antenna

Abstract

A windshield comprising: an outer transparent ply defining an inner surface and an outer surface located opposite to the inner surface; an inner transparent ply defining an outer surface and an inner surface located opposite to the outer surface; an intermediate layer disposed between the inner surface of the outer transparent ply and the inner surface of the inner transparent ply; a circularly polarized antenna disposed on the outer surface of the inner transparent ply; a unidirectional antenna disposed on the inner surface of the outer transparent ply and the outer surface of the inner transparent ply; and a broadband antenna disposed on the outer surface of the inner transparent ply.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority to U.S. Provisional Patent Application No. 63 / 519,071, filed on August 11, 2023, and U.S. Patent Application No. 18 / 798,509, filed on August 8, 2024, the entire disclosures of which are incorporated herein by reference.

Background Art

[0002] Field of the Invention The invention disclosed herein relates to antennas, and more particularly, to high - frequency antennas for automotive glass.

[0003] Description of Related Art Antennas for receiving and / or transmitting high frequencies such as AM, FM, TV, DAB, RKE, etc. are often carried on or incorporated into automotive window glass such as the front windshield and rear window. Such antennas are formed by printing conductive lines such as silver or copper on the transparent portion of the window glass or by laminating metal wires or metal strips between the transparent layers of the vehicle's window glass. The antennas not only provide aerodynamic benefits to the vehicle but also give the vehicle's exterior an aesthetically pleasing streamlined look.

[0004] In recent years, the automotive industry has been developing vehicles that can communicate via radio frequency signals and other communication channels. Such vehicles are sometimes called "connected cars." New vehicle models offer an increasing list of features, including improved safety and the ability to enable dedicated narrow-range radio (DSRC) communication for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication. The automotive industry is currently moving from assisted driving to autonomous driving. Each new vehicle connectivity requires an antenna corresponding to its respective communication channel, whether cellular, WLAN, or DSRC. In some cases, cellular services may require as many as six antennas, and V2V and V2I communication may require another six DSRC antennas. Designing antennas that can fit into the available space in a vehicle presents significant challenges. Integrating antennas into the vehicle's windows offers several benefits, including improved aesthetics, simplified antenna packaging, reduced weight, deterrence against theft and vandalism, and the elimination of holes in the vehicle body that are prone to water ingress and other problems. Therefore, there is a need for an antenna that can operate at high frequencies (e.g., above 1 GHz) and can be mounted on a vehicle without protruding from the exterior or into the interior of the passenger compartment.

[0005] The rapid growth of connected vehicle communications is creating a need to integrate an increasing number of antennas into vehicles. Therefore, there is a need for cellular, DSRC, Wi-Fi, WLAN, and Bluetooth® antennas that can be mounted on the surface of the vehicle but do not extend from the exterior or protrude into the interior passenger compartment. Furthermore, there is a practical requirement that such antennas be integrated into existing vehicle components as standard equipment at minimal cost. It is also important that such antennas maintain the aesthetics or appearance of the vehicle and require only limited modifications to existing window glass structures and manufacturing processes. Additionally, a single antenna with broadband characteristics capable of transmitting and receiving across the entire 5G, Wi-Fi, and DSRC frequency bands in a unidirectional manner is needed to provide maximum reception capability. [Overview of the project]

[0006] The present invention relates to a windshield, which includes an outer transparent ply defining an inner surface and an outer surface located opposite to the inner surface; an inner transparent ply defining an outer surface and an inner surface located opposite to the outer surface; an intermediate layer disposed between the inner surface of the outer transparent ply and the inner surface of the inner transparent ply; a circularly polarized antenna disposed on the outer surface of the inner transparent ply; a unidirectional antenna disposed on the inner surface of the outer transparent ply and the outer surface of the inner transparent ply; and a broadband antenna disposed on the outer surface of the inner transparent ply.

[0007] In some non-limiting embodiments or aspects, a circularly polarized antenna may include: a ground plane having four faces, the inner edges of the four faces of the ground plane defining a slot therein; a cruciform antenna feeding structure defining a first element and a second element, the second element substantially perpendicular to the first element, and the first element extending into a slot in the first face of the ground plane; and a tuning stub extending from the second face of the ground plane, the tuning stub extending substantially perpendicular to the second face toward the antenna feeding structure. The slot and the antenna feeding structure extending within the slot may form a coplanar waveguide. The slot may be a tapered slot, and the slot widens conically toward the inner edge of the first face of the ground plane. The slot may be configured to improve antenna impedance matching.

[0008] In some non-limiting embodiments or aspects, the circularly polarized antenna may include a coaxial cable, the coaxial cable including an outer shield and a central conductor, the coaxial cable connected to a coplanar waveguide, the portion of which of the outer shield is in contact with a first surface of the ground plane, and the central conductor is connected to a first element of the antenna feeding structure. The coplanar waveguide may support a wide impedance bandwidth.

[0009] In some non-limiting embodiments or aspects, a second element of the antenna feeding structure may be configured for broadband antenna impedance tuning. A first element of the antenna feeding structure may be configured to supply energy to a circularly polarized antenna in a first mode. A tuning stub may be configured to excite the circularly polarized antenna and cause it to resonate in a second mode. The first and second modes are orthogonal modes having the same amplitude and orthogonal phase. The circularly polarized antenna may be configured to transmit and receive right-hand circularly polarized signals. The right-hand circularly polarized signals may be GNSS signals. The circularly polarized antenna may have a broad bandwidth, covering the L1, L2, L3, L4, and L5 bands in GNSS from 1000 MHz to 1850 MHz. The ground plane may be rectangular.

[0010] In some non-limiting embodiments or aspects, the windshield may further include a non-conductive glass plate and a film substrate attached to the non-conductive glass plate, the film substrate being positioned between the non-conductive glass plate and the circularly polarized antenna, and the non-conductive glass plate being attached to the outer surface of an inner transparent ply. The windshield may be a window, a black window, a roof window, a non-conductive transparent substrate, or a non-conductive opaque substrate. The ground plane may include at least one opening. The circularly polarized antenna may be configured to receive left-hand circularly polarized signals.

[0011] In some non-limiting embodiments or aspects, the unidirectional antenna comprises a first conductive layer disposed between the inner surfaces of an outer transparent ply and an inner transparent ply, the first conductive layer comprising a plurality of patches, the plurality of patches comprising a first patch, a second patch, and a third patch, the first conductive layer defining the outer periphery, the plurality of patches being spaced apart, parallel to each other and adjacent to each other, and a second conductive layer disposed on the outer surface of the inner transparent ply, the second conductive layer comprising a plurality of slots, the second conductive layer defining the outer periphery, the plurality of slots comprising the first slot and The second conductive layer may include two slots, the length of the second slot being longer than the length of the first slot, the second conductive layer being aligned laterally with respect to the first conductive layer such that the outer periphery of the first conductive layer is aligned with the inner periphery of the second conductive layer and the first slot is aligned with the outer periphery of the first patch, and the first slot of the second conductive layer being spaced apart from the multiple patches of the first conductive layer such that an electrical signal applied around the first slot is electromagnetically coupled to the multiple patches of the first conductive layer, and a transmission line electrically connected to the first slot at a power supply position in the center of the first slot.

[0012] In some non-limiting embodiments or aspects, the second conductive layer may be an electrical grounding element of a unidirectional antenna. The first slot may define a first longitudinal plane and a second longitudinal plane, and the first slot is a drive slot. The second slot may be longer than the first slot and spaced apart from the first slot on the first longitudinal plane of the first slot such that when the signals radiated from the drive slot merge at the feed point, the transmitted signals from the drive slot reflected by the second slot have a phase difference of π. The second slot may be a slot of a reflector element.

[0013] In some non-limiting embodiments or aspects, the outer periphery of the first patch may be aligned laterally with respect to the first longitudinal plane of the first slot and overlap with the second longitudinal plane of the first slot, and the first patch may be positioned on the second longitudinal plane of the first slot. The maximum electromagnetic field in the first slot may be generated at the center of the first slot, and the maximum electric field of the first patch may be generated at the central edge of the first patch. Energy may be electromagnetically coupled between the first slot and the first patch. The first patch may be the first director of a unidirectional antenna.

[0014] In some non-limiting embodiments or aspects, the second and third patches may be adjacent to the first patch on the second longitudinal plane of the first slot, parallel to and equally spaced. The second patch may be the second director of a unidirectional antenna, and the third patch may be the third director of a unidirectional antenna. The first, second, and third directors may be electromagnetically coupled to each other so as to attract the antenna's radiation pattern toward the third director. The first and second slots may be rectangular, L-shaped, or U-shaped. The transmission line may be a coaxial cable having a central conductor surrounded by an outer shield, the outer shield connected to the second longitudinal plane of the first slot, and the central conductor connected to the first longitudinal plane of the first slot. The coaxial cable and the first slot can transmit and receive electromagnetic energy between the second slot of the second conductive layer and the first, second, and third patches of the first conductive layer. The second slot reflects the signal from the first slot and combines with the first, second, and third patches of the first conductive layer to achieve unidirectional radiation from the unidirectional antenna. The bandwidth of the unidirectional antenna can cover Wi-Fi under the IEEE 802.11a / ac standard from 5.18 GHz to 5.85 GHz and the DSRC band from 5.85 to 5.925 GHz.

[0015] In some non-limiting embodiments or aspects, the lengths of the first slot and the first patch may determine the resonant frequency of the unidirectional antenna, and the widths of the first slot and the first patch may affect the resonant resistance of the unidirectional antenna. The transmission line may be a microstrip line etched into a substrate mounted on the outer surface of an inner transparent ply. The unidirectional antenna may be excited through two coupling stages, one coupling stage between the microstrip line and the first slot of the second conductive layer, and the other coupling stage between the first and second slots of the second conductive layer and the first, second, and third patches of the first conductive layer. The microstrip line may be oriented perpendicular to the centerline of the first slot and be bent perpendicularly between the first and second slots so that the microstrip line intersects only the first slot. The unidirectional antenna may be incorporated into a windshield, rear window, or side window to create a diversity antenna system having an omnidirectional far-field radiation pattern in the direction of the ground.

[0016] In some non-limiting embodiments or aspects, the broadband antenna includes a dielectric substrate, a conductive sheet on the dielectric substrate, a first tapered slot radiator comprising a first slot opening formed in the conductive sheet, a first tapered opening formed in the conductive sheet, the first tapered opening being formed between the first slot opening and a first surface of the conductive sheet, the first tapered opening gradually increasing in size from the first slot opening toward the first surface of the conductive sheet, and a first impedance matching opening of the conductive sheet formed in an elliptical shape adjacent to the second end of the first slot opening, and a second tapered slot radiator A second tapered slot radiator may include: a second slot opening having a first end and a second end formed in a conductive sheet; a second tapered opening formed in the conductive sheet, the second tapered opening being formed between the second slot opening and a second surface of the conductive sheet, the second tapered opening gradually increasing in size from the second slot opening toward the second surface of the conductive sheet; and a second impedance matching opening in the conductive sheet, formed in an elliptical shape adjacent to the second end of the second slot opening; and a transmission line electrically connected to the first slot opening and the second slot opening.

[0017] In some non-limiting embodiments or aspects, the first and second slot openings may be spaced apart, parallel to each other, and adjacent to each other. The central portions of the first and second slot openings of the broadband antenna may define the antenna feed point. A transmission line spanning the first and second slot openings may be configured to simultaneously excite a first tapered slot radiator and a second tapered slot radiator. The first tapered slot radiator may have a radiated beam directed toward a first surface of a conductive sheet, and the second tapered slot radiator may have a radiated beam directed toward a second surface of the conductive sheet. The size of the opening of the first tapered slot radiator is larger than the size of the opening of the second tapered slot radiator. The first tapered slot radiator may be tuned for lower frequency bands, and the second tapered slot radiator may be tuned for higher frequency bands. The broadband antenna may be configured to transmit and receive 4G LTE signals and 5G sub-6 signals.

[0018] In some embodiments or aspects, this disclosure may be characterized by one or more of the following numbered clauses:

[0019] Clause 1: A windshield comprising: an outer transparent ply defining an inner surface and an outer surface located opposite to the inner surface; an inner transparent ply defining an outer surface and an inner surface located opposite to the outer surface; an intermediate layer disposed between the inner surface of the outer transparent ply and the inner surface of the inner transparent ply; a circularly polarized antenna disposed on the outer surface of the inner transparent ply; a unidirectional antenna disposed on the inner surface of the outer transparent ply and the outer surface of the inner transparent ply; and a broadband antenna disposed on the outer surface of the inner transparent ply.

[0020] Clause 2. The circularly polarized antenna includes a ground plane having four surfaces, wherein an inner edge of the four surfaces of the ground plane defines a slot therein, the ground plane, and a cross-shaped antenna feeding structure, the antenna feeding structure defines a first element and a second element, the second element is substantially perpendicular to the first element, and the first element extends into the slot on the first surface of the ground plane, the cross-shaped antenna feeding structure, and a tuning stub extending from a second surface of the ground plane, the tuning stub extending substantially perpendicular to the second surface toward the antenna feeding structure, the tuning stub, the front glass according to Clause 1.

[0021] Clause 3: The front glass according to Clause 2, wherein the slot and the antenna feeding structure extending into the slot form a coplanar waveguide.

[0022] Clause 4: The front glass according to any one of Clauses 2 to 3, wherein the slot is a tapered slot, and the slot expands conically toward the inner edge of the first surface of the ground plane.

[0023] Clause 5: The front glass according to any one of Clauses 2 to 4, wherein the slot is configured to improve antenna impedance matching.

[0024] Clause 6: The circularly polarized antenna includes a coaxial cable, the coaxial cable includes an outer shield and a center conductor, the coaxial cable is connected to the coplanar waveguide, a part of the outer shield contacts the first surface of the ground plane, and the center conductor is connected to the first element of the antenna feeding structure, the front glass according to any one of Clauses 2 to 5.

[0025] Clause 7: The front glass according to any one of Clauses 2 to 6, wherein the coplanar waveguide supports a wide impedance bandwidth.

[0026] Clause 8: The second element of the antenna power supply structure is the front glass according to any one of Clauses 2 to 7, which is configured for broadband antenna impedance tuning.

[0027] Clause 9: The first element of the antenna power supply structure is the front glass according to any one of Clauses 2 to 8, which is configured to supply energy to the circularly polarized antenna in the first mode.

[0028] Clause 10: The tuning stub is configured to excite the circularly polarized antenna to resonate in the second mode, and the first mode and the second mode are orthogonal modes having the same amplitude and orthogonal phases. The front glass according to any one of Clauses 2 to 9.

[0029] Clause 11: The circularly polarized antenna is configured to transmit and receive right-handed circularly polarized signals. The front glass according to any one of Clauses 2 to 10.

[0030] Clause 12: The right-handed circularly polarized signal is a GNSS signal. The front glass according to Clause 11.

[0031] Clause 13: The circularly polarized antenna has a wide bandwidth and covers the L1, L2, L3, L4, and L5 bands of 1000 MHz to 1850 MHz in GNSS. The front glass according to any one of Clauses 1 to 12.

[0032] Clause 14: The ground plane is rectangular. The front glass according to any one of Clauses 1 to 13.

[0033] Clause 15: Further includes a non-conductive glass plate and a film substrate attached to the non-conductive glass plate. The film substrate is disposed between the non-conductive glass plate and the circularly polarized antenna, and the non-conductive glass plate is attached to the outer surface of the inner transparent ply. The front glass according to any one of Clauses 1 to 14.

[0034] Clause 16: The windshield is a window, a black window, a roof window, a non-conductive transparent substrate, or a non-conductive opaque substrate, as described in any one of Clauses 1 to 15.

[0035] Clause 17: The windshield as described in any one of Clauses 1 to 16, wherein the ground plane includes at least one opening.

[0036] Clause 18: The windshield as described in any one of Clauses 1 to 17, wherein the circular polarization antenna is configured to receive left-hand circular polarization signals.

[0037] Clause 19: The unidirectional antenna comprises a first conductive layer disposed between the inner surfaces of the outer transparent ply and the inner transparent ply, the first conductive layer comprising a plurality of patches, the plurality of patches comprising a first patch, a second patch, and a third patch, the first conductive layer defining the outer periphery, the plurality of patches being spaced apart, parallel to each other and adjacent to each other, and a second conductive layer disposed on the outer surface of the inner transparent ply, the second conductive layer comprising a plurality of slots, the second conductive layer defining the outer periphery, the plurality of slots comprising a first slot and a second slot, the length of the second slot being the length of the first slot A windshield according to any one of Clauses 1 to 18, comprising: a second conductive layer longer than the length of the first conductive layer, the second conductive layer being aligned laterally with respect to the first conductive layer such that the outer periphery of the first conductive layer is aligned with the inner periphery of the second conductive layer and the first slot is aligned with the outer periphery of the first patch, and the first slot of the second conductive layer being spaced apart from the plurality of patches of the first conductive layer such that an electrical signal applied around the first slot is electromagnetically coupled to the plurality of patches of the first conductive layer; and a transmission line electrically connected to the first slot at a power supply position in the center of the first slot.

[0038] Clause 20: The windshield according to Clause 19, wherein the second conductive layer is the electrical grounding element of the unidirectional antenna.

[0039] Clause 21: The windshield according to any one of Clauses 19 to 20, wherein the first slot defines a first longitudinal surface and a second longitudinal surface, and the first slot is a drive slot.

[0040] Clause 22: The windshield according to Clause 21, wherein the second slot is longer than the first slot and is spaced apart from the first slot in the first longitudinal plane of the first slot such that when the signals radiated from the drive slot merge at the power supply position, the transmitted signals from the drive slot reflected by the second slot have a phase difference of π.

[0041] Clause 23: The windshield as described in any one of Clauses 19 to 22, wherein the second slot is a reflector element slot.

[0042] Clause 24: The windshield according to any one of Clauses 21 to 23, wherein the outer periphery of the first patch is aligned laterally with respect to the first longitudinal surface of the first slot and overlaps with the second longitudinal surface of the first slot, and the first patch is positioned on the second longitudinal surface of the first slot.

[0043] Clause 25: A windshield according to any one of Clauses 19 to 24, wherein the maximum electromagnetic field in the first slot occurs at the center of the first slot, and the maximum electric field in the first patch occurs at the central edge of the first patch.

[0044] Clause 26: A windshield according to any one of Clauses 19 to 25, wherein energy is electromagnetically coupled between the first slot and the first patch.

[0045] Clause 27: The first patch is the windshield described in any one of Clauses 1 to 26, which is the first director of the unidirectional antenna.

[0046] Clause 28: The windshield according to any one of Clauses 21 to 27, wherein the second patch and the third patch are adjacent to the first patch on the second longitudinal surface of the first slot, parallel to and at equal intervals from the first patch.

[0047] Clause 29: The windshield as described in any one of Clauses 19 to 28, wherein the second patch is the second director of the unidirectional antenna, and the third patch is the third director of the unidirectional antenna.

[0048] Clause 30: The windshield according to Clause 29, wherein the first director, the second director, and the third director are electromagnetically coupled to each other such as to attract the radiation pattern of the antenna toward the third director.

[0049] Clause 31: The windshield as described in any one of Clauses 19 to 30, wherein the first slot and the second slot are rectangular, L-shaped, or U-shaped.

[0050] Clause 32: The windshield according to any one of Clauses 21 to 31, wherein the transmission line is a coaxial cable having a central conductor surrounded by an outer shield, the outer shield being connected to the second longitudinal surface of the first slot, and the central conductor being connected to the first longitudinal surface of the first slot.

[0051] Clause 33: The windshield according to Clause 32, wherein the coaxial cable and the first slot transmit and receive electromagnetic energy between the second slot of the second conductive layer and the first patch, second patch, and third patch of the first conductive layer.

[0052] Clause 34: The windshield according to any one of Clauses 19 to 33, wherein the second slot reflects the signal from the first slot and combines with the first, second, and third patches of the first conductive layer to enable unidirectional radiation to the unidirectional antenna.

[0053] Clause 35: The bandwidth of the unidirectional antenna is the same as that of any one of Clauses 1 to 34, covering the 5.18 GHz to 5.85 GHz Wi-Fi under the IEEE 802.11a / ac standard and the 5.85 to 5.925 GHz DSRC band, as specified in any one of Clauses 1 to 34.

[0054] Clause 36: The windshield according to any one of Clauses 19 to 35, wherein the length of the first slot and the first patch determines the resonant frequency of the unidirectional antenna, and the width of the first slot and the first patch affects the resonant resistance of the unidirectional antenna.

[0055] Clause 37: The windshield according to any one of Clauses 19 to 36, wherein the transmission line is a microstrip line etched onto a substrate attached to the outer surface of the inner transparent ply.

[0056] Clause 38: The windshield according to any one of Clauses 19 to 37, wherein the unidirectional antenna is excited through two coupling stages, one coupling stage located between the microstrip line and the first slot of the second conductive layer, and the other coupling stage located between the first and second slots of the second conductive layer and the first patch, second patch, and third patch of the first conductive layer.

[0057] Clause 39: The windshield according to any one of Clauses 19 to 38, wherein the microstrip line is oriented perpendicular to the center line of the first slot and is bent perpendicularly between the first slot and the second slot such that the microstrip line intersects only the first slot.

[0058] Clause 40: The windshield described in any one of Clauses 1 to 39, which is incorporated into the windshield, rear window, or side window to create a diversity antenna system having an omnidirectional far-field radiation pattern in the direction of the ground.

[0059] Clause 41: The broadband antenna includes a dielectric substrate, a conductive sheet on the dielectric substrate, a first tapered slot radiator comprising a first slot opening formed in the conductive sheet having a first end and a second end, a first tapered opening formed in the conductive sheet, the first tapered opening being formed between the first end and the first surface of the first slot opening of the conductive sheet, the first tapered opening gradually increasing from the first end toward the first surface of the first slot opening of the conductive sheet, and a first impedance matching opening of the conductive sheet formed in an elliptical shape adjacent to the second end of the first slot opening, and a second tapered slot radiator. A windshield according to any one of claims 1 to 40, comprising: a second slot opening having a first end and a second end formed in the conductive sheet; a second tapered opening formed in the conductive sheet, the second tapered opening being formed between the first end and the second surface of the second slot opening of the conductive sheet, the second tapered opening gradually increasing in size from the first end toward the second surface of the second slot opening of the conductive sheet; and a second impedance matching opening in the conductive sheet, formed in an elliptical shape adjacent to the second end of the second slot opening; and a transmission line electrically connected to the first slot opening and the second slot opening.

[0060] Clause 42: The windshield according to Clause 41, wherein the first slot opening and the second slot opening are spaced apart, parallel to each other, and adjacent to each other.

[0061] Clause 43: A windshield according to any one of Clauses 41 to 42, wherein the central portions of the first and second slot openings of the broadband antenna define the antenna feed point.

[0062] Clause 44: The windshield according to any one of Clauses 41 to 43, wherein the transmission line spanning the first slot opening and the second slot opening is configured to simultaneously excite the first tapered slot radiator and the second tapered slot radiator.

[0063] Clause 45: The windshield according to any one of Clauses 41 to 44, wherein the first tapered slot radiator has a radiation beam directed toward the first surface of the conductive sheet, and the second tapered slot radiator has a radiation beam directed toward the second surface of the conductive sheet.

[0064] Clause 46: A windshield according to any one of Clauses 41 to 45, wherein the size of the opening of the first tapered slot radiator is larger than the size of the opening of the second tapered slot radiator.

[0065] Clause 47: The windshield as described in any one of Clauses 41 to 46, wherein the first tapered slot radiator is tuned for a lower frequency band, and the second tapered slot radiator is tuned for a higher frequency band.

[0066] Clause 48: The windshield as described in any one of Clauses 1 to 47, wherein the broadband antenna is configured to transmit and receive 4G LTE signals and 5G sub-6 signals. [Brief explanation of the drawing]

[0067] [Figure 1] This is a perspective view of a vehicle having at least one antenna according to one non-limiting aspect of the present invention formed on the windshield, rear window, and roof glass. [Figure 2] This is a top view of the windshield of the vehicle shown in Figure 1, which has at least one antenna according to a non-limiting aspect of the present invention. [Figure 3] This is a partial cross-sectional view of a circularly polarized antenna along line 2-2 on the windshield of Figure 1, according to a non-limiting aspect of the present invention. [Figure 4] This is a partial cross-sectional view of a circularly polarized antenna along line 2-2 on the windshield of Figure 1, according to a non-limiting aspect of the present invention. [Figure 5a] This is a top view of a circularly polarized antenna according to a non-limiting aspect of the present invention. [Figure 5b] This is a top view of a circularly polarized antenna according to a non-limiting aspect of the present invention. [Figure 6a] This is a top view of an antenna feeding structure for a circularly polarized antenna according to a non-limiting aspect of the present invention. [Figure 6b] This is a top view of an antenna feeding structure for a circularly polarized antenna according to a non-limiting aspect of the present invention. [Figure 7] This is a plan view showing the dimensions of a circularly polarized antenna according to a non-limiting aspect of the present invention. [Figure 8] This is a table listing the dimensions of the embodiments of the present invention as defined in Figure 7. [Figure 9] Figure 7 is a graph showing the measured frequency response of the circularly polarized antenna. [Figure 10] Figure 7 is a graph showing the measured axial ratio of the circularly polarized antenna. [Figure 11] This is a partial cross-sectional view of a unidirectional antenna along line 2-2 on the windshield of Figure 1, according to a non-limiting aspect of the present invention. [Figure 12] This is a partial cross-sectional view of a unidirectional antenna along line 2-2 on the windshield of Figure 1, according to a non-limiting aspect of the present invention. [Figure 13]This is a top view of a unidirectional antenna according to a non-limiting aspect of the present invention. [Figure 14] This is an exploded view of a unidirectional antenna having a microstrip feed line according to a non-limiting aspect of the present invention. [Figure 15] This is an exploded view of a unidirectional antenna having a coaxial cable feed line according to a non-limiting aspect of the present invention. [Figure 16] This is a plan view identifying selected dimensions of a unidirectional antenna according to a non-limiting aspect of the present invention. [Figure 17] This is a table listing the dimensions of the present invention identified in Figure 16. [Figure 18] Figures 13, 16, and 17 are graphs showing the measured frequency response of the unidirectional antenna. [Figure 19] This graph shows the vertical polarization gain pattern of a unidirectional antenna acquired at DSRC frequency and elevation angle 0°. [Figure 20] This graph shows the vertical polarization gain pattern of a unidirectional antenna at DSRC frequency and an elevation angle of 10°. [Figure 21] This is a top view of a broadband antenna having a microstrip feed line according to a non-limiting aspect of the present invention. [Figure 22] This is a top view of a broadband antenna having a coaxial cable feed line according to a non-limiting aspect of the present invention. [Figure 23] This is a top view of a broadband antenna according to a non-limiting aspect of the present invention. [Figure 24] This graph shows the measured frequency response of a broadband antenna according to a non-limiting aspect of the present invention. [Figure 25] This graph shows the measured radiation pattern of a broadband antenna according to a non-limiting aspect of the present invention. [Modes for carrying out the invention]

[0068] When used herein, terms indicating space or direction, such as “left,” “right,” “inside,” “outside,” “up,” and “down,” and similar terms, relate to the disclosures shown in the drawings. However, it should be understood that various alternative directions can be assumed in this disclosure, and therefore such terms should not be considered limiting. Furthermore, when used herein, all numerical values ​​representing dimensions, physical properties, processing parameters, component amounts, reaction conditions, etc., used herein and in the claims should be understood to be modified in all cases by the term “approximately” or “about.” Therefore, unless otherwise indicated, the numerical values ​​described in the following specification and claims may vary depending on the desired properties to be obtained by this disclosure. In any case, each numerical value should be interpreted by applying ordinary rounding techniques, taking into account at least the reported number of significant figures, and not as an attempt to limit the application of principles equivalent to those in the claims. Furthermore, it should be understood that all ranges disclosed herein include the values ​​of the start and end ranges and any subranges contained within those ranges. For example, a range written as "1-10" should be considered to include all subranges between the minimum value of 1 and the maximum value of 10 (including 1 and 10), that is, all subranges starting with a minimum value of 1 or greater and ending with a maximum value of 10 or less, such as 1-3.3, 4.7-7.5, 5.5-10, etc. "A" or "an" refers to one or more.

[0069] As used herein, “joined,” “connected,” and similar terms mean that two or more elements are joined, linked, fixed, connected, communicated, or otherwise related to one another (e.g., mechanically, electrically, fluidly, optically, electromagnetically). In various examples, elements may be related directly or indirectly. For example, element A may be directly related to element B. For another example, element A may be indirectly related to element B, for example, via another element C. It will be understood that not all relationships between various disclosed elements are necessarily shown. Therefore, other connections may exist besides those shown in the figures.

[0070] Where used herein, the phrase “at least one of ~” means, when used with a list of items, that different combinations of one or more items from the list may be used, and that only one of each item in the list may be required. For example, “at least one of item A, item B, and item C” may, but is not limited to, item A or item A and item B. This example may also include item A, item B, and item C, or item B and item C. In other examples, “at least one of ~” may, for example, be two item A, one item B, and ten item C, or four item B and seven item C, or any other suitable combination.

[0071] According to a non-limiting embodiment, Figure 1 shows a vehicle 10 having a windshield 12, a rear window 14, and at least two side window panes 16 on each side of the vehicle 10, according to a non-limiting embodiment or aspect. The windshield 12 and the rear window 14 may include a concealment band 32, which is attached by screen printing an opaque ink onto the window pane and then firing the periphery of the window pane. The purpose of the concealment band 32 may be to conceal antenna elements and other devices located near the edge of the glass. The antenna 20 is formed in the windshield 12 within the silhouette of the concealment band 32 to minimize the visibility of the antenna 20. Multiple antennas may be present within the concealment band of the windshield 12. While the embodiment of Figure 1 shows the antenna 20 formed in the windshield 12, the antenna 20 may also be located in the rear window 14, the side window panes 16, or any other laminated window pane or sunroof on the vehicle 10. The antenna 20 may also be formed in a window that is not part of the vehicle, such as a building window.

[0072] According to a non-limiting embodiment, Figure 2 shows a windshield 12 having at least one antenna 20. As shown in the figure, the windshield 12 has four antennas 20. It will be understood that the windshield may have any number of antennas 20. It will also be understood that at least one antenna may be installed on either the windshield 12 or the side window glass 16. The antennas 20 may be circularly polarized antennas 20a, unidirectional antennas 20b, or broadband antennas 20c.

[0073] According to a non-limiting embodiment, Figure 3 is a partial cross-sectional view of a circularly polarized antenna 20a on a windshield 12 along line 2-2 in Figure 1. The windshield 12 may be laminated window glass including an inner transparent ply 34 and an outer transparent ply 30, which may be made of glass. The inner transparent ply 34 and the outer transparent ply 30 may be bonded together by an intermediate layer 36. Preferably, the intermediate layer 36 may be made of polyvinyl butyral (PVB) or a similar material. The outer transparent ply 30 may define an outer surface 130 (conventionally called the first surface) that defines the outside of the windshield 12 and an inner surface 132 (conventionally called the second surface). The inner surface 132 is located on the outer transparent ply 30 opposite to the outer surface 130. The inner transparent ply 34 has an inner surface 134 (conventionally called the third surface) that faces the inside of the windshield 12 and an outer surface 136 (conventionally called the fourth surface) that defines the inside of the windshield 12 and faces the inside of the vehicle. The intermediate layer 36 is located between surface 132 and surface 134. The coordinate system 100 of the circularly polarized antenna 20 on the windshield 12 is shown. The x and y axes define the plane of the circularly polarized antenna 20a on the outer surface 136 of the inner transparent ply 34. The z axis is directed outward from the circularly polarized antenna 20a on the outside of the windshield 12.

[0074] According to non-limiting embodiments of the present invention, as shown in Figures 1 and 3, the windshield 12 may include a concealing band 32, such as a painted band, which is attached to the outer transparent ply 30 by screen printing an opaque ink onto the periphery of the inner surface 132 of the outer transparent ply 30 and then firing the periphery on the outer transparent ply 30. The concealing band 32 may have a closed inner edge 38 that defines the boundary of the daytime running light opening (DLO) of the windshield 12. The concealing band 32 may be wide enough to cover the antenna 20 located inside the windshield 12 and other devices included near the outer periphery of the windshield 12.

[0075] Continuing to refer to Figure 3, the windshield 12 may include a conductive layer 22 positioned on the outer surface 136 of the inner transparent ply 34. The intermediate layer 36, the inner transparent ply 34, and the outer transparent ply 30 may function as dielectric substrates for the conductive layer 22. The windshield 12 may include transmission lines 24 connected to the conductive layer 22. The conductive layer 22 can be constructed in many ways. For example, the conductive layer may be a conductive paint, a metal film deposited by sputtering or vapor deposition, or a silver paste screen meshed onto a non-conductive panel. Furthermore, the conductive layer may be formed on the surface of a single layer of non-conductive glass, such as a tempered glass window, or on the surface of any one of the multilayer glass or multilayer plastic layers of a laminated transparent body, or it may be bonded to the surface of a non-conductive body panel, such as fiberglass, an interior panel, or an exterior panel.

[0076] According to an unlimiting aspect of the present invention, Figure 4 is a partial cross-sectional view of a circularly polarized antenna 20a on a windshield 12 along line 2-2 in Figure 1. The windshield 12 may include an inner transparent ply 34, an outer transparent ply 30, and an intermediate layer 36 between them. The circularly polarized antenna 20a may include a conductive layer 42 formed on a thin, flexible film substrate 46, such as polyester (PET), Kapton, Mylar, or some other flexible dielectric substrate, and attached to the outer surface 136 of the inner transparent ply 34 by an adhesive layer 44. The adhesive layer 44 may be any suitable adhesive or transfer tape that allows the substrate 46 to be effectively fixed to the inner transparent ply 34. A transmission line 48 may be connected to the conductive layer 42.

[0077] According to an unspecified aspect of the present invention, Figure 5a shows the structure of a circularly polarized antenna 20a. The circularly polarized antenna 20a may be a CPW-fed rectangular slot antenna in which a tuning stub 54 is introduced on one side of a ground plane 52 printed on the curved surface of a vehicle glass to generate a circularly polarized signal. The circularly polarized antenna 20a may be configured to operate in the GNSS frequency band to transmit or receive right-hand circularly polarized signals in much of the upper half-space (z>0) and left-hand circularly polarized signals in much of the lower half-space (Z<0). The circularly polarized antenna 20a can be printed directly on the vehicle glass or on a suitable substrate fixed to the vehicle glass. The circularly polarized antenna 20a may include a rectangular ring-shaped ground plane 52 having an outer edge 52a defining the outer periphery of the circularly polarized antenna 20a and an inner edge 52b defining the slots 56. The circularly polarized antenna 20a can be excited by a cruciform antenna feeding structure 60 including a first element 62 and a second element 64. A portion 62a of the first element 62 may extend to the upper surface of the ground plane 52 to form a CPW feed line 70. The antenna feed structure 60 can enhance the coupling between the CPW feed line 70 and the slot 56. The ground plane 52 includes a tuning stub 54 that extends substantially perpendicularly into the slot 56 from one surface of the ground plane toward the first element 62 of the antenna feed structure 60.

[0078] Continuing to refer to Figure 5a, the second element 64 of the cruciform antenna feeding structure 60 can be used to adjust the impedance of the antenna 20a to 50Ω, and has a first part 64a and a second part 64b, with the first part 64a being mainly for high-band tuning and the second part 64b being for low-band tuning. The antenna 20a excited by the cruciform feeding structure 60 can generate a first resonant mode, while the tuning stub 54 introduced into the ground plane 52 generates a second resonant mode. The two orthogonal modes, having the same amplitude and orthogonal phase, therefore generate a circularly polarized signal. Observed from the +z direction, the surface current on the ground plane 52 flows counterclockwise at different phase moments (0°, 90°, 180°, and 270°). The circularly polarized antenna 20a can generate an RHCP signal in the +z direction, while an LHCP signal is generated in the -z direction.

[0079] In some non-limiting embodiments or aspects, the antenna structure may be modified due to constraints such as the physical space or fixtures required to fabricate the antenna structure. Referring to Figure 5b, a non-limiting embodiment of a circularly polarized antenna 20a having a different antenna layout from the antenna 20a shown in Figure 5a is shown. As shown in Figure 5b, the circularly polarized antenna 20a includes an aperture 58 defined by an edge 52c on the ground plane 52. Multiple apertures can be introduced into the plane of the ground 52.

[0080] Referring to Figure 6a, a coplanar waveguide 70 for a circularly polarized antenna 20a according to a non-limiting aspect of the present invention is shown. The end 62a of the first element 62 of the antenna feeding structure 60 may extend beyond the dotted line 52c into the upper plane of the ground plane 52. The end 62a extending into the ground plane 52 may form a feeding line 62a. The feeding line 62a may extend into a slot 72 of the ground plane and be separated from the ground plane 52. The slot 72 may widen conically toward a slot 56. A tapered slot 72 may improve the impedance matching of the antenna. The coplanar waveguide uses a single metal layer on the same side of the substrate to support a wide impedance bandwidth and easy device integration.

[0081] Continuing to refer to Figure 6a, a transmission line is shown. The transmission line may be a coaxial cable 80 having a central conductor 84 and an outer shield 82. The central conductor 84 is electrically connected to a feed line 62a, while the outer shield 82 is electrically connected to a ground plane 52 via a solder pad 86 or some other means. For example, the coaxial cable 80 may be electrically connected to a transmitter (not shown) when the antenna 20a is used as a transmitting antenna, or to a receiver (not shown) when the antenna 20a is used as a receiving antenna. Furthermore, the received signal on the coaxial cable 80 can be amplified using an amplifier such as a low-noise amplifier (not shown). The main advantage of the present invention is that it combines desired antenna electrical characteristics with physical components in a way that allows the antenna 20a to be easily incorporated into an existing windshield or other transparent ply using an existing manufacturing process, and allows the antenna 20a to be easily connected to an electronic circuit by conductive connections.

[0082] Referring to Figure 6b, a coplanar waveguide 70 for a circularly polarized antenna 20a according to an aspect of the present invention is shown. The transmission line may be a coaxial cable 80 arranged parallel to one plane of the ground plane 52 and may be used to feed the antenna 20a. The coaxial cable 80 may include a central conductor 84 and an outer shield 82. The central conductor 84 is electrically connected to the feed line 62a, while the outer shield 82 may be electrically connected to the ground plane 52 via a solder pad 86 or some other means. An opening 58 introduced into the ground 52 may facilitate an overmolding process (not shown) to protect the connection joint between the coaxial cable 80 and the antenna 20a.

[0083] Referring to Figure 7, the dimensions of a circularly polarized antenna 20a according to an embodiment of the present invention are shown. The size of the rectangular loop-shaped ground plane 52, the coplanar waveguide 70, the cross-shaped feeding structure 60, and the tuning stub 54 are designed according to the dimensions shown in Figure 8. The antenna 20a may be printed on the outer surface 136 of the inner transparent ply 34. The thickness of the inner and outer transparent plies may be 2.3 mm, the relative permittivity 7.5, and the loss tangent tanδ = 0.02. The thickness of the intermediate layer 36 may be 0.8 mm, the relative permittivity 3.3, and the loss tangent tanδ = 0.05. The lengths Lg, Ls and widths Wg, Ws of the ground plane 52 and slot 56 determine the resonant frequency of the antenna 20a. The coplanar waveguide 70 with the cross-shaped antenna feeding structure 60 supports a wide impedance bandwidth in the GNSS frequency band. The right-hand circular polarization of the antenna is primarily caused by a tuning stub 54 introduced to the left of the ground plane 52.

[0084] An embodiment shown in Figure 7, having the dimensions listed in Figure 8, was manufactured for the windshield of a car. Antenna 20a is positioned on the passenger side of the third visor area of ​​the windshield 12. Figure 9 is a graph of the measured return loss (S11) of antenna 20a. The return loss was observed to be less than -10dB in the 910MHz to 2000MHz range, with a center frequency of 1455MHz and a bandwidth of 74.9%. As shown in Figure 10, the measured 3dB axial ratio bandwidth is 59.6% in the 1000MHz to 1850MHz range. This indicates that the antenna covers the entire GNSS frequency band in the L5 (1176.45MHz), L2 (1227.6MHz), L4 (1379.913MHz), L3 (1381.05MHz), and L1 (1575.42MHz) bands.

[0085] Referring to Figure 11, a unidirectional antenna 20b in a windshield 12 according to a non-limiting embodiment of the present invention is shown. The unidirectional antenna 20b may include a first conductive layer 22 and a second conductive layer 24. The first conductive layer 22 may include a first patch 22a, a second patch 22b, and a third patch 22c arranged across a concealing band 32 on the inner surface 132 of the outer transparent ply 30. The second conductive layer 24 may be arranged on the outer surface 136 of the inner transparent ply 34. The second conductive layer 24 may be substantially parallel to the first conductive layer 22 and spaced apart from the first conductive layer 22. The first patch 22a, the second patch 22b, and the third patch 22c are arranged parallel and symmetrically with respect to a longitudinal axis intersecting the geometric center of the second conductive layer 24. The intermediate layer 36 and the inner transparent ply 34 can function as dielectric substrates for the first conductive layer 22 and the second conductive layer 24.

[0086] Continuing with reference to Figure 11, the first conductive layer 22 and the second conductive layer 24 can be implemented in other ways as further illustrated herein. The first conductive layer 22 and the second conductive layer 24 may consist of conductive paint, a metal film deposited by sputtering or vapor deposition, and a silver paste screen meshed onto a non-conductive panel. Furthermore, the first conductive layer 22 and the second conductive layer 24 may be formed on the surface of a single layer of non-conductive glass, such as a tempered glass window, or on the surface of any layer of a multilayer transparent body of glass or plastic layers. The first conductive layer 22 and the second conductive layer 24 may also be bonded to the surface of a non-conductive body panel, such as an internal or external fiberglass panel.

[0087] Referring to Figure 12, a unidirectional antenna 20b according to a non-limiting aspect of the present invention is shown. The second conductive layer 24 may be replaced by an attachment 240 as an add-on to the windshield 12 after the windshield 12 has been manufactured. The windshield 12 may include an inner transparent ply 34, an outer transparent ply 30, and an intermediate layer 36 between them. The attachment 240 may include a conductive layer 67 formed on a thin, flexible film substrate 66, such as polyester (PET), Kapton, Mylar, or any other flexible dielectric substrate, and adhered to the outer surface 136 of the inner transparent ply 34 by an adhesive layer 64. The adhesive layer 64 may be any suitable adhesive or transfer tape that allows the substrate 66 to be effectively fixed to the inner transparent ply 34. A transmission line 68 may be connected to the first conductive layer 22.

[0088] Referring to Figures 13-15, patches 22a, 22b, and 22c of the first conductive layer 22 may be directors of the unidirectional antenna 20b. The patches of the first conductive layer 22 may have any contour shape, such as rectangular, circular, triangular, or elliptical. In the examples of the disclosed embodiments, a rectangular contour shape is preferred. The second conductive layer 24 may function as an electrical ground plane. The first conductive layer 22 may work together with the second conductive layer 24, the intermediate layer 36, and the inner transparent ply 34 to define the structure of the unidirectional antenna 20b. The second conductive layer 24 may define a first slot 42a and a second slot 42b. The first slot 42a may be positioned laterally on the second conductive layer 24 and symmetrically with respect to a longitudinal axis intersecting the center of the second conductive layer 24. The second slot 42b may be positioned parallel to and spaced apart from the first slot 42a, and the length of the second slot 42b may be longer than that of the first slot 42a. The first slot 42a and the second slot 42b may have various contours and shapes, such as straight, L-shaped, or U-shaped slots.

[0089] Continuing to refer to Figures 13-15, when the signal transmission line is connected to the periphery of the first slot 42a, the first slot 42a becomes an excitation element. In this respect, the second slot 42b can function as a parasitic element that can function as a director or reflector, depending on its relative length compared to the excitation element and its distance from the driving element. The transmitted wave from the excitation element 42a is reflected by the parasitic element 42b. When the waves radiated from the excitation slot 42a rejoin at the feed point and have a round-trip phase difference of π, the transmitted signal and the reflected signal cancel each other out, and the parasitic element functions as a reflector. Constructive interference occurs when the phase difference between the transmitted signal and the reflected signal is 2π. In this state, the parasitic element 42b functions as a director. The second slot 42b may be longer than the first slot 42a and function as a reflector.

[0090] Figure 13 is a top view of a unidirectional antenna 20b. The unidirectional antenna 20b includes a first conductive layer 22 and a second conductive layer 24. The first conductive layer 22 includes three rectangular patches 22a, 22b, and 22c, and the second conductive layer 24 includes two rectangular slots 42a and 42b. The first slot 42a is an excitation slot that can be excited by a transmission line. The second slot 42b is longer than the first slot 42a and may be positioned to function as a reflector slot, from which more signal is radiated in the "+x" direction. Energy is electromagnetically coupled through the excitation slot 42a in the second conductive layer 24. The three rectangular patches 22a, 22b, and 22c on the first conductive layer 22 are parasitic patches that function as antenna directors. The first slot 42a can be oriented with respect to the central edge of the first patch 22a of the first conductive layer 22, since the central edge of the first patch 22a is the location of the maximum electric field of the first patch 22a. To achieve maximum coupling, the first slot 42a may be parallel to the radiating edge 46 of the first patch 22a, or it may overlap with the radiating edge 46. Patches 22a, 22b, and 22c can act as directors to a unidirectional antenna, directing energy further in the "+x" direction and increasing the antenna gain. Three directors are preferred because the effect of adding additional directors on the antenna gain is limited.

[0091] Referring to Figure 14, according to an indefinite aspect of the present invention, a unidirectional antenna 20b is fed by a microstrip line 74 etched into the bottom of a thin substrate 40. The unidirectional antenna 20b is excited by two very similar coupling mechanisms: one between the microstrip line 74 and the first slot 42a, and the other between slots 42a, slot 42b and patches (22a, 22b, and 22c) on the first conductive layer 22. The characteristic impedance and width of the microstrip line 74 affect the electromagnetic coupling to the first slot 42a. For maximum coupling, the microstrip line 74 is oriented with respect to the first slot 42a such that the longitudinal dimension of the microstrip line 74 is oriented perpendicular to the longitudinal centerline of the first slot 42a, which is defined as the midpoint between the long-side edges of the first slot 42a. The microstrip line 74 intersects with the first slot 42a and then bends at a right angle between the first slot 42a and the second slot 42b, so that the line of the microstrip 74 excites only the first slot 42a and the second slot 42b can function as a parasitic reflector for the slot antenna. The coordinate system 100 of the unidirectional antenna 20b on the windshield 12 is shown. The x and y axes define the plane of the unidirectional antenna 20b on the outer surface 136 of the inner transparent ply 34. The z axis is directed outward from the unidirectional antenna 20b to the outside of the windshield 12.

[0092] Referring to Figure 15, a unidirectional antenna 20b according to a non-limiting aspect of the present invention is shown. The unidirectional antenna 20b can be fed directly through a first slot 42a using a coaxial cable 50 having a central conductor 54 and an outer shield 52. The central conductor 54 may extend over the first slot 42a and may be electrically connected to the furthest side of the first slot 42a at a solder pad 56 on a second conductive layer 24. The outer shield 52 may be electrically connected to the near side of the first slot 42a at a solder pad 58 on the second conductive layer 24. The second slot 42b is longer than the first slot 42a and functions as a reflector, and patches 22a, 22b, and 22c may function as directors to the first slot 42a. An advantage of the invention of the present disclosure is that, by combining the advantageous electrical properties of the antenna with the components of the physical building blocks, the antenna can be more easily incorporated into current windshield designs or other transparent body designs using existing manufacturing processes. Another advantage of the antenna of the present disclosure is that the antenna can be connected more easily and conveniently by conductive connections to electronic circuits located outside the antenna.

[0093] Referring to Figure 16, exemplary dimensions of a unidirectional antenna according to a non-limiting aspect of the present invention are shown. The patch elements 22a, 22b, and 22c of the first conductive layer 22 and the second conductive layer 24, as well as the slots 42a and 42b, are all sized relatively according to the dimensions enumerated in Figure 17. The length L of slot 42a s1 and the length L of patch 22a p1 This determines the resonant frequency of the slot antenna. The width W of the first slot 42a s1 and width W of the first patch 22a p1 This affects the resonant resistance of the slot antenna, and the wider the patch, the lower the resistance. The coupling level between the first slot 42a and the first patch 22a is mainly due to the length L of the first slot 42a. s1 The length L of the second slot 42b is determined by the back radiation level. s2 The length L of the first slot 42a is s1The second slot 42b is longer than the first slot 42a and acts as a reflector for the first slot 42a. Patches 22a, 22b, and 22c act as directors to the slot antenna, with the first patch 22a being slightly larger than the second patch 22b, and the second patch 22b being slightly larger than the third patch 22c. The patches are deposited closely together in parallel so as to electromagnetically couple with each other and pull the antenna's radiation pattern in the "+x" direction.

[0094] Embodiments of the patch antennas shown in Figures 13, 15, and 16, having the dimensions defined in Figure 17, were manufactured for the windshield of a 2023 Cadillac Celeste electric vehicle. The unidirectional antenna was positioned on the upper passenger side of the windshield, adjacent to the third visor area. The unidirectional antenna is not visible because it is positioned behind a black painted band. Figure 18 is a graph of the measured return loss (S11) of the antenna. Of the power supplied to the antenna, the return loss S11 is a comparative measure of the amount of power reflected from the antenna and the amount of power "received" and radiated by the antenna. Figure 18 shows that the return loss is less than -10 dB in the frequency range of 5.1–6.3 GHz. This means the antenna can be used with UNII, ISM, IEEE 802.11a and 802.11ac, Wireless Local Area Networks (RLAN), Fixed Wireless Access Systems (FWA), WiMAX, and MESH wireless networks in the 5.18–5.85 GHz band, as well as the DSRC band in the 5.85–5.925 GHz band.

[0095] Regarding Figure 19, the vehicle antenna gain pattern was measured in the outdoor antenna range. The vehicle antenna radiation patterns for vertical polarization at frequencies of 5.8 GHz, 5.9 GHz, and 6.0 GHz are shown, respectively. The elevation angle is 0°. The maximum gain of the patch antenna is approximately 2 dBi, and it is pointed forward of the vehicle.

[0096] Referring to Figure 20, the vehicle antenna radiation pattern with vertical polarization at an elevation angle of 10° is shown. The patch antenna has a maximum gain of approximately 3 dBi and is directed forward of the vehicle. The half-power width in the azimuth plane is approximately 70°. Antenna gain and beamwidth also depend on the mounting angle of the vehicle's windshield. Windshield antennas provide better coverage in the forward vehicle direction than in the rear or lateral directions. Antennas can be integrated into the windshield, rear window, or side window for diversity antenna systems with an omnidirectional far-field radiation pattern in the direction of the ground.

[0097] Referring to Figures 3, 4, and 21, in non-limiting aspects of the present invention, the broadband antenna 20c may include a dielectric substrate and a ground plane 200 disposed on one side of the surface of the substrate having a plurality of tapered slot radiators 210. The broadband antenna 20c may be disposed on the outer surface 136 of the inner transparent ply 34. The first tapered slot radiator 210a may include a first slot opening 202a, a first tapered opening 204a, and a first impedance matching opening 206a in the ground plane 200. The first slot opening 202a may be formed in the ground plane 200, and the first slot opening 202a defines a first end 212a and a second end 214a opposite the first end. The first tapered opening 204a may be formed in the ground plane 200, beginning at the first end 212a of the first slot opening 202a and ending at the first surface 216 of the ground plane 200. The first tapered opening 204a may generally expand from the first end 212a of the first slot opening 202a toward the first surface 216 of the ground plane 200. The first impedance matching opening 206a in the ground plane 200 may be formed elliptically adjacent to the second end 214a of the first slot opening 202a. It will be understood that the first impedance matching opening 206a may be formed in other suitable shapes such as circular or rectangular. The first impedance matching opening 206a may be formed to function as an open circuit to the first tapered slot radiator.

[0098] Continuing to refer to Figure 21, the second tapered slot radiator 210b may include a second slot opening 202b, a second tapered opening 204b, and a second impedance matching opening 206b in the ground plane 200. The second slot opening 202b may be formed in the ground plane 200 between a first end 212b and a second end 214b opposite the first end 212b. The second tapered opening 204b may generally extend from the first end 212b of the second slot opening 202b toward the second surface 218 of the ground plane 200. The second impedance matching opening 206b in the ground plane 200 may be formed in an elliptical shape adjacent to the second end 214b of the second slot opening 202b. It will be understood that the second impedance matching opening 206b may be formed in other suitable shapes such as circular or rectangular. The second impedance matching aperture 206b may be formed to function as an open circuit to the second tapered slot radiator 210b. Each tapered slot radiator 210 has a directional beam 220 directed toward the opening 222 of the tapered slot radiator 210. The first slot aperture 202a and the second slot aperture 202b may be spaced apart, parallel to each other, and adjacent to each other.

[0099] Continuing to refer to Figure 21, the broadband antenna 20c may have two or more tapered slot radiators directed to different faces of the ground plane 200 with multiple beams 220, providing better coverage than an antenna with a single tapered slot. The broadband antenna 20c may be configured to transmit and receive 5G sub-6 signals and 4G LTE signals. The first slot opening 202a and the second slot opening 202b may be placed very close to each other and parallel to each other. The antenna feed line may intersect the first slot opening 202a and the second slot opening 202b at a 90° right angle, and can simultaneously feed the first slot radiator 210 and the second slot radiator 210 in phase. The first tapered slot opening 202a may have an axis of symmetry which is also the centerline of the beam 220a of the first tapered slot radiator. The second tapered opening 202b has an axis of symmetry that is also the centerline of the beam 222b of the second tapered slot radiator 210b. The angle φ between the axes formed by beams 220a and 220b may be adjustable depending on the signal coverage requirements of the antenna and the physical position of the antenna. The angle φ may be tunable between 30° and 180°. A broadband antenna 20c having two or more tapered slot radiators 210 directed to different faces of the ground plane 200 with multiple beams can provide better signal coverage than an antenna with a single tapered slot. The broadband antenna 20 may be configured to transmit and receive 5G sub-6 cellular signals and 4G LTE cellular signals.

[0100] Continuing to refer to Figure 21, according to an unlimiting aspect of the present invention, a broadband antenna 20c may be fed by a microstrip line 208 etched into the bottom surface of a substrate. The broadband antenna 20c may be excited by electromagnetic coupling between the microstrip line 208 and the first slot 202a and the second slot 202b. The characteristic impedance and width of the microstrip line 208 affect the electromagnetic coupling to the first slot 202a and the second slot 202b. For maximum coupling, the microstrip line 208 may be oriented with respect to the first slot 202a and the second slot 202b such that the longitudinal dimension of the microstrip line 208 is oriented perpendicular to the first slot 202a and the second slot 202b. After crossing the first slot 202a and the second slot 202b, the microstrip line 208 may be terminated with a quarter-wavelength radial stub of open circuit for broadband antenna matching.

[0101] Referring to Figure 22, a broadband antenna 20c according to a non-limiting aspect of the present invention is shown. The broadband antenna 20c may be directly fed through a first slot 202a and a second slot 202b using a coaxial cable 800 having a central conductor 806 and an outer shield 802. For example, the broadband antenna 20c may be directly fed through the central portion of the first slot opening 202a and the central portion of the second slot opening 202b using a coaxial cable 800 having a central conductor 806 and an outer shield 802. The central conductor 806 may extend over the first slot 202a and the second slot 202b and may be electrically connected to the furthest side of the first slot 202a at a solder pad 808b on the ground plane 200. The outer shield 802 may be electrically connected to the near side of the second slot 202b at a solder pad 808b on the ground plane 200.

[0102] Referring to Figure 23, a broadband antenna 20c according to an unlimiting aspect of the present invention is shown. The broadband antenna 20c may have two tapered slot radiators 210a and 210b, the first tapered slot radiator 210a may have a wider aperture than the second slot radiator 210b. The first slot radiator 210a may be tuned for a lower frequency band, and the second tapered slot radiator 210b may be tuned for a higher frequency band. In the case of the tapered slot antenna 20c, the length of the aperture generally needs to be at least half the wavelength at the minimum operating frequency. The broadband antenna 20c may have two tapered slot radiators 210a and 210b having an aperture 222a with width L1 and an aperture 222b with width L2. L1 may be greater than L2. Each slot radiator 210 can be tuned for different applications. For example, the first tapered slot radiator 210a may be tuned for a mobile LTE antenna with a lower frequency tuned to 700 MHz, and the second tapered slot radiator 210b may be tuned for the 2.4 GHz and 5 GHz Wi-Fi frequency band or the 5.8 GHz V2V frequency band.

[0103] Referring to Figure 24, the frequency response of the antenna is shown. For example, the frequency response of the antenna is well matched from 600 MHz to over 6.5 GHz. This antenna exhibits broadband properties, covering the entire 4G LTE band and 5G sub-6 band. This frequency response was measured using the broadband antenna shown in Figure 21, which has coaxial feeding as shown in Figure 22, fabricated on the windshield of an electric vehicle. The broadband antenna has a total length of 150 mm and a width of 90 mm and is designed to operate at a minimum frequency of 600 MHz. The antenna is printed on the outer surface 136 of the inner transparent ply 34. The thickness of the inner and outer transparent plies 34 is 2.3 mm, the relative permittivity is 7.5, and the loss tangent is tanδ = 0.02. The thickness of the intermediate layer 36 is 0.8 mm, the relative permittivity is 3.3, and the loss tangent is tanδ = 0.05. Antenna 20 is positioned behind a black painted band on the upper passenger side of the windshield, with two tapered slot openings facing away from the vehicle. Figure 26 shows the measured return loss (S11) performance of the antenna. Of the power supplied to the antenna, the return loss S11 is a comparative measure between the amount of power reflected from the antenna and the amount of power "received" and radiated by the antenna.

[0104] Referring to Figure 25, the vehicle antenna radiation pattern with vertical polarization at an elevation angle of 0° is shown at 700 MHz. The radiation pattern has two main beams directed towards the two sides of the vehicle, as expected. The maximum gain of the exemplary pattern is approximately 10–12 dBi. The antenna radiation pattern also depends on the mounting angle of the vehicle's windshield. An antenna mounted on the windshield provides good coverage in the lateral direction. The antenna may be printed on the side windows to improve forward and rearward coverage and form an antenna diversity system with a nearly omnidirectional far-field radiation pattern in the ground direction.

[0105] While the disclosed invention is described and illustrated by reference to certain preferred embodiments and models, it should be understood that various modifications may be adopted without departing from the spirit of the invention or the following claims.

Claims

1. It is the windshield, An outer transparent ply defining the inner surface and the outer surface located on the opposite side of the inner surface, An inner transparent ply defining the outer surface and the inner surface located on the opposite side of the outer surface, An intermediate layer disposed between the inner surface of the outer transparent ply and the inner surface of the inner transparent ply, A circularly polarized antenna is disposed on the outer surface of the inner transparent ply, A unidirectional antenna is disposed on the inner surface of the outer transparent ply and on the outer surface of the inner transparent ply, A broadband antenna disposed on the outer surface of the inner transparent ply, The windshield, including the windshield.

2. The aforementioned circularly polarized antenna is A ground plane having four faces, wherein the inner edges of the four faces of the ground plane define a slot therein, A cross-shaped antenna feeding structure, wherein the antenna feeding structure defines a first element and a second element, the second element being substantially perpendicular to the first element, and the first element extending into the slot of the first face of the ground plane, A tuning stub extending from a second surface of the ground plane, wherein the tuning stub extends substantially perpendicular to the second surface toward the antenna feeding structure, A windshield according to claim 1, including the windshield described in claim 1.

3. The windshield according to claim 2, wherein the slot and the antenna feeding structure extending within the slot form a coplanar waveguide, the slot is a tapered slot, the slot widens conically toward the inner edge of the first surface of the ground plane, the slot is configured to improve antenna impedance matching, the circularly polarized antenna includes a coaxial cable, the coaxial cable includes an outer shield and a central conductor, the coaxial cable is connected to the coplanar waveguide, a portion of the outer shield is in contact with the first surface of the ground plane, and the central conductor is connected to the first element of the antenna feeding structure.

4. The windshield according to any one of claims 2 to 3, wherein the first element of the antenna feeding structure is configured to supply energy to the circularly polarized antenna in a first mode, the tuning stub is configured to excite the circularly polarized antenna and cause it to resonate in a second mode, the first mode and the second mode are orthogonal modes having the same amplitude and orthogonal phase, the circularly polarized antenna is configured to transmit and receive a right-hand circularly polarized signal, the right-hand circularly polarized signal is a GNSS signal, the circularly polarized antenna may have a wide bandwidth and cover the L1, L2, L3, L4, and L5 bands of 1000 MHz to 1850 MHz in GNSS.

5. The aforementioned unidirectional antenna is, A first conductive layer disposed between the inner surfaces of the outer transparent ply and the inner transparent ply, wherein the first conductive layer comprises a plurality of patches, the plurality of patches comprising a first patch, a second patch, and a third patch, the first conductive layer defining the outer periphery, and the plurality of patches being spaced apart, parallel to each other, and adjacent to each other, A second conductive layer disposed on the outer surface of the inner transparent ply, wherein the second conductive layer includes a plurality of slots, the second conductive layer defines an outer periphery, the plurality of slots include a first slot and a second slot, the length of the second slot is longer than the length of the first slot, the second conductive layer is aligned laterally with respect to the first conductive layer such that the outer periphery of the first conductive layer is aligned with the inside of the outer periphery of the second conductive layer, and the first slot is aligned with the outer periphery of the first patch, and the first slot of the second conductive layer is spaced apart from the plurality of patches of the first conductive layer such that an electrical signal applied around the first slot is electromagnetically coupled to the plurality of patches of the first conductive layer, A transmission line electrically connected to the first slot at the power supply position in the center of the first slot, A windshield according to any one of claims 1 to 4, including the windshield described in any one of claims 1 to 4.

6. The windshield according to claim 5, wherein the second conductive layer is the electrical grounding element of the unidirectional antenna, the first slot defines a first longitudinal plane and a second longitudinal plane, the first slot is a drive slot, the maximum electromagnetic field in the first slot is generated at the center of the first slot, the maximum electric field of the first patch is generated at the central edge of the first patch, the energy is electromagnetically coupled between the first slot and the first patch, and the first patch is the first director of the unidirectional antenna.

7. The windshield according to claim 6, wherein the second slot is longer than the first slot, and is spaced apart from the first slot on the first longitudinal surface of the first slot such that when the signals radiated from the drive slot merge at the power supply position, the transmitted signals from the drive slot reflected by the second slot have a phase difference of π, the outer periphery of the first patch is aligned laterally with respect to the first longitudinal surface of the first slot and overlaps the second longitudinal surface of the first slot, and the first patch is positioned on the second longitudinal surface of the first slot.

8. The windshield according to any one of claims 5 to 7, wherein the second patch and the third patch are adjacent to the first patch on the second longitudinal plane of the first slot, parallel to and equally spaced, the second patch is the second director of the unidirectional antenna, and the third patch is the third director of the unidirectional antenna, and the first director, the second director and the third director are electromagnetically coupled to each other so as to attract the radiation pattern of the antenna toward the third director.

9. The windshield according to any one of claims 5 to 8, wherein the transmission line is a coaxial cable having a central conductor surrounded by an outer shield, the outer shield is connected to the second longitudinal surface of the first slot, the central conductor is connected to the first longitudinal surface of the first slot, and the coaxial cable and the first slot transmit and receive electromagnetic energy between the second slot of the second conductive layer and the first patch, second patch, and third patch of the first conductive layer.

10. The windshield according to any one of claims 5 to 9, wherein the second slot reflects the signal from the first slot and combines with the first, second, and third patches of the first conductive layer to achieve unidirectional radiation from the unidirectional antenna, and the bandwidth of the unidirectional antenna covers the 5.18 GHz to 5.85 GHz Wi-Fi under the IEEE 802.11a / ac standard and the 5.85 to 5.925 GHz DSRC band.

11. The windshield according to any one of claims 5 to 10, wherein the length of the first slot and the first patch determines the resonant frequency of the unidirectional antenna, and the width of the first slot and the first patch affects the resonant resistance of the unidirectional antenna.

12. The windshield according to any one of claims 5 to 11, wherein the transmission line is a microstrip line etched onto a substrate attached to the outer surface of the inner transparent ply, the unidirectional antenna is excited through two coupling stages, one coupling stage located between the microstrip line and the first slot of the second conductive layer, and the other coupling stage located between the first and second slots of the second conductive layer and the first patch, second patch, and third patch of the first conductive layer, the microstrip line is oriented perpendicular to the center line of the first slot, and is bent perpendicularly between the first slot and the second slot such that the microstrip line intersects only the first slot.

13. The aforementioned broadband antenna is Dielectric substrate and The conductive sheet on the dielectric substrate, A first tapered slot radiator, A first slot opening having a first end and a second end is formed within the conductive sheet, A first tapered opening formed in the conductive sheet, wherein the first tapered opening is formed between the first end and the first surface of the first slot opening of the conductive sheet, and the first tapered opening gradually increases in size from the first end toward the first surface of the first slot opening of the conductive sheet, A first impedance matching opening in the conductive sheet, which is formed in an elliptical shape adjacent to the second end of the first slot opening, The first tapered slot radiator includes, A second tapered slot radiator, A second slot opening having a first end and a second end is formed within the conductive sheet, A second tapered opening formed in the conductive sheet, wherein the second tapered opening is formed between the first end and the second surface of the second slot opening of the conductive sheet, and the second tapered opening gradually increases in size from the first end toward the second surface of the second slot opening of the conductive sheet, A second impedance matching opening in the conductive sheet, which is formed in an elliptical shape adjacent to the second end of the second slot opening, The second tapered slot radiator includes, A transmission line electrically connected to the first slot opening and the second slot opening, A windshield according to any one of claims 1 to 12, including the windshield described in any one of claims 1 to 12.

14. The windshield according to claim 13, wherein the first slot opening and the second slot opening are spaced apart, parallel to each other, and adjacent to each other, the central portions of the first slot opening and the second slot opening of the broadband antenna define the antenna feed point, and the transmission line spanning the first slot opening and the second slot opening is configured to simultaneously excite the first tapered slot radiator and the second tapered slot radiator.

15. The windshield according to any one of claims 13 to 14, wherein the first tapered slot radiator has a radiation beam directed toward the first surface of the conductive sheet, the second tapered slot radiator has a radiation beam directed toward the second surface of the conductive sheet, the size of the opening of the first tapered slot radiator is larger than the size of the opening of the second tapered slot radiator, the first tapered slot radiator is tuned for a lower frequency band, the second tapered slot radiator is tuned for a higher frequency band, and the broadband antenna is configured to transmit and receive 4G LTE signals and 5G sub-6 signals.

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