WO2022168119A1 - A printed antenna circuit on a windshield of a vehicle and a system thereof - Google Patents

A printed antenna circuit on a windshield of a vehicle and a system thereof Download PDF

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Publication number
WO2022168119A1
WO2022168119A1 PCT/IN2022/050093 IN2022050093W WO2022168119A1 WO 2022168119 A1 WO2022168119 A1 WO 2022168119A1 IN 2022050093 W IN2022050093 W IN 2022050093W WO 2022168119 A1 WO2022168119 A1 WO 2022168119A1
Authority
WO
WIPO (PCT)
Prior art keywords
antenna
antenna circuit
vehicle
glazing
printed
Prior art date
Application number
PCT/IN2022/050093
Other languages
French (fr)
Inventor
Arunvel Thangamani
Senthilkumar R
Monisha DHANABAL
Balamurugan TS
Original Assignee
Saint-Gobain Glass France
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Saint-Gobain Glass France filed Critical Saint-Gobain Glass France
Publication of WO2022168119A1 publication Critical patent/WO2022168119A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/1271—Supports; Mounting means for mounting on windscreens
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/28—Combinations of substantially independent non-interacting antenna units or systems
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/40—Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
    • H01Q9/42—Resonant antennas with feed to end of elongated active element, e.g. unipole with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Definitions

  • the present invention relates to printed electronic circuits on an automotive glazing. Particularly, the present invention relates to printed antenna circuit on the glazing of a vehicle, more particularly, it relates to printed antenna circuit on the windshield of a vehicle.
  • glazing refers to any and all the glass or polymer or similar material within a structure or the installation of any piece of glass or the similar material within a sash or frame.
  • the glass windows of an automobile are referred to as glazing.
  • two or more layers of glass or a similar material are fused together with an interlayer in the middle. The fusion is completed with pressure and heat and it prevents the sheets of glass or polymer or the similar material from breaking.
  • Antennas are used to convert electrical power into radio waves (for broadcast) or radio waves into electrical power (reception). Generally, they are used in conjunction with a transmitter or receiver. Antennas are used in vehicles as well for signal communications. In most cars, it is used for receiving radio broadcasts for recreational purpose. Some vehicles, such as commercial or government vehicles, use them to transmit and receive radio signals for the purpose of communicating either with each other or with a central dispatch.
  • Whip antenna is traditionally used in vehicles. Such antennas are attached to vehicles as the antennas for car radios and two-way radios for wheeled vehicles. Although whip antennas are capable of being used even in higher frequency like high frequency (HF), very high frequency (VHF) and ultra-high frequency (UHF) radio bands, but higher cost and cumbersome implementation are major disadvantages of such antennas.
  • Another kind of antenna system in vehicle include systems with separate antenna components that are implemented as attachments to the printed circuit board (PCB). But these arrangements are disadvantageous if they suffer from drawbacks like the increased cost and weight, and in certain cases they tend to fail if used as an RF system.
  • PCB printed circuit board
  • printed antennas that are made from conducting inks such as and not limited to silver paste, copper paste or tin paste.
  • the printed antennas made from such conductive ink may be configured to function as RF antennas such as FM/AM printed antennas.
  • a defogging heater wire may be configured as an FM printed antenna.
  • US20010010506A1 discloses an antenna structure for a vehicle having an antenna disposed as a print or sticker antenna on a front window glass FM and AM waves reception.
  • the therein disclosed antenna has a loop-shaped antenna element disposed near the upper edge portion of the front window glass and has two or three connected radiators used for both horizontal and vertical polarization.
  • the gain over the bandwidth for this referred solution is not substantial as compared to open monopole radiator type and further, zero driver view blockage is not possible with this solution.
  • Another reference is made to CA2979604C that relates to a vehicle antenna pane for separating a vehicle interior from external surroundings.
  • the antenna disclosed in said prior art is most suitable for satellite- supported navigation, in particular for reception of a right circularly polarized GPS signal. Such antenna involves complex constructional features and is not preferred for frequency communication in the lower band.
  • JPH11312913A discloses a window glass antenna system for automobile.
  • the disclosure provides an antenna pattern for radio reception on a left window glass by printing or the like of a conductive paste material.
  • such solutions are not suitable for front window glass or windshield due to high obstruction on the driver view.
  • the antenna includes multiple loops that are printed on a quarter glass with copper striplines.
  • This multiloop structure is capable of broadening the operating band by efficiently using the given space of the quarter glass and raising the vertical gain by maximizing the z-directed currents.
  • the multiloop structure is so designed that it can be placed along the conducting frame of the vehicle so that it has the added benefit of a superior field of view compared with other types of glass antennas.
  • this solution is not suitable for vehicles having no sidelite or backlite such as 3 wheeler autorickshaws or other light commercial vehicles.
  • PCB printed circuit board
  • airloop based antenna topology is also not suitable for low frequency application because of the higher electrical length requirements.
  • such antenna used for FM reception includes multi conductor lines making them well fit for sidelite and backlit of automotive glasses and inappropriate for the windshield. Because of the length requirements and the presence of multiple lines prior art antennas system such as the airloop based antenna topology will affect the driver zone and the reflection properties.
  • transparent antenna has good reflection and optical characteristics for automotive glazing application, however, the realization cost of ink printing and complex active element integration high.
  • Most vehicles existent in the art and the solutions of the prior art are directed at the use external antenna and on backlit printed defogger circuit for FM reception. Even though some of the solutions are directed at the printing the antenna on the front window or the windshield, all of them are either directed at printing antenna circuit hindering the view of the driver or they relate to solutions that are directed at printing antenna traces using expensive transparent ink.
  • Such solutions are less feasible when viewed from an implementation point of view, especially for passenger vehicles such as and not limited to 3 wheeler auto and even 4 wheeler vehicle such as and not limited to mini trucks. These vehicles do not have the presence of a backlite or that of a sidelites.
  • An object of the present invention is to provide a printed antenna circuit overcoming the drawbacks of the prior art.
  • Another object of the present invention is to provide a system having a simple antenna for radio frequency reception on a vehicle.
  • Another object of the present invention is to provide a cost-effective printed antenna on the windshield of a vehicle for radio frequency reception.
  • Yet another object of the present invention is to provide a printed antenna on the windshield of a vehicle having zero driver view blockage.
  • Still another object of the present invention is to provide an antenna for vehicle having good passive gain and good coverage in enclosed locations.
  • a further object of the present invention is to provide an antenna on an automotive glazing near to the metal environment of the vehicle without hindering the functionality of the antenna.
  • a still further object of the present invention is to provide a system with a printed monopole antenna on the windshield of a vehicle configured for exhibiting dual polarization characteristics.
  • a printed antenna circuit on a glazing of a vehicle comprises a printed monopole antenna configured for exhibiting dual polarization characteristics.
  • the conducting traces of the antenna circuit on the glazing (preferably windshield) of the vehicle is optimally placed near to a periphery of the vehicle to provide necessary isolation over the ground and from the interference of the nearby metal environment of the vehicle.
  • a system for signal transmission and reception in a vehicle comprises at least one antenna circuit having a printed monopole antenna configured for exhibiting dual polarization characteristics.
  • the conducting traces of the antenna circuit on a glazing (preferably windshield) of the vehicle is optimally placed adjacent to a periphery of the vehicle to provide necessary isolation over the ground and from the interference of the nearby metal environment of the vehicle and a connecting wire connecting the feed junction to a receiver unit.
  • the various aspects of the present invention provide a single antenna structure configured to receive the electromagnetic waves in polarization diversity mode as both horizontal and vertical, thereby providing better coverage.
  • the conductive lines of the antenna circuit are optimally configured to be advantageously placed in a suitable location on the glazing.
  • the conductive lines of the antenna define the antenna design and includes one or more curved structures. Said structure may include curved lines based designs that are placed near the periphery of the glazing or may include curved structure such as a serpentine design or a meander structure.
  • the printed antenna circuit disclosed provides the necessary isolation over the ground or nearby metal environment interference and at the same time renders no blockage of driver view. Additionally, the unique antenna design on the glazing, which may be, preferably a windshield is aesthetically pleasing.
  • FIG. 1 illustrates a windshield having two different printed antenna circuit according to an embodiment of the present invention.
  • FIGs. 2 (a)-(c) illustrate the different designs of the printed antenna circuit on a windshield showing the feed junction according to an embodiment of the present invention.
  • FIG. 3 illustrates a system for signal transmission and reception in a vehicle according to an embodiment of the present invention.
  • FIG. 4 illustrates an inner view of a metal cavity of the system for signal transmission and reception according to an embodiment of the present invention.
  • FIG. 5 illustrates an exemplary embodiment of the placement of the different components of the system according to the present invention.
  • substantially' used in the present disclosure is used in order to avoid the mathematical rigidity of any characteristic, parameter, or value. This is meant to indicate that the corresponding characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including and not limited to for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
  • the present disclosure is directed at a single antenna structure that is configured to receive the electromagnetic waves and exhibit diverse polarization.
  • the antenna structure disclosed herein is capable of exhibiting both horizontal and vertical polarization diversity mode for better coverage.
  • the placement of the conductive lines of the antenna on an automotive glazing is optimised to provide the necessary isolation over the ground and/or the nearby metal environment. Said metal environment is provided by the vehicle body.
  • isolation is known to one skilled in the art and it may be regarded as a scenario of no conductive losses or no radiative losses scenario.
  • any radio frequency (RF) tuning circuit is length of a transmission line and it mainly follows equation (1) provided in the following disclosure.
  • the length is mainly chosen based on the type of antenna to be selected.
  • the conventional patch antenna requires half wavelength for radiation and for monopole case, quarter wavelength is sufficient for effective radiation.
  • the use of patch based topology is very complex, especially when considering AM/FM based application. This issue is reasoned for the requirement of higher wavelength and the requirement of more glazing area. This has been detailed in the prior art section of the present disclosure.
  • the antenna circuit or the antenna element is defined by the area of the element which implies both length and width of such parameters are critical.
  • FIG. 1 illustrates at least two different implementations of this embodiment of the invention. It includes at least one printed monopole antenna configured for exhibiting dual polarization characteristics.
  • the conducting traces of the printed monopole antenna comprises a single feed junction, and at least one radiators.
  • Conducting trace is general type of transmission line adapted to control at least two basic parameters of an antenna.
  • the length and width of the radiator is used for frequency matching and impedance matching respectively.
  • Antenna is a type of transformer between the source and air. Hence, the impedance is important for good matching and trade off with minimum trace width feasibility.
  • the main polarization for FM signal is vertical and it may be affected due to ground reflection. Accordingly, for applications involving moving vehicles, a dual polarized antenna receiver is most suitable.
  • the antenna includes at least one top radiator in horizontal orientation and another radiator in vertical orientation. The radiators are operationally oriented to capture both the polarization simultaneously for better coverage.
  • the disclosed antenna topology is optimally designed for good ground immunity.
  • the antenna circuit on an automotive glazing is optimally placed adjacent to periphery of the glazing (such as and not limited to a windshield) of the vehicle. This advantageously provides good isolation over the ground or nearby metal environment interference.
  • the antenna topology is oriented to advantageously render no obstacle in driver’s view.
  • a suitable topology for monopole antenna Since the use of patch based topology for antenna is very complex for AM/FM application due to the requirement of higher wavelength and since it occupies more glazing area, a suitable topology ought to be selected as monopole antenna. For effective radiation, it is noted that a quarter wavelength radiator is sufficient and the remaining may be obtained from ground currents by the vehicle body.
  • the medium is not an air so above is changed with inclusion of guided medium parameters as permittivity and permeability.
  • X g c/ pc*f (where X g - guided wavelength, p&e -Permeability & Permittivity)
  • the printed antenna on the windshield of a vehicle In an exemplary embodiment of the present invention is provided the printed antenna on the windshield of a vehicle.
  • the significance of ground current is directly obtained from the windshield frame. This is sufficient enough to produce the ground matching for FM signal and however it is not sufficient for AM reception.
  • the complete vehicle body will give much influence on AM signal than FM signal reception.
  • the present embodiment advantageously includes an optimized topology for a monopole antenna for automotive applications. The effect of the optimisation is significantly vital for low frequency segments.
  • FIG. 2 provides an antenna circuit architecture or antenna designs according to the disclosed embodiment.
  • the conducting traces of the antenna circuitry including at least one antenna circuit.
  • the optimised conducting trace includes a unique antenna design as depicted in FIGs. 2(a)-2(c).
  • the conducting traces of said antenna circuit includes a unique antenna design having curved lines extending form the at least one radiators.
  • the optimised antenna topology is advantageous specially for windshield of 3 wheelers like auto rickshaws.
  • the conducting traces are provided considering the deep bending or a curved profile of such windshield.
  • the conducting traces of the antenna comprises a feed junction having a single feed point (202), and at least one radiator (201).
  • the antenna may be configured for radio frequency communication amplitude modulation (AM) and/or frequency modulation (FM) frequency bands, but however not limited to this.
  • the antenna circuit is configured for radio frequency communication in the range 88MHz to 108MHz.
  • the antenna circuitry mainly comprises feed line, radiators and frame clearance distance.
  • the feed line is mainly considered for effective matching between the FM receiver impedance and antenna source impedance.
  • the source impedance of the antenna is 50 ohm and receiver impedance is 75 ohm, hence suitable transformation of circuitry is required for good matching.
  • the antenna circuit (120) includes a feedline and radiator element (105) that extends into conducting lines LI and L2 of the conducting trace of the antenna circuit as is depicted in FIG. 3.
  • a small strip (like a small circle shaped strip) and length of strip combination is used as feedline for the topology.
  • One of the radiators of the antenna may extend as LI of the circuit and another radiator of antenna may extend as L2 of the circuit.
  • the conducting traces of said antenna circuit includes a unique antenna design having curved lines extending from the at least one radiators. The design may include simple curved lines extending along the boundary of the glazing or may include a meander or serpentine structure, but however not limited these.
  • FIG. 2(a) shows an exemplary embodiment of an antenna design on a windshield.
  • the radiators (201, 203) of the antenna structure extends as at least two lines LI, and L2 near the outer boundary of the windshield having optimal frame clearance distance.
  • the edge distance which is the distance of a line from the outer border (200) of the windshield is ‘a’ with respect to a first conducting line LI, another edge distance is ‘b’ with respect to the conducting line LI, and ‘c’ with respect to a second conducting line L2.
  • edge distance ‘a’ may be in the range 55 mm-65 mm
  • ‘b’ may be in the range 45mm-75mm
  • ‘c’ may be in the range 55 mm-75 mm.
  • the distance of the feed junction (202) from the outer border of the windshield may be in the range 50 mm-80 mm.
  • FIG. 2(b) shows another exemplary embodiment of an antenna design on a windshield having two antenna circuitry.
  • the optimally placed antenna circuit comprises a conducting line (LI) from a radiator (201) extending into a curved structure.
  • the optimisation of the location of placement of the antenna unit and further the design of the curved structure of the antenna may be fine-tuned considering one or more parameters such as and not limited to the aesthetics of the glazing, the driver’s view area, the metal environment of the vehicle, the losses of signals, and efficiency in terms of antenna functionality.
  • Said curved structure is having a meander-like shape or a serpentine line.
  • the edge distance (c) of the conducting line (LI) extending into the curved structure (the meander-like shape or a serpentine line for this case) from an outer border (200) of the windshield may be 20 mm-75 mm, preferably 20 mm-50 mm. Additionally, such a structure of the antenna design advantageously reduces the size of antenna.
  • the glazing of the vehicle having the printed antenna may include laminated glass or tempered glass.
  • Said antenna circuit may be printed on an optimised location on the tempered glass or on the one or more layers of the laminated glass or on a thin polymer adapted to be disposed within the glazing.
  • the windshield of the vehicle may have tempered glass wherein the antenna circuit such as the circuit in FIG. 2(a) or FIG. 2(b) may be printed on any suitable face of the windshield without blocking the driver’s view.
  • the windshield may be laminated comprising two plies or layers of glass laminated with an interlayer material, such as and not limited to poly vinyl butyral, in between.
  • the antenna circuit may be printed on a thin polymer (such as and not limited to polyamide) adapted to be embedded within the laminated glazing.
  • the polymer unit on which the antenna is printed is adapted for offering durability and adhesive functionality for being embedded in laminated glazing.
  • the thickness of the polymer unit may be chosen in the range 100p-300p.
  • the size and material of the polymer unit may be chosen based on the ease of embedding into the laminated glazing.
  • the windshield can advantageously comprise another printed antenna circuit, as shown in FIG. 2 (b).
  • radiators (201’, 203’) originating from the feed junction (202’) extends to form conducting traces that run along the periphery of the windshield.
  • one antenna circuit may be used for FM/AM antenna application and another one is used or may be reserved for future LTE/GPS/RFID applications.
  • both the printed antenna circuit may be used for FM/AM reception in which one may be used as main and the other may be used as a back-up.
  • the antenna circuit may be configured for other applications without departing from the scope of the disclosure.
  • the optimised printed antenna circuit appear aesthetically pleasing as well, thereby enhancing the look and feel of the windshield of the vehicle.
  • the printed antenna is optimally positioned on the vehicle to improve passive gain and is placed at any location of the glazing.
  • the printed antenna circuitry is so designed that it is aesthetically placed around the border of the windshield.
  • this antenna circuitry may optimally be placed in a ceramic region of the windshield and may also be placed at any zones of the windshield as well.
  • FIG. 2 (a) shows a windshield with a single antenna circuit.
  • the conducting traces of the printed monopole antenna comprises a single feed junction, and two radiators, such that said radiators are forming a structure at the feed junction resembling a substantially right angled structure.
  • the optimized printed antenna circuit of the disclosed embodiment is configured to effectively tune in and function effectively, even when being in close proximity to the metal environment of a vehicle.
  • the conductive lines of the antenna circuit of the disclosed embodiment is advantageously optimised to be placed in ceramic painting region of the windshield.
  • the optimization of the conductive lines of the antenna circuit is in such a way that it provides good isolation over the ground or nearby metal environment interference and at the same time it does not make any compromise on the driver view.
  • FIG. 3 illustrates a system (100) for signal reception in a vehicle according to an embodiment of the present invention.
  • the system comprises at least one antenna circuit having a printed monopole antenna configured for exhibiting dual polarization characteristics.
  • the conducting traces (110) of the antenna circuit is printed on a glazing such as a windshield of a vehicle.
  • the antenna includes radiator and feed junction (105) operably connected via a connecting wire (104) to a receiving unit (110).
  • the connecting wire (104) may for instance be single core connecting wire and the like.
  • the receiving unit (110) may be placed around the windshield or any suitable place in the vehicle .
  • the antenna of the disclosed system may have connectors wherein said connectors may be press-button or push button.
  • the windshield may be surrounded by an outer frame border (300), in which the elements of the receiving unit (110) may be positioned.
  • the connecting wire (104) which may be a soldering wire connects the electronic circuit element (103) from the feed point, in which the electronic circuit element (103) may be placed on the outer frame border (300) of the windshield.
  • the cable (102) which may be an RF coaxial cable connects the electronic circuit element (103) to the FM/AM receiver.
  • the electronic circuit element (103) is further adapted to render mechanical support and are affixed in the metal body of the vehicle.
  • the antenna is connected to an electronic circuit element (103).
  • the electronic circuit element (103) may be and not limited to metal cavity or amplifier module.
  • FIG. 4 discloses the inside of a board of the metal (for example and not limited to aluminium) cavity which will be used for cable soldering and the same may be replaced by active module in future.
  • the electronic circuit element (103) can be an amplifier.
  • the electronic circuit element (103) is further operationally connected to a RF receiver.
  • the RF receiver may for instance be Frequency modulation/ Amplitude modulation (FM/AM) receiver.
  • the metal cavity includes via holes for top and ground connections. Further, the metal cavity includes center connection for enabling connection to signal line.
  • the signal line may be a connection 50/ 70-ohm signal line. In a nonlimiting implementation, the signal line is 70-ohm coaxial cable.
  • FIG. 5 depicts an exemplary instance of the placement of the different components of the system, advantageously placed on the outer frame of the enclosing the glass portion of the windshield.
  • the FM/AM receiver of the system may be placed on the bottom portion (FM/AM receiver location 1) of the outer frame of the windshield, alternatively it may be placed on the top portion (FM/AM receiver location 2) of the outer frame of the windshield.
  • the different components of the receiving unit (110) may be assembled at a location option 1 alternatively, it may be located at a location option 2, as shown in FIG. 5.
  • the placement of the receiving unit (110) as disclosed is not included as limitation to the present invention, but to enhance the understanding of the skilled person. Other possible implementation may also be made without deviating from the scope of the present disclosure.
  • assembly of a standard windshield in the metallic frame for an exemplary vehicle has been disclosed.
  • a suitable rubber gasket is wrapped around the windshield and the same is ensured as an inner side of gasket.
  • the sub-assembly is then fixed with a 3 wheeler windshield frame and the same is ensured as an outer side gasket to be fitted with the frame by standard tools. Rectification of any projection or bulge in the windshield assembly is brought forth by using suitable tools.
  • the present invention is also valid for a three-piece windshield.
  • a three-piece windshield conducting traces may be connected through a small sub assembly at the metal junction. The in-between metal partition is effectively used for wiring for RF feeding and interconnection.
  • a sidelite is used for FM/AM antenna application and another one is used or reserved for future LTE/GPS/RFID applications.
  • an antenna network is deposited with a conductive material on the face of the automotive glazing or on any polymer material (including PVB).
  • additional provision for sealing the gap between the antenna/antenna substrate and the glass may be provided and the design to be optimised to avoid lamination issues.
  • the process has to be optimised to avoid any contact of the radiating part of the antenna with metal body or any other metal. Provision for the grounding of the antenna should also be optimised to reduce losses.
  • the developed printed FM antenna on vehicle glazing is a value added product of existing glazing using the conductive silver printing method. It is a replacement of existing glazing with the same mounting procedures as known generally.
  • other components like small connecting cable, amplifier/active module, RF coaxial and the like may be mounted on metal frame in simple manner which is nearby feed point for making radio connectivity. This feature makes the present invention advantageous suitable for retrofit (aftermarket).
  • the antenna circuit may be printed on glass of a vehicle both laminated and non-laminated.
  • the antenna may also be printed on glass facade.
  • application specific customisation and/or modifications may then be required.
  • a set of conventional float glass is used for manufacturing of windshield for incorporating the printed antenna circuit disclosed herein above.
  • the glasses may have a thickness of around 3mm. Similar regular processes are applied to the bottom glass as well for printing logo and conductive traces through high quality screen printers.
  • silver ink is mainly used.
  • Other suitable conductive inks may also be used that serve the purpose.
  • a non- conductive coating is provided for anti-corrosion. Post this coating, the printed inks are cured at standard temperature using furnace.
  • At least two glasses are merged with an adhesive layer such as and not limited to a Polyvinyl butyral (or PVB) layer.
  • an adhesive layer such as and not limited to a Polyvinyl butyral (or PVB) layer.
  • the lamination of the automotive glass is performed using further standard automotive glazing manufacturing processes such as bending, preheating and autoclaving.
  • the antenna disclosed herein may be printed on laminated or non-laminated glasses, catering to the application requirements.
  • the present invention is disclosed incorporation of windshield for a 3 wheeler vehicle. From a windshield, appropriate pieces of the boundary layer such as a rubber gasket are removed to enable connections for radio frequency (RF) connector or other cable provisions for including the antenna circuit of disclosed herein above.
  • RF radio frequency
  • This procedure is simple and is easily fitted for single piece windshield.
  • the disclosed invention is so valid for three-piece windshield.
  • the three-piece windshield conducting traces are connected through a small sub assembly at the metal junction. Further, the space in between metal partition of the three-piece windshield, is effectively used for wiring for RF feeding and interconnection thereof.
  • the disclosed assembly of the disclosed antenna circuit is by no way a limitation, and other suitable assembly process or procedure can be followed as required by the implementation. This process has been disclosed as an example only for enabling the understanding of a skilled person.
  • Table 2 shows a radiation pattern gain comparison of reference vertical rod antenna with a printed glazing antenna as per the present disclosure. From the table 2, it is evidenced that the disclosed printed FM antenna has the receiving capability of FM signal at both vertical and horizontal polarization with the margin of around 7 dB difference.
  • the FM signals are transmitted only in vertical polarization but the signals are changing its polarization once hit the ground and other obstacles.
  • a dual mode/polarization diversity contributes a lot during the travel in the higher multipath environments like under tunnel, crowded tall building area, dense tree and other fixed foliage.
  • the disclosed printed antenna of the present invention is advantageously configured to receive both the polarization signals with the margin of 7dB is evidenced from the measured radiation pattern results with the reference antenna comparison (as shown in the above table).
  • the reference rod kind of vertical telescopic antenna only supports the vertical polarization reception instead of horizontal signal because of its natural vertical structure.
  • the disclosed invention facilitates the single antenna structure to receive the electromagnetic waves in polarization diversity mode as both horizontal and vertical for better coverage.
  • the placement of conductive line any location on the glazing is optimized in such a way that will provide good isolation over the ground/ nearby metal environment interference as well as no blockage of driver view.
  • the unique antenna design for windshield is provided factoring good aesthetics, deep bending/ curved profile of the windshield and backup for retrofit market as well.
  • the optimised printed antenna is cost effective and suitable for passenger friendly vehicles like 3 wheeler auto-rickshaws and light commercial vehicles.

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Abstract

The present disclosure provides a printed antenna circuit (120) on a windshield of a vehicle and a system (100) for signal transmission and reception in a vehicle. The printed monopole antenna (120) configured for exhibiting dual polarization characteristics. The conducting traces of the antenna circuit on the windshield of the vehicle is optimally placed adjacent to a periphery of a windshield of the vehicle. The disclosed invention is customised to provide necessary isolation over the ground and from interference of the nearby metal environment of the vehicle.

Description

A PRINTED ANTENNA CIRCUIT ON A WINDSHIELD OF A VEHICLE AND A SYSTEM THEREOF
FIELD OF TECHNOLOGY
The present invention relates to printed electronic circuits on an automotive glazing. Particularly, the present invention relates to printed antenna circuit on the glazing of a vehicle, more particularly, it relates to printed antenna circuit on the windshield of a vehicle.
BACKGROUND
Background description includes information that may be useful in understanding the present disclosure. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed disclosure, or that any publication specifically or implicitly referenced is prior art.
It is known to one skilled in the art that glazing refers to any and all the glass or polymer or similar material within a structure or the installation of any piece of glass or the similar material within a sash or frame. The glass windows of an automobile are referred to as glazing. For laminated glazing, two or more layers of glass or a similar material, are fused together with an interlayer in the middle. The fusion is completed with pressure and heat and it prevents the sheets of glass or polymer or the similar material from breaking.
In the recent years, the use of antenna for radio frequency transmission has been increasing. Antennas are used to convert electrical power into radio waves (for broadcast) or radio waves into electrical power (reception). Generally, they are used in conjunction with a transmitter or receiver. Antennas are used in vehicles as well for signal communications. In most cars, it is used for receiving radio broadcasts for recreational purpose. Some vehicles, such as commercial or government vehicles, use them to transmit and receive radio signals for the purpose of communicating either with each other or with a central dispatch.
Whip antenna is traditionally used in vehicles. Such antennas are attached to vehicles as the antennas for car radios and two-way radios for wheeled vehicles. Although whip antennas are capable of being used even in higher frequency like high frequency (HF), very high frequency (VHF) and ultra-high frequency (UHF) radio bands, but higher cost and cumbersome implementation are major disadvantages of such antennas. Another kind of antenna system in vehicle include systems with separate antenna components that are implemented as attachments to the printed circuit board (PCB). But these arrangements are disadvantageous if they suffer from drawbacks like the increased cost and weight, and in certain cases they tend to fail if used as an RF system. Further, known in the art are printed antennas that are made from conducting inks such as and not limited to silver paste, copper paste or tin paste. The printed antennas made from such conductive ink may be configured to function as RF antennas such as FM/AM printed antennas. In certain vehicle, a defogging heater wire may be configured as an FM printed antenna.
Reference is made to US20010010506A1 that discloses an antenna structure for a vehicle having an antenna disposed as a print or sticker antenna on a front window glass FM and AM waves reception. The therein disclosed antenna has a loop-shaped antenna element disposed near the upper edge portion of the front window glass and has two or three connected radiators used for both horizontal and vertical polarization. However, the gain over the bandwidth for this referred solution is not substantial as compared to open monopole radiator type and further, zero driver view blockage is not possible with this solution. Another reference is made to CA2979604C that relates to a vehicle antenna pane for separating a vehicle interior from external surroundings. The antenna disclosed in said prior art is most suitable for satellite- supported navigation, in particular for reception of a right circularly polarized GPS signal. Such antenna involves complex constructional features and is not preferred for frequency communication in the lower band.
Reference is made to JPH11312913A that discloses a window glass antenna system for automobile. The disclosure provides an antenna pattern for radio reception on a left window glass by printing or the like of a conductive paste material. However, such solutions are not suitable for front window glass or windshield due to high obstruction on the driver view.
Another reference is made to, Seungbeom Ahn, et al. DESIGN OF AN ON-GLASS VEHICLE ANTENNA USING A MULTILOOP STRUCTURE, Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 107- 110, 2010; Published online in Wiley InterScience
( .interscience. iley.com), that relates to an on-glass antenna with a multiloop structure for FM radio reception in a recreational vehicle (RV). The antenna includes multiple loops that are printed on a quarter glass with copper striplines. This multiloop structure is capable of broadening the operating band by efficiently using the given space of the quarter glass and raising the vertical gain by maximizing the z-directed currents. The multiloop structure is so designed that it can be placed along the conducting frame of the vehicle so that it has the added benefit of a superior field of view compared with other types of glass antennas. However, this solution is not suitable for vehicles having no sidelite or backlite such as 3 wheeler autorickshaws or other light commercial vehicles.
It has been found that printed circuit board (PCB) based antennas is not a suitable for glazing applications or for being embedded within laminated glasses. Although thin flexible antenna is good for such glazing applications but they require high dielectric and permeability property substrate. Further, airloop based antenna topology is also not suitable for low frequency application because of the higher electrical length requirements. Additionally, such antenna used for FM reception includes multi conductor lines making them well fit for sidelite and backlit of automotive glasses and inappropriate for the windshield. Because of the length requirements and the presence of multiple lines prior art antennas system such as the airloop based antenna topology will affect the driver zone and the reflection properties.
Although, transparent antenna has good reflection and optical characteristics for automotive glazing application, however, the realization cost of ink printing and complex active element integration high. Most vehicles existent in the art and the solutions of the prior art are directed at the use external antenna and on backlit printed defogger circuit for FM reception. Even though some of the solutions are directed at the printing the antenna on the front window or the windshield, all of them are either directed at printing antenna circuit hindering the view of the driver or they relate to solutions that are directed at printing antenna traces using expensive transparent ink. Such solutions are less feasible when viewed from an implementation point of view, especially for passenger vehicles such as and not limited to 3 wheeler auto and even 4 wheeler vehicle such as and not limited to mini trucks. These vehicles do not have the presence of a backlite or that of a sidelites. External antennas in such vehicles may not be helpful due to heavy metal enclosure. Additionally, the aesthetics are compromised. Still further, the other factors that adversely affect the incorporation of printed antenna on front glass or windshield of these vehicles are increased cost. Besides, the factors that detailed above, and the issue of metal interference persists when an antenna is implemented around the metal body of the vehicle. In the light of the prior art discussed hitherto, there is a need of a simple cost effective solutions relating to an antenna for radio wave transmission/reception for vehicle causing no drive view hindrance. Additionally, it is desirable for such an antenna to have good passive gain and good coverage in enclosed locations.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a printed antenna circuit overcoming the drawbacks of the prior art.
Another object of the present invention is to provide a system having a simple antenna for radio frequency reception on a vehicle.
Another object of the present invention is to provide a cost-effective printed antenna on the windshield of a vehicle for radio frequency reception.
Yet another object of the present invention is to provide a printed antenna on the windshield of a vehicle having zero driver view blockage.
Still another object of the present invention is to provide an antenna for vehicle having good passive gain and good coverage in enclosed locations.
A further object of the present invention is to provide an antenna on an automotive glazing near to the metal environment of the vehicle without hindering the functionality of the antenna.
A still further object of the present invention is to provide a system with a printed monopole antenna on the windshield of a vehicle configured for exhibiting dual polarization characteristics.
These and other objects of the invention are achieved by the following aspects of the invention. The following disclosure presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This presents some concept of the invention in a simplified form to a more detailed description of the invention presented later. It is a comprehensive summary of the disclosure and it is not an extensive overview of the present invention. The intend of this summary is to provide a fundamental understanding of some of the aspects of the present invention.
In an aspect of the present invention is disclosed a printed antenna circuit on a glazing of a vehicle. The printed antenna circuit comprises a printed monopole antenna configured for exhibiting dual polarization characteristics. The conducting traces of the antenna circuit on the glazing (preferably windshield) of the vehicle is optimally placed near to a periphery of the vehicle to provide necessary isolation over the ground and from the interference of the nearby metal environment of the vehicle.
In another aspect of the present invention is disclosed a system for signal transmission and reception in a vehicle. The system comprises at least one antenna circuit having a printed monopole antenna configured for exhibiting dual polarization characteristics. The conducting traces of the antenna circuit on a glazing (preferably windshield) of the vehicle is optimally placed adjacent to a periphery of the vehicle to provide necessary isolation over the ground and from the interference of the nearby metal environment of the vehicle and a connecting wire connecting the feed junction to a receiver unit.
The various aspects of the present invention provide a single antenna structure configured to receive the electromagnetic waves in polarization diversity mode as both horizontal and vertical, thereby providing better coverage. The conductive lines of the antenna circuit are optimally configured to be advantageously placed in a suitable location on the glazing. The conductive lines of the antenna define the antenna design and includes one or more curved structures. Said structure may include curved lines based designs that are placed near the periphery of the glazing or may include curved structure such as a serpentine design or a meander structure. The printed antenna circuit disclosed provides the necessary isolation over the ground or nearby metal environment interference and at the same time renders no blockage of driver view. Additionally, the unique antenna design on the glazing, which may be, preferably a windshield is aesthetically pleasing.
The significant features of the present invention and the advantages of the same will be apparent to a person skilled in the art from the detailed description that follows in conjunction with the annexed drawings. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The following briefly describes the accompanying drawings, illustrating the technical solution of the embodiments of the present invention or the prior art, for assisting the understanding of a person skilled in the art to comprehend the invention. It would be apparent that the accompanying drawings in the following description merely show some embodiments of the present invention, and persons skilled in the art can derive other drawings from the accompanying drawings without deviating from the scope of the disclosure.
FIG. 1 illustrates a windshield having two different printed antenna circuit according to an embodiment of the present invention.
FIGs. 2 (a)-(c) illustrate the different designs of the printed antenna circuit on a windshield showing the feed junction according to an embodiment of the present invention.
FIG. 3 illustrates a system for signal transmission and reception in a vehicle according to an embodiment of the present invention.
FIG. 4 illustrates an inner view of a metal cavity of the system for signal transmission and reception according to an embodiment of the present invention.
FIG. 5 illustrates an exemplary embodiment of the placement of the different components of the system according to the present invention.
Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the disclosure.
DETAILED DESCRIPTION OF THE INVENTION
The present disclosure is now discussed in more detail referring to the drawings that accompany the present application. It would be appreciated by a skilled person that this description to assist the understanding of the invention but these are to be regarded as merely exemplary.
Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.
The terms and words used in the following description are not limited to the bibliographical meanings and the same are used to enable a clear and consistent understanding of the invention. Accordingly, the terms/phrases are to be read in the context of the disclosure and not in isolation. Additionally, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
The term 'substantially' used in the present disclosure is used in order to avoid the mathematical rigidity of any characteristic, parameter, or value. This is meant to indicate that the corresponding characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including and not limited to for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
The present disclosure is directed at a single antenna structure that is configured to receive the electromagnetic waves and exhibit diverse polarization. The antenna structure disclosed herein is capable of exhibiting both horizontal and vertical polarization diversity mode for better coverage. The placement of the conductive lines of the antenna on an automotive glazing is optimised to provide the necessary isolation over the ground and/or the nearby metal environment. Said metal environment is provided by the vehicle body. The term isolation is known to one skilled in the art and it may be regarded as a scenario of no conductive losses or no radiative losses scenario.
The basic requirement of any radio frequency (RF) tuning circuit is length of a transmission line and it mainly follows equation (1) provided in the following disclosure. Generally, for an antenna, it is complicated because the length is mainly chosen based on the type of antenna to be selected. The conventional patch antenna requires half wavelength for radiation and for monopole case, quarter wavelength is sufficient for effective radiation. However, the use of patch based topology is very complex, especially when considering AM/FM based application. This issue is reasoned for the requirement of higher wavelength and the requirement of more glazing area. This has been detailed in the prior art section of the present disclosure. For such conventional patch antenna, the antenna circuit or the antenna element is defined by the area of the element which implies both length and width of such parameters are critical. Such patch antennas are a requirement for cases where a higher frequency of communication is needed. Accordingly, in an embodiment of the present invention is disclosed a simple antenna circuit for radio frequency reception on a vehicle. FIG. 1 illustrates at least two different implementations of this embodiment of the invention. It includes at least one printed monopole antenna configured for exhibiting dual polarization characteristics. The conducting traces of the printed monopole antenna comprises a single feed junction, and at least one radiators.
Conducting trace is general type of transmission line adapted to control at least two basic parameters of an antenna. The length and width of the radiator is used for frequency matching and impedance matching respectively. Antenna is a type of transformer between the source and air. Hence, the impedance is important for good matching and trade off with minimum trace width feasibility. The main polarization for FM signal is vertical and it may be affected due to ground reflection. Accordingly, for applications involving moving vehicles, a dual polarized antenna receiver is most suitable. In an embodiment of the present invention, the antenna includes at least one top radiator in horizontal orientation and another radiator in vertical orientation. The radiators are operationally oriented to capture both the polarization simultaneously for better coverage. The disclosed antenna topology is optimally designed for good ground immunity. In an implementation of the present invention, the antenna circuit on an automotive glazing is optimally placed adjacent to periphery of the glazing (such as and not limited to a windshield) of the vehicle. This advantageously provides good isolation over the ground or nearby metal environment interference. The antenna topology is oriented to advantageously render no obstacle in driver’s view.
Further disclosed herein is a suitable topology for monopole antenna. Since the use of patch based topology for antenna is very complex for AM/FM application due to the requirement of higher wavelength and since it occupies more glazing area, a suitable topology ought to be selected as monopole antenna. For effective radiation, it is noted that a quarter wavelength radiator is sufficient and the remaining may be obtained from ground currents by the vehicle body. The basic requirement of RF follows the following equation: X = c/f (Where C- speed of light & f- operating frequency) (1)
The medium is not an air so above is changed with inclusion of guided medium parameters as permittivity and permeability. Thus,
Xg= c/ pc*f (where Xg- guided wavelength, p&e -Permeability & Permittivity)
In the following is provided is given Table 1 that presents some design calculation of FM/AM antenna design:
Table 1
Figure imgf000011_0001
In an exemplary embodiment of the present invention is provided the printed antenna on the windshield of a vehicle. In the disclosed embodiment of the present invention, for FM signal reception, the significance of ground current is directly obtained from the windshield frame. This is sufficient enough to produce the ground matching for FM signal and however it is not sufficient for AM reception. As a result, the complete vehicle body will give much influence on AM signal than FM signal reception. As a result, the present embodiment advantageously includes an optimized topology for a monopole antenna for automotive applications. The effect of the optimisation is significantly vital for low frequency segments. FIG. 2 provides an antenna circuit architecture or antenna designs according to the disclosed embodiment.
The conducting traces of the antenna circuitry including at least one antenna circuit. The optimised conducting trace includes a unique antenna design as depicted in FIGs. 2(a)-2(c). The conducting traces of said antenna circuit includes a unique antenna design having curved lines extending form the at least one radiators. The optimised antenna topology is advantageous specially for windshield of 3 wheelers like auto rickshaws. The conducting traces are provided considering the deep bending or a curved profile of such windshield. The conducting traces of the antenna comprises a feed junction having a single feed point (202), and at least one radiator (201). In an implementation of the present invention, the antenna may be configured for radio frequency communication amplitude modulation (AM) and/or frequency modulation (FM) frequency bands, but however not limited to this. In a preferred embodiment, the antenna circuit is configured for radio frequency communication in the range 88MHz to 108MHz.
The antenna circuitry mainly comprises feed line, radiators and frame clearance distance. The feed line is mainly considered for effective matching between the FM receiver impedance and antenna source impedance. In general, the source impedance of the antenna is 50 ohm and receiver impedance is 75 ohm, hence suitable transformation of circuitry is required for good matching.
In an embodiment of the present invention is disclosed that the antenna circuit (120) includes a feedline and radiator element (105) that extends into conducting lines LI and L2 of the conducting trace of the antenna circuit as is depicted in FIG. 3. A small strip (like a small circle shaped strip) and length of strip combination is used as feedline for the topology. One of the radiators of the antenna may extend as LI of the circuit and another radiator of antenna may extend as L2 of the circuit. The conducting traces of said antenna circuit includes a unique antenna design having curved lines extending from the at least one radiators. The design may include simple curved lines extending along the boundary of the glazing or may include a meander or serpentine structure, but however not limited these.
In an implementation of the present invention, reference is made to FIG. 2(a) that shows an exemplary embodiment of an antenna design on a windshield. The radiators (201, 203) of the antenna structure extends as at least two lines LI, and L2 near the outer boundary of the windshield having optimal frame clearance distance. The edge distance which is the distance of a line from the outer border (200) of the windshield is ‘a’ with respect to a first conducting line LI, another edge distance is ‘b’ with respect to the conducting line LI, and ‘c’ with respect to a second conducting line L2. As per said implementation of the present invention edge distance ‘a’ may be in the range 55 mm-65 mm, ‘b’ may be in the range 45mm-75mm and ‘c’ may be in the range 55 mm-75 mm. Further, the distance of the feed junction (202) from the outer border of the windshield may be in the range 50 mm-80 mm. In an implementation of the present invention, reference is made to FIG. 2(b) that shows another exemplary embodiment of an antenna design on a windshield having two antenna circuitry. The optimally placed antenna circuit comprises a conducting line (LI) from a radiator (201) extending into a curved structure. The optimisation of the location of placement of the antenna unit and further the design of the curved structure of the antenna may be fine-tuned considering one or more parameters such as and not limited to the aesthetics of the glazing, the driver’s view area, the metal environment of the vehicle, the losses of signals, and efficiency in terms of antenna functionality. Said curved structure is having a meander-like shape or a serpentine line. The edge distance (c) of the conducting line (LI) extending into the curved structure (the meander-like shape or a serpentine line for this case) from an outer border (200) of the windshield may be 20 mm-75 mm, preferably 20 mm-50 mm. Additionally, such a structure of the antenna design advantageously reduces the size of antenna.
In an embodiment of the present invention, the glazing of the vehicle having the printed antenna may include laminated glass or tempered glass. Said antenna circuit may be printed on an optimised location on the tempered glass or on the one or more layers of the laminated glass or on a thin polymer adapted to be disposed within the glazing. In an implementation of the present invention, the windshield of the vehicle may have tempered glass wherein the antenna circuit such as the circuit in FIG. 2(a) or FIG. 2(b) may be printed on any suitable face of the windshield without blocking the driver’s view. Alternatively, the windshield may be laminated comprising two plies or layers of glass laminated with an interlayer material, such as and not limited to poly vinyl butyral, in between. The antenna circuit may be printed on a thin polymer (such as and not limited to polyamide) adapted to be embedded within the laminated glazing. The polymer unit on which the antenna is printed is adapted for offering durability and adhesive functionality for being embedded in laminated glazing. The thickness of the polymer unit may be chosen in the range 100p-300p. The size and material of the polymer unit may be chosen based on the ease of embedding into the laminated glazing.
In an implementation of the present invention, the windshield can advantageously comprise another printed antenna circuit, as shown in FIG. 2 (b). Just like the first circuitry, radiators (201’, 203’) originating from the feed junction (202’), extends to form conducting traces that run along the periphery of the windshield. In such cases, one antenna circuit may be used for FM/AM antenna application and another one is used or may be reserved for future LTE/GPS/RFID applications. Alternatively, both the printed antenna circuit may be used for FM/AM reception in which one may be used as main and the other may be used as a back-up. The antenna circuit may be configured for other applications without departing from the scope of the disclosure. The optimised printed antenna circuit appear aesthetically pleasing as well, thereby enhancing the look and feel of the windshield of the vehicle.
In an embodiment of the present invention, it is disclosed that the printed antenna is optimally positioned on the vehicle to improve passive gain and is placed at any location of the glazing. The printed antenna circuitry is so designed that it is aesthetically placed around the border of the windshield. Alternatively, this antenna circuitry may optimally be placed in a ceramic region of the windshield and may also be placed at any zones of the windshield as well.
The printed antenna is optimally placed to avoid the losses due to metal interferences. The printing of the antenna is facilitated adjacent to the metal environment of the windshield of the vehicle. FIG. 2 (a) shows a windshield with a single antenna circuit. The conducting traces of the printed monopole antenna comprises a single feed junction, and two radiators, such that said radiators are forming a structure at the feed junction resembling a substantially right angled structure. Generally, although most radiator structure of the prior art are capable of receiving signals, however, they pose drive view obstruction and cause high interference with nearby metal body. However, the optimized printed antenna circuit of the disclosed embodiment is configured to effectively tune in and function effectively, even when being in close proximity to the metal environment of a vehicle. The conductive lines of the antenna circuit of the disclosed embodiment is advantageously optimised to be placed in ceramic painting region of the windshield. The optimization of the conductive lines of the antenna circuit is in such a way that it provides good isolation over the ground or nearby metal environment interference and at the same time it does not make any compromise on the driver view.
FIG. 3 illustrates a system (100) for signal reception in a vehicle according to an embodiment of the present invention. The system comprises at least one antenna circuit having a printed monopole antenna configured for exhibiting dual polarization characteristics. The conducting traces (110) of the antenna circuit is printed on a glazing such as a windshield of a vehicle. The antenna includes radiator and feed junction (105) operably connected via a connecting wire (104) to a receiving unit (110). The connecting wire (104) may for instance be single core connecting wire and the like. The receiving unit (110) may be placed around the windshield or any suitable place in the vehicle . The antenna of the disclosed system may have connectors wherein said connectors may be press-button or push button. The windshield may be surrounded by an outer frame border (300), in which the elements of the receiving unit (110) may be positioned. The connecting wire (104) which may be a soldering wire connects the electronic circuit element (103) from the feed point, in which the electronic circuit element (103) may be placed on the outer frame border (300) of the windshield. The cable (102) which may be an RF coaxial cable connects the electronic circuit element (103) to the FM/AM receiver. The electronic circuit element (103) is further adapted to render mechanical support and are affixed in the metal body of the vehicle.
The antenna is connected to an electronic circuit element (103). The electronic circuit element (103) may be and not limited to metal cavity or amplifier module. FIG. 4 discloses the inside of a board of the metal (for example and not limited to aluminium) cavity which will be used for cable soldering and the same may be replaced by active module in future. According to an alternative implementation, the electronic circuit element (103) can be an amplifier. The electronic circuit element (103) is further operationally connected to a RF receiver. In an implementation of the present invention, the RF receiver may for instance be Frequency modulation/ Amplitude modulation (FM/AM) receiver. The metal cavity includes via holes for top and ground connections. Further, the metal cavity includes center connection for enabling connection to signal line. The signal line may be a connection 50/ 70-ohm signal line. In a nonlimiting implementation, the signal line is 70-ohm coaxial cable.
FIG. 5 depicts an exemplary instance of the placement of the different components of the system, advantageously placed on the outer frame of the enclosing the glass portion of the windshield. As per an implementation of this embodiment of the present invention, the FM/AM receiver of the system may be placed on the bottom portion (FM/AM receiver location 1) of the outer frame of the windshield, alternatively it may be placed on the top portion (FM/AM receiver location 2) of the outer frame of the windshield. According to an implementation of this embodiment, the different components of the receiving unit (110) may be assembled at a location option 1 alternatively, it may be located at a location option 2, as shown in FIG. 5. It would be appreciated by the person skilled in the art that the placement of the receiving unit (110) as disclosed is not included as limitation to the present invention, but to enhance the understanding of the skilled person. Other possible implementation may also be made without deviating from the scope of the present disclosure. In an embodiment of the present disclosure, assembly of a standard windshield in the metallic frame for an exemplary vehicle has been disclosed. According to the present invention, a suitable rubber gasket is wrapped around the windshield and the same is ensured as an inner side of gasket. The sub-assembly is then fixed with a 3 wheeler windshield frame and the same is ensured as an outer side gasket to be fitted with the frame by standard tools. Rectification of any projection or bulge in the windshield assembly is brought forth by using suitable tools. Small pieces of the gasket may then be removed or small holes may be made for RF connector/cable provision. The above procedure is best and conveniently fitted for a single piece windshield. The present invention is also valid for a three-piece windshield. In an implementation of the present embodiment, a three-piece windshield conducting traces may be connected through a small sub assembly at the metal junction. The in-between metal partition is effectively used for wiring for RF feeding and interconnection.
As per one embodiment of the present invention, in a vehicle a sidelite is used for FM/AM antenna application and another one is used or reserved for future LTE/GPS/RFID applications. In this disclosed assembling method, an antenna network is deposited with a conductive material on the face of the automotive glazing or on any polymer material (including PVB). Besides, in scenarios of providing the antenna in a face 2 or face 3 of a laminate, additional provision for sealing the gap between the antenna/antenna substrate and the glass may be provided and the design to be optimised to avoid lamination issues. With respect to antenna, the process has to be optimised to avoid any contact of the radiating part of the antenna with metal body or any other metal. Provision for the grounding of the antenna should also be optimised to reduce losses.
The developed printed FM antenna on vehicle glazing is a value added product of existing glazing using the conductive silver printing method. It is a replacement of existing glazing with the same mounting procedures as known generally. In addition, other components like small connecting cable, amplifier/active module, RF coaxial and the like may be mounted on metal frame in simple manner which is nearby feed point for making radio connectivity. This feature makes the present invention advantageous suitable for retrofit (aftermarket).
In an alternate implementation of the disclosed invention, the antenna circuit may be printed on glass of a vehicle both laminated and non-laminated. The antenna may also be printed on glass facade. However, for proper working of the antenna circuit, however, application specific customisation and/or modifications may then be required.
In another embodiment of the present invention is disclosed fabrication of windshield of a mini truck. According to this embodiment of the invention, a set of conventional float glass is used for manufacturing of windshield for incorporating the printed antenna circuit disclosed herein above. No processing is required in the top glass except regular processes. The glasses may have a thickness of around 3mm. Similar regular processes are applied to the bottom glass as well for printing logo and conductive traces through high quality screen printers. For printing the conductive traces on the glass, silver ink is mainly used. Other suitable conductive inks may also be used that serve the purpose. On top of that printed antenna circuitry, a non- conductive coating is provided for anti-corrosion. Post this coating, the printed inks are cured at standard temperature using furnace. Further to this, at least two glasses are merged with an adhesive layer such as and not limited to a Polyvinyl butyral (or PVB) layer. The lamination of the automotive glass is performed using further standard automotive glazing manufacturing processes such as bending, preheating and autoclaving. The antenna disclosed herein may be printed on laminated or non-laminated glasses, catering to the application requirements.
In an embodiment of the present invention is disclosed incorporation of windshield for a 3 wheeler vehicle. From a windshield, appropriate pieces of the boundary layer such as a rubber gasket are removed to enable connections for radio frequency (RF) connector or other cable provisions for including the antenna circuit of disclosed herein above. This procedure is simple and is easily fitted for single piece windshield. Furthermore, the disclosed invention is so valid for three-piece windshield. The three-piece windshield conducting traces are connected through a small sub assembly at the metal junction. Further, the space in between metal partition of the three-piece windshield, is effectively used for wiring for RF feeding and interconnection thereof. The disclosed assembly of the disclosed antenna circuit is by no way a limitation, and other suitable assembly process or procedure can be followed as required by the implementation. This process has been disclosed as an example only for enabling the understanding of a skilled person.
Further, disclosed herein is a comparative study between the herein disclosed antenna circuit and a reference antenna of prior art. Table 2 shows a radiation pattern gain comparison of reference vertical rod antenna with a printed glazing antenna as per the present disclosure. From the table 2, it is evidenced that the disclosed printed FM antenna has the receiving capability of FM signal at both vertical and horizontal polarization with the margin of around 7 dB difference.
Table 2
Figure imgf000018_0001
In general, the FM signals are transmitted only in vertical polarization but the signals are changing its polarization once hit the ground and other obstacles. A dual mode/polarization diversity contributes a lot during the travel in the higher multipath environments like under tunnel, crowded tall building area, dense tree and other fixed foliage. The disclosed printed antenna of the present invention is advantageously configured to receive both the polarization signals with the margin of 7dB is evidenced from the measured radiation pattern results with the reference antenna comparison (as shown in the above table). The reference rod kind of vertical telescopic antenna only supports the vertical polarization reception instead of horizontal signal because of its natural vertical structure.
Some of the advantages of the present invention are:
• The disclosed invention facilitates the single antenna structure to receive the electromagnetic waves in polarization diversity mode as both horizontal and vertical for better coverage.
• In the disclosed invention, the placement of conductive line any location on the glazing is optimized in such a way that will provide good isolation over the ground/ nearby metal environment interference as well as no blockage of driver view.
• The unique antenna design for windshield is provided factoring good aesthetics, deep bending/ curved profile of the windshield and backup for retrofit market as well.
• In between metal junction of the three-piece windshield is used for wiring and connectivity between the different circuits on the glazing. The optimised printed antenna is cost effective and suitable for passenger friendly vehicles like 3 wheeler auto-rickshaws and light commercial vehicles.
Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which they are performed.
Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.
The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Certain features, that are for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in a sub combination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.
The description in combination with the figures is provided to assist in understanding the teachings disclosed herein, is provided to assist in describing the teachings, and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other teachings can certainly be used in this application. As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such method, article, or apparatus. Further, unless expressly stated to the contrary, "or" refers to an inclusive- or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
Also, the use of "a" or "an" is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise. For example, when a single item is described herein, more than one item may be used in place of a single item. Similarly, where more than one item is described herein, a single item may be substituted for that more than one item.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent that certain details regarding specific materials and processing acts are not described, such details may include conventional approaches, which may be found in reference books and other sources within the manufacturing arts.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.
List of reference numerals appearing in the accompanying drawings and the corresponding features: 100: a system for signal reception in a vehicle
101 : RF Receiver
102: cable
103: an electronic circuit element 104: a connecting wire
105: radiator and feed junction
110: conducting traces of an antenna circuit
120: antenna circuit
LI, and L2: conducting trace of the antenna circuit 200: outer border of the windshield
201, 203, 201’, 203’ : the radiators
202, 202’: feed junction
‘a’, ‘b’ and ‘c’: edge distance
300: an outer frame border

Claims

1. An antenna circuit on a glazing of a vehicle comprising: a printed monopole antenna configured for exhibiting dual polarization characteristics; wherein conducting traces of said antenna circuit is optimally placed near a periphery of the glazing to provide necessary isolation over the ground.
2. The antenna circuit as claimed in claim 1, wherein the conducting traces of said printed monopole antenna comprises a feed junction having a single feed point (202), and at least one radiator (201); and said printed antenna is configured for radio frequency communication in amplitude modulation (AM) and/or frequency modulation (FM) bands.
3. The antenna circuit as claimed in any one of the preceding claims, wherein said antenna circuit is configured for radio frequency communication in the range 88MHz to 108MHz.
4. The antenna circuit as claimed in any one of the preceding claims, wherein length of the antenna is quarter of the wavelength of the radio wave.
5. The antenna circuit as claimed in any one of the preceding claims, wherein the conducting traces of said antenna circuit includes a unique antenna design having curved lines extending from the at least one radiators.
6. The antenna circuit as claimed in any one of the preceding claims, wherein the optimally placed antenna circuit comprises a conducting line (LI) from a radiator (201) extending into a curved structure wherein an edge distance (c) of the conducting line (LI) extending into the curved structure from an outer border (200) of the glazing is 20 mm-75 mm.
7. The antenna circuit as claimed in any one of the preceding claims, wherein the optimally placed antenna circuit comprises conducting lines (LI, L2) extending from two radiators (201, 203); wherein an edge distance (a) of a first conducting line (LI) from an outer border (200) of the glazing is 55 mm-65 mm, another edge distance (b) of the first conducting line (LI) from the outer border (200) of the glazing is 55 mm-75 mm, and the edge distance (c) of the second conducting line (L2) from the outer border (200) of the glazing is 55 mm-75 mm.
8. The antenna circuit as claimed in any one of the preceding claims, wherein the radiators (201, 203) of the monopole antenna are configured to form a structure at the feed point resembling substantially a right angled structure.
9. The antenna circuit as claimed in any one of the preceding claims, wherein the single feed junction includes a small strip of conducting trace, wherein a combination of said small strip and length of the strip are configured as a feed line for the antenna circuit.
10. The antenna circuit as claimed in any one of the preceding claims, wherein the two radiators (201, 203) are configured to capture both horizontal polarization and vertical polarization simultaneously for better signal coverage; and one radiator (201) placed at a top position with respect to the glazing is in horizontal orientation and another radiator (203) is in vertical orientation.
11. The antenna circuit as claimed in any one of the preceding claims, wherein the printed antenna is optimally placed on the vehicle to improve passive gain; and is placed at any location of the glazing, wherein said glazing includes a curved profile with a deep bent.
12. The antenna circuit as claimed in any one of the preceding claims, wherein the glazing of the vehicle includes laminated glass or tempered glass.
13. The antenna circuit as claimed in any one of the preceding claims, wherein said antenna circuit is printed on an optimised location on the tempered glass or on the one or more layers of the laminated glass or on a thin polymer adapted to be disposed within the glazing.
14. A system for signal transmission and reception in a vehicle comprising: at least one antenna circuit (120) having a printed monopole antenna configured for exhibiting dual polarization characteristics; wherein conducting traces of said antenna circuit on a glazing of the vehicle is optimally placed adjacent to a periphery of the glazing of the vehicle to provide necessary isolation over the ground and from the interference of the nearby metal environment of the vehicle; and a connecting wire (104) connecting the feed junction (105) to a receiver unit (110).
15. The system as claimed in any one of the preceding claims, wherein the optimally placed antenna circuit includes conducting traces forming a unique antenna design having curved lines extending from at least one radiators of the antenna.
16. The system as claimed in any one of the preceding claims, includes a sub assembly for interconnection between the conducting traces.
17. The system as claimed in any one of the preceding claims, wherein the connecting wire (104) is a single core connecting wire configured to connect the feed junction via an electronic circuit element (103) to an amplitude modulation/frequency modulation receiver.
18. The system as claimed in any one of the preceding claims, comprising another aesthetically placed antenna circuit for diversity reception or as a replacement of a first antenna circuit.
19. A windshield of a vehicle having a printed antenna as claimed in any one of claims 1- 13, wherein said printed antenna is optimally and aesthetically placed on the windshield without hindering the driver’s view.
PCT/IN2022/050093 2021-02-05 2022-02-03 A printed antenna circuit on a windshield of a vehicle and a system thereof WO2022168119A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN202141005032 2021-02-05
IN202141005032 2021-02-05

Publications (1)

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WO2022168119A1 true WO2022168119A1 (en) 2022-08-11

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Application Number Title Priority Date Filing Date
PCT/IN2022/050093 WO2022168119A1 (en) 2021-02-05 2022-02-03 A printed antenna circuit on a windshield of a vehicle and a system thereof

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106654595A (en) * 2017-02-08 2017-05-10 华南理工大学 High-gain and low-profile vehicle-mounted antenna

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106654595A (en) * 2017-02-08 2017-05-10 华南理工大学 High-gain and low-profile vehicle-mounted antenna

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