Surface wave self-inhibiting antenna and vehicle glazing

Abstract

The application discloses a surface wave self-suppression antenna and vehicle-mounted glass, and the antenna comprises a transition structure, a radial current line, a feeding patch and a feeding structure, the transition structure and the radial current line serving as radiators of the antenna, the transition structure being a center-symmetrical circular ring-shaped or circular ring-shaped patch; the radial current line comprises a plurality of strip lines, the plurality of strip lines are radially distributed along a circumference, one end of each strip line is connected with the transition structure, and the other end is open; a distribution direction of each strip line is along a radial direction, and reverse extension lines of each strip line intersect at a point; the feeding structure comprises at least two feeding units, the feeding units are arranged at the same angle as one of the strip lines, and are equally angularly distributed along a circumference of the feeding patch, one end of each feeding unit is connected with the feeding patch, and the other end is connected with the transition structure. The application can maximize the avoidance of generation of surface waves, has vertical polarization characteristics, and realizes horizontal omnidirectional radiation.

Description

Technical Field

[0001] This invention relates to a surface wave self-suppressing antenna and automotive glass, belonging to the field of antenna technology. Background Technology

[0002] As one of the core radiating components for wireless communication in intelligent connected vehicles, the performance of vehicle-mounted antennas directly affects the communication quality of the intelligent connected vehicle communication system. Currently, the mainstream vehicle-mounted antennas include vehicle-mounted glass antennas, which integrate antenna functions with glass technology. Additionally, V2X systems provide assurance for vehicle-to-vehicle communication, allowing a moving car to perceive the status of surrounding vehicles and make driving strategies based on surrounding vehicle data, ensuring safe driving. V2X antennas are key components for radiating and receiving electromagnetic waves in vehicle-mounted V2X systems; excellent V2X antenna performance can improve V2X wireless channel quality and enhance communication and sensing performance.

[0003] However, current automotive glass has large area and high dielectric constant electrical properties, which can lead to serious surface wave problems. In the V2X band, when an antenna is placed on such a glass surface, some of the electromagnetic waves it radiates will continue to propagate and reflect along the interface between the glass and the air, without being effectively radiated into free space. This results in antenna pattern distortion and reduced radiation efficiency, weakening the antenna's radiation performance.

[0004] Traditional surface wave (SW) suppressors typically employ electromagnetic bandgap structures, defective ground structures, or metasurface structures to suppress SW propagation. However, these methods are generally complex and bulky, and the added structures introduce insertion loss. Therefore, it is necessary to design an antenna that can be integrated into vehicle glass. This antenna must be able to suppress SW generation through its own structural design without introducing additional structures, avoid the adverse effects of SW, and improve the communication quality of intelligent connected vehicle communication systems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a surface wave self-suppression antenna that can minimize the generation of surface waves, has vertical polarization characteristics, and achieves horizontal omnidirectional radiation.

[0006] Another object of the present invention is to provide a vehicle glass comprising the above-described antenna.

[0007] The objective of this invention can be achieved by adopting the following technical solutions:

[0008] A surface wave self-suppressing antenna includes a transition structure, a radial current line, a feed patch, and a feed structure, wherein the transition structure and the radial current line serve as radiators of the antenna.

[0009] The radial current line includes multiple strip lines, which are distributed radially along the circumference. One end of each strip line is connected to the transition structure, and the other end is open. The distribution direction of each strip line is radial, and the reverse extensions of each strip line intersect at a point.

[0010] The power supply structure includes at least two power supply units, which are positioned at the same angle as one of the strip lines and are distributed at equal angles around the center of the power supply patch. One end of each power supply unit is connected to the power supply patch, and the other end is connected to the transition structure.

[0011] Furthermore, the multiple strip lines are distributed at equal angles, the current in each strip line flows in the radial direction, and the current amplitude distribution on each strip line is consistent.

[0012] Furthermore, when there are an even number of striplines, for each stripline, there is another stripline with the same current amplitude distribution and the same phase in the opposite direction, and these two striplines are arranged symmetrically.

[0013] Furthermore, the length of each stripline is one-quarter of the wavelength at the antenna's operating frequency.

[0014] Furthermore, the transition structure is a centrally symmetrical annular or near-annular patch.

[0015] Furthermore, the transition structure completely surrounds the power supply patch, and there is a gap between the transition structure and the power supply patch.

[0016] Furthermore, the power supply patch has a circular, near-circular, annular, near-annular, or polygonal structure.

[0017] Furthermore, the center of the power supply patch coincides with the intersection of the center of the transition structure and the reverse extension of the strip line.

[0018] The objective of this invention can also be achieved by adopting the following technical solutions:

[0019] A surface wave self-suppressing antenna includes a transition structure, a radial current line, a feed line, and a feeding structure, wherein the transition structure and the radial current line serve as radiators of the antenna.

[0020] The radial current line includes multiple strip lines, which are distributed radially along the circumference. One end of each strip line is connected to the transition structure, and the other end is open. The distribution direction of each strip line is radial, and the reverse extensions of each strip line intersect at a point.

[0021] The power supply structure includes a power supply unit, which is located at the geometric center of the transition structure. The transition structure and the power supply unit are connected by a power supply wire.

[0022] Furthermore, the feeder line includes two feeder strip lines, which are respectively connected to the beginning and end of the current integration line on the feeder unit port.

[0023] Furthermore, of the two feed striplines, one feed stripline is longer than the other. The shorter feed stripline is the radius of the transition structure, while the longer feed stripline is bent multiple times, with the bent portion forming an arc segment. The length of the longer feed stripline is the radius of the transition structure plus the length of the arc segment, and the length of the arc segment is half the wavelength at the antenna's operating frequency.

[0024] Furthermore, when there are an even number of striplines, for each stripline, there is another stripline with the same current amplitude distribution and phase in the opposite direction. These two striplines are arranged symmetrically, and a slot is cut in the middle of the two symmetrical striplines.

[0025] Another objective of this invention can be achieved by adopting the following technical solution:

[0026] A vehicle-mounted glass includes a glass substrate and the aforementioned surface wave self-suppression antenna, wherein the surface wave self-suppression antenna is etched on the surface of the glass substrate.

[0027] The present invention has the following advantages over the prior art:

[0028] 1. The surface wave self-suppression antenna of the present invention has a planar structure and is etched on the glass surface. Therefore, it does not require drilling or grooving of the glass and has no impact on the structural strength of the glass. At the same time, the surface wave self-suppression function of the antenna comes from the antenna's own special current distribution. Unlike traditional methods, it does not require the introduction of complex electromagnetic bandgap structures, metasurface structures, or other complex additional structures. Therefore, the overall size of the antenna is small and can be set in the black edge area of ​​the glass, without obstructing the view of the driver and passengers in the vehicle, and without affecting driving safety or overall aesthetics.

[0029] 2. In the antenna of this invention, the current in the radial current lines flows in the radial direction, and the radial current lines at any angle have the same amplitude distribution. The direction of current flow is perpendicular to the electric field direction in the TE and TM modes of the surface waves inside the glass, or the direction is not perpendicular but the field integral is zero, so that the surface waves cannot be excited by the radiator, thus achieving self-suppression of surface waves. Therefore, the antenna's radiation pattern and radiation efficiency are not affected, and the antenna performance is guaranteed.

[0030] 3. In the antenna of the present invention, the current in the radial current line flows in the radial direction, and the radial current in multiple strip lines forms a ring magnetic current, which is equivalent to an electric dipole placed perpendicular to the horizontal plane, thereby realizing horizontal omnidirectional radiation and having vertical polarization characteristics.

[0031] 4. The antenna of the present invention can also be modified by replacing the feed patch with a feed wire to significantly reduce the number of feed units and simplify the feed process.

[0032] 5. The antenna of the present invention achieves a radiation null on the upper side of the passband by creating slots on two symmetrical strip lines in the radial current line, forming currents flowing in opposite directions on both sides of the slots; on the other hand, the size of the central angle corresponding to the arc segment of the feed line controls another radiation null located on the lower side of the passband. The antenna has two radiation nulls, located on both sides of the passband, giving the antenna filtering performance. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the surface wave self-suppression antenna of Embodiment 1 of the present invention.

[0035] Figure 2 This is a schematic diagram of the glass substrate structure of Embodiment 1 of the present invention.

[0036] Figure 3 This is a current distribution diagram for 6GHz in Embodiment 1 of the present invention.

[0037] Figure 4 This is a three-dimensional radiation pattern at 6 GHz according to Embodiment 1 of the present invention.

[0038] Figure 5 This is a 6GHz horizontal two-dimensional radiation pattern of Embodiment 1 of the present invention.

[0039] Figure 6 This is a schematic diagram of the surface wave self-suppression antenna of Embodiment 2 of the present invention.

[0040] Figure 7 This is a current distribution diagram for 6GHz in Embodiment 2 of the present invention.

[0041] Figure 8 This is a 6GHz horizontal two-dimensional radiation pattern of Embodiment 2 of the present invention.

[0042] Figure 9 This is a schematic diagram of the surface wave self-suppressing antenna in Embodiment 3 of the present invention.

[0043] Figure 10 This is a current distribution diagram for 6GHz in Embodiment 3 of the present invention.

[0044] Figure 11 This is a three-dimensional radiation pattern at 6 GHz according to Embodiment 3 of the present invention.

[0045] Figure 12 This is a 6GHz horizontal two-dimensional radiation pattern of Embodiment 3 of the present invention.

[0046] Figure 13 This is a schematic diagram of the surface wave self-suppressing antenna in Embodiment 4 of the present invention.

[0047] Figure 14 This is a current distribution diagram within a 6GHz bandwidth range for Embodiment 4 of the present invention.

[0048] Figure 15 This is a current distribution diagram at the upper bandwidth of 7.2 GHz in Embodiment 4 of the present invention.

[0049] Figure 16 This describes the influence of the sixteenth and twentieth strip lines of Embodiment 4 of the present invention on the upper radiation null point of the antenna.

[0050] Figure 17 This illustrates the effect of the central angle of the arc segment of the fourth feed strip in Embodiment 4 of the present invention on the radiation null point on the lower side of the antenna.

[0051] Figure 18 The radiation efficiency and S of Embodiment 4 of the present invention 11 curve.

[0052] Figure 19 This is a three-dimensional radiation pattern at 6 GHz according to Embodiment 4 of the present invention.

[0053] Figure 20 This is a 6GHz horizontal two-dimensional radiation pattern of Embodiment 4 of the present invention.

[0054] Wherein, 101-first transition structure, 102-first radial current line, 1021-first stripline, 1022-second stripline, 1023-third stripline, 1024-fourth stripline, 103-first feed patch, 104-first feed structure, 1041-first feed unit, 1042-second feed unit, 1043-third feed unit, 1044-fourth feed unit, 105-glass substrate, 1051-first glass component, 1052-intermediate layer, 1053-second glass component, 201-second transition structure, 202-second radial current line, 2021-fifth stripline, 2022-sixth stripline, 2023-seventh stripline, 2024-eighth stripline, 203-second feed patch, 204-second feed structure, 2041-fifth feed unit. 2042 - Sixth feed unit, 301 - Third transition structure, 302 - Third radial current line, 3021 - Ninth strip line, 3022 - Tenth strip line, 3023 - Eleventh strip line, 3024 - Twelfth strip line, 303 - First feed line, 3031 - First feed strip line, 3032 - Second feed strip line, 304 - Third feed structure, 401 - Fourth transition structure, 40 21-Thirteenth strip line, 4022-Fourteenth strip line, 4023-Fifteenth strip line, 4024-Sixteenth strip line, 4025-Seventeenth strip line, 4026-Eighteenth strip line, 4027-Nineteenth strip line, 4028-Twentieth strip line, 403-Second feeder line, 4031-Third feeder strip line, 4032-Fourth feeder strip line, 404-Fourth feeder structure. Detailed Implementation

[0055] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0056] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have the transmission of electrical signals or data between them.

[0057] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, integral, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, integrals, steps, operations, components, parts, or combinations thereof. Furthermore, the terms used in this specification include any and all combinations of the associated listed items.

[0058] Example 1:

[0059] like Figure 1 As shown, this embodiment provides a surface wave self-suppressing antenna. The antenna includes a first transition structure 101, a first radial current line 102, a first feed patch 103, and a first feed structure 104. The first transition structure 101 and the first radial current line 102 serve as the antenna radiators, and the first feed patch 103 serves as the antenna's common electrical ground. The radiators and the first feed patch 103 are connected through the first feed structure 104. The antenna is etched onto the surface of a glass substrate 105, which can be used to construct automotive glass.

[0060] In this embodiment, the first transition structure 101 is a centrally symmetrical annular patch. The first transition structure 101 completely surrounds the power supply patch, and there is a gap between the first transition structure 101 and the first power supply patch 103. It can be understood that the first transition structure 101 can also be a quasi-annular patch.

[0061] The first radial current line 102 in this embodiment includes four strip lines, namely the first strip line 1021, the second strip line 1022, the third strip line 1023 and the fourth strip line 1024. The four strip lines are radially distributed at equal angles along the circumference of the transition structure. The interval between any two adjacent strip lines is 90°. One end of each strip line is connected to the transition structure, and the other end is open. The length of each strip line is one-quarter wavelength at the antenna operating frequency, and the width is 10 mm. The distribution direction of each strip line is radial, and the reverse extension lines of each strip line intersect at a point.

[0062] In this embodiment, the first power supply patch 103 has a circular structure, and the center of the first power supply patch 103 coincides with the intersection of the center of the first transition structure 101 and the reverse extension line of the strip line. It can be understood that the first power supply patch 103 can also be a quasi-circular, annular, or polygonal structure.

[0063] The first feeding structure 104 in this embodiment includes four feeding units, the number of which is the same as the number of striplines. The four feeding units are the first feeding unit 1041, the second feeding unit 1042, the third feeding unit 1043, and the fourth feeding unit 1044. The eight feeding units are distributed at equal angles along the circumference of the first feeding patch 103, with a 90° interval between any two adjacent feeding units. One end of each feeding unit is connected to the first feeding patch 103, and the other end is connected to the first transition structure 101. The current integration lines on the four feeding units all point from the first feeding patch 103 to the first transition structure 101, achieving equal amplitude and phase feeding, so that the current on the four striplines in the first radial current line 102 is distributed radially with the same amplitude and phase.

[0064] Furthermore, the aforementioned stripline distribution and feeding method ensure that the current distribution on the antenna satisfies the special current distribution condition for surface wave self-cancellation. Specifically, the current in each stripline flows in phase radially, and the current amplitude distribution on each stripline is consistent, with equal angles along the circumference. Under this special current distribution, the direction of current flow is perpendicular to the electric field direction of the n=0 mode in TE and TM modes, or not everywhere perpendicular to the electric field direction of most higher-order modes, but the field integral is zero. Calculating the excitation coefficients using the reciprocity theorem proves that surface waves in most modes cannot be excited by radial current lines, thus achieving surface wave self-suppression. Simultaneously, the current in each stripline flows radially, and the radial currents in the four striplines form a ring-shaped magnetic current, equivalent to an electric dipole placed perpendicular to the horizontal plane, thereby achieving horizontal omnidirectional radiation and vertical polarization characteristics.

[0065] In this embodiment, the glass substrate 105 can be a sunroof, a front windshield, or a rear windshield, such as... Figure 2 As shown, the glass substrate 105 includes a first glass element 1051, an intermediate layer 1052, and a second glass element 1053. The first glass element 1051 includes a first surface and a second surface, and the second glass element 1053 includes a third surface and a fourth surface. The first surface is away from the third surface, the second surface is close to the third surface, the third surface is close to the second surface, and the fourth surface is away from the second surface. When the glass substrate 105 is installed on a vehicle, the first surface, the second surface, the third surface, and the fourth surface are viewed from inside the vehicle through the window. The intermediate layer 1052 can be made of PVB (Polyvinyl Butyral), which can bond the first glass element 1051 and the second glass element 1053 together through a lamination process to form a laminated glass. This can effectively improve the strength and toughness of the glass substrate 105, as well as its impact resistance and safety performance.

[0066] The surface wave self-suppression antenna of this embodiment can be disposed on the first, second, third, or fourth surface of the glass substrate 105. That is, the first transition structure 101, the first radial current line 102, the first feed patch 103, and the first feed structure 104 are coplanar and can be disposed on the first, second, third, or fourth surface. In addition, the surface wave self-suppression antenna can be disposed in the black edge area of ​​the glass substrate 105, so as not to affect the light transmission performance of the transparent area of ​​the glass substrate 105. Preferably, the first transition structure 101, the first radial current line 102, the first feed patch 103, and the first feed structure 104 are coplanar and disposed in the black edge area of ​​the fourth surface of the glass substrate 105. This facilitates feeding, has high radiation efficiency, does not affect the light transmission performance of the transparent area of ​​the glass substrate 105, and has low manufacturing difficulty.

[0067] like Figure 3 As shown, through the first feeding structure 104, an equal-radial and in-phase radial current is excited in the first radial current line 102. The current flows from one side of the first radial current line 102 near the first transition structure 101 to the other side. The current distribution satisfies the special current distribution condition for surface wave self-cancellation. This makes the direction of current flow perpendicular to the electric field of the n=0 mode in the TE and TM mode surface waves in the glass substrate 105, and not perpendicular to the electric field of most higher-order modes everywhere, but the total field integral is zero. According to the reciprocity theorem, the excitation coefficient can be calculated, and it can be proved that the surface waves of most modes cannot be excited by the first radial current line 102, thereby achieving surface wave self-suppression. At the same time, the radial currents on the first strip line 1021, the second strip line 1022, the third strip line 1023 and the fourth strip line 1024 form a ring magnetic current, i.e., a magnetic current loop, which is equivalent to an electric dipole placed perpendicular to the glass substrate 105. Thus, the antenna described in this embodiment achieves horizontal omnidirectional radiation and has vertical polarization characteristics.

[0068] like Figure 4 and Figure 5 The figure shows the three-dimensional radiation pattern and the two-dimensional horizontal radiation pattern of the surface wave self-suppressing antenna of this embodiment. As can be seen from the figure, in the horizontal direction, the antenna radiation pattern is approximately circular, and there is no pitting or cracking caused by surface waves. Furthermore, the vertical polarization level is 6 dB higher than the horizontal polarization level. Therefore, it can be seen that the surface wave self-suppressing antenna of this embodiment achieves suppression of surface waves inside the glass, while also achieving horizontal omnidirectional radiation and having vertical polarization characteristics.

[0069] Example 2:

[0070] like Figure 6As shown, this embodiment provides a surface wave self-suppressing antenna, whose structure and size are basically the same as those in Embodiment 1, and the feeding structure is simplified. The antenna includes a second transition structure 201, a second radial current line 202, a second feeding patch 203, and a second feeding structure 204. The second transition structure 201 and the second radial current line 202 serve as the radiators of the antenna, and the second feeding patch 203 serves as the common electrical ground of the antenna. The radiators and the second feeding patch 203 are connected through the second feeding structure 204.

[0071] The second radial current line 202 in this embodiment includes four strip lines, namely the fifth strip line 2021, the sixth strip line 2022, the seventh strip line 2023, and the eighth strip line 2024. The four strip lines are radially distributed at equal angles along the circumference of the second transition structure 201. The interval between any two adjacent strip lines is 90°. One end of each strip line is connected to the second transition structure 201, and the other end is open. The length of each strip line is one-quarter wavelength at the antenna operating frequency, and the width is 12 mm. The distribution direction of each strip line is radial, and the reverse extensions of each strip line intersect at a point.

[0072] The second feeding structure 204 in this embodiment includes two feeding units, namely the fifth feeding unit 2041 and the sixth feeding unit 2042. The two feeding units are distributed at equal angles along the circumference of the second feeding patch 203, with a 180° interval between them. One end of each feeding unit is connected to the second feeding patch 203, and the other end is connected to the second transition structure 201. The current integration lines on both feeding units point from the second feeding patch 203 to the second transition structure 201, achieving equal amplitude and phase feeding. At this time, due to the symmetry of the structure, the fifth stripline 2021 and the seventh stripline 2023 are symmetrical, and the currents on their upper sides exhibit equal amplitude and phase characteristics; similarly, the sixth stripline 2022 and the eighth stripline 2024 are symmetrical, and the currents are equal amplitude and phase. It is worth noting that, at this time, due to the current shunting effect, the equal amplitude and phase currents between the asymmetrical striplines cannot be guaranteed.

[0073] Furthermore, this current distribution can satisfy a more relaxed special current distribution condition for surface wave self-suppression: First, the number of strip lines must be even; second, for any strip line, there must be another strip line in its opposite direction, and the currents on both must be of equal amplitude and in phase; under this relaxed condition, any two strip lines that are not in opposite directions do not need to satisfy the same current amplitude distribution, nor do they need to satisfy the equal angular distribution along the circumference.

[0074] Furthermore, in Example 1, when only two striplines exist, they are distributed 180° apart along the circumference, and the currents on the two striplines are of equal amplitude and in phase, satisfying the surface wave self-cancellation condition. The more relaxed special current distribution condition for surface wave self-suppression in Example 2 can be understood as a superposition of several sets of cases in Example 1 involving only two striplines distributed in opposite directions along the circumference. Based on the superposition principle, a similar surface wave suppression effect can be achieved without requiring all striplines to be equiangularly distributed and have consistent current amplitudes.

[0075] like Figure 7 As shown, the radial current in the second radial current line 202 is excited through the second feeding structure 204, and the symmetry ensures that the currents on the symmetrical strip lines are of equal amplitude and in phase. Its current distribution satisfies a more relaxed special current distribution condition for surface wave self-suppression. According to the superposition principle, it will also have a surface wave suppression effect similar to the special current distribution condition in Embodiment 1, so that surface waves cannot be excited by the second radial current line 202, thereby achieving surface wave self-suppression. At the same time, the radial currents on the fifth strip line 2021, the sixth strip line 2022, the seventh strip line 2023 and the eighth strip line 2024 form a ring magnetic current, i.e., a magnetic current loop, which is equivalent to an electric dipole placed perpendicular to the glass substrate. Thus, the antenna described in this embodiment achieves horizontal omnidirectional radiation and has vertical polarization characteristics.

[0076] Figure 8 The figure shows the horizontal two-dimensional radiation pattern of the surface wave self-suppressing antenna in this embodiment. As can be seen from the figure, the radiation pattern of the antenna is approximately circular in the horizontal direction. There are no pits or lobes caused by the surface waves. This shows that the surface wave suppression can still be achieved under relaxed current distribution conditions. At the same time, it achieves horizontal omnidirectional radiation and has vertical polarization characteristics.

[0077] Example 3:

[0078] like Figure 9 As shown, this embodiment provides a surface wave self-suppressing antenna. Compared with embodiments 1 and 2, this embodiment significantly modifies the feeding structure and reduces the number of feeding ports to one, further simplifying the feeding process. The antenna includes a third transition structure 301, a third radial current line 302, a first feed line 303, and a third feeding structure 304. The third transition structure 301 and the third radial current line 302 serve as the radiators of the antenna. Unlike the feed patch in embodiments 1 and 2, this embodiment no longer uses the feed patch as the common electrical ground of the antenna. The third transition structure 301 and the third feeding structure 304 are connected through the first feed line 303, thereby exciting the radiators of the antenna.

[0079] The third transition structure 301 in this embodiment is a quasi-ring structure, and it is broken in the 45° and 225° directions to suppress interference resonance near the passband.

[0080] The third radial current line 302 in this embodiment includes four strip lines, namely the ninth strip line 3021, the tenth strip line 3022, the eleventh strip line 3023, and the twelfth strip line 3024. The four strip lines are radially distributed at equal angles along the circumference of the transition structure. The interval between any two adjacent strip lines is 90°. One end of each strip line is connected to the transition structure, and the other end is open. The length of each strip line is one-quarter wavelength at the antenna operating frequency, and the width is 6 mm. The distribution direction of each strip line is radial, and the reverse extension lines of each strip line intersect at a point.

[0081] The first feed line 303 in this embodiment includes two feed strips, namely the first feed strip 3031 and the second feed strip 3032. The third feed structure 304 in this embodiment includes a feed unit located at the geometric center of the third transition structure 301. One end of the first feed strip 3031 and the second feed strip 3032 are respectively connected to the beginning and end of the current integration line on the port of the feed unit. At the same time, to ensure symmetry, their other ends are connected to the -45° and 135° positions of the third transition structure 301, that is, the axes of symmetry of the ninth strip 3021 and the twelfth strip 3024, and the axes of symmetry of the tenth strip 3022 and the eleventh strip 3023. The length of the first feed stripline 3031 is equal to the radius of the third transition structure 301. The second feed stripline 3032 is formed by multiple bends, with the bent portions forming arc segments. The length of the second feed stripline 3032 is the radius of the third transition structure 301 plus the length of the arc segment. The length of the arc segment is half the wavelength of the antenna's operating frequency. This is used to adjust the opposite phases at both ends of the feed port to be the same, ensuring that the excitation at the two contact points of the first feed line 303 and the third transition structure 301 is equal in amplitude and phase. Furthermore, under this excitation, the currents on each pair of symmetrical third radial current lines satisfy the property of equal amplitude and phase, and also satisfy the special current distribution condition for surface wave self-cancellation. In addition, the widths of the first feed stripline 3031 and the second feed stripline 3032 can be optimized and adjusted to achieve better matching.

[0082] like Figure 10 As shown, after passing through two paths of unequal length in the first feed line 303, the third feed structure 304 achieves equal-amplitude and in-phase excitation of the third transition structure 301, exciting the radial current in the third radial current line 302, and ensuring equal-amplitude and in-phase currents on the symmetrical strip lines due to symmetry. However, although this embodiment reduces the number of feed ports and simplifies the feed, its radiation pattern is not ideal, such as... Figure 11 and12 As shown in the three-dimensional and two-dimensional radiation patterns of the antenna, the gain is low, the roundness is insufficient, and the radiation pattern is distorted towards the axis of the first feed line 303. Therefore, further improvements are needed.

[0083] Example 4:

[0084] like Figure 13 As shown, this embodiment provides a surface wave self-suppressing antenna, which includes a fourth transition structure 401, a fourth radial current line, a second feed line 403, and a fourth feed structure 404. The fourth transition structure 401 and the fourth radial current line serve as the radiators of the antenna. The fourth transition structure 401 and the fourth feed structure 404 are connected through the second feed line 403, thereby exciting the radiators of the antenna.

[0085] The fourth transition structure 401 in this embodiment is a quasi-ring structure, and it is broken in the 45° and 225° directions to suppress interference resonance near the passband.

[0086] The fourth radial current line in this embodiment includes eight strip lines, namely the thirteenth strip line 4021, the fourteenth strip line 4022, the fifteenth strip line 4023, the sixteenth strip line 4024, the seventeenth strip line 4025, the eighteenth strip line 4026, the nineteenth strip line 4027, and the twentieth strip line 4028. The eight strip lines are radially distributed at equal angles along the circumference of the transition structure. The interval between any two adjacent strip lines is 45°. One end of each strip line is connected to the transition structure, and the other end is open. The length of each strip line is one-quarter wavelength at the antenna operating frequency, and the width is 3mm. The distribution direction of each strip line is radial, and the reverse extension lines of each strip line intersect at a point. Among them, the sixteenth strip line 4024 and the twentieth strip line 4028 are located in the 45° and 225° directions, respectively. Therefore, they are divided into two parts by slotting to connect the two sides after the fourth transition structure 401 is disconnected.

[0087] The second feed line 403 and the fourth feed structure 404 in this embodiment are completely consistent with the corresponding structures in embodiment 3 in terms of size and structure. The second feed line 403 includes two feed strip lines, namely the third feed strip line 4031 and the fourth feed strip line 4032. Through a feed port and two feed lines of different lengths, the fourth transition structure 401 is fed with equal amplitude and in phase at -45° and 135°.

[0088] Figure 14For the current distribution within the 6GHz bandwidth of this embodiment, due to the equal-amplitude and in-phase feeding of the fourth transition structure 401 at -45° and 135° and the symmetry of the entire structure, the currents on the striplines in opposite directions—namely, the thirteenth stripline 4021, the seventeenth stripline 4025, the fourteenth stripline 4022, the eighteenth stripline 4026, the fifteenth stripline 4023, the nineteenth stripline 4027, the sixteenth stripline 4024, and the twentieth stripline 4028—exhibit an equal-amplitude and in-phase distribution. However, the current amplitude and phase on the striplines in non-opposite directions are not necessarily equal. In this case, the current distribution on the striplines satisfies the special current distribution condition for surface wave self-cancellation.

[0089] Figure 15 As shown in the current distribution at the upper bandwidth of 7.4 GHz in this embodiment, the sixteenth stripline 4024 and the twentieth stripline 4028 are divided into two parts by slots, and the current directions on both sides of the slots are opposite, which will introduce a radiation null point. It is worth noting that although the current directions on both sides of the slots are opposite, the corresponding sides of the sixteenth stripline 4024 and the twentieth stripline 4028 still maintain an equal amplitude and in-phase current distribution, so it will not affect the surface wave resistance performance.

[0090] Figure 16 To modify the effect of the sixteenth stripline 4024 and the twentieth stripline 4028 on the upper radiation null point of the antenna in this embodiment, the radiation null point moves downward as the length of the stripline increases; conversely, the radiation null point moves upward as the length decreases.

[0091] Figure 17 This embodiment modifies the effect of the central angle of the arc segment corresponding to the fourth feed strip 4032 on the radiation null point on the lower side of the antenna. It can be seen that by adjusting the central angle of the arc segment, the frequency of another radiation null point can be changed. The larger the angle, the longer the arc segment, and the lower the corresponding radiation null point frequency; conversely, the smaller the angle, the shorter the arc segment, and the higher the radiation null point frequency.

[0092] Figure 18 The radiation efficiency curve and S of the surface wave self-suppressed antenna in this embodiment are shown. 11 The annular portion of the fourth transition structure 401 introduces additional current path length, resulting in slightly different resonant frequencies for each radial current line. This introduces new resonant points and further widens the bandwidth. It also introduces additional radiation nulls to improve out-of-band rejection. As can be seen, the antenna in this embodiment achieves a -10dB bandwidth of 5.84-6.77GHz, fully covering the V2X band for automotive communication, and achieves an efficiency better than 71% and up to 74%. Furthermore, there are radiation nulls at 5.3GHz and 7.2GHz, which gives the antenna filtering capabilities.

[0093] Figure 19 and Figure 20 This diagram shows the three-dimensional radiation pattern and the two-dimensional horizontal radiation pattern of the surface wave self-suppressing antenna in this embodiment. Compared with the structure in Embodiment 3, this embodiment adds four striplines located at 45°, 135°, 225°, and 315°, thereby reducing the spacing angle between adjacent striplines from 90° to 45°. It is understood that as the spacing angle decreases, the equivalent magnetic flux spacing corresponding to each stripline decreases, resulting in higher continuity and a closer approximation of a circular overall equivalent magnetic flux loop. This means the antenna is closer to an electric dipole placed perpendicular to the horizontal plane, thus improving its radiation performance. It can be seen that the introduction of four additional striplines improves the gain and the roundness of the radiation pattern, resulting in better omnidirectional antenna performance and improved cross-polarization discrimination. Furthermore, no pits or lobes caused by surface waves are observed, indicating that this embodiment also achieves surface wave suppression, realizes horizontal omnidirectional radiation, and possesses vertical polarization characteristics.

[0094] In summary, the surface wave self-suppressing antenna of the present invention is a planar antenna with a simple structure. It does not require drilling or slotting on the glass substrate, making it easy to manufacture. Furthermore, its own structure suppresses surface wave generation, eliminating the need for additional surface wave suppression components and avoiding the adverse effects of surface waves on antenna performance. In addition, the antenna achieves omnidirectional horizontal radiation and possesses vertical polarization characteristics. In intelligent connected vehicle communication systems, the omnidirectional horizontal radiation ensures signal transmission and reception in all directions, while the vertical polarization enables the antenna system to achieve higher-quality communication, making it of significant research value and applicable to a wide range of scenarios.

[0095] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0096] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A surface wave self-suppressing antenna, characterized in that, It includes a transition structure, a radial current line, a feed patch, and a feed structure, wherein the transition structure and the radial current line serve as radiators of the antenna; The radial current line includes multiple strip lines, which are radially distributed at equal angles along the circumference. One end of each strip line is connected to the transition structure, and the other end is open. The distribution direction of each strip line is radial, and the reverse extensions of each strip line intersect at a point. The power supply structure includes at least two power supply units, which are positioned at the same angle as one of the strip lines and are distributed equidistantly around the center of the power supply patch along the circumference. One end of each power supply unit is connected to the power supply patch, and the other end is connected to the transition structure. The current integration line on the power supply unit points from the power supply patch to the transition structure, achieving equal amplitude and phase power supply, so that the current on each strip line in the radial current line is distributed radially.

2. The surface wave self-suppressing antenna according to claim 1, characterized in that, When there are an even number of striplines, for each stripline, there is another stripline with the same current amplitude distribution and the same phase in the opposite direction, and these two striplines are arranged symmetrically.

3. The surface wave self-suppressing antenna according to claim 1, characterized in that, The length of each stripline is one-quarter of the wavelength at the antenna's operating frequency.

4. The surface wave self-suppressing antenna according to claim 1, characterized in that, The transition structure is a centrally symmetrical annular or near-annular patch.

5. The surface wave self-suppressing antenna according to claim 1, characterized in that, The transition structure completely surrounds the power supply patch, and there is a gap between the transition structure and the power supply patch.

6. The surface wave self-suppressing antenna according to claim 1, characterized in that, The power supply patch has a circular, near-circular, annular, near-annular, or polygonal structure.

7. The surface wave self-suppressing antenna according to claim 1, characterized in that, The center of the power supply patch coincides with the intersection of the center of the transition structure and the reverse extension of the strip.

8. A surface wave self-suppressing antenna, characterized in that, It includes a transition structure, a radial current line, a feed line, and a feed structure, wherein the transition structure and the radial current line serve as radiators of the antenna; The radial current line includes multiple strip lines, which are radially distributed at equal angles along the circumference. One end of each strip line is connected to the transition structure, and the other end is open. The distribution direction of each strip line is radial, and the reverse extensions of each strip line intersect at a point. The power supply structure includes a power supply unit located at the geometric center of the transition structure. The transition structure and the power supply unit are connected by a power supply line, which includes two power supply strips. The two power supply strips are respectively connected to the beginning and end of the current integration line on the port of the power supply unit. The power supply unit port and the two power supply strips provide equal amplitude and in-phase power to the transition structure, so that the current on each strip in the radial current line is distributed radially.

9. The surface wave self-suppressing antenna according to claim 8, characterized in that, Of the two feed striplines, one feed stripline is longer than the other. The shorter feed stripline is the radius of the transition structure. The longer feed stripline is bent multiple times, with the bent portion forming an arc segment. The length of the longer feed stripline is the radius of the transition structure plus the length of the arc segment. The length of the arc segment is half the wavelength of the antenna's operating frequency.

10. The surface wave self-suppressing antenna according to claim 8, characterized in that, When there are an even number of striplines, for each stripline, there is another stripline with the same current amplitude distribution and the same phase in the opposite direction. These two striplines are arranged symmetrically, and a slot is made between the two symmetrical striplines.

11. A type of automotive glass, comprising a glass substrate, characterized in that, It also includes the surface wave self-suppressing antenna according to any one of claims 1-10, wherein the surface wave self-suppressing antenna is etched on the surface of the glass substrate.

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