Antenna

Abstract

The embodiment of the invention provides an antenna, and the antenna comprises a radiation patch which is used for generating main radiation; a metal grounding plate; the spiral metal unit is located between the radiation patch and the metal grounding plate and used for generating parasitic radiation, and the parasitic radiation is used for being overlapped with the main radiation so as to expand the axial ratio beam width of the antenna; the electromagnetic band gap unit is arranged on the outer side of the metal grounding plate in a surrounding mode and used for generating a surface wave band gap in a working frequency band of the antenna, the surface wave band gap is used for inhibiting surface waves propagating along the surface of the metal grounding plate so as to improve the front-to-back ratio of the antenna, and the spiral metal unit is located between the radiation patch and the metal grounding plate so as to improve the front-to-back ratio of the antenna. Electromagnetic coupling can be enhanced, so that miniaturization of the antenna is realized. On the basis of realizing miniaturization, wide beam and high front-to-back ratio are cooperatively realized.

Description

Technical Field

[0001] This application relates to the field of antenna technology, and in particular to an antenna. Background Technology

[0002] With the rapid development of wireless communication technology, antenna performance faces increasingly higher demands. On the one hand, the compact physical layout of mobile devices requires antennas to be miniaturized and have a low profile. On the other hand, to ensure reliable connections in dynamic scenarios such as high-speed movement and attitude changes, antennas need to have wide beam coverage. Furthermore, in complex electromagnetic environments, to suppress interference and ensure communication quality, antennas must also have a high front-to-back ratio radiation characteristic. Therefore, how to achieve antenna miniaturization, wide beam, and high front-to-back ratio performance simultaneously within limited space constraints has become an urgent problem to be solved. Summary of the Invention

[0003] In view of the above problems, embodiments of this application are proposed to provide an antenna that overcomes or at least partially solves the above problems.

[0004] To address the aforementioned problems, in a first aspect of this application, an embodiment discloses an antenna, comprising: Radiation patch, used to generate main radiation; Metal grounding plate; A spiral metal unit, located between the radiating patch and the metal ground plane, is used to generate parasitic radiation, which is superimposed on the main radiation to extend the axial ratio beamwidth of the antenna. An electromagnetic bandgap element is disposed around the outside of the metal ground plane and is used to generate a surface wave bandgap within the operating frequency band of the antenna. The surface wave bandgap is used to suppress surface waves propagating along the surface of the metal ground plane to improve the front-to-back ratio of the antenna.

[0005] Optionally, the radiating patch includes a radiating patch body, a slit, and a power feeding patch, wherein the slit is located between the radiating patch body and the power feeding patch.

[0006] Optionally, it also includes a support substrate, wherein the spiral metal units are distributed circumferentially along the side of the support substrate, and the support substrate is located between the radiating patch and the metal ground plane.

[0007] Optionally, the spiral metal unit includes multiple metal strips, and the extending direction of the metal strips forms a preset inclination angle with the side of the supporting substrate.

[0008] Optionally, it also includes a power supply probe located between the power supply patch and the metal ground plane.

[0009] Optionally, the electromagnetic bandgap unit includes an upper electromagnetic bandgap substrate and a lower electromagnetic bandgap substrate stacked together.

[0010] Optionally, the electromagnetic bandgap unit further includes a first metal patch, a second metal patch, and a third metal patch, with the upper electromagnetic bandgap substrate located between the first metal patch and the second metal patch, and the lower electromagnetic bandgap substrate located between the second metal patch and the third metal patch.

[0011] Optionally, the electromagnetic bandgap unit further includes a parasitic patch, which is disposed around the outside of the radiating patch.

[0012] Optionally, the electromagnetic bandgap unit further includes a metallized via, which penetrates the upper electromagnetic bandgap substrate and the lower electromagnetic bandgap substrate, and is electrically connected to the first metal patch, the second metal patch and the third metal patch.

[0013] Optionally, the electromagnetic bandgap unit further includes a conductive element located between the parasitic patch and the first metal patch.

[0014] The embodiments of this application have the following advantages: This application provides an antenna comprising a radiating patch for generating main radiation; a metal ground plane; a helical metal element located between the radiating patch and the metal ground plane for generating parasitic radiation, which is superimposed on the main radiation to extend the axial ratio beamwidth of the antenna; and an electromagnetic bandgap element surrounding the outside of the metal ground plane for generating a surface wave bandgap within the antenna's operating frequency band. The surface wave bandgap suppresses surface waves propagating along the surface of the metal ground plane, thereby improving the antenna's front-to-back ratio. The helical metal element, located between the radiating patch and the metal ground plane, enhances electromagnetic coupling, thus achieving antenna miniaturization. Based on miniaturization, a wide axial ratio beamwidth and a high front-to-back ratio are synergistically achieved. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an antenna according to this application; Figure 2 This is an exploded view of one type of antenna in this application; Figure 3 This is a return loss diagram of an antenna according to this application; Figure 4 This is an axial ratio diagram of an antenna according to this application; Figure 5 This is a partial enlarged view of the electromagnetic bandgap element of this application; Figure 6 This is a top view of an antenna according to this application; Figure 7 This is a bottom view of an antenna according to this application; Figure 8 This is a normal gain diagram of an antenna according to this application; Figure 9 This is the radiation pattern of an antenna according to this application at 1.227 GHz; Figure 10 This is the radiation pattern of an antenna according to this application at 1.575 GHz; Figure 11 This is an axial ratio beamwidth diagram of an antenna in the xOz plane at a frequency of 1.227 GHz according to this application; Figure 12 This is an axial ratio beamwidth diagram of an antenna in the yOz plane at a frequency of 1.227 GHz according to this application; Figure 13 This is an axial ratio beamwidth diagram of an antenna in the xOz plane at a frequency of 1.575 GHz according to this application; Figure 14 This is an axial ratio beamwidth diagram of an antenna in the yOz plane at a frequency of 1.575 GHz according to this application; Figure 15 This is a graph showing the front-to-back ratio of an antenna according to this application as a function of frequency.

[0016] Explanation of reference numerals in the attached figures: 100-Radiating patch, 110-Radiating patch body, 120-Gap, 130-Feed patch, 200-Metal ground plane, 300-Spiral metal unit, 310-Metal strip, 400-Electromagnetic bandgap unit, 410-Upper electromagnetic bandgap substrate, 420-Lower electromagnetic bandgap substrate, 430-First metal patch, 440-Second metal patch, 450-Third metal patch, 460-Parasitic patch, 470-Metalized via, 480-Conductive component, 500-Support substrate, 600-Feed probe. Detailed Implementation

[0017] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Global Navigation Satellite Systems (GNSS) are gradually becoming a core infrastructure for automobiles. In advanced driver assistance and autonomous driving systems, the provision of vehicle absolute position (latitude and longitude) information is highly dependent on GNSS, making the antenna, as a key component for receiving satellite signals, crucial, and its performance directly determining the reliability and accuracy of the GNSS.

[0019] In obstructed environments such as urban canyons and under overpasses, the number of visible satellites from a single satellite system may be insufficient for effective positioning due to building obstruction. Therefore, modern antennas must achieve multi-band coverage, simultaneously supporting the frequency bands of multiple navigation systems, including GPS L1 / L2, BeiDou B1 / B3, GLONASS G1, and Galileo E1. This multi-system collaboration increases the number of visible satellites, ensuring basic positioning reliability in obstructed scenarios. However, achieving reliable positioning places more stringent performance requirements on antennas. First, the antenna must possess high and stable gain. In complex electromagnetic vehicle environments, signals are susceptible to interference, leading to a decrease in the receiver's signal-to-noise ratio (SNR). High gain effectively improves the SNR, ensuring stable acquisition and tracking under weak signal conditions. Second, multipath interference resistance is crucial. Multipath effects, where direct satellite signals are superimposed with signals reflected from buildings and road surfaces, are the main sources of positioning errors in urban environments. Multipath resistance design mainly considers two aspects: firstly, improving the antenna's front-to-back ratio. Surface waves propagating from the antenna ground plane diffract at the edges, generating strong backscattering. This backscattering is predominantly in the form of left-hand circularly polarized waves, making it highly susceptible to receiving multipath interference signals from the rear. Therefore, suppressing surface wave scattering to reduce backscattering and improve the front-to-back ratio is crucial for multipath interference mitigation. Secondly, it is necessary to extend the antenna's 3dB axial ratio beamwidth. Global Navigation Satellite System (GNSS) signals are right-hand circularly polarized waves. An antenna that maintains good circular polarization radiation over a wider angular range indicates stronger reception capability for direct right-hand circularly polarized waves from low-elevation satellites, while also better suppressing reflected left-hand circularly polarized waves deviating from the main axis. Simultaneously, a stable phase center is required; the antenna's equivalent phase center must remain stable within the operating frequency band and at different elevation angles, otherwise, measurement errors will be directly introduced. Finally, to adapt to diverse vehicle-mounted installation scenarios, the antenna must achieve all performance indicators within a very small space.

[0020] Currently, antennas designed with low dielectric constant substrates tend to be large, especially in the lateral dimension. To achieve multipath resistance and other performance characteristics, a common technique is to stack multiple radiating patches to achieve multi-band coverage. However, this increases the antenna's profile height, often resulting in an overall thickness exceeding 20mm. This makes it difficult to integrate existing antennas into automotive environments. Therefore, achieving miniaturization, wide beamwidth, and high aspect ratio within limited space constraints has become a pressing issue.

[0021] Figure 1 A schematic diagram of the structure of an antenna according to this application is shown, the antenna comprising: Radiation patch 100 is used to generate main radiation; Metal grounding plate 200; A spiral metal unit 300 is located between the radiating patch 100 and the metal ground plane 200 to generate parasitic radiation, which is superimposed with the main radiation to extend the axial ratio beamwidth of the antenna. An electromagnetic bandgap element 400 is disposed around the outside of the metal ground plane 200 to generate a surface wave bandgap within the operating frequency band of the antenna. The surface wave bandgap is used to suppress surface waves propagating along the surface of the metal ground plane 200 to improve the front-to-back ratio of the antenna.

[0022] Specifically, the antenna has a radiating patch 100 as the main radiating element for generating main radiation. Additionally, a metal ground plane 200 serves as the antenna's ground reference surface and reflector, forming the basic antenna structure in conjunction with the radiating patch 100. A spiral metal unit 300 is positioned between the radiating patch 100 and the metal ground plane 200. Through the combined action of the spirally wound metal strip 310 on the spiral metal unit 300 and the supporting substrate 500, distributed coupling capacitances are formed between adjacent turns and between the spiral metal unit 300 and the radiating patch 100. This allows for the use of a smaller radiating patch 100 while maintaining the same operating frequency, achieving antenna miniaturization. Simultaneously, the radiating patch 100 is connected to a feed probe 600. The slender feed probe 600 introduces an inductive impedance at high frequencies, and this coupling capacitance provides the opposite capacitive reactance. This effectively counteracts the influence of the inductive impedance, further extending the antenna's input impedance bandwidth. Simultaneously, when the radiating patch 100 is operational, its near field couples to the helical metal unit 300, exciting an induced current on its surface. This induced current, acting as a secondary source, radiates electromagnetic waves, i.e., parasitic radiation. This parasitic radiation superimposes with the primary radiation in space, effectively expanding the antenna's axial ratio beamwidth. Furthermore, electromagnetic bandgap units 400 are arranged around the outer side of the metal ground plane 200, generating surface wave bandgap within the operating frequency band. This suppresses surface waves propagating along the surface of the metal ground plane 200, reducing back radiation caused by surface wave diffraction and improving the antenna's front-to-back ratio.

[0023] In another antenna of this application, the antenna may include a radiating patch 100 as a main radiating element for generating main radiation, and a metal ground plane 200 as a reflecting element, which, together with the radiating patch 100, achieves directional radiation of the antenna. To improve the overall performance of the antenna, a spiral metal element 300 is provided between the radiating patch 100 and the metal ground plane 200, and a coupling capacitor is introduced between the radiating patch 100 and the metal ground plane 200. The radiating patch 100 is connected to a feed probe 600. The slender feed probe 600 introduces an inductive impedance at high frequencies. This coupling capacitor compensates for the inductive impedance, enabling the antenna to maintain the same operating frequency while requiring a smaller physical size for the radiating patch 100, thereby directly achieving antenna miniaturization. Simultaneously, the spiral metal element 300, as a parasitic radiating element, induces parasitic radiation under the near-field excitation of the main radiation generated by the radiating patch 100. This parasitic radiation superimposes with the main radiation in the low elevation angle region, thereby effectively extending the axial ratio beamwidth of the antenna. Based on this, to improve the front-to-back ratio of the antenna, an electromagnetic bandgap element 400 is arranged around the outside of the metal ground plane 200. This can generate a surface wave bandgap within the antenna's operating frequency band, thereby suppressing surface waves propagating along the surface of the metal ground plane 200, reducing diffraction that occurs when surface waves propagate to the edge of the metal ground plane 200 from the source, and significantly reducing the antenna's back radiation.

[0024] The antenna in this embodiment includes a radiating patch 100 for generating main radiation; a metal ground plane 200; a spiral metal element 300 located between the radiating patch 100 and the metal ground plane 200 for generating parasitic radiation, which is superimposed on the main radiation to extend the axial ratio beamwidth of the antenna; and an electromagnetic bandgap element 400 surrounding the outside of the metal ground plane 200 for generating a surface wave bandgap within the antenna's operating frequency band. The surface wave bandgap is used to suppress surface waves propagating along the surface of the metal ground plane 200 to improve the antenna's front-to-back ratio. The spiral metal element 300 in the antenna can achieve miniaturization by introducing a coupling capacitor. At the same time, the parasitic radiation generated by the spiral metal element 300 as a parasitic radiation element is superimposed with the main radiation generated by the radiating patch 100, which expands the axial ratio beamwidth of the antenna. On this basis, the electromagnetic bandgap element 400 generates a surface wave bandgap to suppress the surface waves on the metal ground plane 200, thereby reducing back radiation and improving the front-to-back ratio of the antenna. On the basis of miniaturization, a wide axial ratio beamwidth and a high front-to-back ratio are achieved in synergy.

[0025] In an optional embodiment of this application, the radiating patch 100 includes a radiating patch body 110, a slit 120, and a power feeding patch 130, wherein the slit 120 is located between the radiating patch body 110 and the power feeding patch 130.

[0026] The radiating patch 100 may include a radiating patch body 110, slots 120, and a power feeding patch 130. The radiating patch body 110 can be of various sizes and shapes. Multiple slots 120 can be etched into the central region of the radiating patch body 110. For example, if the radiating patch body 110 is a circular metal patch with a radius of 36 mm, four slots 120 can be etched about 20 mm from the center. Specifically, these slots can be orthogonal "quasi-cross" shaped with a width of 1 mm. Simultaneously, the power feeding patch 130 is isolated from the radiating patch body 110 by the slots 120. The power feeding patch 130 can be composed of two orthogonal rectangular arms of unequal lengths. For example, the longer arm may be 10 mm × 4 mm, and the shorter arm may be 8 mm × 5 mm. The specific dimensions and shapes can be determined by those skilled in the art based on their needs; this embodiment of the invention does not impose specific limitations on these aspects.

[0027] The radiating patch 100 in this embodiment includes a radiating patch body 110, slots 120, and a feed patch 130, with the slots 120 located between the radiating patch body 110 and the feed patch 130. The radiating patch body 110 provides the main radiating surface. By etching four slots 120, the feed patch 130 is formed in the central region of the radiating patch body 110. The slots 120 can introduce capacitive reactance, thereby canceling the inductive effect in the feed circuit. This can extend the input impedance bandwidth of the antenna. At the same time, the combination of the orthogonally distributed slots 120 and the feed patch 130 supports the antenna to achieve good circularly polarized radiation.

[0028] In an optional embodiment of this application, a support substrate 500 is further included, wherein the spiral metal units 300 are distributed circumferentially along the side surface of the support substrate 500, and the support substrate 500 is located between the radiating patch 100 and the metal ground plane 200.

[0029] Furthermore, a support substrate 500 can be formed between the radiating patch 100 and the metal ground plane 200 to provide a mounting carrier for the spiral metal unit 300. The radiating patch 100 is located on one side of the support substrate 500, which is a shell and can be manufactured in various ways. For example, the support substrate 500 can be integrally formed by additive manufacturing (such as 3D printing) from a cylinder with a height of 12.5 mm and a radius of 36 mm, with a top thickness of 1.5 mm and a side thickness of 1 mm. Further, the spiral metal unit 300 can be provided on the side of the support substrate 500 by printing, etching, or electroplating. The specific arrangement can be determined by those skilled in the art based on their needs, and this embodiment of the invention does not specifically limit this.

[0030] In this embodiment, the antenna further includes a support substrate 500 between the radiating patch 100 and the metal ground plane 200. Spiral metal units 300 are distributed circumferentially along the side surface of the support substrate 500, providing stable support for the entire antenna. Supporting the radiating patch 100 above the metal ground plane 200 also provides a mounting carrier for the spiral metal units 300. Simultaneously, the circumferential distribution of the spiral metal units 300 along the side surface of the support substrate 500 allows them to effectively introduce coupling capacitance and generate controllable parasitic radiation, interfering with the main radiation in the low elevation angle region, thereby significantly extending the antenna's 3dB axial ratio beamwidth.

[0031] Figure 2 An exploded view of an antenna according to this application is shown. In an optional embodiment of this application, the spiral metal unit 300 includes a plurality of metal strips 310, the extension direction of which is at a predetermined angle to the side of the support substrate 500.

[0032] To further extend the axial ratio beamwidth, the spiral metal unit 300 includes multiple metal strips 310. The extending direction of the multiple metal strips 310 can form a preset tilt angle with the side of the support substrate 500. Preferably, the preset tilt angle can be set to 45°. Multiple metal strips 310 can be provided, each with a specific width, and are circumferentially distributed at equal intervals on the side of the support substrate 500, for example, twenty-nine strips, each of which can be 3.65 mm. The metal strips 310 are wound around the side of the support substrate 500 to form the spiral metal unit 300. Its bottom is electrically connected to the metal ground plane 200 to form a short-circuit structure, and its top extends to a position approximately level with the end of the support substrate 500 near the radiating patch 100. It should be noted that the specific tilt angle, shape, number, and width of the metal strips 310 can be determined by those skilled in the art based on their needs, and the embodiments of the present invention do not specifically limit these aspects.

[0033] The spiral metal unit 300 in this embodiment includes multiple metal strips 310. The extension direction of the metal strips 310 forms a predetermined tilt angle with the side of the supporting substrate 500, which can introduce the required coupling capacitance. This allows the metal strips 310 to function as effective parasitic radiation units, generating parasitic radiation with specific directionality under the excitation of the main radiation field. The coupling between the radiating patch 100 and the spiral metal unit 300 mainly occurs in the low elevation angle region. Therefore, through size optimization design, the circular polarization radiation of the antenna in the low elevation angle region can be improved, thereby extending the axial ratio beamwidth by 3dB. Thus, the axial ratio beamwidth is extended while achieving antenna miniaturization.

[0034] In an optional embodiment of this application, a power supply probe 600 is also included, located between the power supply patch 130 and the metal ground plane 200.

[0035] The antenna includes a feed probe 600 positioned between the feed patch 130 and the metal ground plane 200. One end of the feed probe 600 is electrically connected to the feed patch 130, while the other end passes through a feed protection hole in the metal ground plane 200 and connects to a broadband sequential rotating feed network located below the metal ground plane 200, thereby achieving broadband circularly polarized radiation. The feed probe 600 can be configured in various shapes. For example, it can be a metal post with a radius of 0.8 mm. When the feed probe 600 passes through the metal ground plane 200, it separates from the ground plane 200 through the feed protection hole. Since the capacitive reactance effect generated by the radiating patch 100 cancels out the inductive effect of the slender feed probe 600, it is beneficial to further extend the input impedance bandwidth of the antenna. Figure 3 The return loss diagram of an antenna according to this application is shown. It can be seen that the return loss of the antenna is less than -10dB in the frequency range of 1.03GHz to 1.82GHz, indicating good impedance matching within this frequency band. Meanwhile, Figure 4 The diagram shows the axial ratio of an antenna according to this application. It can be seen that the axial ratio is less than 3dB in the 1.06GHz to 1.92GHz range, indicating that the antenna maintains good circular polarization characteristics within this frequency band. This demonstrates that the antenna can cover the frequency bands of major vehicle-mounted global navigation satellite systems, such as GPS L1 / L2, BeiDou B1 / B3, GLONASS G1, and Galileo E1. By simultaneously receiving signals from multiple systems, the number of visible satellites in obstructed scenarios such as urban canyons and under overpasses can be significantly increased, ensuring positioning reliability.

[0036] In this embodiment, the antenna further includes a feed probe 600 between the feed patch 130 and the metal ground plane 200, establishing a feed loop from the broadband sequential rotating feed network to the radiating patch 100, providing the basis for signal transmission and excitation. Furthermore, the inductive effect introduced by the elongated feed probe 600 is electrically canceled out by the capacitive reactance effect generated by the radiating patch 100. This optimizes the antenna's input impedance characteristics, thereby significantly extending the antenna's input impedance bandwidth and providing a crucial guarantee for the antenna to achieve broadband operation covering multiple frequency bands.

[0037] Figure 5 A partially enlarged view of the electromagnetic bandgap unit of this application is shown. In an optional embodiment of this application, the electromagnetic bandgap unit 400 includes an upper electromagnetic bandgap substrate 410 and a lower electromagnetic bandgap substrate 420 stacked together.

[0038] Specifically, the electromagnetic bandgap unit 400 may further include an upper electromagnetic bandgap substrate 410 and a lower electromagnetic bandgap substrate 420 stacked together. A metal ground plane 200 is printed on the side of the upper electromagnetic bandgap substrate 410 near the supporting substrate 500. For example, a metal ground plane 200 with a radius of 60 mm can be formed by copper plating on the upper electromagnetic bandgap substrate 410. The upper electromagnetic bandgap substrate 410 and the lower electromagnetic bandgap substrate 420 are stacked together, which can form a compact lateral layout, which is beneficial to reducing the overall size of the antenna. For example, the radius of the upper electromagnetic bandgap substrate 410 and the lower electromagnetic bandgap substrate 420 can be 67.3 mm, and the thickness can be 0.8 mm. It is formed using a low dielectric constant substrate FR-4.

[0039] The electromagnetic bandgap unit 400 in this embodiment includes an upper electromagnetic bandgap substrate 410 and a lower electromagnetic bandgap substrate 420 stacked together. This stacking method improves the overall mechanical strength of the electromagnetic bandgap unit 400, especially under conditions such as vehicle vibration and temperature changes, maintaining the stability of the relative positions between layers and ensuring antenna reliability. Furthermore, vertical stacking makes full use of space, allowing for the integration of more structures without increasing the antenna's radial dimension.

[0040] In an optional embodiment of this application, the electromagnetic bandgap unit 400 further includes a first metal patch 430, a second metal patch 440, and a third metal patch 450, the upper electromagnetic bandgap substrate 410 is located between the first metal patch 430 and the second metal patch 440, and the lower electromagnetic bandgap substrate 420 is located between the second metal patch 440 and the third metal patch 450.

[0041] In specific applications, the electromagnetic bandgap unit 400 can also be provided with a first metal patch 430, a second metal patch 440, and a third metal patch 450. The upper electromagnetic bandgap substrate 410 is located between the first metal patch 430 and the second metal patch 440, and the lower electromagnetic bandgap substrate 420 is located between the second metal patch 440 and the third metal patch 450. The first metal patch 430, the second metal patch 440, and the third metal patch 450 can be arc-shaped patches of the same shape and size, and their projections completely overlap in the direction perpendicular to the upper electromagnetic bandgap substrate 410 and the lower electromagnetic bandgap substrate 420. This ensures the symmetry of the electromagnetic field and current distribution in the vertical direction. This avoids asymmetric radiation, making the surface wave suppression effect of the electromagnetic bandgap unit 400 more uniform.

[0042] The electromagnetic bandgap unit 400 in this embodiment further includes a first metal patch 430, a second metal patch 440, and a third metal patch 450. The upper electromagnetic bandgap substrate 410 is located between the first metal patch 430 and the second metal patch 440, and the lower electromagnetic bandgap substrate 420 is located between the second metal patch 440 and the third metal patch 450, forming a stacked electromagnetic bandgap unit 400. This is equivalent to constructing a distributed spatial filter, which effectively suppresses the propagation of surface waves, thereby significantly reducing the back diffraction at the edge of the antenna's metal ground plane 200, thus greatly improving the antenna's front-to-back ratio and enhancing the antenna's ability to suppress reflected interference signals in complex multipath environments.

[0043] Figure 6 A top view of an antenna according to this application is shown. In an optional embodiment of this application, the electromagnetic bandgap element 400 further includes a parasitic patch 460, which is disposed around the outside of the radiating patch 100.

[0044] The electromagnetic bandgap unit 400 may further include parasitic patches 460. These parasitic patches 460 are disposed around the outer side of the radiating patch 100. Specifically, the number of parasitic patches 460 is the same as the number of first metal patches 430 included in the electromagnetic bandgap unit 400. For example, there may be thirteen parasitic patches 460, each of which may be an arc-shaped structure with an outer radius of 66.3 mm, an inner radius of 45 mm, and an arc angle of 23°, uniformly distributed in a ring around the center of the radiating patch 100.

[0045] The electromagnetic bandgap element 400 in this embodiment also includes a parasitic patch 460, which is disposed around the outside of the radiating patch 100. The electromagnetic waves radiated by the parasitic patch 460 are superimposed in space with the electromagnetic waves generated by the radiating patch 100. By optimizing the size, shape, and position of the parasitic patch 460, the parasitic radiation field it generates can compensate for the circular polarization characteristics of the main radiation field in regions other than the main radiation direction, especially in the low elevation angle region. This extends the antenna's 3dB axial ratio beamwidth at low elevation angles, enabling the antenna to receive satellite signals from even lower elevation angles.

[0046] Figure 7 A bottom view of an antenna according to this application is shown. In an optional embodiment of this application, the electromagnetic bandgap unit 400 further includes a metallized via 470, which penetrates the upper electromagnetic bandgap substrate 410 and the lower electromagnetic bandgap substrate 420. The metallized via 470 is electrically connected to the first metal patch 430, the second metal patch 440 and the third metal patch 450.

[0047] Specifically, the electromagnetic bandgap unit 400 may further include a metallized via 470. The metallized via 470 is disposed through the upper electromagnetic bandgap substrate 410 and the lower electromagnetic bandgap substrate 420. Specifically, the metallized via 470 penetrates the entire stacked structure in the vertical direction and is electrically connected to the first metal patch 430, the second metal patch 440, and the third metal patch 450, thereby making the first metal patch 430, the second metal patch 440, and the third metal patch 450 a single unit in the vertical direction. The potential of the first metal patch 430, the second metal patch 440, and the third metal patch 450 is flattened at the connection of the metallized via 470, thereby enhancing the electromagnetic coupling strength between the metal patches in the vertical direction.

[0048] In this embodiment, the first metal patch 430, the second metal patch 440, and the third metal patch 450 are spaced apart by the upper electromagnetic bandgap substrate 410 and the lower electromagnetic bandgap substrate 420, forming a distributed capacitance between adjacent metal patches. The metallized via 470 connecting the first metal patch 430, the second metal patch 440, and the third metal patch 450 is equivalent to an inductor. This capacitor and inductor together constitute a basic resonant unit. Multiple basic resonant units are periodically arranged around the edge of the metal ground plane 200, forming a periodic electromagnetic bandgap unit 400 with band-stop characteristics. Electrically isolated from the metal ground plane 200, it forms a "space filter" that presents high impedance to surface waves in a specific frequency band, thereby suppressing surface waves generated by the radiating patch 100 and propagating along the metal ground plane 200. By blocking the propagation of surface waves to the edge of the metal ground plane 200, back radiation caused by edge diffraction can be reduced, thereby improving the front-to-back ratio of the antenna.

[0049] In an optional embodiment of this application, the electromagnetic bandgap unit 400 further includes a conductive element 480 located between the parasitic patch 460 and the first metal patch 430.

[0050] The electromagnetic bandgap unit 400 may further include a conductive element 480. The conductive element 480 is located between the parasitic patch 460 and the first metal patch 430. Specifically, the upper end of the conductive element 480 is electrically connected to the parasitic patch 460, and its lower end is electrically connected to the first metal patch 430. Preferably, the conductive element 480 is a columnar structure made of metal, for example, a metal cylinder with a radius of 1.5 mm. The parasitic patches 460 around the radiating patch 100 correspond one-to-one with the first metal patch 430, and can transmit part of the surface wave to the top parasitic patch 460 for secondary radiation. At the same time, the parasitic patch 460 and the radiating patch 100 are coupled to form a parasitic radiation unit. The electromagnetic waves radiated by the parasitic radiation unit are superimposed with the electromagnetic waves of the radiating patch 100, which can further extend the axial ratio beamwidth by 3 dB.

[0051] In this embodiment, the conductive element 480 establishes a conductive channel between the parasitic patch 460 and the first metal patch 430. This channel guides the surface wave energy to be suppressed to the top parasitic patch 460, where it is converted into secondary radiation. This secondary radiation superimposes on the primary radiation in space, effectively extending the antenna's 3dB axial ratio beamwidth in the low elevation region. This allows for wider signal reception angle coverage, thereby improving the reliability of navigation and positioning in complex multipath environments.

[0052] An embodiment of this application discloses an antenna, including a radiating patch 100 for generating main radiation; a metal ground plane 200; a spiral metal element 300 located between the radiating patch 100 and the metal ground plane 200, composed of multiple metal strips 310 spirally arranged along the side of a supporting substrate 500, with its bottom short-circuited to the metal ground plane 200, for generating parasitic radiation, which is superimposed on the main radiation to extend the axial ratio beamwidth; and an electromagnetic bandgap element 400 surrounding the outer side of the metal ground plane 200. This unit comprises multiple layers of periodically arranged first metal patches 430, second metal patches 440, third metal patches 450, and metallized vias 470, maintaining a non-common ground state with the metal ground plane 200. It is used to generate a surface wave bandgap within the antenna's operating frequency band. The surface wave bandgap suppresses surface waves propagating along the surface of the metal ground plane 200, thereby improving the antenna's front-to-back ratio. The spiral metal element 300, located between the radiating patch 100 and the metal ground plane 200, enhances electromagnetic coupling, thus achieving antenna miniaturization. Based on miniaturization, a wide axial ratio beam and high front-to-back ratio are synergistically achieved. The spiral metal element 300, located between the radiating patch 100 and the metal ground plane 200, replaces the traditional vertical short-circuit post. The spiral metal element 300 can introduce coupling capacitance. While reducing the antenna's lateral dimensions, the parasitic radiation field generated on the surface of the spiral metal element 300 superimposes with the main radiation field in the low elevation angle region, significantly extending the antenna's 3dB axial ratio beamwidth. The electromagnetic bandgap element 400, arranged around the outer side of the metal ground plane 200, forms a surface wave bandgap within the operating frequency band due to its non-grounded periodic structure. This surface wave bandgap exhibits high impedance to surface waves propagating along the metal ground plane 200, effectively suppressing harmful backscattering radiation caused by surface waves propagating to the edge of the metal ground plane 200 and diffracting. This directly improves the antenna's front-to-back ratio and enhances its ability to suppress multipath reflection interference. A conductive channel is established between the electromagnetic bandgap element 400 and the top parasitic patch 460 through connecting structures such as the conductive element 480. This channel guides some of the suppressed surface wave energy to the parasitic patch 460 for secondary radiation, further extending the axial ratio beamwidth.

[0053] By working in conjunction with the electromagnetic bandgap unit 400, which is specifically designed to suppress surface waves, the energy dissipation along the metal ground plane 200 can be reduced at the source, thereby ensuring that more energy is used for effective radiation. Furthermore, by using the spiral metal unit 300 and the parasitic patch 460 as parasitic radiation units of the main radiation patch 100, the electromagnetic energy coupled from the main radiation patch 100 can be redistributed to the low elevation angle region. This structure can significantly extend the axial ratio beamwidth. Figure 8 The normal gain diagram of an antenna according to this application is shown. It can be seen that the antenna gain is stable across the entire frequency band and is better than 4dBic. Figure 9 The radiation pattern of an antenna according to this application at 1.227 GHz is shown. It can be seen that the antenna gain reaches 5.18 dBic at the key frequency of 1.227 GHz. Figure 10 The radiation pattern of an antenna according to this application at 1.575 GHz is shown. It can be seen that at the critical frequency of 1.575 GHz, the antenna gain reaches 4.59 dBic. This high and stable gain characteristic can improve the system signal-to-noise ratio and avoid performance degradation in edge bands due to gain fluctuations when multiple systems are working together. The structure composed of the spiral metal unit 300, the electromagnetic bandgap unit 400, and its parasitic patch 460 can achieve ultra-wide axial ratio beam radiation while maintaining high forward gain.

[0054] Furthermore, the parasitic patch 460 connected to the spiral metal unit 300 and the electromagnetic bandgap unit 400 works together to significantly extend the circularly polarized beamwidth in the low elevation angle region and suppress surface waves, thereby reducing harmful back radiation. Specifically, the spiral metal unit 300, as a parasitic radiating element of the radiating patch 100, generates a parasitic radiation field that superimposes with the main radiation field in the low elevation angle region, directly extending the axial ratio beamwidth. Furthermore, the electromagnetic bandgap unit 400 and its connected parasitic patch 460 compensate for the circular polarization characteristics of the main radiation field. This extends the antenna's axial ratio beamwidth by 3 dB at low elevation angles, enabling the antenna to receive satellite signals from even lower elevation angles. Figure 11 This diagram illustrates the axial ratio beamwidth of an antenna in the xOz plane at a frequency of 1.227 GHz. The 360° radius of the entire circle is redefined as ranging from -180° to +180°, where 0° represents the direction of the antenna's normal. In this coordinate system, the maximum angular positions with an axial ratio of 3dB are found on both sides of the normal direction (one positive and one negative). The absolute values ​​of these two angles are then added together to obtain the axial ratio beamwidth. It can be seen that at 1.227 GHz, the maximum negative angle is -100.3°, and the maximum positive angle is 97.5°. The sum of the absolute values ​​of these two values ​​is 197.8°, meaning the 3dB axial ratio beamwidth in the xOz plane can reach 197.8°. Figure 12 The diagram shows the axial ratio beamwidth of an antenna in the yOz plane at a frequency of 1.227 GHz. Similarly, at a frequency of 1.227 GHz, the antenna has a maximum negative angle of -111.8° and a maximum positive angle of 106.7°. The sum of the absolute values ​​of the two values ​​is 218.5°, which means that the 3dB axial ratio beamwidth in the yOz plane can reach 218.5°. Figure 13 The diagram shows the axial ratio beamwidth of an antenna in the xOz plane at a frequency of 1.575 GHz. Similarly, at a frequency of 1.575 GHz, the antenna has a maximum negative angle of -111.2° and a maximum positive angle of 134.8°. The sum of the absolute values ​​of the two values ​​is 246°, which means that the 3dB axial ratio beamwidth in the xOz plane can reach 246°. Figure 14 The diagram shows the axial ratio beamwidth of an antenna in the yOz plane at a frequency of 1.575 GHz. Similarly, at 1.575 GHz, the antenna has a maximum negative angle of -120.9° and a maximum positive angle of 80.1°. The sum of the absolute values ​​of these two values ​​is 201°, meaning the 3dB axial ratio beamwidth in the yOz plane can reach 201°. This axial ratio beamwidth coverage ensures that the antenna maintains excellent right-hand circularly polarized wave reception capability for direct signals from multiple satellites. Simultaneously, Figure 15 The diagram shows the front-to-back ratio of an antenna according to this application as a function of frequency. It can be seen that the front-to-back ratio of the antenna at 1.575 GHz is 23.17 dB, greater than 20 dB, and at 1.227 GHz it is 14.29 dB, greater than 14 dB. Based on the effective suppression of surface waves by the electromagnetic bandgap element 400, the left-hand circularly polarized waves diffracted by the edge of the metal ground plane 200 can be weakened. The extremely wide axial ratio beam combined with the high front-to-back ratio indicates that the antenna has excellent anti-multipath interference capability, which can improve navigation and positioning accuracy in complex road environments. At the same time, the antenna's profile height can be as low as 12.5 mm, achieving low profile performance. Furthermore, the coupling capacitance introduced by the helical metal element 300 achieves structural miniaturization. This size allows it to be integrated into automotive environments where thickness is extremely sensitive, such as inside the rearview mirror housing, within a shark fin antenna assembly integrating a 4G / 5G communication module, or in a concealed area above the windshield, thus avoiding components such as wiper motors. Furthermore, the antenna is primarily manufactured using a printing process on low-dielectric-constant substrates, effectively reducing costs. Additionally, the antenna as a whole is symmetrically distributed around the axis of the supporting substrate 500, with its radiating patch 100, spiral metal unit 300, and electromagnetic bandgap unit 400 arranged to achieve phase center stability. Simultaneously, the antenna employs sequential rotating feed technology, using a broadband sequential rotating feed network with four feed probes 600 exciting the top feed patch 130, thereby meeting the antenna's phase center stability requirements.

[0055] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0056] The antenna provided in this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An antenna, characterized in that, include: Radiation patch, used to generate main radiation; Metal grounding plate; A spiral metal unit, located between the radiating patch and the metal ground plane, is used to generate parasitic radiation, which is superimposed on the main radiation to extend the axial ratio beamwidth of the antenna. An electromagnetic bandgap element is disposed around the outside of the metal ground plane and is used to generate a surface wave bandgap within the operating frequency band of the antenna. The surface wave bandgap is used to suppress surface waves propagating along the surface of the metal ground plane to improve the front-to-back ratio of the antenna.

2. The antenna according to claim 1, characterized in that, The radiating patch includes a radiating patch body, a slit, and a power feeding patch, wherein the slit is located between the radiating patch body and the power feeding patch.

3. The antenna according to claim 2, characterized in that, It also includes a support substrate, wherein the spiral metal units are distributed circumferentially along the side of the support substrate, and the support substrate is located between the radiating patch and the metal ground plane.

4. The antenna according to claim 3, characterized in that, The spiral metal unit includes multiple metal strips, and the extending direction of the metal strips is at a predetermined angle to the side of the supporting substrate.

5. The antenna according to claim 4, characterized in that, It also includes a power supply probe located between the power supply patch and the metal ground plane.

6. The antenna according to claim 1, characterized in that, The electromagnetic bandgap unit includes an upper electromagnetic bandgap substrate and a lower electromagnetic bandgap substrate stacked together.

7. The antenna according to claim 6, characterized in that, The electromagnetic bandgap unit further includes a first metal patch, a second metal patch, and a third metal patch. The upper electromagnetic bandgap substrate is located between the first metal patch and the second metal patch, and the lower electromagnetic bandgap substrate is located between the second metal patch and the third metal patch.

8. The antenna according to claim 7, characterized in that, The electromagnetic bandgap unit also includes a parasitic patch, which is disposed around the outside of the radiating patch.

9. The antenna according to claim 8, characterized in that, The electromagnetic bandgap unit further includes a metallized via, which penetrates the upper electromagnetic bandgap substrate and the lower electromagnetic bandgap substrate, and is electrically connected to the first metal patch, the second metal patch and the third metal patch.

10. The antenna according to claim 9, characterized in that, The electromagnetic bandgap unit further includes a conductive element located between the parasitic patch and the first metal patch.

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