A small circularly polarized patch antenna with an extremely small size

Abstract

The present invention discloses a small circularly polarized patch antenna of extremely small size, comprising: a dielectric substrate having a first surface and a second surface facing each other; a driving patch and a coupling patch, each of which is a right triangle, adjacently and spaced apart on the first surface of the dielectric substrate and electromagnetically coupled to form a circularly polarized axis ratio zero point; a row of metallized vias on each side of the dielectric substrate corresponding to the driving patch and the coupling patch, the two rows of metallized vias being electrically connected to the driving patch and the coupling patch, respectively; and a floor, the floor being disposed on the second surface of the dielectric substrate. The technical solution of the present invention can achieve the requirements of miniaturization and integration of circularly polarized antennas. The antenna is not only a radiator but also has the functions of power splitting and phase shifting. The mechanism for achieving phase shifting based on coupling has more stable phase shift characteristics.

Description

Technical Field

[0001] The present invention relates to the field of microwave communication technology, and in particular to a small circularly polarized patch antenna with an extreme size. Background Art

[0002] Compared to linearly polarized antennas, circularly polarized antennas can overcome polarization mismatch, multipath effects, and channel crosstalk during signal transmission. To adapt to the trend toward system miniaturization and integration, miniaturized circularly polarized antennas have been used in many wireless communication systems. The main approaches to achieving small-sized circularly polarized patch antennas are as follows.

[0003] First, a high-dielectric-constant substrate is used to create a circularly polarized square slotted patch antenna by loading four branches onto the substrate. While using a high-dielectric-constant substrate can make the antenna smaller, it can lead to a significant decrease in antenna bandwidth and gain, as well as high production costs.

[0004] Second, slot or slot loading is employed. By creating slots or slots in the dielectric substrate, the effective current path of the antenna can be extended, shifting the antenna's resonant frequency toward a lower frequency, thereby miniaturizing the antenna. The slots and slots can be of varying shapes and sizes, resulting in varying degrees of size reduction.

[0005] Third, by using a short-circuit probe for loading, the antenna size can be greatly reduced compared to a half-wave resonant square patch by loading a short-circuit parasitic branch on the dielectric substrate.

[0006] Secondly, conventional circular polarization implementations, such as single-fed circular polarization based on degenerate mode separation, are simple to implement but suffer from phase sensitivity. This makes circular polarization degradation or flipping easily occur under external interference, significantly impacting circular polarization performance. Another example is dual-fed / multi-fed circular polarization based on an external phase-shifting structure. The 90° phase difference required for circular polarization is not generated by the antenna itself, but rather by the power distribution and phase shifting functions provided by the feed network. This results in stable circular polarization performance and wide bandwidth, but the disadvantage is the need for an additional power splitter and phase-shifting network, which not only increases cost but also occupies a larger area.

[0007] Although the structural design of the small-sized circularly polarized patch antenna of the above structure can reduce the size of a part of the antenna, most of them face problems such as unstable phase shift or complex structure, which makes it difficult to meet the design requirements of miniaturization and integration of communication systems.

[0008] In view of this, it is necessary to propose further improvements to the current small-sized, phase-shift unstable circularly polarized patch antenna structure. Summary of the Invention

[0009] In order to solve at least one of the above technical problems, the main object of the present invention is to provide a small circularly polarized patch antenna with an extremely small size.

[0010] To achieve the above objectives, the present invention adopts a technical solution of providing a small circularly polarized patch antenna of extreme size, comprising:

[0011] a dielectric substrate having a first surface and a second surface opposite to each other;

[0012] A driving patch and a coupling patch, each of which is a right triangle, is adjacent to and spaced apart from the first surface of the dielectric substrate and is electromagnetically coupled to form a circularly polarized axial ratio zero point. A row of metallized vias is defined on each side of the dielectric substrate corresponding to the driving patch and the coupling patch, and the two rows of metallized vias are electrically connected to the driving patch and the coupling patch, respectively.

[0013] The floor is arranged on the second surface of the dielectric substrate.

[0014] Optionally, the driving patch and the coupling patch are arranged adjacent to a right angle side thereof and the combination of the two is roughly in a triangle shape, and the two rows of metallized vias are arranged orthogonally.

[0015] Optionally, the driving patch and the coupling patch are arranged adjacent to a right angle side and the combination of the two is roughly triangular, and the two rows of metallized vias are arranged side by side and are both located in a straight line.

[0016] Optionally, the driving patch and the coupling patch are adjacently arranged at their oblique sides and the combination of the two is roughly rectangular, and the two rows of metallized vias are orthogonally arranged.

[0017] Optionally, it also includes a feeding structure consisting of a metal probe and an outer conductor of an SMA connector, wherein the metal probe is arranged on a dielectric substrate, and one end of the metal probe is electrically connected to the driving patch, and the other end is arranged away from the floor; the outer conductor of the SMA connector is electrically connected to the floor.

[0018] Optionally, the thickness of the dielectric substrate is approximately 0.01-0.1 times the vacuum wavelength.

[0019] Optionally, the radiation side length of the driving patch and the coupling patch is 1 / 4 of the medium wavelength at the resonant frequency.

[0020] Optionally, the spacing between each row of the metallized vias is greater than 0.01 times the vacuum wavelength and less than the side length of the driver patch.

[0021] The technical solution of the present invention mainly includes a dielectric substrate, a driving patch and a coupling patch, wherein the driving patch and the coupling patch are a right triangle, and the dielectric substrate is provided with a corresponding driving patch and coupling patch.

[0022] The two rows of metalized vias on the patch are electrically connected to the driving patch and the coupling patch respectively. The electromagnetic coupling between the driving patch and the coupling patch generates two equal amplitudes, orthogonal polarizations and phases.

[0023] The mode with a difference of 90 degrees forms a circular polarization axis ratio zero point to achieve circular polarization; in the present invention, the antenna is not only a radiator, but also has the function of power division and phase shifting, realizing the excitation of two orthogonal polarizations with equal amplitudes and a phase difference of 90 degrees; the mechanism of phase shifting is based on coupling, which is different from the degenerate mode separation of the traditional method.

[0024] The coupling type and strength determine the difference, resulting in a more stable phase-shift characteristic. Furthermore, both the driver and coupling patches are equipped with metalized vias, resulting in a radiating edge that is smaller than that of a traditional square patch antenna. When the two patches couple to form circular polarization, the overall antenna area is reduced by over 30% compared to a traditional square patch antenna, meeting miniaturization design requirements and facilitating integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0026] Figure 1 A top view of a small circularly polarized patch antenna of extreme size according to an embodiment of the present invention;

[0027] Figure 2 This is a front view of a small circularly polarized patch antenna of extreme size according to an embodiment of the present invention;

[0028] Figure 3 An isometric view of a small circularly polarized patch antenna of extreme size according to an embodiment of the present invention;

[0029] Figure 4 5 is a top view of a small circularly polarized patch antenna of extreme size according to another embodiment of the present invention; Figure 5 This is a front view of a small circularly polarized patch antenna of extreme size according to another embodiment of the present invention;

[0030] Figure 6 FIG1 is an isometric view of a small circularly polarized patch antenna of an extremely small size according to another embodiment of the present invention;

[0031] Figure 7 A top view of a small circularly polarized patch antenna of extreme size according to another embodiment of the present invention;

[0032] Figure 8 This is a front view of a small circularly polarized patch antenna of extreme size according to another embodiment of the present invention;

[0033] Figure 9 FIG. 1 is an isometric view of a small circularly polarized patch antenna of an extremely small size according to another embodiment of the present invention; FIG. Figure 10 This is a curve showing the axial ratio variation with frequency of a small circularly polarized patch antenna of an extremely small size according to an embodiment of the present invention;

[0034] Figure 11 This is a curve showing the axial ratio variation with frequency of a small circularly polarized patch antenna of an extremely small size according to another embodiment of the present invention;

[0035] Figure 12 This is a curve showing the change in axial ratio versus frequency of a small circularly polarized patch antenna of extreme size according to another embodiment of the present invention;

[0036] Figure 13 The sectional radiation patterns of φ=0° and φ=90° at the optimal axial ratio frequency point of the extremely small circularly polarized patch antenna of an embodiment of the present invention are shown;

[0037] Figure 14 The sectional radiation patterns of φ=0° and φ=90° at the optimal axial ratio frequency point of the extremely small circularly polarized patch antenna of another embodiment of the present invention are shown;

[0038] Figure 15 This is a cross-sectional radiation pattern of φ=0° and φ=90° at the optimal axial ratio frequency point of a small circularly polarized patch antenna of an extremely small size according to another embodiment of the present invention.

[0039] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0041] It should be noted that the descriptions of "first", "second", etc. in the present invention are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0042] Unlike related art designs for small-scale circularly polarized patch antennas, which, while capable of reducing some antenna size, often suffer from large size and complex structure, making them difficult to meet the design requirements of miniaturized and integrated communication systems, this solution proposes an extremely small circularly polarized patch antenna. This design aims to reduce antenna size and streamline the structure to meet the requirements of integrated communication systems. The specific structure of this extremely small circularly polarized patch antenna is described in the following examples.

[0043] Please refer to Figures 1 to 9 , Figure 1 A top view of a small circularly polarized patch antenna of extreme size according to an embodiment of the present invention; Figure 2 This is a front view of a small circularly polarized patch antenna of extreme size according to an embodiment of the present invention; Figure 3 An isometric view of a small circularly polarized patch antenna of extreme size according to an embodiment of the present invention; Figure 4 A top view of a small circularly polarized patch antenna of extreme size according to another embodiment of the present invention; Figure 5 This is a front view of a small circularly polarized patch antenna of extreme size according to another embodiment of the present invention; Figure 6 FIG1 is an isometric view of a small circularly polarized patch antenna of an extremely small size according to another embodiment of the present invention; Figure 7 A top view of a small circularly polarized patch antenna of extreme size according to another embodiment of the present invention; Figure 8 This is a front view of a small circularly polarized patch antenna of extreme size according to another embodiment of the present invention; Figure 9 This is an isometric view of another embodiment of the present invention, a small circularly polarized patch antenna of extreme size. In an embodiment of the present invention, the small circularly polarized patch antenna of extreme size is applied to a microwave communication system. The small circularly polarized patch antenna of extreme size includes:

[0044] A dielectric substrate (5, 5a, 5b), wherein the dielectric substrate (5, 5a, 5b) has a first surface and a second surface opposite to each other;

[0045] A driving patch (1, 1a, 1b) and a coupling patch (2, 2a, 2b), wherein the driving patch (1, 1a, 1b) and the coupling patch (2, 2a, 2b) are both right-angled triangles, are adjacent to and spaced apart from each other on the first surface of a dielectric substrate (5, 5a, 5b), and are electromagnetically coupled to form a circularly polarized axis ratio zero point; a row of metallized vias (3, 3a, 3b) is provided on one side of the dielectric substrate (5, 5a, 5b) corresponding to the driving patch (1, 1a, 1b) and the coupling patch (2, 2a, 2b); the two rows of metallized vias (3, 3a, 3b) are electrically connected to the driving patch (1, 1a, 1b) and the coupling patch (2, 2a, 2b), respectively;

[0046] A floor (6, 6a, 6b) is provided on the second surface of the dielectric substrate (5, 5a, 5b).

[0047] Specifically, the dielectric substrate (5, 5a, 5b) mainly carries the driving patch (1, 1a, 1b) and the coupling patch (2, 2a, 2b). The metal probe (4, 4a, 4b) is the inner conductor of the SMA connector, and the floor (6, 6a, 6b) is printed on the second surface of the dielectric substrate (5, 5a, 5b). The driving patch (1, 1a, 1b) and the coupling patch (2, 2a, 2b) are adjacent and spaced apart. The driving patch (1, 1a, 1b) and the coupling patch (2, 2a, 2b) are both isosceles right triangles. The electromagnetic coupling between the two patches can generate two orthogonal polarization modes. The coupling model between the two patches can be equivalent to the circuit model of a J converter. The coupling coefficient can be adjusted by changing the patch spacing, patch size, and the number of metalized vias (3, 3a, 3b), so that the two orthogonal polarization modes can be adjusted to have equal amplitude and a phase difference of 90 degrees, forming a circular polarization axis ratio zero point, thereby achieving circular polarization. The radiation side length of a single patch loaded with metallized vias (3, 3a, 3b) is at least half that of a traditional square patch antenna, so that the overall antenna area is reduced by more than 30% compared with a traditional square patch antenna.

[0048] Specifically, the invention also includes a feeding structure composed of a metal probe (4, 4a, 4b) and an outer conductor (7, 7a, 7b) of an SMA connector. The metal probe (4, 4a, 4b) is arranged on a dielectric substrate (5, 5a, 5b), and one end of the metal probe (4, 4a, 4b) is electrically connected to the driving patch (1, 1a, 1b), and the other end is arranged to avoid the floor (6, 6a, 6b); the outer conductor (7, 7a, 7b) of the SMA connector is electrically connected to the floor (6, 6a, 6b). Specifically, a circular hole is opened in the floor (6, 6a, 6b) at a position corresponding to the metal probe (4, 4a, 4b), and the other end of the metal probe (4, 4a, 4b) avoids the circular hole. In this embodiment, the other end of the metal probe (4, 4a, 4b) is located in the circular hole, but the diameter of the metal probe (4, 4a, 4b) is smaller than the aperture of the circular hole, and the metal probe (4, 4a, 4b) is insulated from the inner wall of the circular hole to prevent short circuit. It is understandable that in order to avoid contact between the metal probe (4, 4a, 4b) and the inner wall of the circular hole, an insulating layer can also be provided on the inner wall of the circular hole to avoid contact between the two. Further, the other end of the metal probe (4, 4a, 4b) is coaxial and cocentric with the circular hole. When the metal probe (4, 4a, 4b) is coaxial and cocentric with the circular hole, the distance between the metal probe (4, 4a, 4b) and the inner wall of the circular hole is the largest. When the diameter of the metal probe (4, 4a, 4b) is small enough, contact can be effectively avoided, and there is no need to provide an insulating layer on the inner wall of the circular hole. It is understandable that in order to avoid contact between the two, it is also possible to consider providing an insulating layer on the end of the metal probe (4, 4a, 4b) that extends into the circular hole.

[0049] The dielectric substrate (5, 5a, 5b) is made of Rogers RT5880, a micro-glass fiber reinforced PTFE composite material with low dielectric constant and low loss, making it very suitable for high-frequency applications. The dielectric substrate (5, 5a, 5b) has a thickness of approximately 0.01-0.1 times the vacuum wavelength. The dielectric substrate (5, 5a, 5b) has a thickness of 0.01 times the vacuum wavelength, 0.05 times the vacuum wavelength, or 0.1 times the vacuum wavelength. The relatively small thickness of the dielectric substrate (5, 5a, 5b) helps reduce the footprint of the entire antenna.

[0050] Specifically, the radiation side length of the driving patch (1, 1a, 1b) and the coupling patch (2, 2a, 2b) is 1 / 4 of the medium wavelength at the resonant frequency, while the side length of the traditional square patch antenna is 1 / 2 of the medium wavelength at the resonant frequency. Therefore, compared with the traditional square patch antenna, the size of the antenna of this solution is halved.

[0051] Specifically, the spacing between each row of the metallized vias (3, 3a, 3b) is greater than 0.01 times the vacuum wavelength and less than the side length of the driver patch. The number of metallized vias (3, 3a, 3b) is multiple, and the specific number can be designed according to actual requirements. The spacing between adjacent metallized vias (3, 3a, 3b) can also be designed according to actual requirements.

[0052] In order to better describe the structure of a small circularly polarized patch antenna of extreme size, embodiments of three structures are described separately below.

[0053] Please refer to Figures 1 to 3 In this embodiment of the extremely small circularly polarized patch antenna, the driver patch 1 and the coupling patch 2 are arranged adjacent to each other at any right angle, forming a roughly triangular shape. The two rows of metallized vias 3 are arranged orthogonally. Within this triangle, the two smaller triangles are spaced apart, and the spacing can be designed based on actual requirements. Specifically, adjusting the patch spacing, patch size, and the number of metallized vias 3 can adjust the coupling coefficient to ensure that the two orthogonal polarization modes are equal in amplitude and 90° out of phase.

[0054] Please refer to Figures 4 to 6 In this embodiment of the extremely small circularly polarized patch antenna, the driver patch 1a and the coupling patch 1a are positioned adjacent to each other on a right angle, forming a roughly triangular shape. The two rows of metallized vias 3a are arranged side by side and lie in a straight line. Within this triangle, the two smaller triangles are spaced apart, and the spacing can be designed based on actual requirements. Specifically, adjusting the patch spacing, patch size, and the number of metallized vias 3a can control the coupling coefficient to ensure that the two orthogonal polarization modes are equal in amplitude and 90° out of phase.

[0055] Please refer to Figures 4 to 6 In this embodiment of the extremely small circularly polarized patch antenna, the driver patch 1b and the coupling patch 2b are positioned adjacent to each other on their hypotenuses, forming a roughly rectangular shape. The two rows of metallized vias 3b are arranged orthogonally. Two small triangles are spaced apart, and the spacing can be designed based on actual requirements.

[0056] Please refer to Figure 10-12 , Figure 10 This is a curve showing the axial ratio variation with frequency of a small circularly polarized patch antenna of an extremely small size according to an embodiment of the present invention; Figure 11 This is a curve showing the axial ratio variation with frequency of a small circularly polarized patch antenna of an extremely small size according to another embodiment of the present invention; Figure 12 This is a curve showing the axial ratio variation with frequency of a small circularly polarized patch antenna of extreme size according to another embodiment of the present invention. Figure 10-12The graph shows how the antenna's axial ratio changes over frequency. The graph shows that the first embodiment of the antenna achieves its optimal axial ratio at 1.535 GHz, the second embodiment at 1.57 GHz, and the third embodiment at 1.535 GHz.

[0057] Please refer to Figure 13-15 , Figure 13 The sectional radiation patterns of φ=0° and φ=90° at the optimal axial ratio frequency point of the extremely small circularly polarized patch antenna of an embodiment of the present invention are shown; Figure 14 The sectional radiation patterns of φ=0° and φ=90° at the optimal axial ratio frequency point of the extremely small circularly polarized patch antenna of another embodiment of the present invention are shown; Figure 15 This is a cross-sectional radiation pattern of φ=0° and φ=90° at the optimal axial ratio frequency point of a small circularly polarized patch antenna of an extremely small size according to another embodiment of the present invention. Figure 13-15 The figures are the cross-sectional radiation patterns of the antennas of the three embodiments at their optimal axial ratio frequency points of φ=0° and φ=90°, and it can be seen that the radiation patterns can all remain stable.

[0058] In summary, this proposal proposes three compact circularly polarized patch antennas of the most compact size, based on the different coupling modes of two short-circuited isosceles triangular patches. The antennas in this design utilize short-circuited triangular patches, which lowers the resonant frequency and significantly reduces the size of the antenna. Furthermore, the use of single-feed coupling to generate circular polarization eliminates the need for additional power splitter and phase shifting networks, further reducing the overall size of the antenna.

[0059] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made by using the contents of the present invention description and drawings under the technical solution of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A small circularly polarized patch antenna of extreme size, characterized in that: include: a dielectric substrate having a first surface and a second surface opposite to each other; A driving patch and a coupling patch, each of which is a right triangle, is adjacent to and spaced apart from the first surface of the dielectric substrate and is electromagnetically coupled to form a circularly polarized axial ratio zero point. A row of metallized vias is defined on each side of the dielectric substrate corresponding to the driving patch and the coupling patch, and the two rows of metallized vias are electrically connected to the driving patch and the coupling patch, respectively. The driving patch and the coupling patch are arranged adjacent to each other at a right angle and the combination of the two is roughly triangular, and the two rows of metallized vias are arranged orthogonally; or The driving patch and the coupling patch are arranged adjacent to each other at a right angle and the combination of the two is roughly triangular, and the two rows of metallized vias are arranged side by side and are located on a straight line; or The driving patch and the coupling patch are arranged adjacent to each other at their oblique sides and the combination of the two is roughly rectangular, and the two rows of metallized vias are arranged orthogonally; The floor is arranged on the second surface of the dielectric substrate.

2. The extremely small circularly polarized patch antenna of claim 1, wherein: It also includes a feeding structure consisting of a metal probe and the outer conductor of an SMA connector. The metal probe is arranged on a dielectric substrate, and one end of the metal probe is electrically connected to the driving patch, and the other end is arranged away from the floor; the outer conductor of the SMA connector is electrically connected to the floor.

3. The extremely small circularly polarized patch antenna of claim 2, wherein: The thickness of the dielectric substrate is 0.01-0.1 times the vacuum wavelength.

4. The extremely small circularly polarized patch antenna of claim 3, wherein: The radiation side length of the driving patch and the coupling patch is 1 / 4 of the medium wavelength at the resonant frequency.

5. The extremely small circularly polarized patch antenna of claim 1, wherein the spacing between each row of the metallized vias is greater than 0.01 times the vacuum wavelength and less than the side length of the driver patch.

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