situated at the corners of the rectangle (square) of the antenna  300 . These securement apertures facilitate attachment or securement of the antenna to a mounting surface via, for instance, threaded fasteners such as screws or nuts-and-bolts, or other suitable fasteners such as rivets. The width of the antenna  300  is about 50 mm+/−0.5, and the height is about 50 mm+/−0.5 mm. The distance between the first aperture  342  and the second aperture  344  or the second aperture  344  and the third aperture  346  is about 44+/−0.35 mm (center-to-center). The distance between the feed probe location  358  and the first side  302  is about 16+/−0.4 mm. The height of the antenna  300  (shown in  FIG. 3B ) is about 16.57 mm, the height of the connector  360  is about 9.5+/−0.4 mm, and the thickness of the layers is about 9.07+/−0.4 mm. 
         [0036]      FIG. 3B  is a side cross-sectional view of an antenna  300  of  FIG. 3A  along a plane formed by the lines  3 A- 3 A, illustrating the layered construction of the planar antenna. The antenna top layer  322  can have a typical printed circuit board (PCB) construction and may be of polytetrafluoroethylene (PTFE) composite formulation. Upon its antenna top layer upper surface  323  is an upper patch (not shown). Probe connection, or SMA center pin, provides linkage from the SMA(F) connector  360  to an upper patch (not shown). An antenna middle layer  324  PCB can be provided which is a structure of uniform thickness; it may be comprised of a composite material with suitable dielectric properties. The bottom surface of the antenna top layer PCB can be permanently attached to the antenna middle layer upper surface  325  of the antenna middle layer  324  of the middle layer PCB, typically via a thin sheet of double-sided adhesive (not shown). The antenna bottom layer  328  of the antenna  300  can also be formed from a typical PCB construction and may be of PTFE composite formulation. On the antenna bottom layer upper surface  329  is the lower patch (not shown). On the bottom surface of the antenna bottom layer  328  is an SMA(F) connector which provides linkage to external devices. The antenna bottom layer upper surface  329  of PCB may be permanently attached to the antenna middle layer bottom surface, typically via a thin sheet of double-sided adhesive. 
         [0037]      FIG. 3C  is a bottom view of antenna  300 . The antenna  300  is planar and has an antenna bottom surface  312 . The antenna  300  has a first side  302 , a second side  304 , a third side  306  and a fourth side  308 . The sides are shown situated at 90 degree angles so that the resulting surface forms a rectangle (or square). A plurality of securement apertures (illustrated as first anchor aperture  342 , second anchor aperture  344 , third anchor aperture  346 , and fourth anchor aperture  348 ) can be provided which are shown situated at the corners of the rectangle (square). These securement apertures allow attachment of the antenna  300  to a mounting surface via, for instance, threaded fasteners such as screws or nuts-and-bolts, or other suitable fasteners such as rivets as illustrated in  FIG. 4 . An SMA(F) connector  360  is attached to the antenna bottom surface  312 , which can be located such that its midpoint is midway between opposing sides (for example second side  304  and fourth side  308 ) and its orthogonal midpoint is 32% of the way between the first side  302  and the third side  306 , situated nearer to side  302 . 
         [0038]      FIG. 3D  illustrates the top substrate of the antenna top layer  322  of the antenna showing the feed probe location  358 .  FIG. 3E  is the bottom layer of the top substrate  322  showing the feed probe location  358 . The top and bottom layer of the top substrate  322  are adhered together to form a single layer. 
         [0039]      FIG. 3F  illustrates the top layer of the bottom substrate  328  with an aperture in the copper for the feed probe location  358  to the top patch.  FIG. 3G  is the bottom layer of the bottom substrate  328 . The top and bottom layer of the bottom substrate  328  are adhered together to form a single layer. 
         [0040]      FIG. 3H  is an enlarged side view of a portion of the antenna  300 , showing the antenna top layer  322 , the antenna middle layer  324  and the antenna bottom layer  328 . Attached to the antenna bottom layer bottom surface  329 ′ is a typical commercially-available SMA(F) connector  360  and connector base  372   
         [0041]      FIG. 3I  is an enlarged bottom view of a portion of the antenna  300 , looking directly at the antenna bottom surface  312 . Attached to the antenna bottom surface  312  of the antenna  300  is a typical commercially-available SMA(F) connector  360 . The width of the connector  360  is 16+/−0.5 mm with a distance between the first connector aperture  362  and the second connector aperture  364  (center-to-center) if about 12.2+/−0.5 mm. The height of the connector is about 6+/−0.5 mm. 
         [0042]      FIG. 4  shows (in exploded isometric view) a typical mounting configuration for antenna  400  to mounting plate  450 , which may be part of a larger structure. The antenna  400  has a planar and rectangular (square) form factor, as illustrated, when viewed from above. The antenna  400  consists of three PCB layers, an antenna top layer  422  of PCB, an antenna middle layer  424  PCB, and an antenna bottom layer  428  as described above with respect to  FIG. 3 . At the corners of the antenna  400 , are a plurality of securement apertures illustrated as four securement apertures (e.g., first anchor aperture  442 , second anchor aperture  444 , third anchor aperture  446 , and fourth anchor aperture  448 ) of circular cross-section. Attached to the antenna bottom surface  412  of antenna  400  is a connector  460  of type SMA(F). There exists in mounting plate  450  an connector aperture  458  corresponding to the SMA(F) connector such that the connector  460  itself can pass through the mounting plate  450 , allowing the bottom surface of antenna  400  to sit flush on the mounting plate  450 . Attachment of the antenna  400  to the mounting plate  450  may be accomplished via the use of a plurality of threaded fasteners  430  passed through securement apertures (e.g., first anchor aperture  442 , second anchor aperture  444 , third anchor aperture  446 , and fourth anchor aperture  448 ) in the antenna  400  and corresponding apertures in the mounting plate  450  and secured using, for example, a plurality of hex nuts  462 . 
         [0043]      FIG. 5  is a side view section-cut of antenna  500  attached to mounting plate  550 . The antenna  500 , comprises a top PCB layer  522 , a middle PCB layer  524 , and a bottom PCB layer  528 , which rests atop mounting plate  550 . Protruding from the antenna top surface  510  of top PCB layer  522  is a probe connection that links the probe to the top patch (not visible). Protruding from the antenna bottom surface  512  is a connector  560  of type SMA(F). A plurality of threaded fasteners  530  attach antenna  500  from antenna top surface  510  to mounting plate  520  and are secured by, for example, a plurality of hex nuts  562  on bottom surface of mounting plate  550 . The distance between the top surface of the mounting plate  550  and the top surface of the top PCB layer  522  (on which the head of the non-conductive threaded fastener  530  sits) is about 7.07 mm. The thickness of the hex nut  562  is about 2.5 mm. 
         [0044]      FIGS. 6A-E  illustrate the top layer PCB with an upper patch antenna  656 .  FIG. 6A  is a top view of the antenna top layer  622  PCB. The antenna top layer  622  is of typical PCB construction and may be of PTFE composite formulation. The antenna top layer  622  can be planar, as illustrated, and of uniform thickness. The antenna top layer  622 , as discussed above, can be formed from a top substrate with a feed probe connection and a bottom layer. The antenna top layer  622  has a top side and a bottom side along with a first side  602 , a second side  604 , a third side  606  and a fourth side  608 , numbered clockwise when viewed from the top side. The sides (first side  602 , second side  604 , third side  606  and fourth side  608 ) are situated at 90 degree angles so that the resulting surface forms a rectangle (or square). There are a plurality of apertures for securement illustrated as four securement or anchor apertures (e.g., first anchor aperture  642 , second anchor aperture  644 , third anchor aperture  646 , and fourth anchor aperture  648 —illustrated as circular apertures situated at the corners of the rectangular (or square) antenna). These securement or anchor apertures allow attachment of the antenna to a mounting surface via, for instance, threaded fasteners such as screws or nuts-and-bolts, or other suitable fasteners such as rivets. The antenna top layer  622  has a top surface  623 . The upper patch antenna  656  resides on the top surface. A connection aperture  658  (as illustrated in  FIG. 6C ) of circular cross-section facilitates probe connection to the top patch of antenna. The connection aperture  658  is located midway between sides  604  and  608  and 32% of the way between sides first side  602  and third side  606 , situated nearer to side first side  602 . The width of the antenna top layer  622  is 50+/−0.2 mm, the height is also 50+/−0.2 mm, and the thickness is 3.2+/−0.2 mm. The distance between the anchor apertures (center-to-center) is 44+/−0.2 mm and the position of the connection aperture  658  is 25+/−0.2 mm from a first edge and 16+/−0.2 mm from a second edge, perpendicular to the first edge. For example, 25+/−0.2 mm from first side  602  and 16+/−0.2 mm from second side  604 . 
         [0045]      FIG. 6B  is a side view of the antenna top layer  622 .  FIG. 6C  is a bottom view of the antenna top layer  622 . It also has a plurality of side (e.g., first side  602 , second side  604 , third side  606  and fourth side  608 ). The sides are situated at 90 degree angles so that the resulting surface forms a rectangle (or square). There are four securement apertures (e.g., first anchor aperture  642 , second anchor aperture  644 , third anchor aperture  646 , and fourth anchor aperture  648 —situated at the corners of the rectangle (square)). These securement or anchor apertures allow attachment of the antenna to a mounting surface via, for instance, threaded fasteners such as screws or nuts-and-bolts, or other suitable fasteners such as rivets. A connection aperture  658  of circular cross-section facilitates probe connection to the top patch of antenna. The connection aperture  658  is located midway between second side  604  and fourth side  608  and 32% of the way between first side  602  and third side  606 , situated nearer to side  602 . 
         [0046]      FIGS. 6D-E  illustrate the upper patch antenna  656 , which is mounted on the upper surface  610  of top layer of the antenna top layer  622 . The antenna top layer  622  is of typical PCB construction and may be of PTFE composite formulation. It is planar and of uniform thickness. The upper patch antenna  656  has six sides  602 ′,  603 ,  604 ′,  606 ′,  607 ,  608 ′. A rectangle is formed by sides  602 ′,  604 ′,  606 ′and  608 ′ numbered clockwise) with truncated corners between sides  602 ′ and  604 ′ and sides  606 ′ and  608 ′ truncated at 45 degree angles to form additional truncated side  603  (between  602 ′ and  604 ′) and  607  (between  606 ′ and  608 ′). The truncated sides  603  and  607  are positioned on opposing corners of the rectangular shape and are of different lengths, where the first truncated side  605  has a first length and the second truncated side  607  has a second length different than the first length. The resulting shape is that of a rectangle (square) with opposite corners truncated, each at a 45 degree angle. Within the bottom patch is a connection aperture (not shown) of circular cross-section that facilitates probe connection to the top patch of antenna. Within the upper patch is a “V-shaped” slot  660  or aperture consisting of two rectangles which overlap slightly, one of which has been rotated 45 degrees with respect to the other. The first rectangular aperture  670  has sides  672 ,  674 ,  676 ,  678 , numbered clockwise when viewed from above. A first pair of sides are 1.5 times the length of a second pair of sides. Sides  672  and  676  are parallel to sides  602 ′ and  606 ′ of the upper patch antenna  656 , while sides  674  and  678  are parallel to sides  604 ′ and  608 ′ of the upper patch antenna  656 . A second rectangular aperture  680  connected to the first rectangular aperture  670  is defined by sides  682 ,  684 ,  686  and  688 , numbered clockwise when viewed from above. A first two of the sides of the second rectangular aperture are the same length as a first two of the sides of the first rectangular aperture. A second two of the sides of the second rectangular aperture are, for example, 0.65 times the length of a second two of the sides of the first rectangular aperture. The second rectangular aperture  680  is positioned relative to the first rectangular aperture  670  so that the second rectangular aperture is rotated 45 degrees with respect to, for example, side  674  of the first rectangular aperture  670 . The two rectangular apertures “overlap” such that the resulting aperture is “V-shaped” with one leg of the V perpendicular and the second leg of the V at a 45 degree angle. The length of side  684  is 7.5+/−0.2 mm; the length of side  686  is 4.9+/−0.2 mm; the distance between side  688  and side  674  is 45 degrees+/−0.2 degrees; the length of side  676  is 5+/−0.2 mm; and the length of side  678  is 7.5+/−0.2 mm. 
         [0047]      FIG. 7A  is a top view of middle PCB layer  724 . Middle PCB layer  724  is of typical PCB construction and may be of composite formulation. The middle PCB layer  724  is planar and of uniform thickness and has a middle PCB top surface  725 . The middle layer PCB has first, second, third and fourth sides  702 ,  704 ,  706 ,  708 , numbered clockwise when viewed from above. The sides  702 ,  704 ,  706 ,  708  are situated at 90 degree angles so that the resulting surface forms a rectangle (or square). A plurality of anchor apertures  742 ,  744 ,  746 ,  748  which are situated at the corners of the rectangle (square). The securement apertures allow attachment of the antenna to a mounting surface via, for instance, threaded fasteners such as screws or nuts-and-bolts, or other suitable fasteners such as rivets. The middle PCB layer  724  has a large, square central aperture  758 . The sides of the central aperture are parallel to sides  702 ,  704 ,  706 , and  708 , such that the middle PCB layer  724  resembles a picture frame. The length and width is 50+/−0.2 mm. The thickness of the middle PCB layer  724  ( FIG. 7B ) is about 2+/−0.15 mm. The width of the square central aperture  758  is about 40+/−0.3 mm. The distance between the apertures (center-to-center) is 44+/−0.2 mm; and length and width of the central aperture  758  is 40+/−0.3 mm. 
         [0048]      FIG. 7B  is a side view of the middle PCB layer  724  and  FIG. 7C  is a bottom view of middle PCB layer  724  with middle PCB bottom surface  725 ′. It has first, second, third and fourth sides  702 ,  704 ,  706 ,  708 . The sides are situated at 90 degree angles so that the resulting surface forms a rectangle (or square). As with other configurations, a plurality of securement apertures are provided, illustrated as four anchor apertures  742 ,  744 ,  746 ,  748  with circular cross-section—situated at the corners of the rectangle (square) to allow attachment of the antenna to a mounting surface via, for instance, threaded fasteners such as screws or nuts-and-bolts, or other suitable fasteners such as rivets. Evident in the figure is the large, square central aperture  758 . 
         [0049]      FIG. 8A  is a top view of antenna bottom layer  828 . As discussed above, the antenna bottom layer has a bottom substrate and a ground plane which forms a bottom layer of the bottom substrate. The antenna bottom layer  828  is of typical PCB construction and may be of PTFE composite formulation. It is planar, of uniform thickness, and has a top surface  829 . It has first, second, third and fourth sides  802 ,  804 ,  806 ,  808 , numbered clockwise when viewed from above. The sides are situated at 90 degree angles so that the resulting surface forms a rectangle (or square). Four apertures are illustrated with circular cross-section  842 ,  844 ,  846 ,  848 —situated at the corners of the rectangle (square). These apertures allow attachment of the antenna to a mounting surface via, for instance, threaded fasteners such as screws or nuts-and-bolts, or other suitable fasteners such as rivets shown in, for example,  FIG. 4 . An aperture  858  of circular cross-section facilitates probe connection to the top patch of antenna. The aperture  858  is located midway between second side  804  and fourth side  808  and 32% of the way between first side  802  and third side  806 , situated nearer to the first side  802 . The lower patch antenna  814  a first side  802 ′, a second side  804 ′, a third side  806 ′, and a fourth side  808 ′. Two opposing truncated ends  803  and  807  are provided. The thickness of the antenna bottom layer  828  ( FIG. 8B ) is about 1.57+/−0.12 mm. The aperture  858  is positioned about 25+/−0.3 mm from the first fourth side  804  and about 16+/−0.3 mm from the first side  802 . 
         [0050]      FIG. 8B  is a side view of antenna bottom layer  828 .  FIG. 8C  is a bottom view of the bottom layer. It has first, second, third and fourth sides  802 ,  804 ,  806 ,  808 , numbered counterclockwise when viewed from above. The sides are situated at 90 degree angles so that the resulting surface forms a rectangle (or square). Illustrated are four connection apertures having a circular cross-section  842 ,  844 ,  846 ,  848  situated at the corners of the rectangle (square) to allow attachment of the antenna to a mounting surface via, for instance, threaded fasteners such as screws or nuts-and-bolts, or other suitable fasteners such as rivets. On the bottom layer PCB is aperture  858  of circular cross-section facilitates probe connection to the top patch of antenna. The aperture is located midway between second side  804  and fourth side  808  and 32% of the way between first side  802  and third side  806 , situated nearer to the first side  802 . Copper plating can be provided on the bottom surface. 
         [0051]      FIG. 8D-E  are a detailed views of lower patch antenna  814 , which is mounted on the top surface  810  of bottom layer PCB  800 . The bottom layer is of typical PCB construction and may be of PTFE composite formulation. It is planar and of uniform thickness. The lower patch antenna  814 , which is mounted on the top surface of the bottom layer PCB, has six sides. The shape is that of a rectangle (formed by sides  802 ′,  804 ′,  806 ′ and  808 ′ numbered clockwise) with corners  803 ,  807  between a first pair of sides  802 ′ and  804 ′ and a second pair of sides  806 ′ and  808 ′ truncated at 45 degree angles to form additional linking sides. The truncated linking sides  803  and  807  are the same length and are positioned at opposite corners of the rectangle. The resulting shape is that of a rectangle (square) with opposite corners truncated, each at a 45 degree angle. Within the bottom patch is an aperture  858  of circular cross-section that facilitates probe connection to the top patch of antenna. The antenna bottom layer  828  of the bottom layer PCB  800  (shown in  FIG. 8E ) is plated with, for example, copper, to facilitate grounding of the antenna assembly when mounted to the grounding plane shown in  FIGS. 4 and 5 . The total length of the sides of the lower patch antenna  814  is 31.8+/−2 mm in length and width (extending the length of the side as though the truncated portion were part of the shape), the truncated portion (e.g.,  803 ) begins at 4.3+/−0.2 mm before the edge of the adjacent side (e.g.,  804 ′). 
         [0052]    In operation the patch is excited by a standard single-pin unbalanced feed. The top patch is probe-fed and the bottom patch is fed via coupling. The bottom patch is fed by coupling between the bottom patch and the feed probe. The two rectangular patches are excited to TM11 resonant modes with each patch resonating at a desired frequency band. The antenna is configurable so that the top patch resonates at an upper resonance, while the lower patch resonates at a lower resonance. A circular polarization is created by truncating corners and feeding the antenna to excited the TM11 mode. The bottom patch axial ratio is thus limited by the TM11 excitation method. Additionally the upper patch&#39;s axial ratio is increased by the use of a v-shaped slot in the upper patch. The patch structure provides the medium gain and directive pattern while the materials choice(s) and substrate thickness(es) deliver the high efficiency. 
         [0053]      FIG. 9  illustrates a return loss over a range of 2000-6000 MHz of an antenna according to the disclosure; 
         [0054]      FIG. 10  illustrates a return loss in free space and centered on three different size metal planes over a range of 2300-6000 MHz for an antenna according to the disclosure; 
         [0055]    The antenna may be implemented using various printed circuit board materials, including Rogers 5870 and commodity FR4.Depending on the substrate material(s) employed, dimensions may need to be adjusted accordingly. Generally, lower-loss materials will deliver higher efficiency and gain. Specifically, substrates with a low dielectric constant and low dissipation factor, can be used such as glass microfiber reinforced polytetrafluoroethylene (PTFE), Teflon®. Such substrates minimize signal transmission loss in order to achieve high efficiency. Antennas employing such materials perform with high efficiencies at WiFi bands from 2400˜2500 MHz and 5150˜5850 MHz of 74% and 67%, and with peak gains of 5.5 dBi and 7.3 dBi respectively, as displayed in  FIGS. 11-13  where  FIG. 11  illustrates a percent efficiency over a range of 2000-6000 MHz,  FIG. 12  illustrates a percent efficiency in free space and centered on three different size metal ground planes over a range of 2000-6000 MHz, and  FIG. 13  illustrates a peak gain over a range of 2000-6000 MHz. 
         [0056]      FIG. 14  illustrates a peak gain in free space and centered on three different size metal ground planes over a range of 2000-6000 MHz for an antenna according to the disclosure; 
         [0057]      FIG. 15  illustrates an average gain over a range of 2000-6000 MHz. 
         [0058]    The upper patch is rectangular in shape with opposite corners truncated at 45 degrees to produce circular polarization. Within the patch is a novel, v-shaped slot configuration, consisting of two rectangular slots, one of which is aligned with a major side of the patch, and a replica that is rotated 45 degrees about the inside corner and shifted left by 1 mm so that it is aligned with one truncated side of the patch. The length and width of each slot is proportional, respectively, to one eighth the wavelength of the upper and lower limits of the higher frequency band. The use of overlapping slots is suitable for wideband antenna matching and delivers the wideband axial ratio of the upper band as shown in  FIGS. 16A-C  which illustrates an axial ratio over a range of 2000-6000 MHz. 
         [0059]    The lower patch is rectangular in shape with opposite corners truncated at 45 degrees to produce circular polarization. Compared to the upper patch, the lower patch has a narrower axial ratio as displayed in  FIGS. 16A-C . 
         [0060]      FIGS. 17A-C  illustrate two-dimensional (2D) radiation patterns in an X-Y plane, an X-Z plane, and a Y-Z plane, and  FIGS. 18A-B  illustrate a three-dimensional (3D) radiation pattern at 2450 MHz and 5550 MHz. 
         [0061]    The antenna described herein offers a number of advantages (in both structure and performance) over existing designs. To wit, the lower and upper frequency bands are arbitrarily related and independently set by the dimensions of the lower and upper patches, respectively. This enables greater flexibility in applications for the antenna than alternatives currently available. In contrast to many current designs, the axial ratio bandwidth of the upper frequency band is large, while retaining a simple feed mechanism. Unlike complex structures offered by many current designs, the structure of the antenna described herein is simply constructed using three printed circuit boards, which are manufactured using standard PCB production techniques. This results in reduced production cost compared to alternatives. The simplicity of the structure itself enables easy integration into a system using the four mounting apertures provided, thus achieving additional cost savings. 
         [0062]    Using a circular polarized signal enables the link to have increased stability for devices where the direction of orientation is unknown or where multipath is an issue. 
         [0063]    A low profile design equipped with an SMA(F) connector, is easy to install inside a housing or directly onto a printed circuit board (PCB) mainboard. The board has a plurality of thru-holes or apertures at the patch corners, allowing users to secure the antenna with screws, as shown in  FIGS. 3 and 4-5 . The antenna has passed ISO 16750 high/low-temperature test and random vibration reliability testing. 
         [0064]    Many module manufacturers specify peak gain limits for any antennas that are to be connected to that module. Those peak gain limits are based on free-space conditions. In practice, the peak gain of an antenna tested in free-space can degrade by at least 1 or 2 dBi when put inside a device. A slightly higher peak gain antenna can be provided to compensate for this effect, providing better performance. 
         [0065]    Antennas are typically incorporated into other devices. Upon testing of the disclosed antennas the antennas&#39; peak gain can be adjusted to fall below a target peak gain limit required by the device into which the antenna is incorporated. 
         [0066]    For example, a module manufacturer may state that the antenna must have less than 2 dBi peak gain, due to the configurability of the disclosed antennas, the module manufacturer would not need to select an embedded antenna that has a peak gain of less than 2 dBi in free-space. A slightly higher free-space peak gain of 3 dBi may be suitable under these target configuration. Once the antenna disclosed herein is integrated into a device requiring less than 2 sBi peak gain, performance will degrade below the target 2 dBi peak gain limit due to the effects of GND plane, surrounding components, and device housing. 
         [0067]    The antennas disclosed herein can be made available as part of a kit. The kit comprises, for example, a planar antenna comprising a substrate having a substantially square shape, a conductive layer attached to a first surface of the substrate wherein the conductive layer further comprises an antenna section which includes a monopole planar inverted-F antenna adapted and configured to efficiently operate in a dual band mode and a radiation control section, and a ground section connected to the inverted-F antenna by a connector region, and a flexible cable adaptable to connect the planar antenna to a target device. Additionally, the kit may include, for example, suitable mounting material, such as 3M adhesive transfer tape. Other components can be provided in the kit as well to facilitate installation of the antenna in a target device. The kit can be packaged in suitable packaging to allow transport. Additionally, the kit can include multiple antennas, such that antennas and cables are provided as 10 packs, 50 packs, 100 packs, and the like. 
         [0068]    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.