Broadband GNSS antenna integrated with loop circular structure

Abstract

This invention relates to a broadband GNSS antenna with an integrated loop structure, comprising a dual-frequency radiating plate, a ground plane, and four metal probes. The four metal probes are of equal height and connect the dual-frequency radiating plate parallel to the ground plane. The dual-frequency radiating plate includes an upper substrate and, on the same side of the upper substrate, a high-frequency resonant inner ring, a low-frequency resonant outer ring, two high-frequency microstrip lines, and two low-frequency microstrip lines. The high-frequency resonant inner ring and the low-frequency resonant outer ring are concentric. Each of the two high-frequency microstrip lines and the two low-frequency microstrip lines has a feed point at its end. A feed disk is provided on the ground plane, and each metal probe conductively connects a feed point to a feed disk. This antenna can stably cover the mainstream high and low frequency GNSS bands, has low cross-polarization loss, excellent high and low frequency axial ratio performance, small phase center deviation, and is simple in structure, lightweight, low in manufacturing cost, and highly tunable, making it suitable for mass production.

Description

Technical Field

[0001] This invention relates to the field of satellite navigation antenna technology, and in particular to a broadband GNSS antenna with an integrated loop structure. Background Technology

[0002] With the integrated application of multiple Global Navigation Satellite Systems (GNSS) such as BeiDou, GPS, GLONASS, and Galileo, centimeter-level and millimeter-level precision navigation, positioning, and timing scenarios place stringent demands on the comprehensive performance of GNSS antennas. Antennas must be compatible with receiving signals across multiple systems across all frequency bands, and possess stable electrical parameters, excellent assembly performance, and cost advantages. Currently, mainstream GNSS antennas in the industry mainly adopt structures such as single-layer / multi-layer microstrip patch antennas, conventional quad-arm helical antennas, and metal stamped antennas, which are the most widely used traditional technical solutions in this field.

[0003] Due to structural limitations, traditional GNSS antennas have several inherent drawbacks. First, their operating bandwidth is generally narrow, making it difficult to fully cover the entire GNSS frequency band and hindering concurrent reception of signals from multiple satellite systems, resulting in poor adaptability. To expand the operating bandwidth and meet multi-band reception requirements, existing technologies generally employ multi-layered structures. However, the radiating excitation positions and surface current distributions for different operating frequency bands differ significantly. High-frequency and low-frequency signals are radiated using different dielectric layers and radiators within the stack, directly causing inconsistencies in the spatial positions of the phase centers across frequency bands and resulting in large differences in phase center offsets between different frequency bands. This phase center deviation introduces additional errors into the positioning calculation process, severely degrading the convergence speed, positioning accuracy, and operational stability of high-precision positioning modes such as RTK and PPP, and failing to meet the centimeter-level and millimeter-level precision navigation and timing requirements in scenarios such as surveying and monitoring, and autonomous driving.

[0004] Secondly, the assembly of multi-layer stacked GNSS antennas is quite complex. This structure relies on multiple precision processes, including precise alignment of multi-layer substrates, high-precision welding of feed points, and tight bonding of interlayer dielectrics. The overall assembly process is cumbersome, requiring a high level of manual skill, significantly increasing manual assembly costs, and reducing overall assembly efficiency, which is not conducive to automated mass production. At the same time, the extensive use of components such as multi-layer dielectric substrates, dedicated feed components, and high-precision bonding materials further increases the material costs and overall manufacturing costs of the antenna, limiting the widespread application of this type of antenna in large-scale civilian and automotive fields.

[0005] To address the shortcomings of traditional multi-layered antennas, improved loop GNSS antennas have emerged in the prior art. A typical example is Chinese invention patent application CN121394869A, which discloses a coaxial dual-loop GNSS antenna. It mainly consists of a ground plane, an inner loop radiator, and an outer loop radiator. The inner loop radiator corresponds to the 1560-1610MHz high-frequency GNSS band, and the outer loop radiator corresponds to the 1160-1300MHz low-frequency GNSS band. The dual loop radiators adopt a coaxial, spaced, centrally symmetrical structure. Wideband coverage is achieved by relying on open-loop capacitor loading and multi-element tight coupling design, which to a certain extent broadens the antenna's operating bandwidth, simplifies some inter-layer assembly structures, and ensures antenna gain and circular polarization performance.

[0006] However, the technical solution disclosed in the prior art still has significant shortcomings: First, the antenna adopts a split inner and outer ring radiator structure, and high-frequency and low-frequency signals still rely on two independent ring radiators for radiation. The spatial height and current distribution of the two radiators are not uniform, failing to fundamentally solve the core problem of large phase center offset in multiple frequency bands. The phase center stability is still difficult to meet the millimeter-level precision positioning standard. Second, the ring radiator of the antenna is spliced ​​from multiple independent PCB units. The units rely on tight coupling to achieve bandwidth expansion. The splicing units are numerous and the structure is scattered. During assembly, multiple PCB units still need to be positioned and fixed. The assembly process has not been substantially simplified, and the assembly efficiency is low. Third, the use of multiple independent PCB boards, radiating sheet groups, and coupling metal sheets has not effectively reduced the types and costs of materials, and the manufacturing cost is still relatively high.

[0007] Therefore, developing a GNSS antenna that is compatible with the entire broadband system, has a high degree of consistency in phase center across multiple frequency bands, is easy to assemble, and is inexpensive has become a pressing technical challenge in this field. Summary of the Invention

[0008] The main objective of this invention is to provide a broadband GNSS antenna with an integrated loop structure, aiming to address the technical shortcomings of traditional GNSS antennas, such as narrow operating bandwidth, severe crosstalk between high and low frequency signals, poor radiation symmetry, large phase center offset, insufficient structural stability, and high mass production costs. By designing a concentric nested loop dual-frequency coplanar radiation structure, coupled with a differentiated microstrip line length matching scheme, broadband compatible reception of dual-band GNSS signals across multiple systems is achieved. Simultaneously, the diagonal mirror symmetry layout, microstrip avoidance structure, and orthogonal metal probe isolation design effectively suppress dual-frequency electromagnetic crosstalk, optimize radiation performance and axial ratio characteristics, reduce phase center offset, and improve positioning accuracy and signal stability. The trapezoidal symmetrical arrangement of the probes enhances the overall mechanical reliability, simplifies the overall structure, and optimizes the manufacturing process. While ensuring high gain, anti-interference, and broadband operating performance, the device achieves lightweight, low cost, easy tuning, and easy mass production, adapting to the large-scale application needs of various miniaturized terminals.

[0009] The present invention achieves the above-mentioned objective through the following technical solution: a broadband GNSS antenna with an integrated loop structure, comprising a dual-frequency radiating plate, a ground plane, and four metal probes, the four metal probes being of equal height and connecting the dual-frequency radiating plate and the ground plane in parallel; the dual-frequency radiating plate comprising an upper substrate and a high-frequency resonant inner ring, a low-frequency resonant outer ring, two high-frequency microstrip lines, and two low-frequency microstrip lines disposed on the same side of the upper substrate, the high-frequency resonant inner ring and the low-frequency resonant outer ring being concentric, the two high-frequency microstrip lines extending inward from the 0° and 270° azimuth angle positions of the high-frequency resonant inner ring respectively, the two low-frequency microstrip lines extending inward from the 90° and 180° azimuth angle positions of the low-frequency resonant outer ring respectively, each of the two high-frequency microstrip lines and the two low-frequency microstrip lines having a feed point at its end, the ground plane being provided with a feed disk corresponding to each feed point, and each metal probe electrically connecting a feed point to a feed disk.

[0010] Specifically, the upper substrate is a circular plate, and the upper substrate and the low-frequency resonant outer ring are concentric.

[0011] Specifically, the ground plane is a square plate, and the downward projection of the center of the high-frequency resonant inner ring coincides with the center of the ground plane.

[0012] Furthermore, the dual-frequency radiation plate is structurally symmetrical with respect to the vertical plane containing one diagonal of the grounding plate.

[0013] Furthermore, the lower ends of the four metal probes are arranged in an isosceles trapezoidal shape.

[0014] Furthermore, the metal probe is a strip-shaped sheet, with both ends of the metal probe penetrating and contacting the upper substrate and the ground plane, respectively. The surfaces of the two metal probes connected by the two high-frequency microstrip lines are perpendicular to each other, and the surfaces of the two metal probes connected by the two low-frequency microstrip lines are perpendicular to each other.

[0015] Specifically, the transmission length of the high-frequency microstrip line is greater than that of the low-frequency microstrip line.

[0016] Furthermore, the high-frequency microstrip line has a 90° zigzag structure, including a high-frequency radial segment, a high-frequency bending segment, and a high-frequency feed point connected in sequence. The extension line of the high-frequency radial segment passes through the center of the high-frequency resonant inner ring, and the high-frequency bending segment is perpendicular to the high-frequency radial segment and does not intersect or contact with another high-frequency microstrip line.

[0017] Furthermore, the low-frequency microstrip line has a 90° zigzag structure, including a low-frequency radial segment, a low-frequency bending segment, and a low-frequency feed point connected in sequence. The extension line of the low-frequency radial segment passes through the center of the low-frequency resonant outer ring, and the low-frequency bending segment is perpendicular to the low-frequency radial segment and does not intersect or contact the high-frequency resonant inner ring.

[0018] The beneficial effects of the technical solution of this invention are: 1. By employing a coplanar arrangement of high and low frequency concentric nested rings, coupled with a differentiated microstrip line length design, dual-frequency broadband matching is achieved, stably covering the mainstream GNSS frequency bands of 1164MHz~1214MHz and 1559MHz~1610MHz. It is compatible with multi-system satellite signal reception, effectively broadening the operating bandwidth. The entire unit adopts a diagonal mirror symmetry structure, combined with a concentric substrate layout, significantly optimizing the radiation pattern, reducing cross-polarization loss, exhibiting excellent high and low frequency axial ratio performance, and minimizing phase center deviation, thus significantly improving positioning accuracy and signal stability.

[0019] 2. A microstrip zigzag avoidance structure combined with an orthogonal metal probe layout forms dual electromagnetic isolation, effectively suppressing crosstalk between high and low frequency signals, improving the independence of dual-frequency operation and signal purity, and enhancing adaptability to complex electromagnetic environments. The four metal probes are arranged symmetrically in an isosceles trapezoidal pattern, ensuring consistent impedance across the four feed lines while significantly improving the mechanical stability of the suspended support of the radiating plate. This results in excellent vibration and deformation resistance, and high overall reliability.

[0020] 3. The antenna structure is extremely simple and highly adjustable. Frequency tuning can be achieved by fine-tuning the microstrip line parameters, adapting to customized needs in multiple scenarios. Compared to traditional ceramic antennas, this solution reduces weight by 35% and cost by 25%. Mass production assembly is simple and consistent. While ensuring high gain, low interference, and wideband stable electromagnetic performance, it also has the advantages of lightweight design and industrialization, making it highly valuable for market applications. Attached Figure Description

[0021] Figure 1 A perspective view of a broadband GNSS antenna with an integrated loop structure, as shown in the embodiment. Figure 2 This is a top view of a broadband GNSS antenna with an integrated loop structure, as shown in the embodiment. Figure 3 An exploded view of a broadband GNSS antenna with an integrated loop structure, as shown in the embodiment. Figure 4 Gain diagram of a broadband GNSS antenna as shown in the example; Figure 5 The axial ratio diagram is shown for a broadband GNSS antenna in an example.

[0022] The numbers in the image represent: 1-Dual-frequency radiating plate, 11-Upper substrate, 12-High-frequency resonant inner ring, 13-Low-frequency resonant outer ring, 14-High-frequency microstrip line, 141-High-frequency radial section, 142-High-frequency bending section, 143-High-frequency feed point, 15-Low-frequency microstrip line, 151-Low-frequency radial section, 152-Low-frequency bending section, 153-Low-frequency feed point; 2-Ground plate, 21-Power supply panel; 3-Metal probe. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments.

[0024] Example: With the rapid iteration of satellite navigation technology, multi-system GNSS satellite navigation, including BeiDou, GPS, GLONASS, and Galileo, has become widespread and is widely used in many fields such as vehicle navigation, UAV mapping, smart wearables, precise positioning, and IoT terminals. Currently, terminal devices place increasingly higher demands on the performance of GNSS antennas. These antennas not only need to be multi-band compatible, have wide bandwidth, low interference, and high stability radiation characteristics, but also require compact, lightweight, and low-cost structures to meet the assembly and mass production needs of miniaturized terminal devices. Traditional GNSS antennas often employ single resonant structures, split-type radiating layouts, or cylindrical feed probe structures. These generally suffer from numerous drawbacks, such as narrow operating bandwidth, severe crosstalk between high and low frequency signals, poor symmetry of the radiating structure, large phase center offset, insufficient structural stability, and high mass production costs. Consequently, they struggle to simultaneously meet the application requirements of multi-system satellite signal reception and miniaturized, low-cost terminal applications. To address the numerous shortcomings of existing technologies, this invention discloses a broadband GNSS antenna with an integrated loop structure. This antenna, through its innovative nested loop radiation structure, orthogonal microstrip feed network, symmetrical overall layout, and differentiated metal probe arrangement design, thoroughly optimizes the core defects of traditional antennas. It possesses outstanding advantages such as broadband operation, independent dual-frequency radiation, strong anti-interference capability, compact and stable structure, and high cost-effectiveness. It can be fully adapted to multi-system and multi-band GNSS satellite signal reception and transmission scenarios, and has extremely high market adaptability and promotion value.

[0025] like Figure 1 As shown, this invention discloses a broadband GNSS antenna with an integrated loop structure. The overall structure is simple and compact, with no redundant components, resulting in extremely high space utilization. It can achieve wide-band GNSS signal coverage and is perfectly compatible with the synchronous reception of GNSS satellite signals from multiple systems. Specifically, the antenna includes a dual-frequency radiating plate 1, a ground plane 2, and four metal probes 3. These four core components cooperate and work together to achieve multiple functions, including signal resonant radiation, ground reflection, power supply conduction, and mechanical support. The four metal probes 3 are arranged at the same height, allowing the dual-frequency radiating plate 1 to be stably mounted above the ground plane 2, achieving a parallel suspended connection between the dual-frequency radiating plate 1 and the ground plane 2. Compared to the non-parallel, non-suspended assembly structure of traditional antennas, this design can form a uniform and well-sealed radiation cavity space between the dual-band radiating plate 1 and the ground plane 2. The electromagnetic field distribution inside the cavity is uniform and stable, which can effectively avoid problems such as radiation signal distortion, gain fluctuation, and impedance mismatch caused by plate tilting and uneven cavity space. It comprehensively ensures the stability and consistency of the overall radiation performance of the antenna, laying a solid structural foundation for the dual-band broadband operating characteristics.

[0026] like Figure 2 and Figure 3As shown, the dual-frequency radiating plate 1, as the core radiating functional component of the antenna, directly determines the antenna's signal resonance, radiation frequency band, and feeding performance. Its core structure includes an upper substrate 11, and integrated high-frequency resonant inner ring 12, low-frequency resonant outer ring 13, two high-frequency microstrip lines 14, and two low-frequency microstrip lines 15, all arranged on the same surface of the upper substrate 11. This invention abandons the traditional design scheme of layered or separate high- and low-frequency radiating structures for dual-frequency antennas, integrating all radiating and feeding structures coplanarly onto the surface of a single upper substrate 11, significantly reducing the overall size of the antenna and achieving a miniaturized design. Among them, the high-frequency resonant inner ring 12 and the low-frequency resonant outer ring 13 adopt a concentric nested arrangement structure to form a unique loop nested radiation system. The inner high-frequency resonant inner ring 12 corresponds to the high-frequency GNSS signal resonant radiation, and the outer low-frequency resonant outer ring 13 corresponds to the low-frequency GNSS signal resonant radiation. Through the integrated design of double-ring nesting, the antenna can achieve independent dual-frequency operation characteristics without the need to stack multiple radiation structures, effectively solving the technical problems of traditional layered dual-frequency antennas with large thickness, severe inter-layer electromagnetic interference, and inconsistent phase centers.

[0027] To further ensure the regularity and symmetry of the radiation structure, the upper substrate 11 adopts a circular plate structure design, and the circular upper substrate 11 and the low-frequency resonant outer ring 13 are strictly arranged concentrically, so that the radiation structure and feeding structure of the entire dual-frequency radiation plate 1 are uniformly and symmetrically distributed with the center as the reference. In traditional GNSS antenna design, substrate eccentricity and asymmetrical radiation structure are the core causes of radiation signal direction deviation, impedance matching imbalance, and increased cross-polarization loss. However, the concentric circular upper substrate 11 of this invention, matched with a nested circular ring radiation structure, can completely avoid various performance defects caused by substrate eccentricity, ensuring uniform and consistent radiation performance of the antenna in all directions, and significantly improving the accuracy and stability of satellite signal reception. At the same time, the coplanar and concentric circular ring radiation structure can effectively reduce the spatial spacing between high-frequency and low-frequency radiation elements, reduce the volume redundancy of multi-band radiation structures, and further enhance the structural advantages of antenna compactness.

[0028] like Figure 2 and Figure 3As shown, the ground plane 2, constructed from a square metal plate, is an indispensable basic functional component of the antenna, primarily undertaking four core functions: antenna grounding and shielding, electromagnetic wave reflection, radiation gain optimization, and structural positioning reference. The metal ground plane 2 effectively shields against electromagnetic clutter interference from the external environment, preventing interference from stray ground signals and terminal equipment circuit signals to the antenna's GNSS navigation signals, thus improving the purity of the antenna signal reception. Simultaneously, the ground plane 2 can directionally reflect the electromagnetic waves radiated by the antenna, correcting the direction of electromagnetic wave radiation, concentrating radiated energy, significantly improving the overall radiation gain of the antenna, and optimizing the antenna's far-field radiation performance. To ensure the high-precision symmetry of the overall structure, this invention strictly defines the assembly reference: the vertical downward projection of the center of the high-frequency resonant inner ring 12 completely coincides with the geometric center of the square ground plane 2, serving as the central reference for the antenna assembly. This reference design provides precise positioning basis for subsequent radiation structure layout, feed network deployment, and metal probe 3 assembly, completely eliminating structural asymmetry problems caused by assembly deviations and ensuring the coaxiality and geometric symmetry of the overall antenna structure.

[0029] Based on the aforementioned central reference, the dual-frequency radiating plate 1 is symmetrically arranged with one of the diagonals of the ground plane 2 as a mirror image. All radiating structures, feed microstrip lines, and feed points are symmetrically arranged along the vertical mirror image of this 135° azimuth angle. This symmetrical structural layout is a key design feature for optimizing antenna radiation performance. Compared to traditional asymmetrical antenna layouts, this symmetrical structure effectively regularizes the antenna radiation pattern, resulting in a more regular and uniformly covered beam, thus completely improving the radiation pattern distortion and beam offset problems caused by asymmetrical structures. Simultaneously, the symmetrical layout significantly reduces signal cross-polarization loss, minimizes polarization signal interference, ensures higher polarization purity of the GNSS satellite signals received by the antenna, and significantly improves signal reception stability and anti-interference capabilities under complex operating conditions.

[0030] To achieve independent feeding and precise excitation of dual-frequency signals, this invention features a refined design for the layout of microstrip lines and feeding points. The common center of the high- and low-frequency resonant rings is used as the coordinate origin, with a horizontal rightward azimuth reference of 0°. This standardizes the azimuth layout of all structures throughout the invention, ensuring standardized and precise structural design and assembly. Specifically, two high-frequency microstrip lines 14 extend inward from the 0° and 270° azimuth positions of the high-frequency resonant inner ring 12, respectively, symmetrically distributed on both sides of the high-frequency resonant inner ring 12, achieving dual-point symmetrical feeding of the high-frequency signal. Two low-frequency microstrip lines 15 extend inward from the 90° and 180° azimuth positions of the low-frequency resonant outer ring 13, respectively, forming a staggered symmetrical layout with the high-frequency microstrip lines 14, avoiding overlapping interference between the high- and low-frequency feeding structures. Each of the two high-frequency microstrip lines 14 and the two low-frequency microstrip lines 15 has an independent feed point at its end, which ultimately forms four independent feed points that do not interfere with each other, corresponding to two high-frequency feeds and two low-frequency feeds respectively, so as to realize independent feeding excitation of high and low frequency signals.

[0031] Corresponding to the four independent feed points of the dual-frequency radiating plate 1, four feed disks 21 are precisely matched and set on the upper surface of the ground plane 2. The feed disks 21 correspond one-to-one with the high-frequency feed point 143 and the low-frequency feed point 153, and are precisely aligned without deviation or misalignment. During assembly, each metal probe 3 corresponds to a set of vertically aligned feed points and feed disks 21, achieving a one-to-one precise conductive connection and constructing four independent and stable feed conduction circuits. At the same time, the four metal probes 3 jointly undertake the mechanical support and fixed positioning function between the dual-frequency radiating plate 1 and the ground plane 2, replacing the bolts, brackets and other auxiliary fixing structures of traditional antennas, simplifying the assembly process, reducing the number of parts, and further realizing the lightweight and integrated design of the antenna.

[0032] The four metal probes 3 are the core composite functional components of this antenna, serving a dual purpose of electrical conduction and mechanical support. Their structural form and spatial layout directly determine the antenna's electrical performance and structural stability. In traditional GNSS antenna designs, most use linearly arranged cylindrical probes. This arrangement results in uneven stress on the suspended radiating plate structure, making it prone to plate tilting and cavity deformation, leading to antenna performance fluctuations. To adapt to the diagonally symmetrical structural features of the entire device and optimize the antenna's mechanical and electrical performance, this invention arranges the lower ends of the four metal probes 3 in an isosceles trapezoidal shape on the ground plane 2 side. This layout provides uniform stress and stronger support stability, completely solving the problem of poor support stability of linearly arranged probes. It significantly improves the mechanical stability of the entire antenna structure, enabling it to adapt to complex working environments such as vibration and bumps, and avoiding antenna structural deformation and performance degradation caused by changes in equipment operating conditions. Meanwhile, the isosceles trapezoidal symmetrical layout can perfectly match the overall structure of the antenna's diagonal mirror symmetry, making the spatial field distribution of the four feed circuits highly consistent, effectively ensuring the impedance consistency of the feed network, avoiding differences in signal feed loss among different circuits due to uneven probe layout, and ensuring uniform and stable dual-frequency signal radiation performance.

[0033] In terms of probe structure design, this invention abandons the traditional solid cylindrical probe structure and adopts a thin strip metal sheet stamped into a metal probe 3. The sheet structure has the advantages of light weight, small size, high utilization rate of conductive cross section, and simple forming process, which can effectively reduce the overall weight of the antenna and production cost, and is suitable for mass stamping production. The two ends of the metal probe 3 penetrate and are attached to the upper substrate 11 and the ground plane 2 respectively. The through-contact assembly method can achieve a gapless and stable assembly of the upper and lower plates, eliminating loosening and misalignment problems, while ensuring the conductivity and stability of the feed circuit, avoiding signal loss, disconnection and other faults caused by poor contact. In order to completely solve the problem of crosstalk between high and low frequency signals, this invention adopts an orthogonal layout design for the probes: the sheet surfaces of the two metal probes 3 connected by the two high frequency microstrip lines 14 are perpendicular to each other, and the sheet surfaces of the two metal probes 3 connected by the two low frequency microstrip lines 15 are perpendicular to each other. By using orthogonally arranged probe structures, an effective electromagnetic isolation barrier can be formed in space, completely blocking electromagnetic coupling interference between high and low frequency feed circuits, avoiding crosstalk and noise superposition problems of dual-frequency signals, and greatly improving the independence and signal purity of dual-frequency antenna operation.

[0034] Compared to traditional cylindrical probes with the same cross-sectional area, the thin-film orthogonal metal probe 3 structure used in this invention has significant mechanical performance advantages. A single thin-film probe can provide high-strength support stability in a single direction, while two sets of orthogonally arranged thin-film probes can achieve stable support in all directions of the horizontal plane, ensuring that the dual-frequency radiation plate 1 does not shake or shift in the entire horizontal plane. Under the premise of using the same amount of consumables, the overall stability of the suspended structure of the plate is greatly improved, achieving dual optimization of consumable utilization and structural stability, and taking into account the design requirements of lightweight, low cost and high stability.

[0035] To overcome the technical bottleneck of narrow bandwidth in traditional GNSS antennas, this invention employs a differentiated microstrip line electrical length design scheme to precisely match the impedance characteristics of high- and low-frequency resonant signals. For example... Figure 2 As shown, in this embodiment, the overall transmission length of the high-frequency microstrip line 14 is significantly greater than that of the low-frequency microstrip line 15. Due to the inherent differences in the resonant frequency, wavelength, and impedance characteristics of high- and low-frequency GNSS signals, precise impedance matching can be achieved for high- and low-frequency signals through targeted design of different electrical lengths. This eliminates impedance mismatch losses in the feeding circuit, allowing both high-frequency and low-frequency signals to achieve efficient feeding and excitation. This effectively expands the high- and low-frequency operating bandwidth of the antenna, solves the defect that the traditional single-line-length microstrip feeding structure cannot simultaneously meet the dual-frequency broadband matching requirements, and significantly improves the broadband adaptability of the antenna, meeting the reception needs of multi-system, wide-band GNSS signals.

[0036] In terms of microstrip line structure, the high-frequency microstrip line 14 adopts a 90° integrated zigzag structure, consisting of three parts connected sequentially: a high-frequency radial section 141, a high-frequency bending section 142, and a high-frequency feed point 143. There are no seams, ensuring the consistency of the feed circuit's conduction and low-loss characteristics. The extension line of the high-frequency radial section 141 precisely passes through the center of the high-frequency resonant inner ring 12, strictly ensuring that the two high-frequency microstrip lines 14 are radially symmetrically arranged with the center as the reference. This ensures that the transmission paths, impedance parameters, and radiation excitation conditions of the two high-frequency feed signals are completely identical, achieving symmetrical and balanced high-frequency signal radiation. The high-frequency bending section 142 is perpendicular to the high-frequency radial section 141, and the high-frequency bending sections 142 of the two high-frequency microstrip lines 14 completely avoid each other, with no intersection, contact, or overlap. This structural design completely eliminates electromagnetic coupling and signal interference between the two high-frequency feed circuits, ensuring the purity and stability of high-frequency GNSS signal radiation and avoiding gain attenuation and axial ratio degradation caused by co-frequency feed interference.

[0037] Corresponding to the structure of the high-frequency microstrip line 14, the low-frequency microstrip line 15 also adopts a 90° integrated zigzag structure, which is integrally formed by the low-frequency radial section 151, the low-frequency bending section 152, and the low-frequency feed point 153 connected in sequence. The structure is regular, the process is simple, and the performance is stable. The extension line of the low-frequency radial section 151 precisely passes through the center of the low-frequency resonant outer ring 13, ensuring that the overall low-frequency feed structure is symmetrical and regular, so that the transmission characteristics of the two low-frequency feed signals are highly unified, and the low-frequency signal is radiated uniformly. The low-frequency bending section 152 is arranged perpendicularly to the low-frequency radial section 151, and the low-frequency bending section 152 completely avoids the radiation area of ​​the high-frequency resonant inner ring 12, without any intersection, contact or overlap with the high-frequency resonant inner ring 12. From the physical structure level, the high and low frequency radiation areas are completely separated, effectively isolating the electromagnetic coupling between the low-frequency feeding structure and the high-frequency resonant structure, avoiding the low-frequency feeding signal from generating noise interference to the high-frequency resonant radiation signal, and preventing high-frequency signal leakage from affecting the low-frequency signal transmission. This further optimizes the antenna's dual-frequency independent radiation performance, allowing the high and low frequency signals to work stably without interference.

[0038] Through professional electromagnetic simulation and physical testing, the novel broadband GNSS antenna of this invention demonstrates excellent radiation performance. The test results are as follows: Figure 4 , Figure 5 As shown. In the GNSS low-frequency band of 1164MHz~1214MHz, the antenna gain is stably maintained in the range of 3dBi~5dBi, the signal reception capability is stable, there is no significant gain fluctuation throughout the range, the axial ratio is controlled in the range of 1.0~2.0dB, the polarization purity is excellent, and the anti-polarization interference capability is strong. In the GNSS high-frequency band of 1559MHz~1610MHz, the antenna gain can reach 4.5dBi~6dBi, the radiation gain is significantly improved, the axial ratio is as low as 0~1.5dB, and the high-frequency signal polarization characteristics are excellent. The comprehensive performance test results show that although the overall performance of this antenna is slightly inferior to that of high-precision professional surveying base station antennas, it can fully meet the needs of civilian high-precision positioning. Compared with mainstream ordinary consumer-grade GNSS antennas on the market, it has an overwhelming advantage in core indicators such as gain stability, axial ratio performance, anti-interference capability, and bandwidth coverage, and can be adapted to the usage needs of most civilian navigation, positioning, and monitoring terminal equipment.

[0039] In terms of structural technology and mass production cost, this antenna has extremely high industrial application value. The entire unit consists of only two PCB boards and four stamped metal parts, with very few components, a simple assembly structure, and convenient assembly procedures. It does not require complex debugging processes, greatly reducing the difficulty of production assembly and labor costs. Compared with traditional mainstream ceramic GNSS antennas, this invention adopts a lightweight structural design with a PCB substrate and stamped metal probes, which can reduce the weight of the entire unit by more than 35%, effectively adapting to application scenarios with stringent weight requirements such as drones, smart wearables, and small IoT terminals. At the same time, the cost of raw materials and processing costs are significantly reduced, and the overall production cost can be reduced by 25%, which has extremely high cost performance and is very suitable for large-scale, mass industrial production.

[0040] In addition, the antenna's structural design boasts excellent performance adjustability and compatibility. The loop radiation structure for different frequency bands is coplanarly integrated, and the high and low frequency radiation excitation positions are highly unified. This minimizes the phase center deviation between multi-band signals, effectively solving the problems of large phase center offset and low positioning accuracy in traditional dual-band antennas, significantly improving the positioning accuracy of terminal equipment. Furthermore, the antenna feed microstrip line is integrally fabricated using a copper-plated substrate process. This mature technology facilitates easy molding and allows for precise adjustment of the antenna's resonant frequency and impedance characteristics by flexibly adjusting the microstrip line's transmission length, bending angle, and placement without altering the overall antenna structure or assembly layout. This enables targeted tuning based on the GNSS signal requirements of different frequency bands and systems, resulting in highly adaptable and modifiable products that can quickly meet various customized antenna development needs.

[0041] In summary, this invention systematically solves common technical challenges in the traditional GNSS antenna industry, such as narrow operating bandwidth, severe crosstalk between dual-frequency signals, poor radiation symmetry, unstable phase center, insufficient structural stability, and high mass production cost, through four core innovative designs: a nested high- and low-frequency loop resonant radiation structure, an orthogonal zigzag microstrip feed network, a diagonally symmetrical overall layout, and a differentiated spatial arrangement of metal probes. This antenna features high integration, a compact structure, small size, and significant weight reduction. It also boasts multiple advantages, including wideband operation, independent dual-frequency radiation, strong anti-interference capability, high positioning accuracy, flexible tuning, and excellent cost-effectiveness. It is fully compatible with the reception and transmission of GNSS satellite signals from multiple systems and frequency bands, including BeiDou, GPS, GLONASS, and Galileo, and can be widely applied in various scenarios such as vehicle navigation, precision mapping, UAV operations, smart terminals, and IoT positioning, showing great promise for industrialization and promotion.

[0042] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A broadband GNSS antenna with an integrated loop structure, characterized in that: The device includes a dual-frequency radiating plate, a ground plane, and four metal probes. The four metal probes are at the same height and are connected parallel to the ground plane. The dual-frequency radiating plate includes an upper substrate and a high-frequency resonant inner ring, a low-frequency resonant outer ring, two high-frequency microstrip lines, and two low-frequency microstrip lines disposed on the same side of the upper substrate. The high-frequency resonant inner ring and the low-frequency resonant outer ring are concentric. The two high-frequency microstrip lines extend inward from the 0° and 270° azimuth angles of the high-frequency resonant inner ring, respectively. The two low-frequency microstrip lines extend inward from the 90° and 180° azimuth angles of the low-frequency resonant outer ring, respectively. Each of the two high-frequency microstrip lines and the two low-frequency microstrip lines has a feed point at its end. The ground plane is provided with a feed disk corresponding to each feed point. Each metal probe electrically connects a feed point to a feed disk.

2. The broadband GNSS antenna with an integrated loop structure according to claim 1, characterized in that: The upper substrate is a circular plate, and the upper substrate and the low-frequency resonant outer ring are concentric.

3. The broadband GNSS antenna with an integrated loop structure according to claim 1, characterized in that: The ground plane is a square plate, and the downward projection of the center of the high-frequency resonant inner ring coincides with the center of the ground plane.

4. The broadband GNSS antenna with an integrated loop structure according to claim 3, characterized in that: The dual-frequency radiation plate is symmetrical with the vertical plane containing one of the diagonals of the grounding plate as a mirror image.

5. The broadband GNSS antenna with an integrated loop structure according to claim 4, characterized in that: The lower ends of the four metal probes are arranged in an isosceles trapezoidal shape.

6. The broadband GNSS antenna with an integrated loop structure according to claim 5, characterized in that: The metal probe is a strip-shaped sheet, with both ends of the metal probe penetrating and contacting the upper substrate and the ground plane, respectively. The surfaces of the two metal probes connected by high-frequency microstrip lines are perpendicular to each other, and the surfaces of the two metal probes connected by low-frequency microstrip lines are perpendicular to each other.

7. The broadband GNSS antenna with an integrated loop structure according to claim 1, characterized in that: The transmission length of the high-frequency microstrip line is greater than that of the low-frequency microstrip line.

8. The broadband GNSS antenna with an integrated loop structure according to claim 7, characterized in that: The high-frequency microstrip line has a 90° zigzag structure, including a high-frequency radial segment, a high-frequency bending segment, and a high-frequency feed point connected in sequence. The extension line of the high-frequency radial segment passes through the center of the high-frequency resonant inner ring. The high-frequency bending segment is perpendicular to the high-frequency radial segment and does not intersect or contact with another high-frequency microstrip line.

9. The broadband GNSS antenna with an integrated loop structure according to claim 7 or 8, characterized in that: The low-frequency microstrip line has a 90° zigzag structure, including a low-frequency radial segment, a low-frequency bending segment, and a low-frequency feed point connected in sequence. The extension line of the low-frequency radial segment passes through the center of the low-frequency resonant outer ring, and the low-frequency bending segment is perpendicular to the low-frequency radial segment and does not intersect or contact the high-frequency resonant inner ring.

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