A single-feed and tightly coupled self-circular polarized antenna

Abstract

The application relates to the field of antennas, in particular to a single-feed and tightly-coupled self-circularly-polarized antenna. The antenna comprises a ground plate, a radiation patch, a connecting device, a feed structure, the radiation patch comprises a first patch and a second patch, the connecting device comprises a first connecting device and a second connecting device, the first patch and the second patch are arranged above the ground plate and form a height interval with the ground plate, the first patch is arranged apart from the second patch, and a near-field coupling region is formed between the first patch and the second patch, the first connecting device is connected with the first patch, the second connecting device is connected with the second patch, the first connecting device and the second connecting device are respectively located at two edge regions of the outer contour of the radiation patch, and a circumferential interval across a main conductor path region is formed between the first connecting device and the second connecting device, and the feed structure feeds radio frequency signals to the antenna. The antenna can realize wideband circularly-polarized radiation under the condition of single feed, does not need an additional power divider or a phase-shifting network, and has a simple structure.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a single-fed and tightly coupled self-circularly polarized antenna. Background Technology

[0002] Global Navigation Satellite Systems (GNSS) are widely used in vehicle navigation, unmanned systems, portable positioning terminals, IoT positioning modules, timing systems, and satellite communication-related equipment. GNSS satellite signals typically use circular polarization during propagation in space. If the receiving antenna uses linear polarization or a structure with poor polarization stability, polarization mismatch loss can easily occur, thus reducing receiver sensitivity and positioning stability. Therefore, GNSS antennas with stable circular polarization radiation capability are a key component in navigation and positioning terminals.

[0003] Existing GNSS circularly polarized antennas typically employ structures such as ceramic dielectric patch antennas, dual-fed circularly polarized patch antennas, slotted perturbation patch antennas, or quad-arm helical antennas. Ceramic dielectric patch antennas can reduce physical size using high-dielectric-constant materials, but these materials generally increase antenna weight and material cost, and may lead to increased dielectric loss and reduced radiation efficiency. Dual-fed circularly polarized patch antennas require power-dividing phase-shifting networks or dual-port excitation structures, resulting in high system complexity and hindering low-cost, miniaturized module integration. While slotted perturbation patch antennas can achieve circular polarization under single-fed conditions, they usually rely on frequency splitting and phase balance of two approximately orthogonal degenerate modes on the patch. When asymmetric perturbations are introduced by the antenna installation environment, terminal housing, or adjacent devices, the axial ratio performance and radiation pattern stability are easily affected.

[0004] In addition, traditional miniaturized GNSS antennas often achieve a lower resonant frequency by shortening the patch size, adding short-circuit structures, introducing high dielectric constant substrates or complex loading networks. However, these methods often sacrifice radiation efficiency, increase structural complexity, or make polarization performance more sensitive to processing errors and assembly tolerances.

[0005] Therefore, it is necessary to propose a GNSS antenna structure that is simple in structure, easy to manufacture, and capable of forming stable circularly polarized radiation under single-feed conditions. This structure should be able to achieve a controlled rotational distribution of current and electric field inside the antenna through the synergistic effect of patch geometry, electric field coupling between patches, and loading of connecting devices, thereby realizing a self-circularly polarized operating mode, while taking into account miniaturization, low cost, and engineering manufacturability. Summary of the Invention

[0006] This invention provides a single-fed and tightly coupled self-circularly polarized antenna, aiming to solve the technical problems existing in traditional GNSS circularly polarized antennas.

[0007] This invention provides a single-fed and tightly coupled self-circularly polarized antenna, comprising a ground plane, a radiating patch, a connecting device, and a feeding structure. The radiating patch includes a first patch and a second patch. The connecting device includes a first connecting device and a second connecting device. Both the first patch and the second patch are disposed above the ground plane and form a height gap with the ground plane. The first patch and the second patch are spaced apart and form a near-field coupling region between them. The first connecting device is connected to the first patch, and the second connecting device is connected to the second patch. The first connecting device and the second connecting device are respectively located at two edge regions of the outer contour of the radiating patch, and a circumferential gap is formed between the first connecting device and the second connecting device across the main conductor path region. The feeding structure feeds radio frequency signals to the antenna.

[0008] As a further improvement of the present invention, the first connecting device and the second connecting device are respectively disposed on two mutually distant edge regions on the outer contour of the radiating patch, so that the first connecting device, the first patch, the near-field coupling region, the second patch and the second connecting device together form a cross-current propagation path.

[0009] As a further improvement of the present invention, the positional arrangement of the first connecting device and the second connecting device includes:

[0010] First positional layout: The first connecting device and the second connecting device are arranged relative to the geometric center of the radiating patch, approximately rotated 180°, or diagonally arranged;

[0011] Second positional layout: The first connecting device and the second connecting device are respectively located on adjacent sides of the radiating patch and close to the diagonal area;

[0012] Third position layout: Based on the first position layout or the second position layout, the first connecting device and the second connecting device are partially offset along the outer periphery or radial direction of the radiating patch.

[0013] As a further improvement of the present invention, the power supply structure includes a power supply device, one end of which is connected to a first patch or a second patch, and the other end of which is connected to an RF chip or an RF port; or, one end of which is connected to an RF chip or an RF port, and the other end of which is open and coupled to the first patch and / or the second patch through a gap.

[0014] As a further improvement of the present invention, the power supply structure includes a matching circuit, and the first connection device or the second connection device is connected to the radio frequency chip or radio frequency port through the matching circuit; the matching circuit includes one or more combinations of capacitors, inductors, resistors, transmission lines, and microstrip tuning stubs.

[0015] As a further improvement of the present invention, the first patch and / or the second patch are provided with a slotted structure that extends the current path, adjusts the resonant frequency, or forms multiple current paths.

[0016] As a further improvement of the present invention, both the first patch and the second patch have a lateral component and a longitudinal component, wherein the length ratio of the long component to the short component in the lateral component and the longitudinal component is less than or equal to 4:1.

[0017] As a further improvement of the present invention, the first patch and / or the second patch are further provided with additional connecting devices, which are disposed in the adjacent area of ​​the first connecting device or the second connecting device.

[0018] As a further improvement of the present invention, the connection device forms a grounding connection, impedance loading, electrical coupling or equivalent boundary control path between the radiating patch and the ground plane. The connection device includes one or more combinations of wires, vias, connecting posts, metal sheets, spring sheets, metallized sidewalls, and flexible connecting pieces; and / or an inductor, capacitor, transmission line segment or inductor-capacitor composite loading structure is added to the connection path of the connection device.

[0019] As a further improvement of the present invention, one or more support legs are provided, wherein the support legs are insulating support legs or conductive support legs; when they are insulating support legs, both ends of the insulating support legs are fixedly connected to the radiating patch and the ground plane, respectively; when they are conductive support legs, one end of the conductive metal leg is fixedly connected to the radiating patch, and the other end is supported on the ground plane through an insulating isolation structure, or one end of the conductive metal leg is fixedly connected to the ground plane, and the other end is supported on the radiating patch through an insulating isolation structure.

[0020] As a further improvement of the present invention, the edge regions of the first patch and / or the second patch are further provided with extensions or folds.

[0021] As a further improvement of the present invention, the power supply device is further provided with additional matching elements, which include one or more combinations of capacitors, inductors, matching networks, microstrip stubs, and transmission line conversion segments connected in series or in parallel.

[0022] As a further improvement of the present invention, the minimum spacing between the first patch and the second patch is set to be within 1 / 10 of the wavelength corresponding to the operating frequency, so as to form a near-field coupling region.

[0023] As a further improvement of the present invention, the spacing arrangement of the first patch and the second patch includes arranging them at the same height or staggered arrangement. In the staggered arrangement, the projections of the first patch and the second patch on the ground plane are spaced apart, partially overlapped, or completely overlapped.

[0024] As a further improvement of the present invention, the first patch and / or the second patch are disposed at an angle relative to the ground plane, or disposed on a folded carrier, curved carrier, inclined carrier, terminal housing or bracket.

[0025] As a further improvement of the present invention, an inter-patch capacitor is provided between the first patch and the second patch. The inter-patch capacitor is a distributed capacitor formed by dielectric filling, relative extensions, interdigitated structures or projected overlapping areas, or a lumped capacitor connected between the first patch and the second patch.

[0026] As a further improvement of the present invention, an air layer, a low dielectric constant dielectric layer, or a composite dielectric layer formed by a combination of the two is provided between the radiating patch and the ground plane.

[0027] The beneficial effects of this invention are:

[0028] (1) This self-circularly polarized antenna can achieve broadband circularly polarized radiation under single-feed conditions without the need for additional power dividers or phase-shifting networks, and has a simple structure.

[0029] (2) A strong electric field coupling is formed between the first patch and the second patch, which can realize current control and electric field rotation through the coupled electric field, which is beneficial to constructing a self-circular polarization working mode.

[0030] (3) The connection device can be in the form of wires, vias, connecting posts or loaded inductors, with flexible structure, which is convenient to implement PCB process, metal stamping process or modular packaging process.

[0031] (4) The patch has two orthogonal components, the transverse and the longitudinal, which can form a current path with a rotational tendency within a limited size, which is beneficial to improving the circular polarization stability.

[0032] (5) By designing the patch in a symmetrical, mirrored, slotted, L-shaped or multi-path manner, polarization rotation can be reversed, frequency can be reduced, miniaturized, and dual-frequency or multi-frequency operation can be achieved, which has good structural scalability. Attached Figure Description

[0033] Figure 1 This is a three-dimensional structural schematic diagram of a self-circularly polarized antenna according to Embodiment 1 of the present invention;

[0034] Figure 2 This is a side view of the self-circularly polarized antenna according to Embodiment 1 of the present invention.

[0035] Figure 3 This is a top view and a schematic diagram of the current and electric field distribution of a self-circularly polarized antenna according to Embodiment 1 of the present invention.

[0036] Figure 4 This is a schematic diagram of the three-dimensional structure of the polarization-rotating antenna in Embodiment 2 of the present invention;

[0037] Figure 5 This is a schematic diagram of the equivalent structure of the connection device connected to the radio frequency chip via a matching circuit in Embodiment 3 of the present invention;

[0038] Figure 6 This is a schematic diagram of the structure of the fourth embodiment of the present invention, which shows the groove on the first patch or the second patch;

[0039] Figure 7 This is a schematic diagram of the structure of the fifth embodiment of the present invention, which provides a multi-path slot on the first patch or the second patch;

[0040] Figure 8 This is a schematic diagram of the L-shaped patch structure in Embodiment Six of the present invention;

[0041] Figure 9 This is a simulation curve of the reflection coefficient of an antenna according to an embodiment of the present invention;

[0042] Figure 10 This is a simulation diagram of the planar radiation characteristics of an antenna at the operating frequency according to an embodiment of the present invention.

[0043] Figure 11 This is a simulation diagram of the axial ratio of an antenna at the operating frequency point according to an embodiment of the present invention. Detailed Implementation

[0044] 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.

[0045] This invention provides a self-circularly polarized antenna, the basic structure of which includes a ground plane 100, a radiating patch, a connecting device, and a feeding structure. The radiating patch includes a first patch 101 and a second patch 103, and the connecting device includes a first connecting device 102 and a second connecting device 104. Both the first patch 101 and the second patch 103 are disposed above the ground plane 100 and form a predetermined height gap with the ground plane 100. The first patch 101 and the second patch 103 are spaced apart, forming a near-field coupling region between them. The first connecting device 102 is connected to the first patch 101, and the second connecting device 104 is connected to the second patch 102. The first connecting device 102 and the second connecting device 104 are respectively located at two edge regions of the outer contour of the radiating patch, and a circumferential gap is formed between the first connecting device 102 and the second connecting device 104 spanning the main conductor path region. The feeding structure feeds radio frequency signals to the antenna.

[0046] The first connecting device 102 and the second connecting device 104 are respectively disposed on two mutually distant edge regions on the outer contour of the radiating patch, so that the first connecting device 102, the first patch 101, the near-field coupling region, the second patch 103 and the second connecting device 104 together form a cross-current propagation path.

[0047] With the outer contour of the radiating patch as the circumferential direction, the first connecting device 102 and the second connecting device 104 are arranged at intervals along the circumferential direction of the outer contour of the radiating patch. The area jointly formed by the first connecting device 102, the first patch 101, the near-field coupling region, the second patch 103, and the second connecting device 104 forms the main conductor path region, allowing each path to run from the first connecting device 102 to the second connecting device 104, or from the second connecting device 104 to the first connecting device 102. Since the first patch 101 and the second patch 103 are alternately coupled to form the main conductor path region of the entire radiating patch, it is preferable that the first connecting device 102 is located at one end of the first patch 101, and the second connecting device 104 is located at the other end of the second patch 103, away from the first patch 101. This ensures that the first connecting device 102 and the second connecting device 104 are as far apart as possible from each other, thereby allowing each path within the radiating patch to achieve the maximum routing distance within the main conductor path region.

[0048] The relative arrangement of the first patch 101, the second patch 103, the first connecting device 102, and the second connecting device 104 can change the rotation direction of the patch current and the coupled electric field through mirror arrangement, rotation arrangement, or rotation followed by mirror arrangement, so as to achieve circular polarization rotation direction switching.

[0049] Both the first patch 101 and the second patch 103 have lateral and longitudinal components. The lateral and longitudinal components can be understood as the effective current path components or effective radiation size components of the patch in two orthogonal directions in the plane. In order to ensure that the two orthogonal components required for circular polarization formation have sufficient amplitude, the longer component of the lateral and longitudinal components is designated as the long component, and the shorter component is designated as the short component. The length ratio of the long component to the short component is preferably set within 4:1 to prevent the patch from being too narrow, thereby avoiding the current or electric field component in one direction being too weak.

[0050] The first connecting device 102 and the second connecting device 104 are respectively located at two edge regions of the outer contour of the radiating patch, and a circumferential gap is formed between them spanning the main patch routing area, so that the main routing areas of the first patch 101 and the second patch 103 are at least partially located between the first connecting device 102 and the second connecting device 104. Preferably, the first connecting device 102 and the second connecting device 104 are arranged relative to the geometric center of the antenna, approximately rotated 180°, or diagonally; they can also be located on adjacent sides but close to diagonal regions, or locally offset along the outer periphery or radial direction of the antenna based on the above preferred positions. The first connecting device 102 and the second connecting device 104 should not be concentrated in the same corner adjacent region, the same side local region, adjacent side close position, or adjacent corner region to avoid local concentration of the main current path and weaken the rotational relationship between the patch current and the coupled electric field. Therefore, the fed current can propagate along the patch traces between the two connecting devices and the coupling region between the patches, so that the patch current and the coupled electric field form a rotating distribution in space, which is conducive to the formation of self-circular polarized radiation.

[0051] The first connecting device 102 and the second connecting device 104 are used to form a grounding connection, impedance loading, electrical coupling, or equivalent boundary control path between the corresponding patch and the ground plane 100, thereby adjusting the current boundary conditions, equivalent resonant length, input impedance, and circular polarization performance of the patch. The connecting devices form a grounding connection, impedance loading, electrical coupling, or equivalent boundary control path between the radiating patch and the ground plane. The connecting devices can be wires, vias, connecting posts, metal sheets, springs, metallized sidewalls, or other conductive connection structures. Inductors, capacitors, transmission line segments, coupling gaps, or inductor-capacitor composite loading structures can also be set in the connection path to achieve frequency adjustment, impedance matching, or circular polarization performance optimization.

[0052] The feeding structure includes a feeding device 105, which is used to feed radio frequency signals to the antenna and achieve impedance matching. The feeding device 105 can be used in a probe feeding method, that is, one end of it is connected to the first patch 101 or the second patch 103, and the other end is connected to the radio frequency chip or radio frequency port; or it can be used in a coupling feeding method, that is, one end of the feeding device 105 is connected to the radio frequency chip or radio frequency port, and the other end is open and maintains a predetermined coupling gap with the first patch 101 and / or the second patch 103, thereby exciting and matching the antenna through electromagnetic field coupling. That is, the other end of the power supply device 105 can be open and located below the first patch 101 or the second patch 103, forming a coupling gap, so that a signal can be fed into one of the first patch 101 or the second patch 103 through the power supply device 105; the power supply device 105 can also be located between the first patch 101 and the second patch 103, in which case the power supply device 105 has a gap with both the first patch 101 and the second patch 103, which is equivalent to the power supply device 105 being located near the near-field coupling region, so the power supply device 105 can feed a signal into the first patch 101 or the second patch 103.

[0053] The minimum spacing between the first patch 101 and the second patch 103 is preferably set within 1 / 10 of the operating wavelength. This close spacing allows for strong electric field coupling between the first patch 101 and the second patch 103, enabling the electric field to not only couple energy but also participate in the formation of current phase and electric field rotation relationships. When the antenna is excited by the feeding device 105, the current can propagate along the first patch 101, the second patch 103, and their coupling region between the first connecting device 102 and the second connecting device 104, forming a directionally controlled current distribution. Simultaneously, a strong coupled electric field is formed between the first patch 101 and the second patch 103, further causing the electric field vector to rotate over time, thereby achieving self-circular polarization.

[0054] Example 1:

[0055] like Figures 1 to 3 As shown, this embodiment discloses a self-circular polarized antenna, including a ground plane 100, a first patch 101, a first connecting device 102, a second patch 103, a second connecting device 104, and a feeding device 105.

[0056] Ground plane 100 provides a reference ground, an electromagnetic reflection surface, and an RF return path. First patch 101 and second patch 103 are disposed above ground plane 100, and the space between them and ground plane 100 can be an air layer, a foam dielectric layer, a low-dielectric-constant dielectric layer, or other supporting dielectric layer. Both first patch 101 and second patch 103 can be metal patches, PCB copper foil, stamped metal sheets, or other conductive sheet structures.

[0057] A first patch 101 and a second patch 103 are spaced apart in a plane. The first patch 101 is located on one side above the ground plane 100, and the second patch 103 is located on the other side above the ground plane 100. A narrow gap is formed between the first patch 101 and the second patch 103, which is used to form an electric field coupling region. Preferably, the minimum distance between the first patch 101 and the second patch 103 is less than or equal to 1 / 10 of the operating wavelength to ensure strong near-field coupling between them.

[0058] Both the first patch 101 and the second patch 103 have effective dimensional components in both the lateral and longitudinal directions. Figure 3 Taking the coordinate direction shown as an example, the lateral component corresponds to the y-direction component, and the longitudinal component corresponds to the x-direction component. The lateral and longitudinal components of the patch together determine the direction of the current and electric field on the patch surface. In order to form the two orthogonal components required for circular polarization, the aspect ratio of the patch is preferably set to within 4:1. This ratio setting can avoid the patch being too narrow, so that both the first patch 101 and the second patch 103 can provide sufficient lateral and longitudinal current components.

[0059] The first connecting device 102 is correspondingly disposed with the first patch 101, and the second connecting device 104 is correspondingly disposed with the second patch 103. Combined Figures 1 to 3 As shown, the first connecting device 102 is disposed on the outer end region of the first patch 101 near the outer contour of the antenna, and is located in the region adjacent to the first corner of the antenna contour; the second connecting device 104 is disposed on the second patch 103 near the outer end region of the antenna contour, and is located in the region adjacent to the second corner of the antenna contour. The regions adjacent to the first corner and the regions adjacent to the second corner are approximately diagonally opposite each other in the antenna plane, or approximately rotated 180° relative to the geometric center of the antenna. Thus, the first connecting device 102 and the second connecting device 104 are respectively located in the regions adjacent to the two opposite corners of the antenna contour, such that the conductor path regions in the first patch 101 and the second patch 103 used to carry the main surface current are at least partially located between them. The fed current can extend from the first corner adjacent area where the first connecting device 102 is located, through the first patch 101, the coupling area between the first patch 101 and the second patch 103, and the second patch 103, to the second corner adjacent area where the second connecting device 104 is located, so that the patch current and the coupling electric field between the patches form a rotating distribution in space, which is beneficial to the formation of self-circular polarized radiation under single-feed conditions.

[0060] A feeding device 105 is disposed on the first patch 101 or its adjacent area to feed radio frequency signals to the antenna and achieve impedance matching. The feeding device 105 may be a probe feeding structure, with one end connected to the first patch 101 and / or the second patch 103 and the other end connected to the radio frequency chip; or it may be a coupled feeding structure, with one end open and maintaining a coupling gap with the patch, and the other end connected to the radio frequency chip, thereby exciting the antenna through electromagnetic coupling.

[0061] During operation, after the radio frequency signal is fed in by the feeding device 105, the current is first distributed on the first patch 101, and then acts on the second patch 103 through the coupling region between the first patch 101 and the second patch 103. Since the first connecting device 102 and the second connecting device 104 are located in non-adjacent outer regions or diagonally arranged, the current on the antenna surface generally tends to flow from the first connecting device 102 to the second connecting device 104. At the same time, a strong electric field coupling is formed in the gap region between the first patch 101 and the second patch 103, and the coupled electric field is distributed in a predetermined direction between the two patches.

[0062] like Figure 3 As shown, the dashed arrows indicate the direction of current distribution on the patch surface, while the solid arrows indicate the electric field distribution between the first patch 101 and the second patch 103. Through the strong electric field coupling between the first patch 101 and the second patch 103, combined with the control of the current boundary conditions by the first connecting device 102 and the second connecting device 104, a current and electric field distribution with a rotational relationship is formed inside the antenna. This rotational distribution is not generated by an external phase-shifting network, but is determined by the patch geometry, electric field coupling, and connecting devices; therefore, it can be called a self-circular polarization operating mode.

[0063] In this embodiment, the electric field coupling between the first patch 101 and the second patch 103 is used to control the current phase and electric field direction; the first connecting device 102 and the second connecting device 104 are used to establish the end current boundary; the feeding device 105 is used to excite the self-spinning electromagnetic field mode and achieve impedance matching. By adjusting the size ratio of the first patch 101 and the second patch 103, the spacing between the two patches, the position of the first connecting device 102 and the second connecting device 104, and the position of the feeding device 105, the antenna can be made to operate in the GNSS L1 band or other target navigation bands.

[0064] The advantages of this embodiment are: in terms of structure, circular polarization radiation can be formed by only two coupling patches and connecting devices, without the need for an additional phase-shifting network; the patch structure is simple and easy to implement using PCB, metal sheet or in-mold metal parts; the strong coupling region between the two patches can enhance the stability of circular polarization formation and is beneficial for impedance matching adjustment.

[0065] It should be noted that this invention does not simply employ a single short-circuit patch structure to form linearly polarized radiation. Instead, it maintains a predetermined distance between the first patch 101 and the second patch 103, creating strong electric field coupling between them. Simultaneously, the connecting device establishes mutually cooperating boundary conditions at the ends or outer regions of different patches, resulting in a controlled propagation direction of the current between the patches and establishing a rotational relationship between the coupled electric field and the patch current. Therefore, this invention can generate self-circularly polarized radiation under single-feed conditions, rather than merely achieving the linearly polarized operating mode of a conventional low-profile patch antenna.

[0066] Furthermore, in this invention, each radiating unit composed of a "patch + connecting device" undertakes both resonant radiation and participates in the formation of circular polarization phase relationship. The spacing, relative position, aspect ratio, position of the connecting device, number of connecting devices, and position of the feed point between the first patch 101 and the second patch 103 all affect the coupling strength and phase relationship between the two radiating units. Therefore, the circular polarization characteristic of this invention originates from the synergistic effect between multiple patch radiating units, rather than from the single patch structure itself.

[0067] Example 2:

[0068] like Figure 4 As shown, this embodiment is another structural form based on Embodiment 1. Compared with Embodiment 1, the basic components of this embodiment still include a ground plane 100, a first patch 101, a first connecting device 102, a second patch 103, a second connecting device 104, and a power supply device 105. The difference is that this embodiment achieves circular polarization rotation direction reversal by symmetrically or mirror-mirroring the positional relationships of the first patch 101, the second patch 103, the first connecting device 102, the second connecting device 104, and the power supply device 105.

[0069] Specifically, in Embodiment 1, the first connecting device 102 and the second connecting device 104 are located outside the antenna, and the current propagates from the first connecting device 102 to the second connecting device 104. In this embodiment, by symmetrically or mirror-arranging the patches and connecting devices, the relative positions of the first connecting device 102 and the second connecting device 104 are changed, thereby altering the propagation direction sequence of the current between the first patch 101 and the second patch 103.

[0070] When the feeding device 105 feeds an RF signal into the antenna of this embodiment, a strong electric field coupling is still formed between the first patch 101 and the second patch 103, but the rotational relationship between the coupled electric field and the surface current of the patch changes in the opposite direction to that of Embodiment 1. As a result, the rotation direction of the electric field vector in the far field of the antenna is reversed, achieving a reversal of the circular polarization rotation direction. For example, when Embodiment 1 forms right-hand circular polarization radiation, this embodiment can form left-hand circular polarization radiation through symmetrical or mirror settings; and vice versa.

[0071] This embodiment illustrates that the circular polarization rotation direction of the present invention can be achieved through structural geometry adjustment without the need for additional feed ports, power divider networks, or external phase shifters. This structure is particularly suitable for GNSS antenna designs that require selection of the circular polarization rotation direction based on the installation direction, satellite system polarization requirements, or terminal layout.

[0072] Example 3:

[0073] like Figure 5 As shown, this embodiment is another structural form based on Embodiment 1. Compared with Embodiment 1, the feeding structure of this embodiment adopts a matching circuit, eliminating the need for an additional independent feeding device 105. Instead, it achieves the same or similar antenna excitation and impedance matching effect as Embodiment 1 by connecting the first connecting device 102 or the second connecting device 104 to the RF chip via the matching circuit.

[0074] Specifically, this embodiment still includes a ground plane 100, a first patch 101, a first connecting device 102, a second patch 103, and a second connecting device 104. The first patch 101 and the second patch 103 are disposed above the ground plane 100 and form an electric field coupling region between them. At least one of the first connecting device 102 and the second connecting device 104 is used not only to form a connection or loading path between the patch and the ground plane 100, but also as part of the radio frequency excitation path.

[0075] In one implementation, the first connection device 102 is connected to the RF chip via a matching circuit. The matching circuit may include capacitors, inductors, resistors, transmission lines, microstrip tuning stubs, or combinations thereof, used to match the impedance between the RF chip port and the antenna input impedance. The RF signal, after passing through the matching circuit, is input to the first connection device 102 and further excites the first patch 101 and the second patch 103. The second connection device 104 is used to form the boundary conditions at the other end of the antenna and the current return path.

[0076] In another implementation, the second connection device 104 is connected to the RF chip via a matching circuit, and the first connection device 102 serves as a ground loading or boundary modulation structure. Both of these methods allow the antenna to be excited without the need for an additional independent feed probe.

[0077] The advantage of this embodiment is that the connecting device simultaneously performs loading, connection, and power supply functions, which helps to further simplify the structure, reduce the profile, and decrease the number of components. For scenarios where RF front-end modules or GNSS chips are directly integrated, this embodiment can combine the matching circuit with the connecting device, thereby improving module integration and reducing trace length and parasitic parameter uncertainties.

[0078] During operation, after the radio frequency signal is input to the first connection device 102 or the second connection device 104 via the matching circuit, it still forms a self-rotating electromagnetic field distribution through the strong electric field coupling between the first patch 101 and the second patch 103. Since the patch shape and the coupling mechanism between the patches have not changed fundamentally, this embodiment can still achieve the same or similar circularly polarized radiation effect as Embodiment 1.

[0079] Example 4:

[0080] like Figure 6 As shown, this embodiment is a further improved structure based on Embodiment 1. Compared with Embodiment 1, this embodiment adds a slotted structure to the first patch 101 and / or the second patch 103 to increase the current path length, thereby achieving a lower resonant frequency and a miniaturized design.

[0081] Specifically, the slotted structure can be disposed on the first patch 101, the second patch 103, or both the first patch 101 and the second patch 103. The slotted structure can be a straight slot, a U-shaped slot, a serpentine slot, a zigzag slot, an arc-shaped slot, an annular slot, a stubby slot, or other slot-shaped structures that can extend the current path. Figure 6 The image shows an example of a slotted structure.

[0082] When a slot is created on the patch, the surface current no longer propagates along a simple straight path, but instead winds around the edge of the slot, thus significantly increasing the equivalent current path length. Similarly, other slotted structures such as U-shaped slots, serpentine slots, and zigzag slots work in a similar manner. The slot openings of these slots are preferably located on the side or outer edge of the first patch 101 and / or the second patch 103, i.e., not facing the opposite position of the first patch 101 and the second patch 103. Such slotted designs can all increase the equivalent current path length. Since the antenna resonant frequency is related to the equivalent current path length, the slotted structure can lower the antenna resonant frequency without a significant increase in the patch's physical size, thereby achieving miniaturization.

[0083] In this embodiment, the first patch 101 and the second patch 103 remain close together to form a strong electric field coupling; the first connecting device 102 and the second connecting device 104 are still used to regulate the current boundary at the end or edge of the patch; the feeding device 105 is still used to feed in the radio frequency signal and achieve impedance matching. The slotted structure is mainly used to extend the current path and adjust the resonant frequency, and does not change the basic mechanism of self-circular polarization formed by inter-patch coupling in this invention.

[0084] In specific designs, the antenna resonant frequency, input impedance, and circular polarization performance can be adjusted by modifying the length, width, opening direction, slot edge spacing, and slot position relative to the connecting device. When the slot structure adopts a serpentine or multi-segmented form, a longer equivalent current path can be obtained in a smaller physical space, thereby further enhancing the miniaturization effect.

[0085] Example 5:

[0086] like Figure 7 As shown, this embodiment is a further extension of the structure based on Embodiment 1. Compared with Embodiment 4, this embodiment also provides a slotted structure on the first patch 101 and / or the second patch 103, but the slotted structure is not only used to increase the current path and reduce the resonant frequency, but also to form multiple current paths, thereby realizing dual-frequency or multi-frequency operation.

[0087] Specifically, L-shaped slots, nested slots, serpentine slots, bifurcated slots, or multi-branched slots can be provided on the first patch 101 and / or the second patch 103. The openings of these slots are located on the inner sides of the first patch 101 and / or the second patch 103, that is, the opposite sides of the first patch 101 and the second patch 103. This type of slot structure can divide the patch surface into multiple effective current path regions. Different current paths correspond to different equivalent electrical lengths, thereby forming different resonant modes at different frequency points, and ultimately realizing dual-frequency or multi-frequency operation.

[0088] For example, in an L-shaped slot structure, a current path propagating along the outer edge of the slot can form a lower-frequency resonance, while a current path propagating along the inner side of the slot or the remaining area of ​​the patch can form another higher-frequency resonance. By rationally designing the size and position of the slot, two or more resonant points can respectively cover one or more frequency bands such as GNSS L1, L2, L5 or BeiDou B1, B2, etc.

[0089] In this embodiment, dual-frequency or multi-frequency operation does not necessarily require multiple feed ports. The feed device 105 can still employ a single probe feed, coaxial feed, or coupled feed structure. The coupling region between the first patch 101 and the second patch 103 is still used to achieve electric field coupling and circular polarization formation; the first connecting device 102 and the second connecting device 104 are still used to provide loading and boundary conditions. The slotted structure is used to introduce multiple current paths and multiple resonance characteristics.

[0090] The advantage of this embodiment is that it achieves multi-frequency navigation reception capability through patch slotting while maintaining a simple overall antenna structure. This structure is suitable for multi-system GNSS terminals, such as positioning devices that simultaneously support GPS, BeiDou, GLONASS, or Galileo systems.

[0091] Example 6:

[0092] like Figure 8 As shown, this embodiment discloses a self-circularly polarized GNSS antenna structure with an L-shaped patch. Compared with Embodiment 1, the first patch 101 and / or the second patch 103 in this embodiment adopt an L-shaped planar profile to form the current or electric field rotation through the lateral and longitudinal components of the L-shaped patch itself.

[0093] Specifically, the first patch 101 may include a first arm extending along a first direction and a second arm extending along a second direction, wherein the first direction and the second direction are preferably perpendicular or approximately perpendicular to each other, thereby forming an L-shaped structure. The second patch 103 may also adopt the same or similar L-shaped structure, or adopt a planar patch structure that cooperates with the first patch 101. The first arm and the second arm correspond to the lateral component and longitudinal component of the patch, respectively. The first arm and the second arm may also be arranged relative to the geometric center of the antenna, approximately rotated 180°.

[0094] To ensure that the L-shaped patch can generate sufficient circularly polarized rotational components, the aspect ratio of the patch along the transverse and longitudinal directions is preferably less than or equal to 4:1. This ratio ensures that the L-shaped patch has sufficient effective length in both orthogonal directions, thereby guaranteeing that the current or electric field has a clear rotational characteristic.

[0095] The first connecting device 102 and the second connecting device 104 are still located on the outside of the antenna and are connected to the first patch 101 or the second patch 103, respectively. The feeding device 105 can be located near the corner area, the area adjacent to the arm end, or the coupling area between the two patches of the L-shaped patch. By adjusting the feeding position, the position of the connecting device, and the length ratio of the L-shaped arm, the antenna can achieve good impedance matching and circular polarization radiation within the target GNSS frequency band.

[0096] During operation, after the radio frequency signal is fed into the L-shaped patch, the current propagates along the L-shaped path, generating a phase difference and direction change between the horizontal and vertical arms. Simultaneously, the coupled electric field between the first patch 101 and the second patch 103 further modulates the current phase relationship, causing the electric field vector to rotate over time. Therefore, this embodiment achieves self-circular polarization through the geometric asymmetry of the L-shaped patch and the coupling between the patches.

[0097] The advantage of this embodiment is that the L-shaped patch structure is simple, occupies flexible space, and is easy to place at the edges, corners, or irregular spaces of terminal devices. For small GNSS modules, vehicle terminals, drone terminals, or wearable devices, this embodiment can be adapted to the installation space.

[0098] Other optional implementation methods:

[0099] In some alternative embodiments, additional connecting devices may be added to the first patch 101 and / or the second patch 103. These additional connecting devices may be located in the vicinity of the first connecting device 102 or the second connecting device 104, and preferably arranged adjacent to or close to the original connecting devices. This allows the additional connecting devices to primarily function as auxiliary loads, optimize current, adjust frequency, or fine-tune impedance, without significantly altering the current distribution in the main patch area or the current rotation relationship required for circular polarization formation. The additional connecting devices may be grounded short-circuit connections or load connections; their number, location, and equivalent impedance value can be optimized according to the target frequency band and axial ratio performance.

[0100] In some alternative embodiments, the first patch 101 and / or the second patch 103 may be provided with one or more support legs. The support legs may be insulated or metal. When insulated, both ends of the insulated support leg are fixedly connected to the radiating patch and the ground plane, respectively. The insulated support leg is mainly used to maintain the height and structural stability between the patch and the ground plane 100. Conductive support legs may be metal, preferably not forming a DC short circuit connection with both the patch and the ground plane 100 simultaneously. The support leg may be fixedly connected to the radiating patch and supported on the ground plane 100 through an insulating isolation structure, or fixedly connected to the ground plane 100 and supported on the radiating patch through an insulating isolation structure, thereby providing mechanical support while avoiding the introduction of additional short circuit paths that would significantly alter the main current distribution.

[0101] Furthermore, the edge regions of the first patch 101 and / or the second patch 103 may also be provided with extensions or folds. The extensions may extend horizontally outward along the edges of the first patch 101 and / or the second patch 103, and the folds may extend horizontally outward at a certain angle along the edges of the first patch 101 and / or the second patch 103. The folds may be metal sheets. One end of the horizontal extension or the folded metal sheet is connected to or integrally formed with the corresponding radiating patch, while the other end extends toward or along the ground plane 100, maintaining a gap with the ground plane 100 or being isolated by a dielectric layer, thereby forming an equivalent capacitance between the patch edge region and the ground plane 100. This type of structure can be used in conjunction with a connection device to form an inductor-capacitor composite loading path, thereby reducing the operating frequency, shortening the patch size, and improving the input impedance.

[0102] In some alternative implementations, additional matching elements may be added to the feed device 105. These matching elements may include series capacitors, parallel capacitors, series inductors, parallel inductors, L-type matching networks, π-type matching networks, T-type matching networks, microstrip open-circuit stubs, microstrip short-circuit stubs, transmission line transition segments, or combinations thereof. By introducing capacitive and / or inductive elements into the feed device 105, the inductive or capacitive components in the antenna input impedance can be compensated, resulting in better impedance matching of the antenna within the target GNSS frequency band.

[0103] In some optional embodiments, an inter-pattern capacitor is provided between the first patch 101 and the second patch 103, forming a coupling gap between them. The inter-pattern capacitor can be a distributed capacitor formed by dielectric filling. The dielectric filling can be an air gap, or it can be filled with a low-dielectric-constant dielectric, foam dielectric, plastic support, or other dielectric materials. By adjusting the width of the coupling gap, the dielectric constant, and the filling area, the electric field coupling strength between the two patches can be changed, thereby adjusting the circular polarization axial ratio, radiation pattern shape, and operating bandwidth. Preferably, the minimum spacing between the first patch 101 and the second patch 103 is set within 1 / 10 of the operating wavelength to ensure strong near-field coupling between them.

[0104] In some embodiments, the inter-pattern capacitance is a distributed capacitor formed by relative extensions, interdigitated structures, or projected overlapping areas, or a lumped capacitor connected between the first patch 101 and the second patch 103. That is, a lumped capacitor is connected between the first patch 101 and the second patch 103, or capacitance-enhancing structures such as relative extensions or interdigitated structures are provided at the adjacent edges of the two patches to further increase the inter-pattern capacitance. The inter-pattern capacitance can enhance the capacitive coupling between the first patch 101 and the second patch 103, causing the antenna resonant frequency to shift downwards, and is beneficial for miniaturization design, impedance matching optimization, and improved circular polarization performance.

[0105] Furthermore, the first patch 101 and the second patch 103 are not limited to being arranged laterally on the same layer, but can also be arranged in a staggered manner. That is, the first patch 101 is set on the first height layer, and the second patch 103 is set on the second height layer, with the two arranged at intervals along a direction perpendicular to the ground plane 100, and their projections on the ground plane 100 forming mutual intervals, partial overlaps, local staggered overlaps, or complete overlaps. Through this projected overlap area, an equivalent capacitive coupling can be formed between the two patches, thereby enhancing capacitive loading and phase modulation capabilities. By adjusting the projected overlap area of ​​the two patches, the spacing between the upper and lower layers, the interlayer dielectric constant, and the overlap position, the equivalent capacitance value and coupling strength can be changed, thereby reducing the antenna resonant frequency, improving impedance matching, and optimizing circular polarization performance. This staggered coupling structure is suitable for GNSS terminals with limited planar space but allowing a certain height, and is also suitable for low-profile circularly polarized antennas implemented with multi-layer PCBs, metal brackets, spring sheets, or three-dimensional conductor structures.

[0106] In some alternative embodiments, the first patch 101 and the second patch 103 may have different sizes or shapes. They may have different lengths, widths, slotting patterns, bending patterns, or connection device positions to adjust the amplitude and phase relationship between the two radiating elements through an asymmetrical structure. This asymmetrical design can be used to improve the circular polarization axial ratio, widen the circular polarization beam, or achieve radiation enhancement in a specific direction.

[0107] In some alternative embodiments, the first patch 101 and / or the second patch 103 may be provided with slots, zigzag lines, serpentine lines, embedded branches, extended branches, bent edges, or multi-level foldback structures. Such structures can increase the current path length on the patch surface, reduce the resonant frequency, and introduce multiple current paths when needed to form dual-frequency or multi-frequency operation. The slot structure can be a U-shaped slot, L-shaped slot, T-shaped slot, serpentine slot, annular slot, arc-shaped slot, or a combination of multiple slot structures.

[0108] In some alternative embodiments, the first patch 101 and the second patch 103 are not limited to being arranged parallel to the ground plane 100, but can also be arranged in a staggered, inclined, folded, curved, or conformal manner. Specifically, the first patch 101 and the second patch 103 can be located at different heights, or at least one of them can have a predetermined tilt angle relative to the ground plane 100; they can also be respectively disposed on the terminal housing, bracket, folded carrier, inclined carrier, or curved carrier.

[0109] In some alternative implementations, the ground plane 100 can be a solid metal ground, or a slotted ground, a partial ground, an irregularly shaped ground, or a device motherboard ground. When the antenna is applied to a terminal device, the ground plane 100 can be composed of an RF motherboard, a metal frame, a shielding cover, a metal bracket, or a combination thereof. The size and shape of the ground plane 100 affect the antenna pattern and the radiation intensity in the upper half of the space, and can be optimized according to the terminal installation environment.

[0110] In some alternative implementations, the connection device is not limited to wires, vias, or connecting posts, but may also be a spring, metal bracket, metallized sidewall, flexible connecting piece, surface-mount inductor, lumped inductor, distributed inductor, shorting post, or a combination thereof. The connection device can directly connect the patch and ground plane 100, or indirectly connect the patch and ground plane 100 through a loading element.

[0111] In summary, this invention enables the antenna to achieve self-circular polarization radiation capability through near-field coupling between multiple low-profile patch radiating elements, boundary adjustment of the connecting device, and feed matching design. Each patch and its connecting device can achieve miniaturized resonance and low-profile integration, while the synergistic coupling between multiple patch radiating elements further achieves circular polarization radiation that is difficult to obtain with ordinary single-patch structures. By adding additional connecting devices, setting support legs, introducing end-to-ground bending, adding capacitive or inductive loading, optimizing the feed matching network, and adjusting the patch coupling relationship, the operating frequency can be further reduced, impedance matching improved, circular polarization beamwidth extended, and the applicability of the GNSS receiving antenna in complex installation environments enhanced.

[0112] like Figure 9 , Figure 10 and Figure 11 As shown, the antenna structure of Embodiment 1 was simulated and verified.

[0113] Figure 9 The simulation curve of the antenna's reflection coefficient is shown in the example diagram. The simulation curve shows that the antenna forms a significant resonance around 1.575 GHz, indicating that this structure has good impedance matching performance near the GNSS L1 band. Using -6 dB as a reference line, the antenna has a certain operating bandwidth near the resonance point, which can meet the matching requirements of GNSS receiving antennas.

[0114] Figure 10This is a simulation diagram of the planar radiation characteristics of an antenna at the operating frequency in this embodiment. Curve 201 represents the RHCP radiation pattern in the xz plane, curve 202 represents the RHCP radiation pattern in the yz plane, curve 203 represents the LHCP radiation pattern in the xz plane, and curve 204 represents the LHCP radiation pattern in the yz plane. Simulation results show that in the main radiation directions, the target circular polarization component is significantly stronger than the cross-circular polarization component, indicating that this embodiment can form effective circular polarization radiation. Combined with the reflection coefficient simulation results, it can be seen that the dual-pattern coupling structure of this embodiment can not only achieve good impedance matching in the GNSS operating frequency band but also realize circular polarization radiation characteristics. Simultaneously, the antenna exhibits right-hand circular polarization RHCP radiation characteristics in all directions, and the RHCP radiation intensity in the upper half-space is significantly higher than that in the lower half-space.

[0115] Figure 11 The figure shows the simulation results of the axial ratio of the antenna in the example at the operating frequency. Curve 301 represents the axial ratio variation curve in the xz plane, and curve 302 represents the axial ratio variation curve in the yz plane. The simulation results show that the antenna in the example has a wide circularly polarized beam coverage at the target operating frequency, achieving an axial ratio AR of less than 3 dB over a wide angular range. This indicates that the antenna not only forms circularly polarized radiation but also maintains stable circular polarization performance over a large spatial angular domain, exhibiting a wide circularly polarized beamwidth. This characteristic is beneficial for GNSS terminals to maintain low polarization mismatch loss and stable satellite signal reception capabilities even under changes in attitude, installation angle deviation, or satellite incident angle.

[0116] Therefore, based on the simulation results of reflection coefficient, circular polarization radiation pattern and axial ratio, it can be seen that the antenna in the embodiment not only has good impedance matching and right-hand circular polarization radiation characteristics near the GNSS operating frequency band, but also has a wide circular polarization beam and better upper half-space radiation coverage capability, making it suitable for GNSS receiving terminals with large attitude changes or limited installation environment.

[0117] 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 single-fed and tightly coupled self-circularly polarized antenna, characterized in that, The device includes a ground plane, a radiating patch, a connecting device, and a feeding structure. The radiating patch includes a first patch and a second patch. The connecting device includes a first connecting device and a second connecting device. The first patch and the second patch are both disposed above the ground plane and form a height gap with the ground plane. The first patch and the second patch are spaced apart and form a near-field coupling region between them. The first connecting device is connected to the first patch, and the second connecting device is connected to the second patch. The first connecting device and the second connecting device are respectively located at two edge regions of the outer contour of the radiating patch, and a circumferential gap is formed between the first connecting device and the second connecting device across the main conductor path region. The feeding structure feeds radio frequency signals to the antenna.

2. The single-fed and tightly coupled self-circularly polarized antenna according to claim 1, characterized in that, The first connecting device and the second connecting device are respectively disposed on two mutually distant edge regions on the outer contour of the radiating patch, so that the first connecting device, the first patch, the near-field coupling region, the second patch and the second connecting device together form a cross-current propagation path.

3. The single-fed and tightly coupled self-circularly polarized antenna according to claim 2, characterized in that, The positional layout of the first connecting device and the second connecting device includes: First positional layout: The first connecting device and the second connecting device are arranged relative to the geometric center of the radiating patch, approximately rotated 180°, or diagonally arranged; Second positional layout: The first connecting device and the second connecting device are respectively located on adjacent sides of the radiating patch and close to the diagonal area; Third position layout: Based on the first position layout or the second position layout, the first connecting device and the second connecting device are partially offset along the outer periphery or radial direction of the radiating patch.

4. The single-fed and tightly coupled self-circularly polarized antenna according to claim 1, characterized in that, The power supply structure includes a power supply device, one end of which is connected to a first patch or a second patch, and the other end of which is connected to an RF chip or an RF port; or, one end of which is connected to an RF chip or an RF port, and the other end of which is open and coupled to the first patch and / or the second patch through a gap.

5. The single-fed and tightly coupled self-circularly polarized antenna according to claim 1, characterized in that, The power supply structure includes a matching circuit, and the first or second connection device is connected to the RF chip or RF port through the matching circuit; the matching circuit includes one or more combinations of capacitors, inductors, resistors, transmission lines, and microstrip tuning stubs.

6. The single-fed and tightly coupled self-circularly polarized antenna according to claim 1, characterized in that, The first patch and / or the second patch are provided with a slotted structure to extend the current path, adjust the resonant frequency, or form multiple current paths.

7. The single-fed and tightly coupled self-circularly polarized antenna according to claim 1, characterized in that, Both the first patch and the second patch have lateral and longitudinal components. In the lateral and longitudinal components, the length ratio of the long component to the short component is less than or equal to 4:

1.

8. The single-fed and tightly coupled self-circularly polarized antenna according to claim 1, characterized in that, The first patch and / or the second patch are further provided with additional connecting devices, which are located in the vicinity of the first connecting device or the second connecting device.

9. The single-fed and tightly coupled self-circularly polarized antenna according to any one of claims 1 to 8, characterized in that, The connection device forms a grounding connection, impedance loading, electrical coupling, or equivalent boundary control path between the radiating patch and the ground plane. The connection device includes one or more combinations of wires, vias, connecting posts, metal sheets, springs, metallized sidewalls, and flexible connecting pieces; and / or inductors, capacitors, transmission line segments, or inductor-capacitor composite loading structures are added to the connection path of the connection device.

10. The single-fed and tightly coupled self-circularly polarized antenna according to any one of claims 1 to 8, characterized in that, It is also provided with one or more support legs, which are either insulating or conductive. When it is an insulating support leg, both ends of the insulating support leg are fixedly connected to the radiating patch and the ground plane, respectively. When it is a conductive support leg, one end of the conductive metal leg is fixedly connected to the radiating patch, and the other end is supported on the ground plane through an insulating isolation structure, or one end of the conductive metal leg is fixedly connected to the ground plane, and the other end is supported on the radiating patch through an insulating isolation structure.

11. The single-fed and tightly coupled self-circularly polarized antenna according to any one of claims 1 to 8, characterized in that, The edge regions of the first patch and / or the second patch are further provided with extensions or folds.

12. The single-fed and tightly coupled self-circularly polarized antenna according to any one of claims 1 to 8, characterized in that, The power supply device is further equipped with additional matching elements, which include one or more combinations of capacitors, inductors, matching networks, microstrip stubs, and transmission line conversion segments connected in series or in parallel.

13. The single-fed and tightly coupled self-circularly polarized antenna according to any one of claims 1 to 8, characterized in that, The minimum spacing between the first patch and the second patch is set to be within 1 / 10 of the wavelength corresponding to the operating frequency, so as to form a near-field coupling region.

14. The single-fed and tightly coupled self-circularly polarized antenna according to any one of claims 1 to 8, characterized in that, The first patch and the second patch can be arranged in a layered manner with the same height or in a staggered manner. In the staggered arrangement, the projections of the first patch and the second patch on the ground plane are spaced apart, partially overlapped, or completely overlapped.

15. The single-fed and tightly coupled self-circularly polarized antenna according to any one of claims 1 to 8, characterized in that, The first patch and / or the second patch are disposed at an angle relative to the ground plane, or disposed on a folded carrier, curved carrier, inclined carrier, terminal housing or bracket.

16. The single-fed and tightly coupled self-circularly polarized antenna according to any one of claims 1 to 8, characterized in that, An inter-patch capacitor is provided between the first patch and the second patch. The inter-patch capacitor is a distributed capacitor formed by dielectric filling, relative extensions, interdigital structures or projected overlapping areas, or a lumped capacitor connected between the first patch and the second patch.

17. The single-fed and tightly coupled self-circularly polarized antenna according to any one of claims 1 to 8, characterized in that, An air layer, a low dielectric constant dielectric layer, or a composite dielectric layer formed by a combination of the two is provided between the radiation patch and the ground plane.

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