Patent Publication Number: US-2023155279-A1

Title: Antenna stack structure

Description:
CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM OF PRIORITY 
     This application is a continuation application to International Application No. PCT/KR2021/009409 with an International Filing Date of Jul. 21, 2021, which claims the benefit of Korean Patent Application No. 10-2020-0092535 filed on Jul. 24, 2020 at the Korean Intellectual Property Office (KIPO), the entire disclosures of which are incorporated by reference herein. 
    
    
     BACKGROUND 
     1. Field 
     The present invention relates to an antenna stack structure. More particularly, the present invention relates to an antenna stack structure including an antenna layer and a ground layer. 
     2. Description of the Related Art 
     As mobile communication technologies have been developed, an antenna for implementing a communication of high frequency or ultra-high frequency band is applied to a display device such as a smartphone, various objects or structures such as a vehicle, an architecture, etc. 
     An optical structure such as a polarizing plate and various sensor structures may be included in the display device. Accordingly, when the antenna is included in the display device, proper arrangement and construction of the antenna to avoid an interference between the optical structure and the sensor structure is needed. 
     Additionally, a space to which the antenna can be applied may be limited by the optical structure and the sensor structure. If an additional film or structure is formed for inserting the antenna, an overall thickness and volume of the display device may be increased. 
     Thus, an antenna construction to obtain sufficient radiation and gain properties of the antenna in a limited space is required. 
     For example, Korean Published Patent Application No. 10-2013-0113222 discloses an antenna structure embedded in a portable terminal, but does not sufficiently disclose an antenna design in consideration of both optical and radiation properties in the display device as described above. 
     SUMMARY 
     According to an aspect of the present invention, there is provided an antenna stack structure having improved radiation property. 
     (1) An antenna stack structure, including: an antenna substrate layer; an antenna unit disposed on a top surface of the antenna substrate layer, the antenna unit including a radiator and an antenna pad; and a display panel including a grounding element disposed on a bottom surface of the antenna substrate layer, wherein the antenna pad is superimposed over the grounding element in a planar view. 
     (2) The antenna stack structure of the above (1), wherein the display panel has a display area and a non-display area, and the grounding element is disposed in the non-display area. 
     (3) The antenna stack structure of the above (2), wherein the display panel includes a TFT electrode and a display device disposed in the display area. 
     (4) The antenna stack structure of the above (3), wherein the TFT electrode of the display panel includes an extension portion extending to the non-display area, and the extension portion of the TFT electrode serves as the grounding element. 
     (5) The antenna stack structure of the above (3), wherein the display panel further includes a bus bar connected to the TFT electrode and disposed in the non-display area, and the bus bar serves as the grounding element. 
     (6) The antenna stack structure of the above (3), wherein the display panel includes a grounding structure formed at the same layer as that of the display device in the non-display area, and the grounding structure serves as the grounding element. 
     (7) The antenna stack structure of the above (3), wherein the display device serves as a ground of the antenna unit. 
     (8) The antenna stack structure of the above (1), wherein the antenna substrate layer includes glass or an optical film. 
     (9) The antenna stack structure of the above (8), wherein the optical film includes a polarizing plate. 
     (10) The antenna stack structure of the above (1), further including a cover window disposed on a top surface of the antenna unit. 
     (11) The antenna stack structure of the above (10), further including a polarizing plate interposed between the cover window and the antenna unit. 
     (12) The antenna stack structure of the above (1), further including a touch sensing structure disposed on a top surface of the display panel. 
     (13) The antenna stack structure of the above (1), wherein the antenna pad includes a signal pad connected to the radiator and a ground pad formed around the signal pad. 
     (14) The antenna stack structure of the above (1), wherein the radiator has a mesh structure. 
     (15) The antenna stack structure of the above (14), wherein the antenna unit further includes a dummy mesh pattern arranged around the radiator. 
     An antenna stack structure according to embodiments of the present invention may include a display panel including a grounding element overlapping an antenna pad in a planar view. The antenna pad may be utilized for matching a resonance frequency and optimizing an impedance so that gain and radiation properties of an antenna may be improved. 
     In some embodiments, an electrode layer of the display panel may serve as a radiation ground, and the antenna stack structure integrated with the display panel may be provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic top planar view illustrating an antenna stack structure in accordance with exemplary embodiments. 
         FIG.  2    is a schematic cross-sectional view illustrating an antenna stack structure in accordance with exemplary embodiments. 
         FIG.  3    is a schematic cross-sectional view illustrating an antenna stack structure in accordance with exemplary embodiments. 
         FIG.  4    is a schematic cross-sectional view illustrating a display panel in accordance with exemplary embodiments. 
         FIG.  5    is a schematic top planar view illustrating an antenna stack structure in accordance with exemplary embodiments. 
         FIG.  6    is a schematic cross-sectional view illustrating an antenna stack structure in accordance with exemplary embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     According to exemplary embodiments of the present invention, there is provided an antenna stack structure in which a pad of an antenna unit and a grounding element of a display panel may overlap each other in a planar view. 
     The antenna stack structure may include, e.g., a microstrip patch antenna fabricated in the form of a transparent film. The antenna stack structure may be applied to communication devices for a mobile communication of a high or ultrahigh frequency band corresponding to a mobile communication of, e.g., 3G, 4G, 5G or more, Wi-fi, Bluetooth, NFC, GPS, etc. 
     Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, those skilled in the art will appreciate that such embodiments described with reference to the accompanying drawings are provided to further understand the spirit of the present invention and do not limit subject matters to be protected as disclosed in the detailed description and appended claims. 
       FIG.  1    is a schematic top planar view illustrating an antenna stack structure in accordance with exemplary embodiments.  FIG.  2    is a schematic cross-sectional view illustrating an antenna stack structure in accordance with exemplary embodiments.  FIG.  2    illustrates only one antenna unit, but a plurality of the antenna units may be arranged on an antenna substrate layer  110  in an array form. 
     Referring to  FIGS.  1  and  2   , an antenna stack structure  10  may include the antenna substrate layer  110 , an antenna unit  120  and a display panel  200 . 
     The antenna substrate layer  110  may be disposed between the antenna unit  120  and the display panel  200  to serve as a dielectric layer of an antenna. 
     The antenna substrate layer  110  may include, e.g., a transparent resin material. For example, the antenna substrate layer  110  may include a polyester-based resin such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate and polybutylene terephthalate; a cellulose-based resin such as diacetyl cellulose and triacetyl cellulose; a polycarbonate-based resin; an acrylic resin such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; a styrene-based resin such as polystyrene and an acrylonitrile-styrene copolymer; a polyolefin-based resin such as polyethylene, polypropylene, a cycloolefin or polyolefin having a norbornene structure and an ethylene-propylene copolymer; a vinyl chloride-based resin; an amide-based resin such as nylon and an aromatic polyamide; an imide-based resin; a polyethersulfone-based resin; a sulfone-based resin; a polyether ether ketone-based resin; a polyphenylene sulfide resin; a vinyl alcohol-based resin; a vinylidene chloride-based resin; a vinyl butyral-based resin; an allylate-based resin; a polyoxymethylene-based resin; an epoxy-based resin; a urethane or acrylic urethane-based resin; a silicone-based resin, etc. These may be used alone or in a combination of two or more thereof. 
     In some embodiments, an adhesive film such as an optically clear adhesive (OCA) or an optically clear resin (OCR) may be included in the antenna substrate layer  110 . 
     In some embodiments, the antenna substrate layer  110  may include an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, glass, or the like. 
     In an embodiment, the antenna substrate layer  110  may be provided as a substantially single layer. In an embodiment, the antenna substrate layer  110  may include a multi-layered structure of at least two layers. 
     A capacitance or an inductance may be formed between the antenna unit  120 , and a grounding element included in the display panel  200 , so that a frequency band at which the antenna stack structure  10  may be operated may be adjusted. 
     In some embodiments, a dielectric constant of the antenna substrate layer  110  may be adjusted in a range from about 1.5 to about 12. When the dielectric constant exceeds about 12, a driving frequency may be excessively decreased, so that driving in a desired high or ultra-high frequency band may not be implemented. For example, if the antenna substrate layer  110  includes glass, the antenna substrate layer  110  may have a dielectric constant from 3.5 to 8. 
     A cover window  150  may be disposed on the antenna unit  120 . The cover window  150  may be disposed on an opposite side from the antenna substrate layer  110 . The cover window  150  may be disposed on a viewing surface or an outermost surface of the antenna stack structure  10 . 
     The cover window  150  may include, e.g., glass or a flexible resin material such as polyimide, polyethylene terephthalate (PET), an acrylic resin, a siloxane-based resin, etc. 
     In some embodiments, a thickness of the cover window  150  may be from about 10 μm to 1,000 μm. Preferably, the thickness of the cover window  150  may be from about 300 μm to 700 μm if the cover window is formed of a flexible resin material, and may be from 10 μm to 100 μm if the cover window is formed of a thin glass. 
     In some embodiments, an upper surface of the antenna unit  120  may directly contact the cover window  150 . 
     In some embodiments, an insulating layer  130  may be disposed on the antenna unit  120 . The insulating layer  130  may cover an upper surface of the antenna unit  120 . The insulating layer  130  may passivate and planarize the upper surface of the antenna unit  120 , and may serve as a supporting layer for a polarizing layer  140  and the cover window  150 . 
     In exemplary embodiments, the insulating layer  130  may include at least one of an organic insulating layer and an inorganic insulating layer. 
     The organic insulating layer may include polyacrylate, polymethacrylate (e.g., PMMA), polyimide, polyamide, polyvinyl alcohol, polyamic acid, polyolefin (e.g., PE, PP), polystyrene, polynorbomene, phenylmaleimide copolymer, polyazobenzene, polyphenylenephthalamide, polyester (e.g., PET, PBT), polyarylate, a cinnamate-based polymer, a coumarin-based polymer, a phthalimidine-based polymer, a chalcone-based polymer, an aromatic acetylene-based polymer, etc. These may be used alone or in a combination thereof. 
     For example, the organic insulating layer may be formed by coating and drying a composition including the above-mentioned polymer material. A thickness of the organic insulating layer may be from about 1 μm to 5 μm, preferably from about 1.5 μm to 2.5 μm. 
     The inorganic insulating layer may include a single layer or a multi-layered structure, and may be formed of a metal oxide or a metal nitride. For example, the inorganic insulating layer may include at least one of SiN x , SiON, Al 2 O 3 , SiO 2  and TiO 2 . 
     For example, the inorganic insulating layer may be formed as a SiON layer or a SiO 2  layer, or a bilayer of SiON and SiO 2  layers. 
     For example, the inorganic insulating layer may be formed by a deposition process such as chemical vapor deposition (CVD) process. The inorganic insulating layer may have a thickness from about 100 nm to 1,000 nm, preferably about 200 nm to 400 nm. 
     In exemplary embodiments, the insulating layer  130  may further include an adhesive layer. The adhesive layer may include a pressure-sensitive adhesive (PSA), an optically clear adhesive (OCA) or an optically clear resin (OCR) including an acrylic resin, a silicone-based resin, an epoxy-based resin, etc. For example, the organic/inorganic insulating layer may be bonded to the polarizing layer  140  or the cover window  150  through the adhesive layer. 
     In exemplary embodiments, a thickness of the adhesive layer may be from about 25 to 300 μm. 
     In exemplary embodiments, the polarizing layer  140  may be disposed on the upper surface of the antenna unit  120 . For example, the polarizing layer  140  may be disposed between the insulating layer  130  and the cover window  150 . The polarizing layer  140  may be bonded to the insulating layer  130  by the adhesive layer. An additional adhesive layer may be formed on the polarizing layer  140 . In this case, the polarizing layer  140  and the cover window  150  may be bonded to each other by the additional adhesive layer. 
     The polarizing layer  140  may include a coating-type polarizer or a polarizing plate. The coating-type polarizer may include a liquid crystal coating layer including a polymerizable liquid crystal compound and a dichroic dye. In this case, the polarizing layer may further include an alignment layer for providing an orientation to the liquid crystal coating layer. 
     For example, the polarizing layer  140  may include a polyvinyl alcohol-based polarizer and a protective film attached to at least one surface of the polyvinyl alcohol-based polarizer. 
     For example, the protective film may include a polymer film such as COP-based, TAC-based, acryl-based or PET-based film. 
       FIG.  3    is a schematic cross-sectional view illustrating an antenna stack structure in accordance with exemplary embodiments. Detailed descriptions on elements and structure substantially the same as or similar to those described with reference to  FIG.  2    may be omitted. 
     Referring to  FIG.  3   , the antenna substrate layer  110  of an antenna stack structure  11  may include an optical film. 
     In some embodiments, the optical film may include a polarizing plate  111 . For example, the optical film may include a laminate of a polarizer  112  and polarizer protective films  114  and  115  formed on at least one surface of the polarizer  112 . The polarizer  112  and the polarizer protective films  114  and  115  may be bonded by, e.g., an adhesive layer. 
     In exemplary embodiments, when the optical film includes the polarizing plate, the polarizing layer  140  may not be interposed between the antenna unit  120  and the cover 
     In an embodiment, a blackened layer may be formed on a viewing side of the antenna unit  120 . In this case, visual recognition of an electrode may be prevented by the blackened layer. 
     In exemplary embodiments, a thickness of the antenna substrate layer  110  may be from 5 μm to 600 μm. If the antenna substrate layer  110  includes the polarizer  112 , a thickness of the polarizer  112  may be from 50 μm to 200 μm. In this case, gain and efficiency of the antenna may be increased. 
     The antenna unit  120  may be disposed on one surface (e.g., a top surface) of the antenna substrate layer  110 . For example, the antenna unit  120  may be directly formed on the top surface of the antenna substrate layer  110 . 
     The antenna unit  120  may include a radiator  122 , a transmission line  124  and/or an antenna pad. 
     For example, the antenna unit  120  may include silver (Ag), gold (Au), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), chromium (Cr), titanium (Ti), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), tin (Sn), molybdenum (Mo), calcium (Ca) or an alloy containing at least one of the metals. These may be used alone or in combination thereof. 
     For example, the antenna unit  120  may include silver (Ag) or a silver alloy (e.g., silver-palladium-copper (APC)), or copper (Cu) or a copper alloy (e.g., a copper-calcium (CuCa)) to implement a low resistance and a fine line width pattern. 
     In some embodiments, the antenna unit  120  may include a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnOx), zinc oxide (ZnOx), indium zinc tin oxide (IZTO), etc. 
     In some embodiments, the antenna unit  120  may include a stacked structure of a transparent conductive oxide layer and a metal layer. For example, the antenna unit  120  may include a double-layered structure of a transparent conductive oxide layer-metal layer, or a triple-layered structure of a transparent conductive oxide layer-metal layer-transparent conductive oxide layer. In this case, flexible property may be improved by the metal layer, and a signal transmission speed may also be improved by a low resistance of the metal layer. Corrosive resistance and transparency may be improved by the transparent conductive oxide layer. 
     In some embodiments, a thickness of the antenna unit  120  may be about 5,000 Å or less, preferably from about 1,000 Å to 5,000 Å. Within this range, a color shift phenomenon from a viewing surface of the antenna stack structure may be suppressed while preventing an increase in resistance of the antenna unit  120 . 
     The radiator  122  may have, e.g., a polygonal plate shape, and the transmission line  124  may extend from one side of the radiator  122  to be electrically connected to the signal pad  126 . The transmission line  124  may be formed as a single member substantially integral with the radiator  122 . 
     In some embodiments, the antenna pad may include a signal pad  126  and may further include a ground pad  128 . For example, a pair of the ground pads  128  may be disposed with the signal pad  126  interposed therebetween. The ground pads  128  may be electrically separated from the signal pad  126  and the transmission line  124 . 
     In an embodiment, the ground pad  128  may be omitted. The signal pad  126  may be formed as an integral member at an end portion of the transmission line  124 . 
     In some embodiments, an end portion of the antenna unit  120  may be electrically connected to a circuit connection structure. The circuit connection structure may include, e.g., a flexible printed circuit board (FPCB). 
     The antenna pad may be electrically connected to an antenna driving integrated circuit (IC) chip through the circuit connection structure such as the flexible printed circuit board. Accordingly, a feeding and a driving control to the antenna unit may be performed by the antenna driving IC chip. 
     The driving IC chip may be directly disposed on the flexible circuit board. For example, the flexible circuit board (FPCB) may further include a circuit or a contact electrically connecting the driving IC chip and the antenna unit. The flexible circuit board (FPCB) and the driving IC chip may be disposed to be adjacent to each other, so that a signal transmission/reception path may be shortened and a signal loss may be suppressed. 
     In an embodiment, the antenna unit  120  may be formed as a mesh structure. For example, the antenna unit  120  may be directly formed on the top surface of the antenna substrate layer  110  by a sputtering process. 
     In exemplary embodiments, the radiator  122  may have a mesh structure. In some embodiments, the transmission line  124  connected to the radiator  122  may also have a mesh structure. 
     The radiator  122  may include the mesh structure, so that transmittance may be improved even when the radiator  122  is disposed in a display area of a display device, thereby preventing electrodes from being visually recognized and preventing an image quality from being deteriorated. 
     A dummy mesh pattern may be disposed around the radiator  122  and the transmission line  124 . The dummy mesh pattern may be electrically and physically spaced apart from the radiator  122  and the transmission line  124  by a separation region. 
     For example, a conductive layer including the above-described metal or alloy may be formed on the antenna substrate layer  110 . The conductive layer may be partially etched along a profile of the radiator  122  and the transmission line  124  to form a separation region while forming the mesh structure. Accordingly, the antenna unit  120  and the dummy mesh pattern isolated by the separation region may be formed on the antenna substrate layer  110 . 
     In some embodiments, the signal pad  126  may be formed as a solid structure to reduce a feeding resistance. For example, the signal pad  126  may be disposed in a non-display area or a light-shielding area of the display device to be bonded or connected to a flexible circuit board and/or an antenna driving IC chip. 
     Accordingly, the signal pad  126  may be disposed at an outside of a user&#39;s viewing area or a display area DA. In an embodiment, the signal pad  126  may substantially consist of a metal or alloy. 
     The display panel  200  may be formed on an opposite surface with respect to the antenna unit  120  of the antenna substrate layer  110  (e.g., a bottom surface of the antenna substrate layer  110 ). 
     The display panel  200  may include a liquid crystal display device, an organic LED display device, an inorganic LED display device, a plasma display device, etc., and may be preferably a self-luminous display device such as the organic LED display device or the inorganic LED display device. 
       FIG.  4    is a schematic cross-sectional view illustrating a display panel in accordance with exemplary embodiments. 
     Referring to  FIG.  4   , the display panel  200  may include a panel substrate  205 , a display device and an encapsulation layer  250  covering the display device. The display device may include an electrode layer, a pixel defining layer  220  and a display layer  230 . The electrode layer may include a pixel electrode  210  and an opposing electrode  240 . 
     The display device and the encapsulation layer  250  may be sequentially formed on the panel substrate  205 . 
     A pixel circuit including a thin film transistor (TFT) electrode  270  may be formed on the panel substrate  205 , and an insulating layer covering the pixel circuit may be formed. The pixel electrode  210  may be electrically connected to, e.g., a drain electrode of the TFT on the insulating layer. 
     The pixel defining layer  220  may be formed on the insulating layer to expose the pixel electrode  210  to define a pixel area. The display layer  230  may be formed on the pixel electrode  210 , and the display layer  230  may include, e.g., a liquid crystal layer or an organic light emitting layer. Preferably, the display layer  230  may include the organic light emitting layer, and the display panel  200  may be an OLED panel. 
     The opposing electrode  240  may be disposed on the pixel defining layer  220  and the display layer  230 . The opposing electrode  240  may serve as, e.g., a common electrode or a cathode of the display panel  200 . The encapsulation layer  250  for protecting the display panel  200  may be stacked on the opposing electrode  240 . 
     In exemplary embodiments, a display device  260  of the display panel  200  may overlap the radiator  122  of the antenna unit  120  in a thickness direction of the antenna stack structure  10 . In this case, the opposing electrode  240  may serve as a ground of the radiator  122 . 
     In exemplary embodiments, the encapsulation layer  250  may serve as the antenna substrate layer  110 . In this case, the display panel  200  and the antenna stack structure  10  may be integrated to provide a thin film structure. 
     The display panel  200  may include a grounding element overlapping the antenna pad of the antenna unit  120  in a planar view of the antenna stack structure  10 . 
     The grounding element may be coupled to the antenna pad to form an inductance or a capacitance. Thus, a resonance frequency and an impedance of the antenna may be adjusted by using the antenna pad. Accordingly, gain and radiation property of the antenna may be improved. 
     The display panel  200  may include a display area DA in which an image is displayed and a non-display area NDA around the display area DA. For example, a display device  260  and the TFT electrode  270  may be disposed in the display area DA. The grounding element may be formed in the non-display area NDA. 
     Referring to  FIGS.  2  and  3   , the grounding element may include the TFT electrode  270 . 
     In exemplary embodiments, the TFT electrode  270  may extend beyond the display area DA to the non-display area NDA. In this case, a portion located in the display area DA may be defined as a display portion  272 , and a portion extending to the non-display area NDA may be defined as an extension portion  274 . 
     Accordingly, as illustrated in  FIG.  1   , the antenna pad  126  and  128  may be superimposed over the extension portion  274  in a planar view, and the extension portion  274  may serve as the grounding element. 
     In exemplary embodiments, the extension portion  274  may include a conductive wiring of the TFT electrode  270 , a trace connected to the TFT electrode  270  or a bus bar (not illustrated) connected to the TFT electrode  270 . 
     For example, the TFT electrode  270 , the trace and the bus bar may be formed of a low-resistance metal, without, e.g., considering transparency, such as silver (Ag), gold (Au), copper (Cu), Aluminum (Al), platinum (Pt), palladium (Pd), chromium (Cr), titanium (Ti), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), iron (Fe), Manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), tin (Sn), molybdenum (Mo), calcium (Ca) or an alloy containing at least one of the metals. Preferably, the low-resistance metal may include copper, aluminum, a silver-palladium-copper alloy or a copper-calcium alloy. In this case, the frequency and impedance of the antenna may be effectively adjusted and matched. 
       FIG.  5    is a schematic top planar view illustrating an antenna stack structure in accordance with exemplary embodiments.  FIG.  6    is a schematic cross-sectional view illustrating an antenna stack structure in accordance with exemplary embodiments. Detailed descriptions on elements and structure substantially the same as or similar to those described with reference to  FIGS.  1  to  4    may be omitted. 
     Referring to  FIGS.  5  and  6   , a display panel  201  of an antenna stack structure  20  may include a grounding structure  280 . The grounding structure  280  may be formed at the same layer or at the same level as that of the display device  260 . 
     In exemplary embodiments, the grounding structure  280  may be formed in the non-display area NDA. Accordingly, the antenna pad  126  and  128  of the antenna unit  120  disposed in the non-display area NDA may be superimposed over the grounding structure. In this case, the grounding structure  280  may be coupled to the antenna pad  126  and  128  as the grounding element, and the frequency and impedance of the antenna may be effectively adjusted. 
     For example, the grounding structure  280  may include the same material as that mentioned above in the TFT electrode  270  as an example, and may be formed in a rod or plate shape. In some embodiments, the grounding structure  280  may include a mesh structure or a solid structure. 
     In some embodiments, the grounding structure  280  may be formed of the same material as that of the TFT electrode  270 , and the extension portion  274  of the TFT electrode  270 , the grounding structure  280  and the antenna pad of the antenna unit  120  may be sequentially stacked to overlap each other. In this case, the extension portion  274  of the TFT electrode  270 , the grounding structure  280  and the antenna unit  120  may be coupled together to improve the gain of the antenna. 
     In exemplary embodiments, the grounding structure  280  may be electrically connected to the ground pad  128  of the antenna unit  120 . For example, the grounding structure  280  and the ground pad  128  of the antenna unit  120  may be connected through a via or a contact penetrating the antenna substrate layer  110 . In some embodiments, the grounding structure  280  may be electrically connected to the ground pad  128  of the antenna unit  120  through a ground wiring bypassing a lateral side of the antenna substrate layer  110 . In this case, the gain of the antenna may be improved. 
     In exemplary embodiments, the grounding structure  280  may be disposed on an opposite surface (e.g., the bottom surface) with respect of the antenna unit  120  of the antenna substrate layer  110 . For example, the grounding structure  280  may be disposed under the antenna pads  126  and  128 . In this case, the grounding structure  280  and the display device  260  may be electrically and physically separated. 
     In exemplary embodiments, the display device  260  may overlap the radiator  122  of the antenna unit  120  in a thickness direction of the antenna stack structure  10 . In this case, the radiator  122  and the entire antenna pad may be utilized to adjust the resonance frequency and impedance of the antenna. 
     In some embodiments, the display device  260  may be formed only in the display area DA and may not overlap the antenna pad. In an embodiment, the display device  260  may overlap an entire area of the antenna unit  120 . 
     In exemplary embodiments, the antenna stack structure  10  may further include a touch sensing structure. The touch sensing structure may be disposed at any area on an upper surface of the display panel  200 . 
     In some embodiments, the touch sensing structure may be formed at an inside of the antenna unit  120 . For example, the touch sensing structure may be formed at the same layer as that of the antenna unit. 
     In some embodiments, the touch sensing structure may be formed at an inside of the antenna substrate layer  110 . For example, if the antenna substrate layer  110  includes the polarizing plate  111 , the touch sensing structure may be embedded in the polarizer protective films  114  and  115 . 
     The touch sensing structure may include, e.g., capacitive sensing electrodes. For example, column direction sensing electrodes and row direction sensing electrodes may be arranged to cross each other. The touch sensing structure may further include traces connecting the sensing electrodes and the driving IC chip to each other. The touch sensing structure may further include a substrate on which the sensing electrodes and the traces are formed.