Orthogonal polarization dual-band co-aperture millimeter wave antenna based on metasurface structure multiplexing

Abstract

The application relates to an orthogonal polarization double-frequency-band common-aperture millimeter wave antenna based on super surface structure multiplexing, which comprises a first metal layer, a first dielectric layer, a second dielectric layer, a second metal layer, a third dielectric layer, a third metal layer, a fourth dielectric layer, a fifth dielectric layer and a fourth metal layer which are sequentially stacked, when the antenna works at a low frequency, the third metal layer and the fourth metal layer constitute a double-layer super surface structure, when the antenna works at a high frequency, the third metal layer and the fourth metal layer constitute a series-fed array, the polarization directions of the super surface structure and the series-fed array are orthogonal, when working at the low frequency, the double-layer rectangular patch array can be regarded as a double-layer super surface, and a feed network is located on the first metal layer, when working at the high frequency, based on the super surface structure multiplexing, the double-layer rectangular patch array is regarded as a stacked microstrip antenna array, and a feed network is located on the third metal layer. The application has higher aperture utilization efficiency, wider bandwidth, lower profile and a planar structure which is easy to integrate.

Description

Technical Field

[0001] This invention relates to the field of wireless communication, and in particular to an orthogonally polarized dual-band common-aperture millimeter-wave antenna based on metasurface structure multiplexing. Background Technology

[0002] With the rapid development of communication technology, communication systems often need to cover multiple frequency bands to meet various requirements. In this case, a single communication system often needs to integrate multiple antennas of different frequency bands. Since the gain of an antenna is mainly determined by the area of ​​its radiating aperture, if the radiating structures used for different frequency bands occupy different apertures, it is difficult to miniaturize a communication system containing multiple antennas of different frequency bands. Because common-aperture antennas can significantly improve aperture utilization efficiency, they contribute to the integration and miniaturization of communication systems, thus attracting increasing attention from researchers.

[0003] Currently, there are two main methods for implementing common-aperture antennas. One is the separate-aperture method, where multiple antennas are placed separately on a plane. This method is simple to design, and the isolation between multiple antennas is often improved through polarization orthogonality or spatial isolation, which helps ensure the performance of each antenna. However, its disadvantages are also obvious: the separate apertures significantly increase the system size, and the antenna aperture utilization efficiency is low. The other method is the stacked-aperture method, where antennas of different frequency bands are stacked vertically. Different antennas occupy a common aperture, thus greatly improving aperture utilization efficiency. Its disadvantages are a higher profile and often narrower antenna bandwidth.

[0004] In recent years, a new design concept called "structural reuse" has been proposed. Its main advantage lies in the fact that while the antenna aperture is reused, the antenna structure itself is also reused, thereby improving aperture utilization efficiency and significantly reducing the antenna profile, which is beneficial for integrated and miniaturized applications. However, judging from the published literature, almost all designs based on structural reuse are often limited by the antenna structure itself. Although the antenna profile is significantly reduced, its narrow bandwidth severely limits its application prospects.

[0005] Chinese patent application CN202011082424.9 discloses a dual-frequency fusion antenna and communication device based on a metasurface, including a reflector, a low-frequency antenna radiating element, a first metasurface, a second metasurface, and a high-frequency antenna radiating element. The high-frequency antenna radiating element is disposed above the reflector, and the low-frequency antenna radiating element is disposed above the high-frequency antenna radiating element. The first and second metasurfaces are located above and below the low-frequency antenna radiating element, respectively. The antenna structure provided by this application is novel, with high isolation and stable radiation pattern. Although this application achieves aperture reuse to some extent, it does not achieve structural reuse.

[0006] In summary, there is currently a lack of a common-aperture antenna with high aperture utilization efficiency, wide bandwidth, and low profile based on structural reuse. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the existing technology by providing an orthogonally polarized dual-band common-aperture millimeter-wave antenna based on metasurface structure reuse. A double-layered metal rectangular array constitutes the antenna's radiating structure. When the antenna operates at low frequencies, this radiating structure can be considered as a double-layered metasurface structure. At high frequencies, this structure is completely reused. The patch array located on the third metal layer is connected by transmission lines to form a double-layered series-fed array. In this case, the radiating structure can be considered as a stacked microstrip antenna array, thereby achieving almost 100% high aperture utilization efficiency and possessing broadband and low-profile characteristics.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] This invention provides an orthogonally polarized dual-band common-aperture millimeter-wave antenna based on metasurface structure reuse, comprising a first metal layer, a first dielectric layer, a second dielectric layer, a second metal layer, a third dielectric layer, a third metal layer, a fourth dielectric layer, a fifth dielectric layer, and a fourth metal layer stacked sequentially. When the antenna operates at low frequencies, the third and fourth metal layers form a double-layer metasurface structure. When the antenna operates at high frequencies, the third and fourth metal layers form a series-feed array. The polarization direction of the metasurface structure is orthogonal to that of the series-feed array, thereby improving isolation. The rectangular patches of the third and fourth metal layers constitute the antenna's radiating structure, and the second metal layer serves as the antenna's ground plane. The antenna can achieve dual-band coverage. The low-frequency feeding network is located on the first metal layer, exciting the antenna's radiation through coupled feeding. The high-frequency feeding network is located on the third metal layer, using microstrip lines to sequentially connect the rectangular patches on the third metal layer, forming a series-feed array together with the fourth metal layer.

[0010] As a preferred technical solution, the low-frequency radiation mode of the antenna is as follows: the rectangular patch array of the third metal layer and the fourth metal layer constitutes a double-layer metasurface structure, which is excited by the low-frequency feed network located in the first metal layer through coupling feed. At this time, the polarization direction of the antenna is vertical.

[0011] As a preferred technical solution, the high-frequency radiation method of the antenna is as follows: the rectangular patch arrays of the third metal layer and the fourth metal layer constitute a double-layer stacked patch array. The patch array located on the third metal layer is connected in series via microstrip lines, and the two columns of patches located in the center are not connected to each other. The patch array located on the third metal layer is fed inward from both ends, with the current amplitude at both ends being the same but the direction being opposite.

[0012] As a preferred technical solution, the third metal layer includes a first metal patch array, and the fourth metal layer includes a second metal patch array, wherein the first metal patch array and the second metal patch array are symmetrically arranged.

[0013] As a preferred technical solution, the first metal patch array includes multiple metal patches and microstrip lines, the metal patches are connected in series through the microstrip lines, and the two columns of metal patches in the middle of the first metal patch array are not directly connected.

[0014] As a preferred technical solution, the third metal layer further includes a balun, wherein the first metal patch array is fed inward from both ends, and the current amplitudes at both ends are the same but the directions are opposite, and the current is provided by the balun.

[0015] As a preferred technical solution, the metal patches in the first metal patch array and the second metal patch array are arranged in a 4×8 configuration.

[0016] As a preferred technical solution, the first metal layer includes a low-frequency power supply network.

[0017] As a preferred technical solution, the low-frequency power supply network includes 2×4 fork-shaped power supply units.

[0018] As a preferred technical solution, the second metal layer has multiple metal slots, which are used to excite the antenna radiation by means of energy carried by the feeding network of the first metal layer through coupling feeding.

[0019] As a preferred technical solution, the metal groove is rectangular.

[0020] As a preferred technical solution, the material of the first dielectric layer is Rogers 4350, the material of the second and fourth dielectric layers is Rogers 4450F, the material of the third and fifth dielectric layers is Rogers 5880, and the material of the first, second, third, and fourth metal layers is copper.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) The antenna has high aperture reuse efficiency, low profile and wide operating bandwidth: By reuse of the double-layer metasurface structure located in the third and fourth metal layers, almost 100% aperture reuse efficiency can be achieved and the overall profile of the antenna is reduced. The double-layer metasurface structure located in the third and fourth metal layers is excited by coupling feeding. The double-layer structure broadens the bandwidth and is conducive to miniaturization. When the antenna radiates at high frequency, the double-layer patch array located in the third and fourth metal layers forms a stacked microstrip antenna array, which also broadens the operating bandwidth of the antenna.

[0023] (2) High isolation between antennas and flexible design: The polarization direction of the low-frequency metasurface radiation is orthogonal to the polarization direction of the high-frequency series-fed array radiation, which can achieve high isolation. At the same time, the influence between the two is small, and the frequency bands of the two antennas can be flexibly designed.

[0024] (3) Planar structure, easy to integrate: The antenna has a planar structure with a low profile, making it easy to integrate and suitable for millimeter wave applications. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the orthogonal polarization dual-band co-aperture millimeter-wave antenna structure based on metasurface structure reuse in Example 1;

[0026] Figure 2 for Figure 1 A schematic diagram of the antenna cross-section;

[0027] Figure 3 for Figure 1 A schematic diagram of the fifth dielectric layer and the fourth metal layer;

[0028] Figure 4 for Figure 1 A schematic diagram of the structure of the third dielectric layer and the third metal layer;

[0029] Figure 5 for Figure 1 Schematic diagram of the structure of the second metal layer and the metal trench;

[0030] Figure 6 for Figure 1 A schematic diagram of the structure of the first dielectric layer and the first metal layer;

[0031] Figure 7 This is a schematic diagram of a metasurface structure reuse method;

[0032] Figure 8 This is a schematic diagram of a double-layer metasurface structure;

[0033] Figure 9 A schematic diagram showing the results of characteristic mode analysis of a bilayer metasurface;

[0034] Figure 10 This is a schematic diagram showing the mode current direction and its pattern at the resonant frequency of each mode in the characteristic mode analysis results of the bilayer metasurface.

[0035] Figure 11 Schematic diagrams of three different power supply methods;

[0036] Figure 12 Simulation and calculation results for three different power supply methods;

[0037] Figure 13 This is a schematic diagram of the transition structure;

[0038] Figure 14 This is a schematic diagram of the simulation results of the transition structure;

[0039] Figure 15 This is a schematic diagram showing the S-parameter simulation and test results of a dual-frequency common-aperture millimeter-wave antenna based on orthogonal polarization and metasurface structure reuse.

[0040] Figure 16 This is a schematic diagram showing the radiation pattern simulation and test results of a dual-frequency common-aperture millimeter-wave antenna with orthogonal polarization based on metasurface structure reuse at 28 GHz and 32 GHz.

[0041] Figure 17 This is a schematic diagram of the radiation pattern simulation and test results of a dual-frequency common-aperture millimeter-wave antenna with orthogonal polarization based on metasurface structure reuse at a frequency of 60 GHz.

[0042] Figure 18 This is a schematic diagram showing the simulation and test results of the gain of a dual-frequency common-aperture millimeter-wave antenna based on orthogonal polarization and metasurface structure reuse.

[0043] Figure 19 Here are the dimensional parameters of a dual-frequency, common-aperture millimeter-wave antenna with orthogonal polarization based on metasurface structure reuse.

[0044] Among them, 11, first dielectric layer, 12, second dielectric layer, 13, third dielectric layer, 14, fourth dielectric layer, 15, fifth dielectric layer, 21, first metal layer, 22, second metal layer, 23, third metal layer, 24, fourth metal layer, 3, balun, 4, low-frequency GSG port, 5, high-frequency GSG port, 6, grounding via. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0046] Example

[0047] This embodiment provides an orthogonally polarized dual-band common-aperture millimeter-wave antenna based on metasurface structure multiplexing, comprising a first metal layer 21, a first dielectric layer 11, a second dielectric layer 12, a second metal layer 22, a third dielectric layer 13, a third metal layer 23, a fourth dielectric layer 14, a fifth dielectric layer 15, and a fourth metal layer 24 stacked sequentially. The rectangular patches of the third and fourth metal layers constitute the antenna's radiating structure, and the second metal layer serves as the antenna's ground plane.

[0048] Figure 7 This is a schematic diagram illustrating the metasurface structure reuse method provided in this embodiment, used to concisely and clearly explain the structure reuse method. Among them, Figure 7 (a) shows a traditional antenna based on a single-layer metasurface radiation. Its feed structure is placed below a ground plane with slots cut into the ground plane, and it is excited using a coupled feed method. Each element is square, with consistent spacing in both the horizontal and vertical directions. Figure 7 In Figure (b), the modified metasurface structure is shown, in which the horizontal length of the unit cells is shortened to make room for the high-frequency feed network. The vertical spacing and length remain unchanged, and its radiation mode is almost unaffected. Figure 7 (c) in Figure 7 Based on (b) above, a layer of metasurface structure with a different width is added to increase the degree of freedom in antenna design and thus increase bandwidth. Furthermore, the dual-layer structure introduces additional coupling capacitance, which is beneficial for miniaturization. Figure 7 In diagram (d), the common-aperture antenna structure is multiplexed. The rectangular patch array at the bottom layer is connected sequentially using transmission lines to form a series-fed stacked microstrip antenna array. The low-frequency antenna is a vertically oriented double-layer metasurface-based radiation mode, excited by a slot in the floor using coupled feeding. The high-frequency antenna reuses the double-layer metasurface structure to form a series-fed stacked microstrip antenna array in the horizontal direction, which improves bandwidth compared to a single-layer patch.

[0049] Figure 8This is a schematic diagram of a double-layer metasurface structure provided by an embodiment of the present invention, used to explain the radiation principle of a low-frequency antenna. It includes a first metal layer, a first dielectric layer, a second dielectric layer, a second metal layer, a third dielectric layer, a third metal layer, a fourth dielectric layer, a fifth dielectric layer, and a fourth metal layer stacked sequentially. Rectangular patches 23 and 24 constitute the antenna's radiation structure, 22 is the antenna's ground plane, and 21 is the antenna's feed structure. The first dielectric layer is made of Rogers 4350 and has a thickness of 0.168 mm. The second and fourth dielectric layers are made of Rogers 4450F and each has a thickness of 0.1 mm. The third and fifth dielectric layers are made of Rogers 5880 and have thicknesses of 0.254 mm and 0.127 mm, respectively. All metal layers are made of copper and each has a thickness of 0.018 mm.

[0050] Figure 9 This is a schematic diagram showing the characteristic mode analysis results of the bilayer metasurface provided in Example 1. The results show that three modes, J1, J2, and J3, can resonate near 32 GHz.

[0051] Figure 10 This diagram illustrates the mode current directions and radiation patterns of each mode at its resonant frequency, based on the characteristic mode analysis results of the bilayer metasurface provided in Example 1. Observation reveals that J1 is the desired mode. J2, J4, and J5 are difficult to excite using slot excitation. The resonant point of J6 is outside the frequency band, while J3 resonates near 32 GHz and is easily excited using slot excitation, which would interfere with our desired mode J1. Therefore, an improved feeding method is needed to suppress the resonance of mode J3.

[0052] Figure 11 Schematic diagrams of three different power supply methods provided in Example 1; Figure 11 (a) in the diagram represents the traditional single-slot structure's power supply method. Figure 11 (b) shows the improved feeding method for the dual-slot structure. Figure 11 (c) in the figure represents the final power supply method for the 2×2 slot array structure.

[0053] Figure 12 Simulation and calculation results are provided for the three different feeding methods provided in Example 1. From the direction of the surface current, it can be seen that using the Case I feeding method, J3 is excited at 32 GHz, resulting in antenna pattern distortion and reduced gain. Using the Case II or Case III feeding methods can suppress the generation of the J3 mode and significantly increase the gain. Among these, Case III has both high gain and aperture efficiency, and was selected as the final feeding method.

[0054] Figure 1-6This embodiment provides a schematic diagram of a dual-frequency common-aperture millimeter-wave antenna based on metasurface structure reuse and orthogonal polarization; compared to Figure 8 The metasurface structure in the middle is doubled in size to increase gain. Figure 1 3D view; Figure 2 This is a side view; Figure 3 The fourth metal layer is located on the fifth dielectric layer, and it is the metasurface structure of the upper layer. Figure 4 This is a schematic diagram of the third metal layer located on the third dielectric layer, including the underlying metasurface structure, the high-frequency feed network, the balun 3, and the high-frequency GSG port 5 and low-frequency GSG port 4 for testing. The patch array is connected in series via microstrip lines, and the two centrally located columns of patches are not interconnected. The patch array located on the third metal layer is fed inwards from both ends, with the current amplitudes at both ends being the same but in opposite directions. This is done to avoid pattern tilting of the high-frequency antenna array and to reduce cross-polarization. Figure 5 This is a schematic diagram of the second metal layer located on the second dielectric layer, which serves as the ground plane of the entire antenna, with slots cut into it to achieve coupled feeding. Figure 6 The first metal layer is located below the first dielectric layer and is the bottom layer, serving as a low-frequency power supply network.

[0055] Figure 13 This is a schematic diagram of the low-frequency transition structure provided in this embodiment. Since the low-frequency power supply network is located at the bottom layer, a coaxial-like transition structure needs to be designed to move to the third layer for ease of testing. It includes a power supply via, a grounding via, and a circular slot. The power supply via is used to transmit energy; the grounding via provides an energy loop, avoiding a parallel plate pattern and reducing surface wave loss; the circular slot forms a coaxial-like structure, and the impedance of the transition structure can be adjusted by adjusting its radius.

[0056] Figure 14 The diagram shows the simulation results of the adapter structure provided in Example 1; it achieves good matching effect in the 28GHz-42GHz range, with an attenuation of only about 0.5dB.

[0057] Figure 15 This diagram illustrates the S-parameter simulation and test results of a dual-frequency common-aperture millimeter-wave antenna based on orthogonal polarization and metasurface structure reuse, as provided in this embodiment. The antenna has a wide operating bandwidth; the simulated and tested -10dB bandwidths at low frequencies are 19.0% (27.7-33.5GHz) and 18.6% (28.2-34.0GHz), respectively. The simulated and tested -10dB bandwidths at high frequencies are 15.3% (54.2-63.2GHz) and 15.5% (54.1-63.2GHz), respectively.

[0058] Figure 16The diagram shows the simulation and test results of the radiation pattern of a dual-frequency common-aperture millimeter-wave antenna based on metasurface structure reuse and orthogonal polarization at 28GHz and 32GHz, provided in this embodiment. It can be seen that the simulation and test results of the antenna radiation pattern are in good agreement, with the maximum radiation direction vertically upward, no distortion, and low sidelobes and differential polarization.

[0059] Figure 17 This embodiment provides a schematic diagram of the radiation pattern simulation and test results of a dual-frequency common-aperture millimeter-wave antenna with orthogonal polarization based on metasurface structure reuse at a frequency of 60 GHz. It can be seen that the simulation and test results of the antenna radiation pattern are in good agreement. The maximum radiation direction is vertically upward, the radiation pattern is almost symmetrical, there is no distortion, and the sidelobes and differential polarization are low.

[0060] Figure 18 This diagram illustrates the simulation and test results of the gain of a dual-frequency, common-aperture millimeter-wave antenna based on orthogonal polarization and metasurface structure reuse, as provided in this embodiment. It can be seen that the simulation and test results of the antenna gain are in good agreement, with high and stable gain. The maximum low-frequency gain occurs at 32 GHz, at 13.76 dBi. The maximum high-frequency gain occurs at 59 GHz, at 17.88 dBi.

[0061] Figure 19 The present embodiment provides the size parameters of a dual-frequency common-aperture millimeter-wave antenna based on orthogonal polarization and metasurface structure reuse.

[0062] The present invention has the following advantages:

[0063] The antenna boasts high aperture reuse efficiency and a low profile. By reusing a double-layer metasurface structure located in the third and fourth metal layers, near 100% aperture reuse efficiency can be achieved, while reducing the overall antenna profile.

[0064] The antenna operates over a wide bandwidth. The dual-layer metasurface structure located on the third and fourth metal layers is excited via coupled feeding. The dual-layer structure broadens the bandwidth and facilitates miniaturization. During high-frequency radiation, the dual-layer patch array on the third and fourth metal layers forms a stacked microstrip antenna array, which also broadens the antenna's operating bandwidth.

[0065] The two antennas offer high isolation and flexible design. The polarization direction of the low-frequency metasurface radiation is orthogonal to the polarization direction of the high-frequency series-fed array radiation, achieving high isolation. Simultaneously, the influence between the two is minimal, allowing for flexible design of the frequency bands for both antennas.

[0066] Planar structure, easy to integrate. The antenna has a planar structure with a low profile, making it easy to integrate and suitable for millimeter-wave applications.

[0067] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A transversely polarized dual-band common-aperture millimeter-wave antenna based on metasurface structure reuse, characterized in that, The antenna comprises a first metal layer (21), a first dielectric layer (11), a second dielectric layer (12), a second metal layer (22), a third dielectric layer (13), a third metal layer (23), a fourth dielectric layer (14), a fifth dielectric layer (15), and a fourth metal layer (24), which are stacked sequentially. When the antenna operates at low frequencies, the third metal layer (23) and the fourth metal layer (24) form a double-layer metasurface structure. When the antenna operates at high frequencies, the third metal layer (23) and the fourth metal layer (24) form a series-fed array. The third metal layer (23) includes a first metal patch array, and the fourth metal layer (24) includes a second metal patch array. The first metal patch array includes multiple metal patches and microstrip lines. The metal patches are connected in series through the microstrip lines, and the two columns of metal patches in the middle of the first metal patch array are not directly connected. The first metal patch array located in the third metal layer (23) is fed inward from both ends. The current amplitudes at both ends are the same, but the directions are opposite. The polarization direction of the low-frequency metasurface radiation is orthogonal to the polarization direction of the series-fed array radiation at high frequencies. The second metal layer (22) serves as the antenna's ground plane. The double-layer metasurface structure is excited by a low-frequency feed network located on the first metal layer (21) through a coupled feed method. The second metal layer (22) has multiple metal slots. The first metal patch array and the second metal patch array are arranged symmetrically.

2. The orthogonally polarized dual-band common-aperture millimeter-wave antenna based on metasurface structure multiplexing according to claim 1, characterized in that, The third metal layer (23) further includes a balun (3), the first metal patch array being fed inward from both ends, with the current amplitudes at both ends being the same and the directions being opposite, the current being provided by the balun (3).

3. The orthogonally polarized dual-band common-aperture millimeter-wave antenna based on metasurface structure multiplexing according to claim 1, characterized in that, The metal patches in the first metal patch array and the second metal patch array are arranged in a 4×8 configuration.

4. The orthogonally polarized dual-band common-aperture millimeter-wave antenna based on metasurface structure multiplexing according to claim 1, characterized in that, The low-frequency power supply network includes multiple fork-shaped power supply units.

5. The orthogonally polarized dual-band common-aperture millimeter-wave antenna based on metasurface structure multiplexing according to claim 1, characterized in that, The metal groove is rectangular.

6. The orthogonally polarized dual-band common-aperture millimeter-wave antenna based on metasurface structure multiplexing according to claim 1, characterized in that, The material of the first dielectric layer (11) is Rogers 4350, the material of the second dielectric layer (12) and the fourth dielectric layer (14) is Rogers 4450F, the material of the third dielectric layer (13) and the fifth dielectric layer (15) is Rogers 5880, and the material of the first metal layer (21), the second metal layer (22), the third metal layer (23) and the fourth metal layer (24) is copper.

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