Broadband circularly polarized antenna based on metasurface and dielectric resonant cavity dual multiplexing technology

Abstract

The invention relates to the technical field of antennas, in particular to a broadband circularly polarized antenna based on a metasurface and dielectric resonant cavity dual multiplexing technology. The antenna comprises a dielectric substrate, a dielectric resonator and a metasurface, the metasurface comprises a plurality of asymmetrical metasurface units distributed in a matrix mode, each asymmetrical metasurface unit comprises a circular ring metasurface part and an asymmetrical cross metasurface part, and each asymmetrical cross metasurface part comprises a first strip-shaped part and a second strip-shaped part. The width of the first strip-shaped part is smaller than that of the second strip-shaped part, the two ends of the first strip-shaped part penetrate through the circular ring metasurface part, and the length of the second strip-shaped part is smaller than the diameter of the inner side of the circular ring metasurface part. According to the broadband circularly polarized antenna based on the metasurface and dielectric resonant cavity dual-multiplexing technology, the axial ratio bandwidth performance of the antenna is further improved through the metasurface and dielectric resonant cavity dual-multiplexing technology and introduction of the asymmetric cross-shaped metasurface part to the circular ring metasurface part, and the actual application requirement of the antenna is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antennas, and particularly relates to a wideband circularly polarized antenna based on a metasurface and a dielectric resonant cavity dual multiplexing technology. BACKGROUND

[0002] With the rapid development of emerging application fields such as radio frequency energy collection, global navigation satellite system and Internet of Things, not only the iteration and upgrading of wireless communication technology are promoted, but also high performance requirements are put forward for antennas as key components of wireless systems. At present, the important indicators of scholars studying antennas mainly focus on wide bandwidth, circular polarization, low power consumption, miniaturization and the like.

[0003] Due to the continuous improvement of the data transmission rate requirement of modern communication systems and the present situation of the increasingly scarce available frequency band resources, wideband has become an inevitable development direction of antenna design. This trend puts forward more strict requirements for the frequency band characteristics of the antenna, especially the realization of a wider effective working bandwidth to meet the demand of high-speed transmission. Compared with using multiple narrowband antennas to meet the wideband demand, the wideband antenna has obvious advantages, which can avoid the problems such as complex structure and reduced communication quality caused by multiple antenna combination.

[0004] However, electromagnetic waves will be disturbed by various factors in the actual propagation process. When the electromagnetic signal propagates through the ionosphere, its polarization direction will be deflected due to the Faraday effect. At the same time, meteorological phenomena such as precipitation and cloud will cause different degrees of signal attenuation. When propagating near the ground, part of the electromagnetic wave will be reflected and scattered when encountering obstacles such as buildings and vegetation, which makes the receiving end not only receive the direct wave, but also receive the reflected wave and scattered wave propagated through different paths. This multi-path propagation effect will cause signal interference, and ultimately lead to the reduction of the accuracy of the received signal. In the satellite communication system, when the electromagnetic wave passes through the ionosphere, the polarization angle of the electromagnetic wave is deflected, and the influence on the low-frequency electromagnetic wave is particularly obvious. In the face of the above more complex application scenarios, due to the obvious directionality, polarization mismatch sensitivity and weak anti-interference ability of the linearly polarized antenna, it has gradually been unable to meet the system requirements, and the use of an antenna capable of radiating or receiving circularly polarized waves can better solve these problems. The circularly polarized antenna has many advantages, as a receiver, it can receive electromagnetic waves of any polarization direction, as a transmitter, the circularly polarized wave it transmits can be received by various linearly polarized antennas, has polarization insensitive and rotational orthogonal characteristics, can avoid polarization mismatch, suppress rain and fog interference and resist multipath fading, and is suitable for satellite communication systems.

[0005] However, the axial ratio bandwidth performance of the current wideband circularly polarized antenna needs to be improved to meet the actual application requirements of the antenna, such as being applied to a high-data wireless communication system with limited space. SUMMARY

[0006] The application aims to provide a wideband circularly polarized antenna based on a metasurface and dielectric resonant cavity dual multiplexing technology to solve the above technical problems.

[0007] To achieve the above-mentioned purpose, the application provides a wideband circularly polarized antenna based on a metasurface and dielectric resonant cavity dual multiplexing technology, which comprises a dielectric substrate, a dielectric resonator arranged on the dielectric substrate, a metasurface arranged on the top of the dielectric resonator, the metasurface comprising a plurality of asymmetric metasurface units arranged in a matrix, the asymmetric metasurface unit comprising a circular ring metasurface part and an asymmetric cross metasurface part, the asymmetric cross metasurface part comprising two first and second strip-shaped parts arranged vertically, the width of the first strip-shaped part being smaller than the width of the second strip-shaped part, and the two ends of the first strip-shaped part penetrating through the circular ring metasurface part, the length of the second strip-shaped part being smaller than the inside diameter of the circular ring metasurface part.

[0008] Preferably, the length and width of the asymmetric metasurface unit are 6.8 mm and 6.1 mm, and the metasurface is provided with 4*4 asymmetric metasurface units arranged in a matrix.

[0009] Preferably, the outside diameter of the circular ring metasurface part is 5.4 mm, and the inside diameter of the circular ring metasurface part is 3.4 mm. The width and length of the first strip-shaped part are 0.3 mm and 6.4 mm respectively, and the inclination angle of the first strip-shaped part is 45°.

[0010] The width and length of the second strip-shaped part are 1 mm and 2.5 mm respectively.

[0011] Preferably, the dielectric resonator is rectangular, and the length and width thereof are 30 mm and 28.5 mm respectively.

[0012] Preferably, a parasitic patch is printed on each of the two adjacent side walls of the dielectric resonator, the width of the parasitic patch is 2.9 mm, the length of one of the parasitic patches is 34 mm, and the length of the other parasitic patch is 37 mm.

[0013] Preferably, a coupling groove is arranged on the ground plane between the dielectric resonator and the dielectric substrate, the coupling groove is a rectangle with two symmetrical cut angles, the length and width of the rectangle are 11.1 mm and 9.6 mm respectively, and the lengths of the two straight sides of the cut angle are 6.5 mm and 5.3 mm respectively.

[0014] Preferably, a feeding microstrip line is printed on the back of the dielectric substrate, one end of the feeding microstrip line is electrically connected to the coupling groove, and the length and width of the feeding microstrip line are 21.2 mm and 2.1 mm respectively.

[0015] Therefore, the broadband circularly polarized antenna based on the dual multiplexing technology of metasurface and dielectric resonator of the present invention has the following beneficial effects: It employs dual multiplexing of dielectric resonator and metasurface, and simultaneously introduces a cross-shaped metasurface portion into the circular metasurface section to form an asymmetric metasurface unit, generating non-uniform surface impedance, thereby exciting orthogonal current components and forming a 90° phase difference, achieving polarization reversal from linear polarization to circular polarization. At 6.5 GHz, a new minimum axial ratio is introduced, effectively widening the antenna's axial ratio bandwidth while ensuring a low profile and simple structure. The axial ratio bandwidth performance of this application is 26.43% (4.99-6.51 GHz), which is 3.97 percentage points higher than that of a single-ring metasurface structure, and the impedance bandwidth is 35.29% (4.55~6.5 GHz), meeting the practical application requirements of the antenna.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a structural diagram of a broadband circularly polarized antenna based on dual multiplexing technology of metasurface and dielectric resonator according to the present invention; Figure 2 This is a schematic diagram of the dielectric resonator structure of the present invention; Figure 3 This is a side view of a broadband circularly polarized antenna based on a metasurface and dielectric resonator dual multiplexing technique; Figure 4 This is a schematic diagram of an asymmetric metasurface unit structure; Figure 5 The diagram shows the structure of the asymmetric metasurface unit for the control group. (a) shows the part with a ring-shaped metasurface; (b) shows the part with a ring-shaped metasurface plus the first strip; and (c) shows the part with a ring-shaped metasurface plus the second strip. Figure 6 The following are the performance curves for control group 2, control group 3, and this embodiment: (a) is the input return loss curve; (b) is the antenna axial ratio curve. Figure 7 For the polarized torsional metasurface of this embodiment, Γ TE / TM and Г TM / TM The amplitude and phase curves; (a) is the amplitude curve; (b) is the phase curve; Figure 8 For the polarized torsional metasurface with different tilt angles of the first stripe in this embodiment, the Γ TE / TM and Г TM / TM The amplitude curve; Figure 9The curve is an axial ratio curve of different lengths of the first strip part and the second strip part of the embodiment; (a) is an axial ratio curve of different lengths of the first strip part; (b) is an axial ratio curve of different lengths of the second strip part; Figure 10 The figure is a graph of the return loss parameter changing with frequency simulated and tested in the embodiment; Figure 11 The figure is a graph of the axial ratio parameter changing with frequency simulated and tested in the embodiment; Figure 12 The figures are patterns simulated in the embodiment at 5.15 GHz; (a) is a pattern in the xoz plane; (b) is a pattern in the yoz plane; Figure 13 The figures are patterns simulated in the embodiment at 5.75 GHz; (a) is a pattern in the xoz plane; (b) is a pattern in the yoz plane; Figure 14 The figures are patterns simulated in the embodiment at 6.1 GHz; (a) is a pattern in the xoz plane; (b) is a pattern in the yoz plane; Figure 15 The figures are patterns simulated in the embodiment at 6.5 GHz; (a) is a pattern in the xoz plane; (b) is a pattern in the yoz plane; Reference signs 1, dielectric substrate; 2, dielectric resonator; 3, asymmetric metasurface unit; 31, circular ring metasurface part; 32, asymmetric cross metasurface part; 321, first strip part; 322, second strip part; 4, parasitic patch; 5, coupling slot; 6, feed microstrip line; 7, ground plane. DETAILED DESCRIPTION

[0018] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0019] The embodiments of the present application will be described in detail below with reference to the drawings.

[0020] As shown in Figure 1 A wideband circularly polarized antenna based on metasurface and dielectric resonant cavity dual multiplexing technology, comprising a dielectric substrate 1, a dielectric resonator 2 is arranged on the dielectric substrate 1, and a metasurface is arranged on the top of the dielectric resonator 2, and a dielectric resonator 2 and a metasurface dual multiplexing technology is adopted. As shown in Figure 2 and Figure 3 The dielectric resonator 2 is rectangular and the length and width are 30mm and 28.5mm respectively, and the two adjacent side walls of the dielectric resonator 2 are printed with parasitic patches 4, the width of the parasitic patch 4 is 2.9mm, and the length of one of the parasitic patches 4 is 34mm, and the length of the other parasitic patch 4 is 37mm. The parasitic patch 4 is equivalent to an ideal electric conductor. When electromagnetic waves interact with the surface of the ideal electric conductor, the current excited on the surface of the parasitic patch 4 will generate two mutually perpendicular linear polarization field components. The two polarization fields exhibit a phase difference of 90° in space, forming orthogonal linear polarization fields, and a new axial ratio minimum point is generated at 5.75GHz, thereby forming an axial ratio passband. A coupling slot 5 is provided on the ground plane 7 between the dielectric resonator 2 and the dielectric substrate 1, the coupling slot 5 is a rectangle with two symmetrical cut angles, the length and width of the rectangle are 11.1mm and 9.6mm respectively, and the lengths of the two straight angles of the cut angle are 6.5mm and 5.3mm respectively. The dielectric resonator 2 is excited through the coupling slot 5, and approximately degenerate TE 111 modes are generated. By multiplexing the dielectric resonator 2 and loading the metasurface above it, the bandwidth is significantly improved and the profile is reduced. The back of the dielectric substrate 1 is printed with a feeding microstrip line 6, the feeding microstrip line 6 feeds the dielectric resonator 2 through the coupling slot 5 etched on the ground plane, and the length and width of the feeding microstrip line 6 are 21.2mm and 2.1mm respectively.

[0021] The coupling slot 5 at the bottom of the initial rectangular structure of the dielectric resonator 2 antenna is cut at an angle, and the coupling electric field of the oblique cut angle slot can be decomposed into two different orthogonal components and , thereby exciting two approximately degenerate TE x 111 and TE y 111 modes, which resonate at 4.6GHz and 5.3GHz respectively, forming an impedance bandwidth of 4.43-5.61GHz, and generating a circular polarization performance of 5.15GHz between the two resonances. The coupling slot 5 is placed obliquely relative to the dielectric resonator 2 to achieve wideband and circularly polarized radiation.

[0022] To further improve the axial ratio bandwidth performance of the antenna, the metasurface comprises a plurality of matrix-distributed asymmetric metasurface units 3, the length and width of the asymmetric metasurface unit 3 are 6.8 mm and 6.1 mm, and the asymmetric metasurface unit 3 is provided with 4*4 matrix distribution. As shown in Figure 4 , the asymmetric metasurface unit 3 comprises a circular ring metasurface part 31 and an asymmetric cross metasurface part 32, the outer diameter of the circular ring metasurface part 31 is 5.4 mm, and the inner diameter of the circular ring metasurface part 31 is 3.4 mm. The asymmetric cross metasurface part 32 comprises two first strip parts 321 and second strip parts 322 arranged vertically, the width of the first strip part 321 is smaller than the width of the second strip part 322, and the two ends of the first strip part 321 pass through the circular ring metasurface part 31, and the length of the second strip part 322 is smaller than the inner diameter of the circular ring metasurface part 31. The width and length of the first strip part 321 are 0.3 mm and 6.4 mm respectively, and the width and length of the second strip part 322 are 1 mm and 2.5 mm respectively. The dielectric resonator 2 works in two orthogonal TM 10 and TM 01 modes with a phase difference of 90° at 6.5 GHz, a new axial ratio minimum value is generated, the impedance bandwidth is widened, and the metasurface effectively reduces the profile height of the antenna. The asymmetric metasurface unit 3 composed of the asymmetric cross metasurface part 32 and the circular ring metasurface part 31 can reduce the size and simplify the structure. Since the asymmetric cross metasurface part 32 is an asymmetric structure, the surface impedance of the asymmetric metasurface unit 3 is unbalanced, which further widens the axial ratio bandwidth without increasing the size of the antenna.

[0023] To verify the technical effects of the technical scheme of the embodiment, the following comparative tests are carried out.

[0024] As shown in Figure 5 , the three control groups are respectively only with a circular ring metasurface part (control group one), with a circular ring metasurface part + a first strip part (control group two), and with a circular ring metasurface part + a second strip part (control group three). The control group two and the control group three are respectively loaded on the metasurface in the direction and the direction on the basis of the symmetric circular ring metasurface unit.

[0025] The embodiment has a circular ring metasurface part 31 + a first strip part 321 + a second strip part 322, and the branch is loaded on the metasurface in the and two directions.

[0026] Control group one: the symmetric circular ring metasurface structure has a minimum axial ratio of 1.2 at 6.5 GHz, and the axial ratio bandwidth is 0.2 GHz. Control group two: the axial ratio minimum value of the circular ring metasurface part + the first strip part is 1.1 at 6.5 GHz, and the axial ratio bandwidth is 0.3 GHz. The surface impedance characteristics are completely symmetrical in the direction, which cannot meet the requirements of polarization conversion.

[0027] like Figure 6 As shown in (a), the middle branch along Oriented metasurface structures achieve the widest impedance bandwidth, such as Figure 6 As shown in (b), the branch along direction and The asymmetric metasurface elements along the direction did not form a continuous 3dB axial ratio bandwidth, but instead used stubs along... and Two-directional asymmetric metasurface elements 3 generate a 3dB axial ratio bandwidth of 4.98–6.56 GHz. The performance comparison of the three metasurface structures demonstrates that to achieve good impedance bandwidth characteristics while maintaining wideband circular polarization performance, it is necessary to… and Applying branches in two directions simultaneously creates a rotation angle. θ The 45° oblique cross-shaped structure, i.e. the asymmetric metasurface unit structure of this embodiment, forms an unbalanced impedance in the y-direction.

[0028] To further verify the polarization conversion principle of the asymmetric metasurface unit 3 structure in this embodiment, the electromagnetic reflection characteristics of the proposed polarization conversion metasurface structure were simulated and analyzed using the Floquet port periodic boundary condition in AnsysHFSS electromagnetic simulation software.

[0029] like Figure 7 The figure shown is Γ of a polarized torsional metasurface. TE / TM and Г TM / TM The amplitude and phase curves. For example... Figure 7 As shown in (a), in the frequency range of 6.7~7.1 GHz, Γ TM / TM The amplitude is less than -10dB, while Γ TE / TM The amplitude is greater than -10dB; this frequency band is the polarization torsion bandwidth. Within this operating frequency band, Γ TM / TM The low value indicates that when a TM-polarized wave is incident, the TM component, which is in the same direction as the incident wave, is significantly suppressed, while the Γ component... TE / TM The high value indicates that the TE polarization component perpendicular to the incident wave is excited in the reflected wave. This result fully demonstrates that when a TM polarized wave is incident, the designed metasurface structure can achieve polarization direction reversal, converting the TM polarized wave into a TE polarized wave.

[0030] Depend on Figure 7 The phase curve shown in (b) indicates that at a frequency of 6.5 GHz, Γ TE / TMThe reflection phase reaches 90°, which indicates that the electric field components of the reflected wave and the incident wave are polarized orthogonally and there is a phase difference of 90° under the action of the asymmetric metasurface unit 3 in the embodiment, proving that the synthetic field formed by the reflected wave and the incident wave realizes circularly polarized radiation.

[0031] To verify the influence of the tilt angle of the first strip part on the antenna performance, performance tests are conducted with different angles, as shown in Figure 8 The geometric asymmetry of the asymmetric metasurface unit 3 reaches the best polarization conversion state when the tilt angle of the first strip part 321 is 45°.

[0032] To verify the influence of the length of the first strip part 321 ( ) and the length of the second strip part 322 ( ) on the antenna performance, as shown in Figure 9 With the increase of , there is no obvious change to the minimum points of the first and second axial ratios, but there is obvious change to the minimum points of the third and fourth axial ratios, and the antenna obtains the best axial ratio bandwidth performance when = 2.5 mm. With different values of , there is significant influence on the minimum point of the fourth axial ratio, and when is 6.2 mm or 6.6 mm, a frequency range with an axial ratio greater than 3 dB is generated, which does not meet the circular polarization condition. Therefore, the widest axial ratio bandwidth can be achieved when is 6.4 mm.

[0033] As shown in Figure 10 and Figure 11 , the return loss parameter and the axial ratio parameter of the antenna simulation and test of the embodiment vary with frequency, and it can be known from the figures that the antenna with the technical scheme adopted in the embodiment works at 4.4 GHz~6.63 GHz, and 4.98 GHz~6.56 GHz is circularly polarized radiation.

[0034] As shown in Figure 12 , Figure 13 , Figure 14 and Figure 15 , the embodiment provides good right-handed circularly polarized radiation at 5.15 GHz, 5.75 GHz, 6.1 GHz and 6.5 GHz.

[0035] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can still be modified or equivalently replaced, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A broadband circularly polarized antenna based on metasurface and dielectric resonant cavity dual multiplexing technology, comprising a dielectric substrate, a dielectric resonator is arranged on the dielectric substrate, and a metasurface is arranged on the top of the dielectric resonator, characterized in that: The super surface comprises a plurality of asymmetric super surface units arranged in a matrix, each asymmetric super surface unit comprising a circular ring super surface part and an asymmetric cross super surface part, the asymmetric cross super surface part comprising two first and second strip parts arranged perpendicularly, the first strip part having a width smaller than that of the second strip part, and the two ends of the first strip part penetrating through the circular ring super surface part, and the length of the second strip part being smaller than the inner diameter of the circular ring super surface part. ​ 2. The wideband circularly polarized antenna based on the dual-multiplexing technology of metasurface and dielectric resonant cavity according to claim 1, characterized in that: The length and width of the asymmetric super surface unit are 6.8 mm and 6.1 mm, and the super surface comprises 4×4 asymmetric super surface units arranged in a matrix.

3. The wideband circularly polarized antenna based on the dual-multiplexing technology of metasurface and dielectric resonant cavity according to claim 1, characterized in that: The outer diameter of the circular ring super surface part is 5.4 mm, and the inner diameter of the circular ring super surface part is 3.4 mm. The width and length of the first strip part are 0.3 mm and 6.4 mm, respectively, and the inclination angle of the first strip part is 45°. The width and length of the second strip part are 1 mm and 2.5 mm, respectively.

4. The wideband circularly polarized antenna based on the dual-multiplexing technology of metasurface and dielectric resonant cavity according to claim 1, characterized in that: The dielectric resonator is rectangular, and the length and width thereof are 30 mm and 28.5 mm, respectively.

5. The wideband circularly polarized antenna based on the dual-multiplexing technology of metasurface and dielectric resonant cavity according to claim 1, characterized in that: Two parasitic patches are printed on the adjacent side walls of the dielectric resonator, and the width of the parasitic patch is 2.9 mm, wherein the length of one parasitic patch is 34 mm, and the length of the other parasitic patch is 37 mm.

6. The wideband circularly polarized antenna based on the dual-multiplexing technology of metasurface and dielectric resonant cavity according to claim 1, characterized in that: A coupling slot is formed on the ground plane between the dielectric resonator and the dielectric substrate, and the coupling slot is a rectangle with two symmetrical cut corners, the length and width of the rectangle being 11.1 mm and 9.6 mm, respectively, and the lengths of the two straight sides of the cut corners being 6.5 mm and 5.3 mm, respectively.

7. The wideband circularly polarized antenna based on the dual-multiplexing technology of metasurface and dielectric resonant cavity according to claim 1, characterized in that: A feeding microstrip line is printed on the back of the dielectric substrate, one end of the feeding microstrip line being electrically connected to the coupling slot, and the length and width of the feeding microstrip line being 21.2 mm and 2.1 mm, respectively.

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