Low profile polarisation reconfigurable millimeter wave antenna based on vanadium dioxide film

Abstract

The application discloses a low-profile polarized reconfigurable millimeter wave antenna based on a vanadium dioxide film, which comprises a first dielectric substrate and a second dielectric substrate arranged in a stack, a metal metasurface structure is printed on the upper surface of the first dielectric substrate, a vanadium dioxide film is loaded between adjacent units of the metal metasurface structure, a metal ground plate is printed on the upper surface of the second dielectric substrate, the metal ground plate is etched with a coupling gap, the second dielectric substrate is provided with an SIW feeding structure, and the SIW feeding structure is connected with a microstrip line structure. The antenna can realize three kinds of polarization reconfiguration in a millimeter wave frequency band under the conditions of low loss and low profile, the polarization types are linear polarization, left-handed circular polarization and right-handed circular polarization respectively, and the switching speed is faster and the isolation degree is higher.

Description

TECHNICAL FIELD

[0001] The application relates to the field of antennas, in particular to a low-profile polarization reconfigurable millimeter wave antenna based on a vanadium dioxide film. BACKGROUND

[0002] Modern communication systems usually need multiple circuits and antennas to support multiple service types, which brings the problem of multi-antenna integration. Reconfigurable antennas can change performance parameters (such as operating frequency, radiation pattern, polarization mode, etc.) in real time, which is conducive to the integration and miniaturization of multifunctional wireless communication systems, and is one of the development directions of new antennas. Reconfigurable antennas need to load control devices to realize function switching, but at the millimeter wave frequency band, the performance of traditional controllers such as PIN diodes and varactor diodes deteriorates. Vanadium dioxide is a phase change material, and its resistivity can change by several orders of magnitude during phase change, so it can be used as a switching device. As a new type of switching device, vanadium dioxide has good performance of low loss and high isolation at the millimeter wave frequency band, so it has been studied more and more.

[0003] In recent years, metamaterials have become a research hotspot due to their unique electromagnetic properties. As a two-dimensional form of metamaterials, metasurfaces have the characteristics of low profile, low loss, low cost and easy processing. By combining vanadium dioxide with metasurfaces to form reconfigurable metasurfaces, a reconfigurable millimeter wave antenna can be constructed (Yang W, Zhou C, Xue Q, et al. Millimeter-Wave Frequency-Reconfigurable Metasurface Antenna Based on Vanadium Dioxide Films [J]. IEEE Transactions on Antennas and Propagation, 2021, 69(8): 4359-4369.). However, current millimeter wave reconfigurable antennas based on vanadium dioxide films are mostly frequency reconfigurable antennas, and cannot achieve polarization reconfiguration, and the antenna profile is generally high, which cannot achieve low profile. SUMMARY

[0004] In order to overcome the above-mentioned defects and shortcomings of the prior art, the purpose of the present application is to provide a low-profile polarization reconfigurable millimeter wave antenna based on a vanadium dioxide film, which can realize polarization reconfiguration of millimeter waves under the conditions of low loss and low profile.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] A low-profile polarized reconfigurable millimeter wave antenna based on vanadium dioxide film, comprising a first dielectric substrate and a second dielectric substrate arranged in a stack, a metal metasurface structure is printed on the upper surface of the first dielectric substrate, and a metal ground plate is printed on the upper surface of the second dielectric substrate.

[0007] The metal metasurface structure comprises M*N super surface units arranged in an array, each super surface unit comprises a central rectangular patch and four rectangular patches at four corners, the central rectangular patch is connected to the four rectangular patches at four corners through a gradient microstrip line, the central rectangular patch is connected to an adjacent super surface unit through a vanadium dioxide film and a bent microstrip line, and the vanadium dioxide film is arranged in a positive 45° diagonal direction and a negative 45° diagonal direction of the first dielectric substrate.

[0008] Further, when the vanadium dioxide film in the positive 45° diagonal direction is a conductor and the vanadium dioxide film in the negative 45° diagonal direction is an insulator, the polarization mode of the antenna is left-handed circular polarization.

[0009] When the vanadium dioxide film in the positive 45° diagonal direction is an insulator and the vanadium dioxide film in the negative 45° diagonal direction is a conductor, the polarization mode of the antenna is right-handed circular polarization.

[0010] When the vanadium dioxide film is an insulator, the polarization mode of the antenna is linear polarization.

[0011] Further, the vanadium dioxide film is arranged between the central rectangular patch and the bent microstrip line, and the shape of the vanadium dioxide film is a rectangular structure or an interdigital structure.

[0012] Further, the metal ground plate is etched to form a coupling gap.

[0013] Further, the coupling gap is a linear gap, and the length direction of the linear gap is at an angle of 45 degrees with the long and wide arrangement direction of the metal metasurface structure.

[0014] Further, the second dielectric substrate is provided with a SIW feeding structure.

[0015] Further, two metal columns are symmetrically arranged in the SIW feeding structure.

[0016] Further, the SIW feeding structure is connected to a microstrip line structure through a transition structure.

[0017] Further, a coupling gap is arranged in the SIW feeding structure.

[0018] A communication device comprising the low-profile polarized reconfigurable millimeter wave antenna.

[0019] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0020] (1) The low-profile polarized reconfigurable millimeter wave antenna based on vanadium dioxide film provided by the application can switch the polarization mode between left-handed / right-handed circular polarization and linear polarization when the state of the vanadium dioxide film is switched between conductor and insulator;

[0021] (2) Compared with the semiconductor switch, MEMS switch and other phase change materials used in general reconfigurable antennas, the vanadium dioxide film has smaller loss, faster switching speed and higher isolation;

[0022] (3) The low-profile polarized reconfigurable millimeter wave antenna based on vanadium dioxide film provided by the application has the characteristics of low profile, and the thickness is only 0.075 lambda;

[0023] (4) The low-profile polarized reconfigurable millimeter wave antenna based on vanadium dioxide film provided by the application has the characteristics of high gain. When the antenna is in the left-handed / right-handed circular polarization state, the maximum gain of the antenna in the band is 6.5dBi. When the antenna is in the linear polarization state, the maximum gain of the antenna in the band is 7dBi. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a three-dimensional view of the application;

[0025] Figure 2 is a super surface unit structure diagram of the application;

[0026] Figure 3 is a side view of the application;

[0027] Figure 4 is a top view of the application;

[0028] Figure 5 is a top view of the super surface unit of the application;

[0029] Figure 6 is a SIW feeding structure schematic diagram of the application;

[0030] Figure 7 is the reflection coefficient curve and the gain curve of the application in the left-handed circular polarization state;

[0031] Figure 8 is the axial ratio curve of the application in the left-handed circular polarization state;

[0032] Figure 9 is the radiation pattern of the application in the left-handed circular polarization state;

[0033] Figure 10 is the reflection coefficient curve and the gain curve of the application in the linear polarization state;

[0034] Figure 11This is the radiation pattern of the present invention in the online polarization state. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0036] Figures 1-3 As shown, a low-profile polarization reconfigurable millimeter-wave antenna based on vanadium dioxide thin film includes a first dielectric substrate 1 and a second dielectric substrate 2 stacked on top of each other, wherein a metal metasurface structure 3 is printed on the upper surface of the first dielectric substrate 1.

[0037] like Figure 4 As shown, the metal metasurface structure 3 is composed of M*N metasurface units 8 arranged in an array. In this embodiment, the metal metasurface structure is composed of 4*4 metasurface units 8, as shown... Figure 5 As shown, the metasurface unit 8 includes a central rectangular patch 9 and four rectangular patches 10 located at the four corners. The central rectangular patch 9 and the four rectangular patches 10 located at the four corners are connected by gradient microstrip lines 11. In this embodiment, the width of the gradient microstrip lines 11 gradually increases from the central rectangular patch 9 to the four corner rectangular patches 10. The central rectangular patch 9 has a vanadium dioxide thin film 12 deposited at the center of its four sides. Specifically, in the horizontal and vertical dimensions, adjacent metasurface units 8 are connected by vanadium dioxide thin films and bent microstrip lines 13.

[0038] The vanadium dioxide thin film has a rectangular or interdigitated shape, but is not limited to these shapes.

[0039] Furthermore, the side length a of the metasurface unit 8 is 0.01λ to λ, the side length c of the central rectangular patch 9 is 0.005λ to 0.5λ, the side length b of the rectangular patches 10 located at the four corners is 0.001λ to 0.1λ, the dimensions w2 of the gradient microstrip line 11 are 0.0005λ to 0.05λ, w3 is 0.001λ to 0.1λ, the width w1 of the bent microstrip line is 0.0005λ to 0.05λ, the width g_c of the vanadium dioxide thin film 12 is 0.0005λ to 0.05λ, and the gap g between the rectangular patches 10 located at the four corners of the metasurface unit and the outer periphery of the unit is 0.001λ to 0.1λ, where λ is the free space wavelength corresponding to the center frequency.

[0040] Furthermore, a metal ground plane 4 is printed on the upper surface of the second dielectric substrate 2, and coupling gaps 5 are etched on the metal ground plane 4. The second dielectric substrate 2 is provided with an SIW feed structure 6, and the SIW feed structure 6 is connected to the microstrip line structure 7.

[0041] Further, the center point of the metasurface structure 3 coincides with the center point of the first dielectric substrate 1, and the long and wide arrangement directions of the metasurface units 8 each have an included angle of 45 degrees with the length direction of the coupling slot 5.

[0042] As shown in Figure 6 particular, the coupling slot is a straight line slot, which is located in the SIW feed structure. The SIW feed structure is a right-angle U-shaped structure composed of metal cylinders, and is connected with the microstrip line structure through a transition structure 15.

[0043] The dimensions of each structure are as follows:

[0044] The dielectric constant ε r of the first dielectric substrate 1 is 2-20, the length a_sap is 0.1λ-3λ, the width b_sap is 0.1λ-3λ, and the thickness H1 is 0.01λ-0.1λ, where λ is the free space wavelength corresponding to the center frequency.

[0045] The dielectric constant ε r of the second dielectric substrate 2 is 2-20, the length a_pcb is 0.5λ-5λ, the width b_pcb is 0.1λ-3λ, and the thickness H2 is 0.01λ-0.1λ, where λ is the free space wavelength corresponding to the center frequency.

[0046] The length of the metal ground plate 4 is 0.5λ-5λ, and the width is 0.1λ-3λ, where λ is the free space wavelength corresponding to the center frequency.

[0047] The length l_slot of the coupling slot 5 is 0.05λ-λ, and the width w_slot is 0.001λ-0.1λ, where λ is the free space wavelength corresponding to the center frequency.

[0048] The length l_siw of the SIW feed structure 6 is 0.05λ-λ, the width w_siw is 0.05λ-λ, and the diameter dv of the metal cylinder used is 0.001λ-0.1λ, where λ is the free space wavelength corresponding to the center frequency.

[0049] The width w_m of the microstrip line structure 7 is 0.001λ-0.1λ, where λ is the free space wavelength corresponding to the center frequency.

[0050] There are two symmetrically placed metal cylinders 14 in the SIW feed structure 6 for impedance matching, and the diameter d_v2 of the metal cylinder 14 is 0.001λ-0.1λ, where λ is the free space wavelength corresponding to the center frequency.

[0051] The transition structure 15 is used to connect the SIW feed structure 6 and the microstrip line structure 7, and the width w_m2 of the transition structure 15 is 0.01λ-λ, where λ is the free space wavelength corresponding to the center frequency.

[0052] The specific dimensions in the embodiment are as follows:

[0053] The side length a of the metasurface unit 8 is 1 mm, the side length c of the central rectangular patch 9 is 0.32 mm, the side length b of the rectangular patch 10 at the four corners is 0.095 mm, the size w2 of the tapered microstrip line 11 is 0.02 mm, w3 is 0.04 mm, the width w1 of the bent microstrip line 13 is 0.015 mm, the width g_c of the vanadium dioxide film 12 is 0.02 mm, and the gap g between the rectangular patch 10 at the four corners of the metasurface unit and the unit periphery is 0.03 mm. The specific length and width can be set according to the frequency requirement of the polarization reconstruction required.

[0054] The material of the first dielectric substrate 1 is sapphire (Al2O3), the dielectric constant ε r is 9.6, the thickness is 0.5 mm, the length a_sap is 6.5 mm, the width b_sap is 6.5 mm, and the thickness H1 is 0.5 mm.

[0055] The material of the second dielectric substrate 2 is Rogers 6010, the dielectric constant ε r is 10.2, the thickness is 0.254 mm, the length a_pcb is 7.9 mm, the width b_pcb is 6.5 mm, and the thickness H1 is 0.5 mm.

[0056] The length of the metal ground plate 4 is 7.9 mm, and the width is 6.5 mm. The metal ground plate 4 needs to completely cover the upper surface of the second dielectric substrate 2.

[0057] The length l_slot of the coupling slot 5 is 3.7 mm, and the width w_slot is 0.14 mm. The length of the coupling slot 5 needs to be adjusted according to the working frequency and impedance matching. The position of the coupling slot 5 in the SIW feed structure 6 needs to be adjusted according to the need of impedance matching. In the embodiment, the center line of the coupling slot 5 is 0.645 mm away from the upper edge of the SIW feed structure 6.

[0058] The length l_siw of the SIW feed structure 6 is 2.15 mm, and the width w_siw is 3.95 mm. The diameter dv of the metal column used is 0.2 mm. The size of the SIW feed structure and the size of the metal column used are adjusted according to the working frequency.

[0059] The width w_m of the microstrip line structure 7 is 0.25 mm, and the width of the microstrip line needs to be adjusted according to the need of impedance matching.

[0060] The diameter d_v2 of the adjusting matching metal column 14 is 0.3 mm, and the position and diameter of the metal column need to be adjusted according to the need of impedance matching adjustment.

[0061] The width w_m2 of the transition structure 15 is 1.2 mm, and the width of the transition structure needs to be adjusted according to the need of impedance matching.

[0062] The G1 direction is the positive 45-degree diagonal direction of the first dielectric substrate, and the G2 direction is the negative 45-degree diagonal direction of the first dielectric substrate.

[0063] Figures 7-10 The performance of the application in the left-handed circular polarization state is shown, when the vanadium dioxide film in the G1 direction on the metasurface unit 8 is a conductor and the vanadium dioxide film in the G2 direction is an insulator, the antenna operates at 29 GHz, and the polarization mode is left-handed circular polarization. Figure 7 The reflection coefficient and gain curve of the application in the left-handed circular polarization state is shown, and the working bandwidth with a reflection coefficient lower than 10 dB is 28-29.8 GHz, the relative bandwidth is 6.22%, and the maximum gain is 6.5 dBi; Figure 8 The axial ratio curve of the application in the left-handed circular polarization state is shown, and the working bandwidth with an axial ratio lower than -3 dB is 28.6-29.5 GHz (3.1%). Figure 9 The radiation pattern of the application in the left-handed circular polarization state is shown, and the radiation pattern is somewhat asymmetric, because the symmetry axis of the metasurface structure 3 and the symmetry axis of the rest of the antenna have a 45-degree angle.

[0064] When the vanadium dioxide film in the G1 direction on the metasurface unit 8 is an insulator and the vanadium dioxide film in the G2 direction is a conductor, the antenna operates at 29 GHz, and the polarization mode is right-handed circular polarization. Since the left-handed circular polarization state and the right-handed circular polarization state are symmetrical to each other, the reflection coefficient curve, the gain curve and the axial ratio curve of the antenna in the right-handed circular polarization state are consistent with those in the left-handed circular polarization state, and the radiation pattern of the antenna in the right-handed circular polarization state is the polarization interchanged radiation pattern of the antenna in the left-handed circular polarization state.

[0065] Figures 10-11 The performance of the application in the linear polarization state is shown, when the vanadium dioxide films in the G1 and G2 directions on the metasurface unit 8 are both insulators, the antenna operates at 30 GHz, and the polarization mode is linear polarization. Figure 10For the reflection coefficient and gain curve of the application in the linear polarization state, it can be seen that the operating bandwidth with the reflection coefficient below 10dB is 29.6-30.3GHz (2.3%), and the maximum gain is 7dBi; Figure 11 For the radiation pattern of the application in the linear polarization state, it can be seen that the radiation pattern is relatively symmetrical, and the cross-polarization and front-back ratio are good.

[0066] Specifically, the low-profile polarization reconfigurable millimeter wave antenna based on the vanadium dioxide film in the embodiment is applied to the metasurface structure by using the VO2 film, a metasurface structure capable of realizing polarization reconfiguration is designed, and finally the structure is used in the millimeter wave antenna, low-profile structure is used for feeding, a low-profile polarization reconfigurable millimeter wave antenna is realized, and the low-profile polarization reconfigurable millimeter wave antenna is suitable for millimeter wave polarization reconfigurable antenna design.

[0067] The above embodiment is a preferred embodiment of the application, but the embodiments of the application are not limited by the above-mentioned embodiments, and any changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principles of the application shall be equivalent replacement modes and shall be included in the protection scope of the application.

Claims

1. A low profile polarisation reconfigurable millimeter wave antenna based on vanadium dioxide thin film, characterized in that, The first dielectric substrate and the second dielectric substrate are arranged in a stack, a metal metasurface structure is printed on the upper surface of the first dielectric substrate, and a metal floor is printed on the upper surface of the second dielectric substrate; The metal metasurface structure comprises M*N super surface units arranged in an array, each super surface unit comprises a central rectangular patch and four rectangular patches at four corners, the central rectangular patch is connected to the four rectangular patches at four corners through a gradient microstrip line, a vanadium dioxide film is arranged between the central rectangular patch and the bent microstrip line, the central rectangular patch is connected through the vanadium dioxide film and the bent microstrip line, the vanadium dioxide film is connected to an adjacent super surface unit through the bent microstrip line, and the vanadium dioxide film is arranged in the positive 45° diagonal direction and the negative 45° diagonal direction of the first dielectric substrate.

2. The low-profile polarisation reconfigurable mmWave antenna according to claim 1, wherein, When the vanadium dioxide film in the positive 45° diagonal direction is a conductor and the vanadium dioxide film in the negative 45° diagonal direction is an insulator, the polarization mode of the antenna is left-handed circular polarization. When the vanadium dioxide film in the positive 45° diagonal direction is an insulator and the vanadium dioxide film in the negative 45° diagonal direction is a conductor, the polarization mode of the antenna is right-handed circular polarization. When the vanadium dioxide films in the two directions are both insulators, the polarization mode of the antenna is linear polarization.

3. The low-profile polarisation reconfigurable mmWave antenna according to claim 1, wherein, The vanadium dioxide film is arranged between the central rectangular patch and the bent microstrip line.

4. The low-profile polarisation reconfigurable mmWave antenna of claim 1, wherein, The metal floor is etched with a coupling gap.

5. The low-profile polarisation reconfigurable mmWave antenna according to claim 4, wherein, The coupling gap is a linear gap, and the length direction of the linear gap is at an angle of 45 degrees with the length direction of the metal metasurface structure.

6. The low-profile polarisation reconfigurable mmWave antenna according to any of claims 1-5, characterised in that, The second dielectric substrate is provided with an SIW feeding structure.

7. The low-profile polarisation reconfigurable mmWave antenna according to claim 6, wherein, Two metal columns are symmetrically arranged in the SIW feeding structure.

8. The low-profile polarisation reconfigurable mmWave antenna of claim 6, wherein, The SIW feeding structure is connected to a microstrip line structure through a transition structure.

9. The low-profile polarisation reconfigurable mmWave antenna of claim 6, wherein, A coupling gap is arranged in the SIW feeding structure.

10. A communication device, characterized by The low-profile polarization reconfigurable millimeter wave antenna comprises the low-profile polarization reconfigurable millimeter wave antenna according to any one of claims 1-9.

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