Dual-frequency co-boresight GNSS antenna

Abstract

This invention relates to the field of antenna technology, and particularly to a dual-band common-aperture GNSS antenna. It includes a ground plane, a feeding device, a radiating patch, and connecting devices. The radiating patch includes a patch body and at least one side branch. The ground plane is disposed at the bottom of the antenna structure, and the radiating patch is disposed above the ground plane. One end of the side branch is electrically connected to the patch body, and the other end of the side branch is open. The patch body serves as the radiating element for a first frequency band, and the side branch serves as the radiating element for a second frequency band. The feeding device inputs radio frequency signals to the radiating patch. Connecting devices are provided at the edge region of the patch body and at the open end region of the side branch, forming an impedance loading or electrical coupling path between the radiating patch and the ground plane. This antenna is independently adjustable for both frequencies and has stable modes. It achieves electrical miniaturization without the need for high-dielectric materials, features an integrated common-aperture design, is simple to manufacture, and has strong adaptability.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a dual-frequency common-aperture GNSS antenna. Background Technology

[0002] Global Navigation Satellite Systems (GNSS) are widely used in surveying and positioning, unmanned systems, vehicle navigation, and communication terminals. With the continuous expansion of application scenarios, higher demands are placed on antenna miniaturization, lightweight design, and multi-frequency integration capabilities. Especially in dual-frequency GNSS applications, it is often necessary to simultaneously cover different frequency bands, such as L1 and L2, to improve positioning accuracy and anti-interference capabilities.

[0003] However, the resonant frequency of traditional patch antennas is primarily determined by their physical dimensions. When low-frequency operation is required, the patch size often must be increased, leading to a larger overall structural volume, which is detrimental to the integration of space-constrained devices. To achieve size compression, existing technologies typically employ high-dielectric-constant materials (such as ceramic substrates) to shorten the equivalent electrical length. However, high-dielectric-constant materials cause electromagnetic energy to concentrate within the dielectric, thereby increasing dielectric loss and reducing radiation efficiency, while also increasing structural weight and manufacturing costs.

[0004] In dual-frequency design, existing technologies typically employ a dual-patent stacked structure to achieve multi-frequency operation. While this type of structure can achieve dual-frequency resonance, it often suffers from the following problems: First, the electromagnetic coupling between radiating units of different frequency bands is difficult to control effectively, leading to resonant frequency drift or impedance matching deterioration; second, the structure is complex, the number of layers increases, and the manufacturing process becomes more difficult.

[0005] Therefore, without relying on high dielectric constant materials, how to achieve dual-frequency independent resonance, stable circular polarization, and common-aperture radiation in a single patch system through reasonable structural design and electric field control, while maintaining lightweight structure and manufacturability, remains a pressing technical problem to be solved in this field. Summary of the Invention

[0006] This invention provides a dual-frequency common-aperture GNSS antenna, aiming to solve the technical problems existing in the application of dual-frequency GNSS antennas in existing patch antennas.

[0007] This invention provides a dual-band common-aperture GNSS antenna, comprising a ground plane, a feeding device, a radiating patch, and a connecting device. The radiating patch includes a patch body and at least one side branch. The ground plane is disposed at the bottom of the antenna structure, and the radiating patch is disposed above the ground plane. One end of the side branch is electrically connected to the patch body, and the other end of the side branch is open. The patch body serves as a radiating element for a first frequency band, and the side branch serves as a radiating element for a second frequency band. The feeding device inputs radio frequency signals to the radiating patch. Connecting devices are provided in the edge region of the patch body and the open-circuit end region of the side branch. The connecting devices form an impedance loading or electrical coupling path between the radiating patch and the ground plane.

[0008] As a further improvement of the present invention, the side branch is a conductor structure electrically connected to the patch body area through a narrow connecting section, and the side branch is spaced apart from the patch body.

[0009] As a further improvement of the present invention, the radiating patch is formed by dividing the patch body, narrow connecting section and side branch by opening a groove on the side. The narrow connecting section and side branch constitute a strip-shaped conductor structure extending from the outer edge of the patch body. The groove is a clear area formed inside the radiating patch.

[0010] As a further improvement of the present invention, the width of the narrow connecting section is no more than 20% of the length of the patch body covered by the side branch.

[0011] As a further improvement of the present invention, the radiation patch is provided with four grooves on the side, and the four grooves extend along the edge of the patch body to form four side branches. The four side branches include a first side branch, a second side branch, a third side branch, and a fourth side branch. The first side branch and the third side branch are arranged opposite each other about the center of the patch body, and the second side branch and the fourth side branch are arranged opposite each other about the center of the patch body, forming two sets of mutually orthogonal side branches.

[0012] As a further improvement of the present invention, a plurality of connecting devices are provided on the edge region of the patch body, and the plurality of connecting devices are evenly distributed along the outer circumferential direction of the patch body.

[0013] As a further improvement of the present invention, the connecting device includes a first connecting device, a second connecting device, a third connecting device, and a fourth connecting device. The first connecting device, the second connecting device, the third connecting device, and the fourth connecting device are evenly distributed along the edge region of the patch body at equal angles and are respectively located in two orthogonal directions of the patch body. The first connecting device and the third connecting device are symmetrically arranged about the center of the patch body, and the second connecting device and the fourth connecting device are symmetrically arranged about the center of the patch body.

[0014] As a further improvement of the present invention, at least one additional connecting device is provided in the edge region of the patch body, and the position of the additional connecting device is offset from the uniformly distributed connecting devices.

[0015] As a further improvement of the present invention, the connection device includes a connection conductor, one end of which is connected to a ground plane and the other end is coupled to the patch body and a side branch at intervals, and / or one end of which is connected to the edge region of the patch body and the open end region of the side branch at intervals, and the other end is coupled to the ground plane at intervals.

[0016] As a further improvement of the present invention, the connecting device further includes a capacitive structural element; the capacitive structural element is connected in series on the connecting conductor, and the two ends of the connecting conductor are respectively connected to the radiating patch and the ground plane; or, one end of the connecting conductor is connected to the radiating patch, the other end of the connecting conductor is connected to one end of the capacitive structural element, and the other end of the capacitive structural element is connected to the ground plane; or, one end of the connecting conductor is connected to the ground plane, and the other end of the connecting conductor is electrically connected to the radiating patch through the capacitive structural element.

[0017] As a further improvement of the present invention, the capacitive structural element is one or more combinations of lumped capacitor, distributed capacitor structure, and equivalent capacitor structure.

[0018] As a further improvement of the present invention, the connecting device includes a connecting portion and a capacitor forming portion. One end of the connecting portion is electrically connected to the edge region and / or the open end region of the side branch of the patch body, or the connecting portion is a conductor structure extending downward along the edge region and / or the open end region of the side branch of the patch body. The capacitor forming portion is mated to the other end of the connecting portion, or the capacitor forming portion is a conductor structure extending horizontally at the other end of the connecting portion. The capacitor forming portion is disposed opposite to the ground plane to form a distributed capacitor.

[0019] As a further improvement of the present invention, one end of the power supply device is connected to the radiating patch and the other end is connected to an external radio frequency port; or one end of the power supply device is connected to an external radio frequency port and the other end is open and maintains a coupling gap with the radiating patch.

[0020] As a further improvement of the present invention, a dielectric layer is formed between the radiating patch and the ground plane. The dielectric layer is an air layer, a low dielectric constant dielectric layer, or a composite dielectric layer formed by combining air and a low dielectric constant dielectric material.

[0021] The beneficial effects of this invention are:

[0022] (1) Dual-frequency independent adjustable and modally stable. The present invention achieves physical isolation of dual-frequency resonant modes through the partitioning structure of the inner and outer regions of the patch, and achieves mode locking through symmetrical capacitive loading, effectively avoiding the mode splitting and axial ratio deterioration caused by dual-frequency coupling, and improving the stability of dual-frequency circular polarization performance.

[0023] (2) Electrical miniaturization can be achieved without high dielectric materials. This invention achieves electrical miniaturization by changing the equivalent electrical length through distributed capacitive loading, thereby shifting the resonant frequency downward. This is achieved through mechanism rather than by compressing the physical size with high dielectric constant ceramic materials. Therefore, it can significantly reduce structural mass and dielectric loss, improve radiation efficiency, and enhance engineering applicability.

[0024] (3) Integrated structural design with common aperture. This invention integrates dual-frequency radiating units within the same patch and ground plane system, sharing the normal main lobe direction, making it suitable for GNSS terminal equipment applications with limited space.

[0025] (4) The process is simple to implement and highly adaptable. The structure can be implemented using standard PCB technology, and the number and form of capacitive loading units can be flexibly configured, which facilitates design optimization according to different GNSS frequency band combinations. Attached Figure Description

[0026] Figure 1 This is a three-dimensional structural diagram of a dual-frequency common-aperture GNSS antenna according to Embodiment 1 of the present invention;

[0027] Figure 2 This is a top view of the dual-frequency common-aperture GNSS antenna in Embodiment 1 of the present invention in the xy-plane direction;

[0028] Figure 3 This is a side view of the dual-frequency common-aperture GNSS antenna in Embodiment 1 of the present invention in the yz plane direction;

[0029] Figure 4 This is a three-dimensional structural diagram of a dual-frequency common-aperture GNSS antenna according to Embodiment 2 of the present invention;

[0030] Figure 5 This is a top view of the dual-frequency common-aperture GNSS antenna in the xy plane and a schematic diagram of its working principle in Embodiment 2 of the present invention;

[0031] Figure 6 This is a cross-sectional view of the manufacturing process of the dual-frequency common-aperture GNSS antenna in a single-layer circuit board structure according to an embodiment of the present invention.

[0032] Figure 7 This is a reflection coefficient curve of the dual-frequency common-aperture GNSS antenna described in Embodiment 2 of the present invention under simulation conditions;

[0033] Figure 8 This is the planar radiation pattern of the dual-frequency common-aperture GNSS antenna in embodiment 2 of the present invention under low-frequency operating conditions;

[0034] Figure 9 This is the planar radiation pattern of the dual-frequency common-aperture GNSS antenna in embodiment 2 of the present invention under high-frequency operating conditions. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0036] The present invention discloses a dual-band common-aperture GNSS antenna, comprising a ground plane 100, a feeding device 102, a radiating patch, and a connecting device. The radiating patch includes a patch body 101 and at least one side branch. The ground plane 100 is disposed at the bottom of the antenna structure, and the radiating patch is disposed above the ground plane 100. One end of the side branch is electrically connected to the patch body 101, and the other end of the side branch is open. The patch body 101 serves as a radiating element for a first frequency band, and the side branch serves as a radiating element for a second frequency band. The feeding device inputs radio frequency signals to the radiating patch. The edge region of the patch body 101 and the open end region of the side branch are both provided with connecting devices, which form an impedance loading or electrical coupling path between the radiating patch and the ground plane 100.

[0037] Example 1

[0038] like Figures 1 to 3 As shown, Figure 1 This is a three-dimensional structural diagram of a dual-frequency common-aperture GNSS antenna provided in Embodiment 1 of the present invention. Figure 2 This is a top view of the antenna in the xy plane. Figure 3 This is a side view of the antenna in the yz plane.

[0039] This embodiment of a dual-band common-aperture GNSS antenna includes a ground plane 100, a feeding device 102, a patch body 101, a set of connecting devices (a first connecting device, a second connecting device, a third connecting device, and a fourth connecting device) disposed in the edge region of the patch body 101, a first side branch 105 and its corresponding fifth connecting device.

[0040] Ground plane 100 is disposed at the bottom of the antenna structure to provide electrical grounding reference and mechanical support. Patch body 101 is disposed above ground plane 100 as a radiating element of the first frequency band; the first side branch 105 is also disposed above ground plane 100 to form a radiating element of the second frequency band.

[0041] The first side branch 105 is a conductor structure electrically connected to the patch body 101 region via a narrow connecting section, and the first side branch 105 and the patch body 101 are spaced apart. The first side branch 105 can be an independent structure, with one end assembled with the edge of the patch body 101 via the narrow connecting section to form an integral radiating patch.

[0042] The radiating patch is formed by dividing the patch body 101, the narrow connecting section, and the first side branch 105 by creating a first groove 106 on the side. The narrow connecting section and the first side branch 105 constitute a strip-shaped conductor structure extending from the outer edge of the patch body 101. The first groove 106 is a clear area formed inside the radiating patch. The first side branch 105 can also be a structure integrally formed with the patch body 101. That is, based on the entire radiating patch, the first groove 106 is created on the side of the radiating patch, dividing the radiating patch into the patch body 101, the first side branch 105, and the narrow connecting section connecting the two.

[0043] The first side branch 105 is formed by a first groove 106 on the patch body 101. The groove is a clear area formed inside the patch, allowing a strip-shaped conductor structure extending outwards to be formed locally on the patch. One end of this side branch is electrically connected to the patch body, while the other end is open, thus forming a relatively independent current path. Through the setting of this groove structure, the patch body 101 is divided into a main patch area and a side branch area in terms of geometry and impedance distribution. The two areas are physically partitioned by the difference in boundary conditions, thereby forming a dual-frequency common-aperture structure within the same ground plane projection area. Among them, the first frequency band forms two orthogonal eigenmodes from the patch body area, which can achieve circular polarization radiation; the second frequency band forms a unidirectional current mode from a single side branch, and therefore exhibits linear polarization radiation in this embodiment. Through the above structural design, the independent formation of dual-frequency resonant modes and electrical miniaturization design are achieved while maintaining an integrated structure.

[0044] To achieve electrical size compression and avoid using high dielectric constant materials, this invention provides capacitive loading connection devices in the edge region of the patch body 101. The connection devices include a first connection device (a first capacitive structural element 103a and a first connecting conductor 104a), a second connection device (a second capacitive structural element 103b and a second connecting conductor 104b), a third connection device (a third capacitive structural element 103c and a third connecting conductor 104c), and a fourth connection device (a fourth capacitive structural element 103d and a fourth connecting conductor 104d). The first to fourth connection devices are evenly distributed at equal angles along the outer edge region of the patch body 101, wherein the first and third connection devices are centrally symmetrically arranged, and the second and fourth connection devices are centrally symmetrically arranged. The connection devices are disposed in the vertical space between the patch body 101 and the ground plane 100, enabling the capacitive structural elements to effectively couple the vertical electric field distribution between the patch and the ground plane.

[0045] The edge region of the patch body 101 is also provided with at least one additional connecting device, the position of which is offset from the uniformly distributed connecting devices. That is, in addition to the existing first, second, third and fourth connecting devices, an additional connecting device can be added between any two existing connecting devices, the position and number of which are unlimited.

[0046] By employing the aforementioned capacitive loading structure, the equivalent reactance distribution at the patch edge region can be altered, extending the patch's equivalent electrical length and thus shifting the resonant frequency downwards. Under symmetrical loading conditions, the changes in the equivalent electrical length of the two orthogonal modes remain consistent, avoiding mode splitting caused by local loading and achieving mode locking, thereby ensuring the stability of the circular polarization performance in the first frequency band. Therefore, the miniaturization mechanism of this invention does not rely on high dielectric constant materials to compress physical dimensions, but rather achieves electrical miniaturization through electric field coupling control, while simultaneously reducing dielectric loss and improving radiation efficiency.

[0047] Furthermore, a fifth connecting device (a fifth capacitive structural element 103e and a fifth connecting conductor 104e) is provided at the top region of the first side branch 105 to regulate the electric field distribution and resonance characteristics of the side branch region. Preferably, the third connecting device is located in the inner region of the first groove, and the fifth connecting device is located in the outer region of the first groove. By combining internal and external loading, the patch body region and the side branch region can be independently tuned, thereby achieving relatively independent control of dual-frequency resonance.

[0048] Taking the first connection device as an example, the first connection device includes a first connection conductor 104a, one end of the first connection conductor 104a is connected to the ground plane 100, and the other end is coupled to the patch body 101 at intervals, and / or one end of the first connection conductor 104a is connected to the edge area of ​​the patch body 101, and the other end is coupled to the ground plane 100 at intervals.

[0049] The first connecting device further includes a first capacitive structural element 103a, which is loaded between the patch body 101 and the ground plane 100 via a first connecting conductor 104a. Specifically, the first capacitive structural element 103a is connected in series in the middle of the first connecting conductor 104a, with both ends of the first connecting conductor 104a connected to the patch body 101 and the ground plane 100 respectively; or one end of the first connecting conductor 104a is connected to the patch body 101, and the other end is electrically connected to the ground plane 100 via the first capacitive structural element 103a; or one end of the first connecting conductor 104a is connected to the ground plane 100, and the other end is electrically connected to the patch body 101 via the first capacitive structural element 103a. The connecting conductor is used to introduce the capacitive structural element into the strong electric field region between the patch and the ground plane, thereby forming an effective capacitive loading path. The structural forms of other connecting devices can be the same as or similar to the first connecting device.

[0050] Capacitive structural elements possess a capacitive component and can be lumped elements, such as chip capacitors, variable capacitors, electrolytic capacitors, ceramic capacitors, and film capacitors, or distributed elements, such as parallel conductors (two or more conductors arranged in parallel, generating an electric field between them to form a capacitor, with the capacitance value adjusted by changing the conductor spacing and length), transmission line structures (such as microstrip lines or coaxial cables), capacitive plates (two parallel metal plates separated by a dielectric layer or air gap to form a capacitor), and planar capacitive structures (metal patterns printed on a PCB, such as finger-like or interlaced structures, with the geometry adjusted to optimize capacitance characteristics). These forms can be flexibly combined according to design requirements to optimize antenna performance. Furthermore, capacitive structural elements can consist of a single capacitor element or multiple elements connected together. To obtain a specific capacitance, a combination of multiple elements can be used instead of a single capacitor element; for example, a capacitive structural element can be replaced by a combination of a capacitor element and an inductive element. Inductive elements possess an inductive component and can be lumped elements, such as chip inductors and chip resistors, or distributed elements, such as wires and coils. Similarly, an inductor can be composed of a single inductor or multiple inductors connected together.

[0051] A dielectric layer is provided between the patch body 101 and the ground plane 100, preferably using air dielectric, a low dielectric constant material, or a composite dielectric structure formed by a combination of both, thereby reducing dielectric loss and structural mass. Since this invention achieves electrical miniaturization through capacitive loading, it does not rely on high dielectric constant ceramic materials, which is beneficial for achieving lightweight and high-efficiency design.

[0052] In this embodiment, the number of capacitive loading devices on the patch body 101 is four, which are centrally symmetrically distributed along the circumference of the patch. This symmetrical arrangement is beneficial for forming two sets of mutually orthogonal electric field vector components on the patch, achieving stable circular polarization radiation. It should be noted that the number and position of the capacitive loading devices can be adjusted according to the target operating frequency and structural symmetry. For example, three, six, or eight loading units can be used, preferably at least three symmetrically distributed along the center of the patch to ensure circular polarization performance.

[0053] The power supply device 102 is used to input radio frequency signals and achieve impedance matching. This embodiment uses a single-feed configuration, with one end of the power supply device 102 connected to the patch body 101 and the other end connected to an external radio frequency port. In other embodiments, a dual-feed or quad-feed structure can be used, with two or four feed lines arranged orthogonally along the x-axis and y-axis. When input signals have equal amplitude and a phase difference of 90°, a stable circular polarization mode can be excited. The power supply device 102 can also use feed lines, probe feeding, coaxial feeding, microstrip feeding, or slot feeding. Furthermore, the power supply device 102 can also use a coupled feeding method, where one end of the power supply device 102 is connected to an external radio frequency port, and the other end is open, maintaining a coupling gap with the radiating patch, inputting energy to the radiating patch through electric field coupling.

[0054] Furthermore, the geometry of the patch body 101 is not limited to a square structure; it can be circular, annular, polygonal, or elliptical. To further reduce the operating frequency and optimize impedance matching, U-shaped grooves, L-shaped grooves, or other gap structures can be introduced on the patch surface to extend the surface current path, achieving frequency control and miniaturization.

[0055] The structural form of the first side branch 105 is not limited to a straight line; it can be a serpentine or zigzag structure. The side branch can be located in the same plane as the patch body to form a groove structure, or it can be bent or folded along the vertical direction. Regardless of its spatial configuration, the side branch electromagnetically constitutes an extended conductor structure electrically connected to the patch body through a narrow connecting section, and forms the main resonant unit of the second frequency band.

[0056] Example 2

[0057] Unlike Example 1, this example uses a symmetrical arrangement of four side branches to enable the second frequency band to form two sets of orthogonal modes, thereby achieving circular polarization. Figure 4 This is a three-dimensional structural diagram of a dual-frequency common-aperture GNSS antenna provided in Embodiment 2 of the present invention. Figure 5 This is a top view of the antenna in the xy plane, used to illustrate the working mechanism of the present invention.

[0058] This embodiment further improves upon Embodiment 1 by providing side branch structures on the four sides of the patch body 101 to achieve a dual-frequency dual-circular polarization collaborative design. Specifically, a first side branch 105 is provided on the first side of the patch body 101, a second side branch 205 is provided on the second side, a third side branch 305 is provided on the third side, and a fourth side branch 405 is provided on the fourth side. The first side branch 105 is formed by a first groove 106, the second side branch 205 is formed by a second groove 206, the third side branch 305 is formed by a third groove 306, and the fourth side branch 405 is formed by a fourth groove 406.

[0059] Four grooves extend along the four edges of the patch body 101, forming an enclosed segmentation structure inside the patch, such as... Figure 5 As shown, the patch is divided into an inner patch region and an outer patch region. The groove alters the current continuity on the patch surface, creating an impedance discontinuity boundary between the main patch region and the side branch region. This results in significantly different current path distributions and equivalent electrical lengths between the inner and outer patches, achieving physical mode partitioning. Specifically, the first side branch is formed by a groove extending along the patch edge, creating an extended conductor structure on the patch periphery that is electrically connected to the main patch region via a narrow connecting segment. The width of the narrow connecting segment is no greater than 20% of the length of the main patch body covered by the side branch. That is, for polygonal patches, the width of the narrow connecting segment is preferably within 20% of the patch side length; for circular patches, the width of the narrow connecting segment is preferably within 20% of the arc length of the patch edge covered by the corresponding side branch. This creates a high-impedance connection region electromagnetically, resulting in a weak coupling relationship between the side branch and the main patch body. Through the above structural design, the side branch forms a second resonant unit electromagnetically distinct from the main patch area, rather than a local disturbance structure used only to extend the current path. This achieves physical isolation and independent control of the dual-frequency resonant modes within the same metal patch system, while maintaining the overall integrated structure and common-aperture radiation characteristics, and enabling independent operation of the dual frequencies.

[0060] The inner region of the patch is a continuous metal structure that can support two sets of mutually orthogonal intrinsic modes (such as...) in the lateral and longitudinal directions. Figure 5(As indicated by the solid arrow in the middle), this region operates in the first frequency band. To achieve miniaturization and circular polarization stability in the first frequency band, a capacitive loading connection device is provided at the edge of the inner region of the patch, including a first connection device (first capacitive structural element 103a and first connecting conductor 104a), a second connection device (second capacitive structural element 103b and second connecting conductor 104b), a third connection device (third capacitive structural element 103c and third connecting conductor 104c), and a fourth connection device (fourth capacitive structural element 103d and fourth connecting conductor 104d). The connection devices are uniformly arranged at equal angles along the outer edge of the inner region of the patch and are located in the vertical space between the patch and the ground plane to regulate the vertical electric field distribution in the inner region of the patch.

[0061] By using symmetrical capacitive loading, the equivalent electrical lengths of the two orthogonal modes can be adjusted synchronously to achieve mode locking, avoiding mode splitting caused by unbalanced loading, thereby forming stable circularly polarized radiation in the first frequency band.

[0062] The peripheral area of ​​the surface mount consists of four side branches. The first side branch 105 is positioned opposite to the third side branch 305, and the second side branch 205 is positioned opposite to the fourth side branch 405. This symmetrical layout allows the peripheral area to also form two sets of mutually orthogonal current distribution patterns (such as...). Figure 5 (As shown by the dashed arrow), it operates in the second frequency band. The oppositely positioned side branches form a symmetrical radiation unit in space, which is beneficial for enhancing normal radiation and improving gain performance through electric field superposition.

[0063] To further adjust the resonant characteristics of the second frequency band, capacitive loading connection devices are respectively installed at the top regions of the four side branches. Specifically, these include: a fifth connection device (fifth capacitive structural element 103e and fifth connecting conductor 104e), a sixth connection device (sixth capacitive structural element 103f and sixth connecting conductor 104f), a seventh connection device (seventh capacitive structural element 103g and seventh connecting conductor 104g), and an eighth connection device (eighth capacitive structural element 103h and eighth connecting conductor 104h). These loading devices are used to adjust the electric field distribution and equivalent reactance characteristics of the side branches, thereby optimizing the resonant frequency and polarization performance of the second frequency band.

[0064] With the above structure, the inner and outer regions of the patch each form independently adjustable dual circular polarization modes, achieving common-aperture radiation within the same ground plane projection area. The two frequency bands are physically isolated by boundary conditions formed by the grooves, while maintaining controllable electromagnetic coupling, thus achieving dual-frequency coordination rather than mutual interference.

[0065] The dual-frequency common-aperture GNSS antenna of this embodiment has the following technical features:

[0066] First, miniaturization and lightweight design. This invention can achieve a lower resonant frequency without relying on a high dielectric constant ceramic substrate. Its miniaturization mechanism comes from the equivalent electrical length extension and mode locking caused by symmetrical capacitive loading, rather than compressing the physical size through dielectric constant. Therefore, it can effectively reduce structural mass and improve radiation efficiency.

[0067] Second, the common-aperture dual-frequency design. A grooved structure creates inner and outer dual regions, enabling independent operation of both frequencies within the same metal patch and ground plane system, while sharing the normal radiation main lobe direction to meet the common-aperture radiation requirements.

[0068] Third, it has strong structural adaptability. The number, location, and reactance type of the capacitive loading connection device can be flexibly adjusted according to the target frequency band, size requirements, and manufacturing process, thereby adapting to different GNSS frequency band combinations and engineering application scenarios.

[0069] Through the above structural design, this embodiment realizes a miniaturized common-aperture antenna structure with dual-frequency dual-circular polarization. While ensuring pattern symmetry and radiation efficiency, it achieves relatively independent and adjustable dual-frequency resonance, which has good engineering implementation value and promotion significance.

[0070] Process Example 1

[0071] This embodiment, based on Embodiment 1, illustrates a specific engineering implementation of a dual-frequency common-aperture GNSS antenna in a single-layer circuit board structure.

[0072] like Figure 6 As shown, and in combination Figures 1 to 3 The dual-band, common-aperture GNSS antenna is mounted in a single-layer printed circuit board structure, and its interlayer relationship is clearly shown in the cross-sectional view in the yz plane. The ground plane 100 is formed on the lower surface of the first dielectric substrate 601 and is a continuous metal layer structure. It serves as the antenna's reflector and grounding layer, providing electrical grounding reference and mechanical support for the upper radiating element.

[0073] The patch body 101 and the first side branch 105 are preferably implemented using a metal sheet structure and are positioned above the ground plane 100 by a supporting structure, maintaining a certain distance from the ground plane. The first dielectric substrate 601 is located above the ground plane 100, and an air dielectric layer is formed between it and the patch body 101. This structure maintains good mechanical stability while helping to reduce dielectric loss and improve radiation efficiency.

[0074] In this embodiment, the capacitive loading connection device is implemented using a distributed capacitor structure. Taking the first connection device as an example, the first connection device includes a first connection portion 604a and a first capacitor forming portion 603a. One end of the first connection portion 604a is electrically connected to the edge region of the patch body 101; or, the first connection portion 604a is a metal conductor structure extending downward from the edge region of the patch body 101, and is electrically connected to the patch body 101 through a bending structure. The first capacitor forming portion 603a is connected to the other end of the first connection portion 604a, or the first capacitor forming portion 603a is a conductor structure extending horizontally at the other end of the first connection portion 604a. The first capacitor forming portion 603a is a conductor trace formed on the upper surface of the first dielectric substrate 601, which is arranged parallel to the lower ground plane 100 and separated by the first dielectric substrate 601, thereby forming a distributed planar capacitor structure. The upper end of the first connecting part 604a is electrically connected to the patch body 101, and the lower end is electrically connected to the first capacitor forming part 603a, so that the capacitive structural element is effectively introduced into the electric field region between the patch and the ground plane.

[0075] Because this distributed capacitor structure is located in the strong electric field region between the chip and the ground plane, it can effectively couple the vertical electric field distribution, thereby changing the equivalent reactance characteristics of the chip. By adjusting the length and width of the conductor traces and their spacing with the ground plane, the equivalent capacitance value can be precisely controlled, enabling a lower resonant frequency and miniaturized electrical design.

[0076] Similarly, the third connection device is composed of a third connection portion 604c and a third capacitor forming portion 603c, and the fifth connection device is composed of a fifth connection portion 604e and a fifth capacitor forming portion 603e. The third capacitor forming portion 603c and the fifth capacitor forming portion 603e are also conductor trace structures formed on the upper surface of the first dielectric substrate 601, arranged parallel to the ground plane 100 and isolated by a dielectric layer, thereby forming distributed capacitance. The first connection device and the third connection device are preferably arranged in a centrally symmetrical manner for symmetrical capacitive loading of the patch body 101; the fifth connection device is used for capacitive tuning of the first side branch 105.

[0077] The symmetrically distributed capacitor loading structure described above enables synchronous adjustment of the two orthogonal modes of the patch panel, achieving a mode-locking effect and avoiding mode splitting caused by unilateral loading. Simultaneously, capacitive loading of the side branches allows independent adjustment of the second frequency band resonant frequency, thus achieving independent controllability of both frequencies.

[0078] This embodiment can be implemented using standard PCB printing technology. The ground plane and capacitive structural components can be formed by conventional copper foil etching, and the connecting conductors can be electrically connected to the patch via metal pillars, vias, or solder structures. The overall structure is stabilized by the circuit board and metal supports, thereby simplifying the manufacturing process and reducing processing costs, giving the antenna good compatibility in terms of structural reliability and engineering manufacturability. Furthermore, based on manufacturing processes and design requirements, the structural form, dimensional parameters, positional relationships, and quantity of the capacitive loading device can be flexibly configured to optimize impedance matching, axial ratio performance, and radiation pattern symmetry.

[0079] Through the above-described process, this embodiment further verifies the feasibility and scalable production capability of the structure of the present invention in actual engineering.

[0080] like Figure 7 and Figure 8 The figures shown are simulation results of the dual-frequency common-aperture GNSS antenna of Embodiment 2 of the present invention, which are used to verify the effectiveness of the structural design and its technical effect of the present invention.

[0081] Figure 7 The image shows the reflection coefficient (S11) curve of the antenna. Simulation results show that the antenna exhibits good impedance matching characteristics in both target operating frequency bands, forming two independent −6 dB operating bandwidths. The center frequency of the first −6 dB band is approximately 1.20 GHz, and the center frequency of the second −6 dB band is approximately 1.57 GHz, indicating that the inner region of the patch and the outer side branch region respectively form stable resonant modes and achieve effective energy radiation within their respective frequency bands.

[0082] The above dual-frequency resonance characteristics demonstrate that by capacitively loading and controlling the patch area and the side branch area separately, relatively independent tuning of the two frequency bands can be achieved, thereby avoiding the modal coupling interference problem commonly found in dual-frequency structures. This result verifies the effectiveness of the proposed "modal partitioning + symmetrical capacitive loading" structure in independent dual-frequency control.

[0083] Figure 8 and Figure 9 The planar radiation characteristics of the antenna at 1.20 GHz and 1.58 GHz are shown respectively. Figure 8 The radiation pattern at a low frequency of 1.20 GHz shows that the antenna exhibits good normal radiation characteristics at low frequencies, with the main lobe direction concentrated in the zenith direction (φ=0°), a main lobe gain of approximately 4 dBi, and good symmetry in the radiation pattern. This result indicates that the orthogonal modes formed in the inner region of the patch can be effectively superimposed, producing stable circularly polarized radiation.

[0084] Figure 9The radiation pattern at a high frequency of 1.58 GHz is shown. Simulation results show that the antenna maintains good normal radiation characteristics even at high frequencies, with a main lobe gain of approximately 5 dBi and good pattern symmetry. Based on the structure of Example 2, the four symmetrically arranged side branches form two sets of orthogonal current distribution modes at high frequencies, and enhance normal radiation through spatial symmetry superposition, thereby achieving circularly polarized radiation in the second frequency band. This result further verifies the rationality of the biorthogonal mode design in the peripheral region.

[0085] As can be seen from the simulation results above, the present invention achieves physical isolation of dual-frequency modes through a groove partition structure, and achieves mode locking and equivalent electric length extension through symmetrical capacitive loading. Thus, it achieves dual-frequency miniaturization design without relying on high dielectric constant materials, while maintaining good radiation pattern symmetry and radiation performance.

[0086] In summary, this invention has good engineering feasibility in terms of miniaturization, lightweight design, dual-frequency common aperture, and high-performance circularly polarized radiation.

[0087] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A dual-frequency common-aperture GNSS antenna, characterized in that, The antenna includes a ground plane, a feeding device, a radiating patch, and connecting devices. The radiating patch includes a patch body and at least one side branch. The ground plane is located at the bottom of the antenna structure, and the radiating patch is located above the ground plane. One end of the side branch is electrically connected to the patch body, and the other end of the side branch is open. The patch body serves as a radiating element for a first frequency band, and the side branch serves as a radiating element for a second frequency band. The feeding device inputs radio frequency signals to the radiating patch. Connecting devices are provided in the edge region of the patch body and the open end region of the side branch. The connecting devices form an impedance loading or electrical coupling path between the radiating patch and the ground plane.

2. The dual-frequency common-aperture GNSS antenna according to claim 1, characterized in that, The side branch is a conductor structure electrically connected to the patch body area through a narrow connecting section, and the side branch is spaced apart from the patch body.

3. The dual-frequency common-aperture GNSS antenna according to claim 1, characterized in that, The radiating patch is formed by creating grooves on the side to separate the patch body, narrow connecting section, and side branch. The narrow connecting section and side branch constitute a strip-shaped conductor structure extending from the outer edge of the patch body. The groove is a clear area formed inside the radiating patch.

4. The dual-frequency common-aperture GNSS antenna according to claim 2 or 3, characterized in that, The width of the narrow connecting section is no more than 20% of the length of the patch body covered by the side branch.

5. The dual-frequency common-aperture GNSS antenna according to claim 1, characterized in that, The radiating patch has four grooves on its side. The four grooves extend along the edge of the patch body to form four side branches. The four side branches include a first side branch, a second side branch, a third side branch, and a fourth side branch. The first side branch and the third side branch are arranged opposite each other about the center of the patch body. The second side branch and the fourth side branch are arranged opposite each other about the center of the patch body, forming two sets of mutually orthogonal side branches.

6. The dual-frequency common-aperture GNSS antenna according to claim 1, characterized in that, The edge region of the patch body is provided with multiple connecting devices, which are evenly distributed along the outer circumferential direction of the patch body.

7. The dual-frequency common-aperture GNSS antenna according to claim 6, characterized in that, The connecting device includes a first connecting device, a second connecting device, a third connecting device, and a fourth connecting device. The first connecting device, the second connecting device, the third connecting device, and the fourth connecting device are evenly distributed along the edge area of ​​the patch body at equal angles and are respectively located in two orthogonal directions of the patch body. The first connecting device and the third connecting device are symmetrically arranged about the center of the patch body, and the second connecting device and the fourth connecting device are symmetrically arranged about the center of the patch body.

8. The dual-frequency common-aperture GNSS antenna according to claim 6 or 7, characterized in that, The edge region of the patch body is also provided with at least one additional connecting device, the position of which is offset from the uniformly distributed connecting devices.

9. The dual-frequency common-aperture GNSS antenna according to any one of claims 1 to 3, 5 to 7, characterized in that, The connection device includes a connecting conductor, one end of which is connected to a ground plane and the other end is coupled to the patch body and a side branch at intervals, and / or one end of which is connected to the edge area of ​​the patch body and the open end area of ​​the side branch at intervals, and the other end is coupled to the ground plane at intervals.

10. The dual-frequency common-aperture GNSS antenna according to claim 9, characterized in that, The connecting device also includes a capacitive structural element; The capacitive structural element is connected in series on the connecting conductor, and the two ends of the connecting conductor are respectively connected to the radiating patch and the ground plane; Alternatively, one end of the connecting conductor is connected to the radiating patch, the other end of the connecting conductor is connected to one end of the capacitive structural element, and the other end of the capacitive structural element is connected to the ground plane; Alternatively, one end of the connecting conductor is connected to the ground plane, and the other end of the connecting conductor is electrically connected to the radiating patch through a capacitive structural element.

11. The dual-frequency common-aperture GNSS antenna according to claim 10, characterized in that, The capacitive structural element is one or more combinations of lumped capacitors, distributed capacitor structures, and equivalent capacitor structures.

12. The dual-frequency common-aperture GNSS antenna according to any one of claims 1 to 3, 5 to 7, characterized in that, The connection device includes a connection portion and a capacitor forming portion. One end of the connection portion is electrically connected to the edge region and / or the open end region of the side branch of the patch body, or the connection portion is a conductor structure extending downward along the edge region and / or the open end region of the side branch of the patch body. The capacitor forming portion is mated to the other end of the connection portion, or the capacitor forming portion is a conductor structure extending horizontally at the other end of the connection portion. The capacitor forming portion is disposed opposite to the ground plane to form a distributed capacitor.

13. The dual-frequency common-aperture GNSS antenna according to any one of claims 1 to 3, 5 to 7, characterized in that, One end of the power supply device is connected to the radiating patch, and the other end is connected to an external radio frequency port; or one end of the power supply device is connected to an external radio frequency port, and the other end is open and maintains a coupling gap with the radiating patch.

14. The dual-frequency common-aperture GNSS antenna according to any one of claims 1 to 3, 5 to 7, characterized in that, A dielectric layer is formed between the radiant patch and the ground plane. The dielectric layer is an air layer, a low dielectric constant dielectric layer, or a composite dielectric layer formed by combining air and a low dielectric constant dielectric material.

Images