Abstract:
Disclosed is a touchscreen antenna system and a method of designing a touchscreen antenna system. The system and method are operative to integrate an antenna with one or more touchscreen components to render a compact and effective system and to provide a more robust operation. The system is configured such that an antenna element, comprising a radiating component or an antenna feeding portion, is electromagnetically coupled to a touchscreen element, including a touch sensor, a touch sensor line, and other active or passive elements of a touchscreen module. Accordingly, the system is capable to mitigate adverse effects, when operating in an environment or under conditions that may affect other systems or be susceptible to being affected by other sources, by designing antenna and touchscreen elements as an integrated unit. Additionally, the system and method provide an enhanced antenna system performance by incorporating touchscreen elements as part of the antenna design.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims priority from co-pending U.S. Provisional Patent Application Ser. No. 62/095,479 entitled “TOUCHSCREEN ANTENNA SYSTEM AND DESIGN METHOD THEREOF” filed with the U.S. Patent and Trademark Office on Dec. 22, 2014, by the inventors herein, the specification of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to antenna systems and methods. More particularly, the present invention relates to antenna systems and to antenna design and manufacturing methods for integrating antennas with touchscreen systems. 
       BACKGROUND OF THE INVENTION 
       [0003]    A number of antenna designs and systems exist within various industries for enabling communications of a touchscreen module at several frequency bands for multiple applications. More specifically, nowadays touchscreen modules may require antennas for Wireless Fidelity (Wi-Fi), Bluetooth, Radio Frequency (RF) identification, near-field communications, and other applications. 
         [0004]    In general, one or more antennas are installed in a touchscreen module. Accordingly, aesthetic issues may arise resulting from the antenna form factor. Thus, the integration of antennas with a touchscreen module have been actively demanded by users. However, integrating an antenna with a touchscreen module brings a number of other issues, such as antenna frequency detuning, RF interference to and from other touchscreen elements, and more importantly, antenna and system degradation performance. This is primarily due to the large number of electrically conductive components present in a touchscreen, including touch sensors, touch sensing lines, electrodes, display, integrated circuits, controllers, transmission lines, etc., that may affect the operational performance of the antenna. 
         [0005]    This situation becomes more critical for touchscreen antenna applications used in portable and handheld electronic devices because of the small size of these units. In recent years, the demand for touchscreen modules requiring antennas has increasingly grown for applications in the computer, mobile platform, and automobile industries. In particular, the implementation of a touchscreen having an antenna integrated has been addressed in the prior art, as described in U.S. Pat. App. No. 20110273382 to Yoo et al. However, these efforts have faced certain challenges and limitations. Specifically, the antenna has been integrated by forming an antenna pattern in the inactive region of one or more of the touchscreen substrates. A major challenge is that the space available in the inactive region is limited to a small area around the edges of these substrates, constraining the size and type of antennas to be used. In addition, antennas are susceptible to being detuned or blocked by the presence of surrounding extraneous materials, unless the antenna is enclosed in a separate module making it bigger and more expensive. 
         [0006]    Likewise, multiple antenna elements are needed to be able to operate at different frequency bands, which make the size requirements significantly larger and the need to use a bigger number of or more complex electronic components, resulting in higher costs. Previous efforts also include enabling the formation of all or respective portions of a touch sensor and an antenna during the same process to reduce manufacturing costs, as described in U.S. Pat. App. No. 20140176819 to Yilmaz. However, these efforts still do not solve the space and performance limitations resulting from undesired effects between touchscreen elements and antenna elements. 
         [0007]    More specifically, a major constraint may result where the antenna receives spurious signals from nearby sources, especially within the touchscreen module, that increase the noise level of the system. Another limitation may result where the antenna radiates spurious signals that may interfere with other internal and external electronic systems. These limitations may compromise the signal integrity of internal and/or external systems or make it very challenging for a touchscreen antenna to meet signal integrity industry standards. 
         [0008]    A way to address the disadvantages of the efforts attempted by the prior art is to design a touchscreen antenna system that operatively integrates a touchscreen element with an antenna element. This would make it possible to enhance the performance and increase the robustness of the overall antenna system while mitigating or eliminating undesired effects, by configuring the touchscreen element to function as a part of the touchscreen antenna system. In particular, a configuration may be designed to integrate an antenna element, a touchscreen element, a feeding mechanism and a corresponding transmission line in a single unit for additional advantages, such as more compactness, lower manufacturing costs, and potential higher signal integrity. 
         [0009]    Currently, there is no well-established method of deterministically creating a touchscreen antenna system that combines antenna elements and touchscreen elements to operate as an integrated antenna unit, over one or more frequency bands of interests, preventing undesired effects between each other and effectively withstanding performance degradation under operational conditions. 
         [0010]    Thus, there remains a need in the art for touchscreen antenna systems and methods to design such systems that are capable of a robust operation at the frequencies of intended applications, while avoiding the problems of prior art systems and methods. 
       SUMMARY OF THE INVENTION 
       [0011]    A touchscreen antenna system and a method of designing a touchscreen antenna system are disclosed herein. One or more aspects of exemplary embodiments provide advantages while avoiding disadvantages of the prior art. The system and method are operative to integrate an antenna with one or more touchscreen components to render a compact and effective system and to provide a more robust operation. The system is configured such that an antenna element, comprising a radiating component or an antenna feeding portion, is electromagnetically coupled to a touchscreen element, including a touch sensor, a touch sensor line, a display unit, a touch controller, and other active or passive elements of a touchscreen module. Accordingly, the system is capable to mitigate adverse effects, when operating in an environment or under conditions that may affect other systems or be susceptible to being affected by other sources, by designing antenna and touchscreen elements as an integrated unit. Additionally, the system and method provide an enhanced antenna system performance by incorporating touchscreen elements as part of the antenna design. 
         [0012]    In general, an antenna may be detuned or offset in frequency under certain operational conditions, such as the presence of any combination of user body parts (e.g., hands, fingers, head or other parts of the body as when such device is placed in a pocket or hung on clothing), conductive materials, or dielectric materials located within a radius of two wavelengths at the lowest frequency of operation in the medium where the antenna element is operating. Particularly, an antenna element integrated within a touchscreen module may be particularly susceptible to frequency detuning. Interference to and from other sources may also present a challenge to the operational performance of such antenna. 
         [0013]    However, by designing a touchscreen antenna system to comprise an antenna element in combination with a touchscreen element it is possible to effectively and efficiently implement an antenna system having an improved performance. Primarily, an antenna element may comprise an active radiation element, a passive radiation element, and an antenna feeding element. Likewise, a touchscreen element may include an active touchscreen element, a passive touchscreen element, and a touch sensor line. The key aspect is to follow an integrated design approach by which the touchscreen element operatively becomes a part of the antenna system by physically and/or capacitively coupling to an antenna element to operate together as an integrated unit. 
         [0014]    A touchscreen antenna system designed according to the method described herein is able to meet these requirements by using a touchscreen element as at least a portion of a radiating element, a parasitic element, or a feeding mechanism to adapt the performance of an antenna element to the actual specifications of the intended applications. In addition, this adaptation may take into consideration the input impedance matching between the antenna element and the transmission line feeding the antenna, which is also a key factor impacting the overall performance of the touchscreen antenna system. 
         [0015]    The method to design a touchscreen antenna system to mitigate adverse effects when operating in a potentially antenna-detuning environment or under conditions that may interfere with other systems or be susceptible to interference from other sources, and for setting up the antenna system dimensional and operational parameters includes the step of determining a location of an antenna element and a feeding mechanism to feed such antenna element within a touchscreen module. 
         [0016]    The method further includes the steps of identifying key operational conditions in which the performance of the antenna element might be affected. These key operational conditions may include, but are not limited to, the presence of any combination of human user body parts (e.g. hands, fingers, head or other parts of the body as when such device is placed in a pocket or hung on clothing), conductive materials, or dielectric materials located within a radius of two wavelengths at the lowest frequency of operation in the medium where said antenna element is operating. 
         [0017]    The method further includes the steps of enhancing such performance by designing one or more antenna elements combined with one or more touchscreen elements to operate integrated as a single antenna system configuration. Accordingly the method allows to design a suitable touchscreen antenna system to be used for the intended application, in terms of performance or other predetermined criteria. 
         [0018]    By significantly adapting the performance of an antenna element by means of integrating a touchscreen element with such antenna element, the touchscreen antenna system and method are able to provide a robust design against frequency detuning, at the frequencies of intended operation, and a significant reduction of undesired effects at frequencies of no operational interest, as compared to designs using standard techniques. This results in touchscreen antenna designs that meet or exceed challenging industry standards, in terms of antenna performance and signal integrity of both internal and external systems. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  shows a top view of a touchscreen antenna system integrating a feeding mechanism with a passive element of a touchscreen; 
           [0020]      FIG. 2  shows a top view of a touchscreen antenna system integrating an adaptive feeding mechanism with an active element of a touchscreen; 
           [0021]      FIG. 3  shows a top view of a touchscreen antenna system fed by using a touch sensor line; 
           [0022]      FIGS. 4A and 4B  show exploded, perspective views of various aspects of a touchscreen antenna system integrating a substrate layer and an antenna fed by a feeding mechanism within the touchscreen module; 
           [0023]      FIGS. 5A and 5B  show various aspects of a touchscreen antenna system integrating a substrate layer and an antenna with other components of a touchscreen module; and 
           [0024]      FIG. 6  shows a schematic view of a method for designing a touchscreen antenna system. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    The following description is of one or more aspects of the invention, set out to enable one to practice an implementation of the invention, and is not intended to limit the invention to any specific embodiment, but to serve as a particular example thereof. Those skilled in the art should appreciate that they may readily use the conception and specific embodiments disclosed as a basis for modifying or designing other methods and systems for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent assemblies do not depart from the spirit and scope of the invention in its broadest form. 
         [0026]      FIG. 1  shows a top view of an exemplary configuration of a touchscreen antenna system  10 , integrated with a typical touchscreen having two layers of touch sensors or active touchscreen elements or electrodes, each sensor having a shape of a parallelogram. A first set of sensors  12   a ,  12   b ,  12   c , and  12   d  are disposed on a first substrate layer (X layer) in a row-column matrix arrangement, wherein the sensors in the same column are physically and electrically connected to each other by a connecting section  14 . The sensors in different columns are not physically connected to each other. Connecting section  14  allows to electrically connect two adjacent sensors in the same column to a touch sensor line  15   a  used to determine the location of a touch on the X layer. 
         [0027]    Likewise, a second set of sensors  16   a ,  16   b , and  16   c  are disposed on a second substrate layer (Y layer) in a row-column matrix arrangement, wherein the sensors in the same row are physically and electrically connected to each other by a connecting section  18 . The sensors in different rows are not physically connected to each other. Connecting section  18  allows to electrically connect two adjacent sensors in the same row to a touch sensor line  15   b  used to determine the location of a touch on the Y layer. 
         [0028]    The first substrate layer, X layer, and the second substrate layer, Y layer, are separated, and electrically isolated, from each other by an interposed insulating layer. Typically, all sensors, connecting sections between sensors, and touch sensor lines are made of a transparent, conductive layer of a material such as Indium tin-oxide (ITO). In addition, the insulating layer, the first substrate layer, and the second substrate layer are disposed on an optically transparent substrate layer. 
         [0029]    The first set of sensors on the X layer and the second set of sensors on the Y layer are interleaved in a manner such that from a top view, the space among any four adjacent sensors on layer X, arranged in a 2-row by 2-column pattern, is occupied by a sensor on layer Y. For instance, the space among sensors  12   a ,  12   b ,  12   c , and  12   d  is occupied by sensor  16   b . Likewise, the space among any four adjacent sensors on layer Y, arranged in a 2-row by 2-column pattern, is occupied by a sensor on layer X. 
         [0030]    Furthermore, a set of touchscreen passive elements or dummy sensors  19 , each having a triangular shape, is typically disposed on the edges of the X layer and or the Y layer to improve visual homogeneity and transparency of the touchscreen, by filling the space in between the active touchscreen sensors closer to the edges of the touchscreen and the edges of the touchscreen. Typically, touchscreen passive element  19  is made of the same material, such as ITO, used to make the active touchscreen sensors and is not physically connected to any other sensor or component. 
         [0031]    Touchscreen antenna system  10  comprises a feeding mechanism  20  integrated with touchscreen passive element  19 . Feeding mechanism  20  is coupled to touchscreen passive element  19  by means of a physical connection or by means of a capacitive coupling at feeding point  21 . Furthermore, touchscreen passive element  19  is capacitively coupled to touchscreen active elements  12   a  and  12   b . Moreover, touchscreen active element  12   a  is electrically connected to touchscreen active element  12   c  and capacitively coupled to touchscreen passive elements  16   a  and  16   b . Similarly, touchscreen active element  12   b  is electrically connected to touchscreen active element  12   d  and capacitively coupled to touchscreen passive elements  16   b  and  16   c.    
         [0032]    In addition, touchscreen passive element  19  may also capacitively couple in a lesser degree to touchscreen active element  16   b  and other touchscreen passive elements. As a result, touchscreen antenna system  10  effectively becomes an antenna array comprising touchscreen passive elements, touchscreen active elements, and touch sensor lines of the touchscreen. In other words, touchscreen antenna system  10  utilizes the touch sensors and touch sensor lines as radiating elements. 
         [0033]    In this configuration, feeding mechanism  20  comprises a coplanar waveguide formed by a center line  22   a , having a rectangular shape and made of conductive material having a 1-mm width, and a ground plane formed by two rectangular sections of conductive material  22   b  and  22   c , each disposed coplanar, in close proximity, and substantially parallel to center line  22   a , as well known to those skilled in the art. Sections  22   b  and  22   c  have preferably similar size and are separated by a distance ranging from 0.25 mm to 5 mm from touchscreen passive element  19 . Center line  22   a  is electrically connected to touchscreen passive element  19  at feed point  21 . 
         [0034]    Moreover, a portion of feeding mechanism  20  may be disposed on a flexible substrate and be a part of a flexible printed circuit (FPC) or may be planar with touchscreen passive element  19 . In general, the dimensions of sensors  12   a  to  12   d  and  16   a  to  16   c  range from 3-mm by 3-mm to 30-mm by 30-mm, depending on the size and specific application of a touchscreen. Preferably, the dimensions of touchscreen passive element  19  correspond to those of a triangle formed by bisecting the parallelogram shape of one of the sensors  12   a  to  12   d  or  16   a  to  16   c  through two opposite vertices. Typically, the spacing between adjacent sensors, such as sensor  12   a  and sensor  16   a  and sensor  12   a  and sensor  19 , is equal or less than 1 mm. 
         [0035]    A location of feed point  21  may be selected to excite a certain current density distribution on touchscreen passive element  19 . Additionally, the size and shape of touchscreen passive element  19  may be configured to increase or decrease the capacitive coupling to surrounding touchscreen elements. Thus, based on a specific configuration, dimensions, and excitation current of touchscreen passive element  19 , touchscreen antenna system  10  may be designed for a specific application. In particular, touch sensor lines  15   a  and  15   b  do not electromagnetically interfere with touchscreen antenna system  10  because touch sensor lines  15   a  and  15   b  typically operate at substantially lower frequencies, within a frequency range such as 100 KHz to 1 MHz, as compared to the frequencies of operation of suitable applications of touchscreen antenna system  10 , which include the Near Field Communications band, operating at around 13.56 MHz and other applications usually operating at or higher than 500 MHz. 
         [0036]      FIG. 2  shows a top view of an alternative exemplary configuration of touchscreen antenna system  10  integrated with a typical touchscreen, having two layers of touch sensors or active touchscreen elements arranged similarly to the touch sensors shown in  FIG. 1 . In this configuration, a feeding mechanism  24 , made of conductive material and comprising a coplanar stripline, as shown in  FIG. 1 , and an adaptive feeding section  26 , is integrated with a touch sensor  28 . In particular, touch sensor  28  is positioned next to an edge of the touchscreen and does not have the typical configuration of a parallelogram. Instead, touch sensor  28  is configured to have a first triangular section  28   a , opposite feeding section  26 , and a second semi-elliptical section  28   b  operatively coupled to feeding section  26 . 
         [0037]    More specifically, section  28   a  transitions smoothly from a triangular shape into the semi-elliptical shape of section  28   b  to allow a more uniform current density distribution on section  28  for better performance of touchscreen antenna system  10 . Preferably sections  28   a  and  28   b  are made of a transparent, conductive layer of a material such as ITO. More preferably, sections  28   a  and  28   b  form a single unit. Alternatively, due to manufacturing considerations, section  28   a  may be part of a parallelogram, and section  28   b  may be disposed on top of an area of such parallelogram, not overlapping section  28   a , resulting in the configuration of sensor  28  shown in  FIG. 2 . 
         [0038]    Preferably, adaptive feeding section  26  is made of conductive material and has a semi-elliptical shape that defines an area smaller than the area defined by the semi-elliptical shape of section  28   b . More preferably, the curved edge of semi-elliptical feeding section  26  adaptively aligns with the curved edge of semi-elliptical section  28   b , such that section  28   b  fully overlaps feeding section  26 . This configuration allows a more uniform current density distribution on section  28  for better performance of touchscreen antenna system  10 . 
         [0039]    In this embodiment, touchscreen antenna system  10  comprises feeding mechanism  24  integrated with touch sensor  28 . Feeding section  26  is coupled to touch sensor  28  by means of a physical connection or by means of a capacitive coupling with section  28   b . Furthermore, touch sensor  28  is capacitively coupled or electrically connected to either touchscreen passive elements or other touch sensors. As a result, touchscreen antenna system  10  effectively becomes an antenna array comprising touchscreen passive elements, touchscreen active elements, and touch sensor lines of the touchscreen. 
         [0040]    Furthermore, the semi-elliptical shape of section  28   b  may require touchscreen passive elements  19   a  and  19   b , adjacent to touch sensor  28 , to be resized or configured differently to the typical triangular shape to avoid overlapping and to meet the visual homogeneity and transparency requirements of the touchscreen. In particular, touch sensor lines  15   a  and  15   b  do not electromagnetically interfere with touchscreen antenna system  10  because touch sensor lines  15   a  and  15   b  typically operate at substantially lower frequencies, within a frequency range such as 100 KHz to 1 MHz, as compared to the frequencies of operation of suitable applications of touchscreen antenna system  10 , which include the Near Field Communications band, operating at around 13.56 MHz and other applications usually operating at or higher than 500 MHz. 
         [0041]    Moreover, in this configuration, feeding section  26  is preferably positioned at the middle region of the curved edge of section  28   b . This positioning of feeding section  26  may require repositioning touch sensor line  15   c  to one side of touch sensor  28  in order to touch sensor  28  without physically interfering with feeding mechanism  24 . Additionally, a portion of feeding mechanism  24  may be disposed on a flexible substrate and be a part of a flexible printed circuit (FPC) or may be planar with touch sensor  28 . 
         [0042]    In yet another exemplary configuration,  FIG. 3  shows a top view of touchscreen antenna system  10  fed by using a touch sensor line  15   a , having two layers of touch sensors or active touchscreen elements arranged similarly to the touch sensors shown in  FIG. 2 . In this configuration, touch sensor  28  is positioned next to an edge of the touchscreen and is operatively connected to touch sensor line  15   a , such that touch sensor line  15   a  operates both to determine the location of a touch on the X layer of the touchscreen and to feed touchscreen antenna system  10 . 
         [0043]    Likewise, touch sensor  28  is configured to have a first triangular section  28   a , opposite touch sensor line  15   a , and a second semi-elliptical section  28   b  operatively connected to touch sensor line  15   a , including by means of a physical connection or by means of capacitive coupling. 
         [0044]    More specifically, section  28   a  transitions smoothly from a triangular shape into the semi-elliptical shape of section  28   b  to allow a more uniform current density distribution on section  28  for better performance of touchscreen antenna system  10 . Preferably, touch sensor  28  and touch sensor line  15   a  form a single unit. Alternatively, due to manufacturing considerations, touch sensor line  15   a  may be disposed on top of or contiguous to touch sensor  28 . 
         [0045]    In this embodiment, touchscreen antenna  10  comprises touch sensor line  15   a  integrated with touch sensor  28 . Furthermore, touch sensor  28  is capacitively coupled or electrically connected to either touchscreen passive elements or other touch sensors. As a result, touchscreen antenna system  10  effectively becomes an antenna array comprising touchscreen passive elements, touchscreen active elements, and touch sensor lines of the touchscreen. 
         [0046]    Furthermore, the semi-elliptical shape of section  28   b  may require touchscreen passive elements  19   a  and  19   b , adjacent to touch sensor  28 , to be resized or configured differently to the typical triangular shape to avoid overlapping and meet the visual homogeneity and transparency requirements of the touchscreen. In particular, touch sensor lines  15   a  and  15   b  do not electromagnetically interfere with touchscreen antenna system  10  because touch sensor lines  15   a  and  15   b  operate at substantially lower frequencies as compared to the frequencies of operation of suitable applications of touchscreen antenna system  10 . 
         [0047]      FIGS. 4A and 4B  show exploded, perspective views of various aspects of a touchscreen antenna system  40  integrating a substrate layer and an antenna fed by a feeding mechanism within the touchscreen module. In particular,  FIG. 4A  shows an exploded, perspective view of touchscreen antenna system  40  integrating a substrate layer  42  and an antenna  44  fed by a feeding mechanism  46  within touchscreen antenna system  40 . Typically, touchscreen antenna system  40  comprises a substantially flat display unit  47 , a touch sensing unit  48 , and a protective layer  49 . 
         [0048]    In general, flat display unit  47  comprises a layer of a substantially conductive material, acting as a ground plane and opposite touch sensing unit  48 , and may consist or be a part of a liquid crystal display (LCD). As previously described, touch sensing unit  48  typically comprises two layers of optically transparent touch sensors, electrically isolated from each other by an interposed transparent insulating layer, and disposed on an optically transparent substrate layer. Protective layer  49  consists of a transparent thin layer of a substrate such as glass or plastic. 
         [0049]    In this configuration, antenna  44  is disposed on substrate layer  42  integrated as an additional layer within touchscreen antenna system  40 . Substrate layer  42  typically consists of a thin film made of optically transparent material, including a polyester film such as polyethylene terephthalate (PET) and a cyclo olefin polymer (COP) material. 
         [0050]    Antenna  44  operates in combination with the ground plane of display unit  47  and may capacitively couple to touch sensing unit  48 . More specifically, the disposition of substrate layer  42  may be ultimately decided based on the design configuration of antenna  44  and a level of interaction of antenna  44  with display unit  47 , touch sensing unit  48 , and protective layer  49 . 
         [0051]    Furthermore, feeding mechanism  46  preferably connects physically to antenna  44  to feed antenna  44 . Alternatively, a connection between antenna  44  and feeding mechanism  46  may be implemented by means of capacitive coupling. In addition, feeding mechanism  46  is also preferably implemented, at least partly, on a dedicated flexible printed circuit. However, antenna  44  may also be partly integrated with feeding mechanism  46 . More preferably, antenna  44  is planar and made of a transparent, conductive layer of a material such as ITO. Alternatively, antenna  44  may be implemented using a conductive material, including a copper mesh and silver nanowires arranged in a linear or a grid pattern to maintain a required optical transparency of antenna  44 . 
         [0052]    Specifically,  FIG. 4B  shows an exploded, perspective view of another exemplary configuration of touchscreen antenna system  40  integrating a feeding mechanism  46   a , disposed on touch sensing unit  48 , with antenna  44 , disposed on substrate layer  42 , such that feeding mechanism  46   a  feeds antenna  44  by means of a capacitive coupling. In this alternate configuration, substrate layer  42  is disposed in between touch sensing unit  48  and protective layer  49 . Preferably, antenna feeding mechanism  46   a  is at least partly disposed on a substrate  46   b  comprising circuit elements operatively connected to touch sensing unit  48 . 
         [0053]    Likewise, antenna  44 , disposed on substrate layer  42 , operates in combination with feeding mechanism  46   a , disposed on a layer other than substrate layer  42 ; the ground plane of display unit  47 ; and touch sensing unit  48 . More specifically, the disposition of substrate layer  42  may be ultimately decided based on the design configuration of antenna  44  and a level of interaction of antenna  44  with display unit  47 , touch sensing unit  48 , and protective layer  49 . 
         [0054]    In another configuration,  FIGS. 5A and 5B  show various aspects of a touchscreen antenna system  50  integrating a substrate layer and an antenna with other components of a touchscreen module. Specifically,  FIG. 5A  shows a top view of touchscreen antenna system  50 , comprising a portion of a substrate layer  52  of a touchscreen. A first region of a transparent conductive material  54  and a second region of a transparent conductive material  56  are disposed on substrate layer  52 . Regions  54  and  56  are in close proximity, but not in physical contact, separated by a gap  58 . Preferably, regions  54 ,  56  and gap  58  are formed by cutting out, etching, or deleting an area of material from a rectangular piece of transparent conductive material disposed on layer  52 . 
         [0055]    Region  54  is configured to perform as an active radiating antenna element and electromagnetically couples to region  56 . Accordingly, region  56  acts as a passive or parasitic antenna element with respect to region  54 . As a result, the configuration of region  54  and the spacing between regions  54  and  56  are determined by the required antenna pattern radiation from regions  54 ,  56  as installed on touchscreen antenna system  50 . 
         [0056]    Additionally, a first trace of conductive material  51 , such as copper or aluminum, is disposed on a portion of an FPC substrate  53  and at least partly overlaps region  54 , such that first trace  51  capacitively couples to first region of transparent conductive material  54 . A second trace of conductive material  55 , such as copper or aluminum, is also disposed on FPC substrate  53  and couples to first trace  51 . Preferably, first trace  51  and second trace  55  are physically connected. In addition, traces  51  and  55  may couple to a portion of a touch sensor line  57 . Thus, traces  51 ,  55  and line  57  may become part of the feeding mechanism of the antenna element defined by region  54 . 
         [0057]    In regards to the configuration shown in  FIG. 5A , trace  51  is defined by a rectangle of approximately 1 mm in width and 10 mm in length. Likewise, trace  55  and line  57  each has a width of approximately 0.5 mm. Also, gap  58  consists of a 1-mm constant spacing between region  54  and region  56 . Unlike region  54 , region  56  is not functionally required for operation of touchscreen antenna system  50 . However, the absence of region  56  may make region  54  more noticeable to the human eye, because the conductive material forming regions  54 ,  56  is typically not fully transparent. Thus, preferably, region  56  remains installed to provide a more uniform look of touchscreen antenna system  50 . 
         [0058]    Typically, gap  58  is defined by a single value ranging from 0.1 mm to 2 mm. In addition, region  54  may be defined by the shape of an edge  59  of region  54 , which is contiguous to gap  58 . The shape of edge  59  approximately follows a Gaussian curve, wherein the maximum value and standard deviation will depend on the specific application as well-known to those skilled in the art. 
         [0059]    Furthermore, the portion of FPC substrate  53 , shown in  FIG. 5A , is defined by a rectangle of approximately 3 mm in width and 10 mm in length, including the area of region  51  disposed on FPC substrate  53 . It should be understood that the width of FPC substrate  53  is generally longer than as shown, because it folds underneath substrate  52  to couple to other components of touchscreen antenna system  50 . Preferably, regions  54  and  56  are planar and made of a film of a material such as ITO. However, regions  54  and  56  may also be implemented by means of another conductive material, including a copper mesh and silver nanowires arranged in a linear or a grid pattern to maintain a required optical transparency. 
         [0060]    Those skilled in the art will recognize that the dimensions and shape of gap  58 , including a variable spacing; traces  51 ,  55 ; regions  54 ,  56 ; and line  57  may be selected or modified to potentially adjust certain performance parameters of touchscreen antenna system  50 , including input impedance, gain, polarization, and antenna efficiency. More specifically,  FIG. 5B  shows a top view of a touchscreen antenna system  50 , as described in reference to  FIG. 5A , wherein touch sensor line  57  is coupled to a number of traces  57   a ,  57   b , and  57   c . Traces  57   a ,  57   b ,  57   c  may act as a frequency tuning stub, allowing the input impedance of touchscreen antenna system  50  to be adjusted within a range of values to improve the overall antenna performance. In this configuration, traces  57   a ,  57   b ,  57   c  have a width of 0.5 mm and a varying length ranging from 0.5 mm to 1.5 mm. Thus, traces  57   a ,  57   b ,  57   c  of line  57  become part of the feeding mechanism of the antenna element defined by region  54 . 
         [0061]    The method of designing a touchscreen antenna system in accordance with certain aspects of an embodiment of the invention defines dimensional and operational parameters of one or more antenna elements and other potential components which may be part of the touchscreen antenna system. These components include electronic components, such as RF filtering elements, electrodes, sensors, controllers, display units, integrated circuits, flexible printed circuits, transmission lines, diodes, switches, resistors, capacitors, and inductors, as well as dielectric magnetic materials, frequency selective surfaces materials to enhance or reduce electromagnetic coupling of such antenna element, and shielding materials, necessary to provide an operational performance of said touchscreen antenna system in a complex surrounding environment for an intended application, as shown in  FIG. 6 , and according to the following:
       1. At step  610 , determining a location of a main antenna structure either on an existing substrate layer of a touchscreen module or on an additional substrate layer to be incorporated into the touchscreen module.   2. Next, at step  620 , determining a feeding mechanism to feed the main antenna structure either from the same substrate layer wherein the main antenna structure will be disposed on or from a different substrate layer.   3. Next, at step  630 , identifying key operational conditions in which the performance of the main antenna structure might be affected. These key operational conditions may include, but are not limited to, the presence of any combination of human user body parts (e.g. hands, fingers, head or other parts of the body as when such device is placed in a pocket or hung on clothing), conductive materials, or dielectric materials located within a radius of two wavelengths at the lowest frequency of operation in the medium where said antenna element is operating.   4. Next, at step  640 , creating an electromagnetic model, for each key operational condition identified in step  630 , to characterize and improve the antenna system performance after completing one or more of the following:
           4.1 Designing one or more main antenna elements, wherein each main antenna element is formed by a first section, comprising a portion of a touch sensor; a second section, comprising a complementary antenna portion, either physically or electromagnetically coupled to the first section; and a third section, comprising an antenna feeding mechanism, either physically or electromagnetically coupled to the second section.   4.2 Designing one or more main antenna elements, wherein each main antenna element is formed by a first section, comprising a primary antenna portion disposed on an area adjacent to a touch sensor; a second section, comprising a complementary antenna portion, either physically or electromagnetically coupled to the first section; and a third section comprising an antenna feeding mechanism, either physically or electromagnetically coupled to the second section.   4.3 Improving key performance parameters, including gain, radiation efficiency, polarization, and input impedance, of one or more main antenna elements, based on a statistical distribution of theoretical and or experimental data corresponding to different operational conditions.   4.4 Designing a touchscreen antenna system, comprising one or more main antenna elements; touch sensors either physically or electromagnetically coupled to one or more main antenna elements; integrated circuits; and other conductive and dielectric materials forming part of the touchscreen module, operating in combination with such touchscreen module.   
           5. Next, at step  650 , evaluating the operation of the touchscreen antenna system, according to performance or other criteria, requirements, and each key operational condition identified in step  630 .   6. Next, at step  660 , repeating steps  610  to  650 , if necessary, for other configurations of the touchscreen antenna system.   7. Last, at step  670 , selecting the most suitable configuration of the touchscreen antenna system (dimensional and operational parameters of each antenna element and other components of the antenna system) for the intended application, in terms of performance or other predetermined criteria.       
 
         [0073]    Those skilled in the art will recognize that the steps above indicated can be correspondingly adjusted for specific antenna configurations and other constraints such as antenna system and touchscreen sensors dimensions; conformality; type, number, and location of touch sensors and associated electrodes; obtrusiveness; operating frequency; 
         [0074]    bandwidth; operational conditions; and surrounding environment as well as available area and location for implementation of the antenna system for each particular application. In particular, a variety of touch sensors, such as capacitive, resistive, acoustic, and force sensors, may be used as one of the touchscreen elements. 
         [0075]    Preferably, the determination of the dimensional and operational parameters of the antenna element and other components of the touchscreen antenna system, the creation of electromagnetic models, and the evaluation and improvement of key performance parameters of the touchscreen antenna system, including but not limited to electromagnetic fields, radiation efficiency, currents, radiation gain patterns, input impedance, and polarization are performed by means of a computer-assisted simulation tool and electromagnetic simulation software, such as Ansys-HFSS commercial software or other methods well-known by those skilled in the art. 
         [0076]    The method and various embodiments have been described herein in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Any embodiment herein disclosed may include one or more aspects of the other embodiments. The exemplary embodiments were described to explain some of the principles of the present invention so that others skilled in the art may practice the invention. Obviously, many modifications and variations of the invention are possible in light of the above teachings. The present invention may be practiced otherwise than as specifically described within the scope of the appended claims and their legal equivalents.