Four-unit circularly polarized antenna array based on decoupling of decoupling network

Abstract

The invention discloses a four-unit circularly polarized antenna array based on decoupling network decoupling, which is characterized in that a grounding plate (1) is arranged between a first dielectric plate (2) and a second dielectric plate (3), four antenna patches (4) are arranged on the upper surface of the first dielectric plate (2), a decoupling network is arranged on the lower surface of the second dielectric plate (3), and metal copper columns (5) are connected with the antenna patches (4) and the decoupling network. The decoupling network has eight ports and comprises four sections of phase shift networks and four 4T-shaped structures, and the phase shift networks and the 4T-shaped structures are arranged in a bending and folding manner through microstrip lines; one end of each of the four phase shift networks is connected with a metal copper column (5), the four T-shaped structures are respectively connected with the other ends of the two adjacent phase shift networks, and the decoupling network does not change the plane area of the antenna array, so that the miniaturization of the antenna structure is ensured; compared with an existing decoupling network, the decoupling network is simple in structure, the decoupling effect is guaranteed, meanwhile, the radiation efficiency is high, the circular polarization performance is not damaged, and the design of a high-performance circular polarization antenna array can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and particularly to a four-element circularly polarized antenna array based on decoupling of a decoupling network. Background Art

[0002] In the application of high-precision GPS systems, the main error source is multipath error. Multipath interference will cause the receiver to receive multiple signals with different delays, resulting in large errors in position information. This has a serious impact on high-precision positioning applications, such as precise positioning, military, and high-speed navigation. Circularly polarized antennas can reduce multipath interference and multipath fading. Secondly, circularly polarized antennas can reduce the "Faraday rotation" effect caused by the ionosphere, which is beneficial to air-ground communication. Due to the significant advantages of circularly polarized antennas in reducing multipath interference and improving the accuracy and stability of GPS positioning, circularly polarized antennas have broad application prospects in GNSS systems. With the diversification of terminal functions and the improvement of performance requirements, the demand for antenna miniaturization is constantly increasing. Adding more antennas and reducing the antenna spacing in miniaturized terminals will lead to strong mutual coupling between antennas. Severe mutual coupling will reduce the efficiency of the antennas and significantly increase the measurement error of the GPS system. Therefore, researchers at home and abroad have been committed to studying methods to improve the isolation of antenna arrays.

[0003] In order to achieve the decoupling of antenna arrays, researchers at home and abroad have proposed many structures and methods, such as defected ground structures, metamaterial structures, neutralization line techniques, and decoupling networks. The defected ground structure is to etch a designed metal groove on the ground plane to block the coupling current of the ground plane, thereby reducing the coupling between the fed unit and the unfed unit. Metamaterials utilize their special electromagnetic response characteristics in antenna decoupling. By designing microstructural units, the guidance of electromagnetic waves is realized, thereby reducing the mutual interference and coupling between antennas. The neutralization line structure is to introduce a conductor line with a special shape, such as a loop or a spiral, to cancel the electromagnetic coupling effect between adjacent antennas, thereby reducing mutual interference. There is also a decoupling network with good performance and a simple structure, which introduces appropriate capacitors, inductors, transmission lines, and other structures into the circuit to make the coupling energy between it and the antennas cancel each other out, achieving the purpose of decoupling. The decoupling network theory is mature, which can effectively improve the isolation of MIMO arrays and contribute to improving the performance of the entire system.

[0004] The decoupling network of the four - element circularly polarized antenna proposed in the papers "Z. Wang and Q. Wu, A Novel Decoupling Feeding Network for Circularly Polarized Patch Arrays Using Orthogonal Mode Decomposition, in IEEE Transactions on Antennas and Propagation, vol. 71, no. 2, pp. 1448 - 1457" and "Y. -M. Zhang, S. Zhang, J. -L. Li and G. F. Pedersen, 'A Transmission - Line - Based Decoupling Method for MIMO Antenna Arrays,' in IEEE Transactions on Antennas and Propagation, vol. 67, no. 5, pp. 3117 - 3131" can achieve a good decoupling effect. However, its antenna size is large and the structure of the decoupling network is complex, which cannot meet the application requirements of miniaturized terminal devices. Designing a GNSS antenna array with excellent performance has practical significance and application value for existing research. The decoupling network theory is mature, which can effectively improve the isolation of the MIMO array and help improve the performance of the entire system. Currently, there are various ideas to reduce the coupling between antennas. Designing a GNSS antenna array with excellent performance has practical significance and application value for existing research. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a four - element circularly polarized antenna array based on decoupling by a decoupling network.

[0006] The purpose of the present invention is achieved through the following technical solutions: The present invention provides a four - element circularly polarized antenna array based on decoupling by a decoupling network, including: a first dielectric plate, a ground plane, a second dielectric plate, antenna patches, and metal copper columns. The ground plane is disposed between the first dielectric plate and the second dielectric plate. Four antenna patches are disposed on the upper surface of the first dielectric plate. A decoupling network is disposed on the lower surface of the second dielectric plate. The metal copper columns penetrate through the first dielectric plate and the second dielectric plate to connect the antenna patches and the decoupling network; The antenna patches are square patches with diagonal truncations, and are arranged by the sequential rotation method with the center of the first dielectric plate as the center of the circle; The decoupling network has eight ports and includes four phase-shifting networks and four 4T structures. The four phase-shifting networks and the four 4T structures are arranged by bending and folding microstrip lines; one end of the four phase-shifting networks is connected to a metal copper column, and the four T-shaped structures are respectively connected to the other ends of two adjacent phase-shifting networks.

[0007] Further, the antenna patch is fed by a single point through a metal copper column. A circular ring is dug out on the antenna patch with the metal copper column as the center. The circular patch corresponding to the position of the metal copper column on the antenna patch forms capacitive coupling with the rest of the antenna patch.

[0008] Further, the operating frequency band of the antenna is located in the RNSS B3 frequency band. The RNSS B3 frequency band is 1.263~1.273 GHz, and the center frequency is 1.268 GHz. The resonant frequency of the antenna in the RNSS B3 frequency band is related to the size of the radiator of the antenna patch.

[0009] Preferably, the decoupling frequency of the decoupling network in the RNSS B3 frequency band is related to the size of the microstrip line.

[0010] The beneficial effects of the present invention are as follows: 1) The decoupling network introduced in the present invention does not change the planar area of the antenna array, ensuring the miniaturization of the antenna structure; the four antenna patches are small in size and low in cost; the proposed four-element antenna has a simpler structure than the existing decoupling network structure, has a higher radiation efficiency while ensuring the decoupling effect, and does not damage the circular polarization performance, and can realize the design of a high-performance circular polarization antenna array. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic structural diagram of a four-element circular polarization antenna array based on decoupling of a decoupling network according to an embodiment of the present invention; Figure 2 It is a top view of the structure of a four-element circular polarization antenna array based on decoupling of a decoupling network according to an embodiment of the present invention; Figure 3 It is a schematic structural diagram of the antenna patch of a four-element circular polarization antenna array based on decoupling of a decoupling network according to an embodiment of the present invention; Figure 4 It is a schematic topological structure diagram of the decoupling network of a four-element circular polarization antenna array based on decoupling of a decoupling network according to an embodiment of the present invention; Figure 5 It is a schematic diagram of the actual model structure of the decoupling network of a four-element circular polarization antenna array based on decoupling of a decoupling network according to an embodiment of the present invention; Figure 6Scattering curves of a four - element circularly polarized antenna array based on decoupling network decoupling in the RNSSB3 frequency band according to an embodiment of the present invention, where Fig. (a) shows the matching of ports 3 - 4, Fig. (b) shows the matching of ports 1 - 2, Fig. (c) shows the isolation of adjacent elements 1 - 4 and 2 - 3, and Fig. (d) shows the isolation of adjacent elements 1 - 3 and 2 - 4; Figure 7 Radiation efficiency curve diagram of a four - element circularly polarized antenna array based on decoupling network decoupling in the RNSSB3 frequency band according to an embodiment of the present invention; Figure 8 Three - dimensional gain diagram of an antenna array of a four - element circularly polarized antenna array based on decoupling network decoupling in the RNSSB3 frequency band according to an embodiment of the present invention; Figure 9 Left - hand and right - hand gain diagrams of a four - element circularly polarized antenna array based on decoupling network decoupling at the center frequency point of 1.268 GHz according to an embodiment of the present invention; Figure 10 Axial ratio schematic diagram of a four - element circularly polarized antenna array based on decoupling network decoupling in the RNSSB3 frequency band according to an embodiment of the present invention; In the figure, 1 - ground plane, 2 - first dielectric layer, 3 - second dielectric layer, 4 - antenna patch, 5 - metal copper column. Detailed implementation manners

[0012] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0013] Exemplarily, the present invention provides a four - element circularly polarized antenna array based on decoupling network decoupling, and its structural schematic diagram is as shown in Figure 1 shown, and the top view of the structure is as shown in Figure 2 shown, including: a first dielectric plate 2, a ground plane 1, a second dielectric plate 3, an antenna patch 4, and a metal copper column 5. The ground plane 1 is arranged between the first dielectric plate 2 and the second dielectric plate 3. Four antenna patches 4 are arranged on the upper surface of the first dielectric plate 2. A decoupling network is arranged on the lower surface of the second dielectric plate 3. The metal copper column 5 penetrates through the first dielectric plate 2 and the second dielectric plate 3 to connect the antenna patch 4 and the decoupling network.

[0014] Exemplarily, the specific structural schematic diagram of the antenna patch 4 is as shown in Figure 3As shown in the figure, the present invention includes four antenna patches 4. The four antenna patches 4 have the same structure, and are all square patches with diagonal truncations. The antenna patches 4 are connected to the decoupling network through metal copper posts 5 and are fed simultaneously. A circular ring is dug out on the antenna patches 4 with the position of the metal copper posts 5 as the center of the circle. The circular patch at the position corresponding to the metal copper posts 5 on the antenna patches 4 forms a capacitive coupling with the rest of the antenna patches 4. The four antenna patches 4 are arranged in a sequential rotation method with the center of the first dielectric plate 2 as the center of the circle.

[0015] Exemplarily, the schematic diagram of the decoupling network topology is as Figure 4 shown, and the actual model structure diagram of the decoupling network is as Figure 5 shown. The specific composition of the decoupling network is four phase-shifting networks with the same electrical length and four 4-T-shaped structures with the same electromagnetic structure. One end of the four phase-shifting networks is connected to the metal copper posts 5, and the four T-shaped structures are respectively connected to the other ends of two adjacent phase-shifting networks. The decoupling frequency of the decoupling network in the RNSS B3 frequency band is related to the dimensions of each section of the microstrip line. It should be noted that in Figure 4 the 4 phase-shifting networks and 4 T-shaped structures shown are all arranged in a bent and folded manner of microstrip lines, which are different in shape from the proposed decoupling network structure, but are consistent with the proposed decoupling network structure in terms of topology. The 4 phase-shifting networks and 4 T-shaped structures can be adjusted according to the actual implementation situation, and are not limited to the embodiments of the present invention.

[0016] Specifically, the resonant frequency of the single-band circularly polarized antenna array is achieved by controlling the size of the square patch, the size of the angular truncated isosceles triangle, and the single-point feeding position. The working frequency band of the decoupling network of the circularly polarized antenna array covers the RNSS B3 frequency band. The RNSS B3 frequency band is 1.263 - 1.273 GHz, and the center frequency is 1.268 GHz. After the decoupling network is added, high-isolation and high-radiation-efficiency circularly polarized antenna performance is achieved in this frequency band. The dimensions in the antenna embodiments are related to the resonant frequency and the decoupling frequency, and can be adjusted according to the actual implementation situation, and are not limited to the embodiments of the present invention.

[0017] Exemplarily, in order to illustrate the decoupling effect of the circularly polarized antenna array, the scattering curve of the present invention in the RNSS B3 frequency band is as Figure 6As shown, the S-parameters of the obtained antenna array are as shown in the figure. In the frequency band of 1.263 - 1.273 GHz, the matching of ports 3 - 4 is better than -12 dB, the isolation between adjacent elements of ports 3 - 4 is better than 12 dB, and better than 24 dB at the center frequency point of 1.268 GHz; the matching of ports 1 - 2 is better than -12 dB, the isolation of ports 1 - 2 is better than 12 dB, and better than 24 dB at the center frequency point of 1.268 GHz; the isolation between adjacent elements 1 - 4 and 2 - 3 is better than 13 dB, and better than -28 dB at the center frequency point of 1.268 GHz; the isolation between adjacent elements 1 - 3 and 2 - 4 is better than -12 dB, and better than 30 dB at the center frequency point of 1.268 GHz. The decoupling effect is good and meets the matching requirements, and the simulation effect is ideal.

[0018] Exemplarily, in order to verify the radiation performance of the circularly polarized antenna array, the radiation efficiency curve diagram of the present invention in the RNSS B3 frequency band is as Figure 7 shown. According to the feeding principle of the sequential rotation method of the antenna array, the feeding phases of the four ports are 0°, 90°, 180°, and 270° in sequence. It can be seen that in the frequency band of 1.263 - 1.273 GHz, the radiation efficiency of this antenna array is between 82 - 86%, and the efficiency performance is good.

[0019] Exemplarily, the three-dimensional gain diagram of the antenna array of the present invention in the RNSS B3 frequency band is as Figure 8 shown. To verify the frontal radiation performance of the antenna array, it can be seen that when the feeding phases of the four ports are 0°, 90°, 180°, and 270° in sequence, the main radiation direction of this antenna array is the +Z-axis direction, which meets the design requirements of the GNSS circularly polarized antenna array.

[0020] Exemplarily, to verify the circular polarization performance of the antenna array, check the left (right) hand circular polarization gain of the antenna array. The left and right hand circular polarization gain diagrams of the present invention at the center frequency point of 1.268 GHz are as Figure 9 shown. In the main radiation direction of the +Z-axis direction, the left hand circular polarization gain is significantly greater than the right hand circular polarization gain diagram. Therefore, it can be judged that the polarization mode of this antenna array is left hand circular polarization. The axial ratio schematic diagram of the present invention in the RNSS B3 frequency band is as Figure 10 shown. It can be seen that the axial ratio is less than 0.6 dB in the frequency band of 1.25 - 1.3 GHz. In engineering, it is considered that the axial ratio of a circularly polarized antenna should be lower than 3 dB. Therefore, the circular polarization performance of this antenna array is good.

[0021] The above are only the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein, and should not be regarded as excluding other embodiments. Instead, it can be used in various other combinations, modifications, and environments, and can be changed within the scope of the concept described herein through the above teachings or the techniques or knowledge in the relevant field. Any changes and variations made by those skilled in the art without departing from the spirit and scope of the present invention shall fall within the protection scope of the appended claims of the present invention.

Claims

1. A four-element circularly polarized antenna array based on decoupling network decoupling, characterized in that: include: A first dielectric plate (2), a ground plate (1), a second dielectric plate (3), an antenna patch (4) and a metal copper column (5), wherein the ground plate (1) is arranged between the first dielectric plate (2) and the second dielectric plate (3), four antenna patches (4) are arranged on the upper surface of the first dielectric plate (2), a decoupling network is arranged on the lower surface of the second dielectric plate (3), and the metal copper column (5) penetrates the first dielectric plate (2) and the second dielectric plate (3) to connect the antenna patch (4) and the decoupling network; The antenna patch (4) is a diagonally truncated square patch, and is arranged by a sequential rotation method with the center of the first dielectric plate (2) as the center of the circle; The decoupling network has eight ports and comprises four phase-shifting networks and four 4T-shaped structures, which are arranged by bending and folding microstrip lines; one end of the four phase-shifting networks is connected to a metal copper column (5), and the four T-shaped structures are respectively connected to the other ends of two adjacent phase-shifting networks.

2. The four-element circularly polarized antenna array based on decoupling network decoupling according to claim 1, characterized in that: The antenna patch (4) is single-point fed via the metal copper column (5), a circular ring is dug out on the antenna patch (4) with the metal copper column (5) as the center of the circle, and a circular patch corresponding to the position of the metal copper column (5) on the antenna patch (4) forms a capacitive coupling with the rest of the antenna patch (4).

3. The four-element circularly polarized antenna array based on decoupling network decoupling according to claim 1, characterized in that: The working frequency band of the antenna is in the RNSS B3 frequency band, which is 1.263-1.273 GHz and has a center frequency of 1.268 GHz. The resonant frequency of the antenna in the RNSS B3 frequency band is correlated with the size of the radiator of the antenna patch.

4. The four-element circularly polarized antenna array based on decoupling network decoupling according to claim 3, characterized in that: The decoupling frequency of the decoupling network in the RNSS B3 frequency band is correlated with the size of the microstrip line.

Images