Millimeter wave three-beam all-dielectric lens antenna

Abstract

The invention relates to the technical field of antennas, in particular to a millimeter wave three-beam all-dielectric lens antenna, which comprises a group of 2 * 2 magnetoelectric dipole array antennas and an all-dielectric circular lens structure, the 2 * 2 magnetoelectric dipole array antenna is used as a feed source and is arranged on the plane side of the all-dielectric circular lens structure, and the feed source directly faces the geometric center of the all-dielectric circular lens structure; the all-dielectric circular lens structure has a direction-controllable three-beam radiation capability; through the reasonable medium structure layout, the multi-beam coverage and the frequency point adaptability are considered while high-gain output is ensured, and the contradiction between the performance and the practicability of the existing scheme is overcome.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antennas, in particular to a millimeter wave three-beam all-dielectric lens antenna. BACKGROUND

[0002] Millimeter wave (mmW) frequency bands have been widely used in high-demand scenarios such as automotive radar, 5th generation mobile communication (5G), high-precision imaging and target recognition, due to their advantages of wide frequency band, high data transmission rate and low communication delay. With the growing demand for multi-target, multi-path and large-capacity communication in these fields, traditional antenna systems face severe challenges, especially in the following aspects: First, the current widely used phased array antenna, although it can realize flexible scanning and precise control of the beam, usually relies on complex feed networks and high-cost radio frequency front-ends, especially in the millimeter wave frequency band, the integration of devices and systems is more difficult. This high complexity and high cost greatly limits the practical deployment of phased array antennas in small-sized and low-cost scenarios. Second, in recent years, dielectric lens antennas have gradually become a powerful candidate to replace phased arrays as a passive, simple structure and easy-to-manufacture antenna form. The dielectric lens has good focusing characteristics and can achieve high gain and high directivity of the radiation performance, and realize fixed beam output without the need for electronic control systems. However, most of the current dielectric lens antenna designs only support single-beam output, and the number of beams is limited, which cannot meet the needs of multi-target detection or multi-user communication. In addition, although some existing multi-beam lens antenna schemes try to generate multiple beams through array feed or multi-focus structure, they often have problems such as poor beam direction stability, uneven beam spacing, complex design process or inability to adapt to multiple operating frequencies in the millimeter wave frequency band.

[0003] Based on the above problems, the present application aims to solve the following technical challenges:

[0004] 1. How to generate three output beams that can be used in the 28-40 GHz millimeter wave frequency band without relying on phase arrays or electronic scanning systems;

[0005] 2. How to reduce the complexity and manufacturing cost of the antenna system by designing a structure made entirely of dielectric materials;

[0006] 3. How to ensure that the three generated beams have stable direction and gain to meet the needs of multi-target detection or multi-user communication. SUMMARY

[0007] To solve the above problems, the application provides a millimeter wave three-beam all-dielectric lens antenna, which has simple structure, low processing cost, and can stably output three fixed beams at multiple frequency points of 28-40 GHz. The millimeter wave three-beam all-dielectric lens antenna comprises a group of 2*2 magnetic electric dipole array antennas and an all-dielectric circular lens structure; the 2*2 magnetic electric dipole array antennas are used as a feed source and are arranged on the plane side of the all-dielectric circular lens structure, and the feed source is opposite to the geometric center of the all-dielectric circular lens structure; the all-dielectric circular lens structure has a three-beam radiation capability with controllable direction.

[0008] The feed source is composed of four linearly polarized magnetic electric dipole antenna units, and each linearly polarized magnetic electric dipole antenna unit comprises, from top to bottom, an upper layer substrate, a prepreg and a lower layer substrate; two metal patches are arranged on the upper surface of the upper layer substrate, and the four corners of the metal patches are provided with rectangular cut corners; a rectangular metal sheet is arranged on the lower surface of the upper layer substrate, and the rectangular metal sheet is provided with a coupling gap; the two metal patches are respectively located on the two sides of the coupling gap, and each metal patch is connected to the rectangular metal sheet through three metallized vias; and a microstrip line is arranged on the lower surface of the lower layer substrate.

[0009] The all-dielectric circular lens structure comprises a plurality of dielectric units, each dielectric unit comprises a square dielectric column, and impedance matching structures are arranged at both ends of the square dielectric column; the impedance matching structure comprises four square holes, and the four square holes are arranged in a 2*2 matrix form at equal intervals.

[0010] The application has the following beneficial effects:

[0011] The path compensation phase and the periodic phase are superimposed to accurately control the direction of the radiation beam.

[0012] High dielectric constant low loss materials and 3D printing process are used to realize a low profile and integrated lens structure.

[0013] The antenna has a compact overall structure, high gain, wide band, high directivity, three-beam high isolation and other advantages.

[0014] The antenna design discards the traditional phase shifter or complex feed network, and can realize three-beam simultaneous radiation without scanning mechanism, and is especially suitable for multi-target detection or multi-user millimeter wave communication scenes. Through reasonable dielectric structure layout, the application ensures high gain output while considering multi-beam coverage and frequency point adaptability, and overcomes the contradiction between performance and practicability of the existing scheme. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is the overall structure diagram of the millimeter wave three-beam all-dielectric lens antenna shown in some embodiments of the application;

[0016] Figure 2 is a side view of a millimeter wave three-beam all-dielectric lens antenna according to some embodiments of the present application;

[0017] Figure 3 is a phase distribution diagram according to some embodiments of the present application;

[0018] Figure 4 is a structure diagram of a dielectric unit according to some embodiments of the present application;

[0019] Figure 5 is a phase and amplitude response curve of a dielectric unit according to some embodiments of the present application;

[0020] Figure 6 is a reflection coefficient curve of a dielectric unit according to some embodiments of the present application;

[0021] Figure 7 is a schematic diagram of a magneto-electric dipole antenna unit according to some embodiments of the present application;

[0022] Figure 8 is a current and slot electric field distribution diagram of a linearly polarized magneto-electric dipole antenna operating at 33 GHz according to some embodiments of the present application; (a) t = 0; (b) t = T / 4; (c) t = T / 2; (d) t = 3T / 4;

[0023] Figure 9 is a S11 and gain curve of a linearly polarized magneto-electric dipole antenna according to some embodiments of the present application;

[0024] Figure 10 is a directional diagram of a linearly polarized magneto-electric dipole antenna according to some embodiments of the present application; (a) E-plane 28 GHz; (b) H-plane 28 GHz; (c) E-plane 34 GHz; (d) H-plane 34 GHz;

[0025] Figure 11 is a design diagram of a quartered microstrip feed network and a simulation model diagram of a press-on connector according to some embodiments of the present application;

[0026] Figure 12 is a structure diagram of a millimeter wave 2x2 antenna array according to some embodiments of the present application;

[0027] Figure 13 is a S11 and gain curve of a millimeter wave 2x2 antenna array according to some embodiments of the present application;

[0028] Figure 14 is a simulation directional diagram of a millimeter wave 2x2 antenna array according to some embodiments of the present application;

[0029] Figure 15 is a radiation directional diagram of lens antennas of different frequencies according to some embodiments of the present application;

[0030] Figure 16 are simulation gain and aperture efficiency curves of the three-beam dielectric lens antenna shown in some embodiments of the present application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0032] Figure 1 is an overall structural diagram of a millimeter wave three-beam all-dielectric lens antenna according to some embodiments of the present application. Figure 2 is a side view of a millimeter wave three-beam all-dielectric lens antenna according to some embodiments of the present application.

[0033] Some embodiments of the present application provide a millimeter wave three-beam all-dielectric lens antenna, as shown in Figure 1 The millimeter wave three-beam all-dielectric lens antenna includes a set of 2x2 Ka-band magnetoelectric dipole array antennas and an all-dielectric circular lens structure. The 2x2 magnetoelectric dipole array antennas are set as a feed source on the planar side of the all-dielectric circular lens structure, and the feed source is directly opposite the geometric center of the all-dielectric circular lens structure. The feed source is used to generate a spherical wave signal, and the all-dielectric circular lens structure focuses and converts the spherical wave signal into a plurality of directional plane waves through phase compensation and focusing functions to realize a three-beam directional radiation function.

[0034] In some embodiments, to realize the three-beam radiation function of the all-dielectric circular lens structure, the path compensation phase and the periodic phase superposition are used to design the phase distribution of the aperture of the all-dielectric circular lens structure.

[0035] Path compensation phase design: In order to realize the precise control of the beam pointing, the all-dielectric circular lens structure adopts an array design and is composed of a plurality of regularly arranged dielectric units. Each dielectric unit includes a square dielectric column and an impedance matching structure arranged at both ends of the square dielectric column. The path compensation phase of each dielectric unit is designed according to Fermat's principle, that is, the electromagnetic path length from the feed source to the dielectric unit is equal, so as to realize the transformation of the spherical wave into the plane wave and improve the beam directivity and gain. The transmission phase of the dielectric unit can be calculated by the following formula:

[0036] (1)

[0037] In the formula, φc(i) represents the path compensation phase of the i-th dielectric unit, (x m ,y n ) represents the center coordinate of the i-th dielectric unit, wherein the dielectric units are regularly arranged to form a full dielectric circular lens structure, m represents the m-th row in the full dielectric circular lens structure, n represents the n-th column in the full dielectric circular lens structure, that is, the i-th dielectric unit is located in the m-th row and the n-th column of the full dielectric circular lens structure; k0 represents the free space wave number, R i represents the distance from the phase center of the feed to the i-th dielectric unit, φ i represents the beam azimuth angle, and θ represents the beam elevation angle.

[0038] Periodic phase design: based on the array antenna theory, in order to obtain the radiation patterns with three beams respectively in directions of -β c , 0° and +β c , a periodic phase modulation needs to be introduced on the surface of the millimeter wave three-beam dielectric lens antenna, wherein β is a target angle. The far-field electric field is expressed as follows:

[0039] (2)

[0040] In the formula, F (θ) represents the far-field electric field at the direction θ, n represents the n-th column in the full dielectric circular lens structure, A i represents the amplitude value of the i-th column of dielectric units, and d represents the unit spacing. In order to ensure the quality of the three-beam radiation pattern, the following conditions need to be met:

[0041] The amplitudes of the three beams in the directions of ±β and 0° are equal, that is,

[0042] (3)

[0043] The first-order derivatives of the amplitudes of the three beams in the directions of ±β c and 0° are zero (extreme points), that is,

[0044] (4)

[0045] Comprehensively considering, given the unit spacing d and the target angle β c , the phase difference φc can be solved to realize the direction control and amplitude balance of the three beams. Wherein, in order to achieve the target angle β c = 28°, the same value needs to be reached for every two adjacent columns of dielectric units in the full dielectric circular lens structure, and thus the two columns of dielectric units are regarded as one column, so d = 2 × p, that is, twice the side length p of the square dielectric column.

[0046] In some embodiments, the present specification adopts a fast modeling method based on the HFSS-MATLAB-API tool library to model the all-dielectric circular lens structure, the design unit spacing d = 4.9 mm, and the phase difference of adjacent dielectric units φc = 120°. The top view of the all-dielectric circular lens structure is shown in Figure 3 The path compensation phase distribution calculated using formula (1) is shown in Figure 3 (a); the periodic phase distribution calculated using formula (2) is shown in Figure 3 (b); and the superimposed phase distribution of the two components is shown in Figure 3 (c). Wherein, the abscissa represents the x coordinate of the lens array, the ordinate represents the y coordinate of the lens array, and the numbers 0-350 represent the realized transmission phase. All results are obtained by numerical analysis using MATLAB. The design results show that the unit spacing mainly determines the beam angle, and the periodic phase difference determines the power distribution between the beams.

[0047] Figure 4 is a dielectric unit structure diagram according to some embodiments of the present specification.

[0048] In some embodiments, the dielectric unit structure provided by the present specification is shown in Figure 4 Each dielectric unit includes a square dielectric column, 4 square holes of the same size are introduced into the two ends of the square dielectric column respectively, and an impedance matching structure (i.e. impedance matching layer, AR structure) is constructed at the two ends of the square dielectric column respectively; the impedance matching structure is used to reduce interface reflection and improve transmission efficiency. The 4 square holes in the impedance matching structure are arranged in a 2x2 matrix form at equal intervals. The square dielectric column and the impedance matching structure are both square cross-section structures, the side length of each square hole is w, and the height is t; the side length of each square dielectric column is p, and the height is h. The dielectric unit has both radiation function and phase control function, without the need for additional phase shifters, thereby significantly reducing the overall array height of the antenna, and having the advantages of compact structure and simple processing.

[0049] The plurality of dielectric units in the all-dielectric circular lens structure are arranged in a regular and compact structure, which is beneficial to the later mechanical processing and system integration. The heights of all dielectric units are not completely the same.

[0050] In some embodiments, the medium unit is prepared by 3D printing technology using PREPERM® TP20280 material. The PREPERM® TP20280 material has a dielectric constant of 4.4 and a loss tangent of 0.004, and has good dielectric properties and low loss characteristics near the frequency of 30 GHz. To verify the electromagnetic performance of the medium unit, a full-wave simulation tool ANSYS HFSS is used for modeling and optimization. In the simulation, the medium unit structure is periodically arranged in the x and y directions, and the Floquet port is used for excitation to simulate the condition of infinite periodic array. By setting the periodic boundary condition, each medium unit is equivalent to a part of the infinite homogeneous array, so as to more accurately reflect the electromagnetic response of the actual lens working. Through optimization analysis, w = 1.75 mm, t = 1.5 mm, and p = 4.9 mm. Figure 5 The phase and amplitude response curves of the medium unit at 34 GHz are shown; Figure 6 The reflection coefficient curve of the medium unit at 34 GHz is shown (S21 (dB) represents the insertion loss of the medium unit, the vertical coordinate represents the transmission phase of the medium unit, the black diagonal line represents the phase response curve of the medium unit during simulation verification, and the red curve represents the amplitude response curve of the medium unit). The simulation results show that at the frequency of 34 GHz:

[0051] a) The reflection coefficient is lower than -17 dB, indicating that the unit has good impedance matching performance;

[0052] b) The transmission coefficient is better than -0.5 dB, which proves that the electromagnetic energy can well penetrate the structure for effective radiation;

[0053] c) The transmission phase of the medium unit changes with the height, and in the range of height h from 3.7 mm to 12.6 mm, a complete 0 to 2π phase shift range is realized, which can meet the requirements of beam shaping and multi-beam forming.

[0054] In addition, the size of the adjacent medium unit changes smoothly, meeting the quasi-continuity requirement, and can effectively approximate the ideal lens phase distribution.

[0055] Figure 7 is a schematic diagram of a magneto-electric dipole antenna unit according to some embodiments of the present specification.

[0056] In some embodiments, the feed source is composed of 4 linearly polarized magneto-electric dipole antenna units, and the linearly polarized magneto-electric dipole antenna unit is realized based on the standard PCB process. As shown in Figure 7As shown, the linearly polarized magnetic and electric dipole antenna unit is composed of two layers of CFG220LZ microwave substrates with a dielectric constant of 2.2 and a loss tangent of 0.0021. The two layers of substrates are bonded by a CT235F prepreg without air gap. The upper substrate (substrate I) has a thickness of 1.524 mm, and the lower substrate (substrate II) has a thickness of 0.127 mm. Two symmetrical metal patches are arranged on the surface of the upper substrate, and the four corners of the patches are cut into rectangular corners, and are connected to the metal ground layer at the bottom of the lower substrate through three metallized vias. The parameter settings of the linearly polarized magnetic and electric dipole antenna unit are shown in Table 1.

[0057] Table 1 Size parameters of linearly polarized magnetic and electric dipole (unit: mm)

[0058] Parameter Value Parameter Value Parameter Value [CDATA[h2]]> 0.127 0.127 ds 0.4 ​ 3.8 h2 1.524 dv 0.65 w1 0.36 p 6.9 ​ 0.36 lm 1.8 lp 1.6 0.38 ​ 0.38 lf 2.24 wp 1.4 lp2 0.36 wf 0.45 slot-p 0.6 0.3 ​ 0.3 wm 0.2

[0059] In the working state, the surface current on the metal patch is mainly distributed along the x direction, and the current at the rectangular corner is also effectively excited, forming a horizontal plane electric dipole equivalent model. To realize planarization and high integration, a microstrip slot coupling structure is used for feeding. Specifically, the metal microstrip line on the substrate II couples energy to the upper patch structure through the slot layer, thereby exciting the antenna unit. This feed structure has good radiation performance.

[0060] In some embodiments, the linearly polarized magnetic and electric dipole antenna unit is modeled and simulated using ANSYS HFSS, and the parameters are optimized. The current distribution and slot electric field of the linearly polarized magnetic and electric dipole antenna unit at the center frequency of 33 GHz are shown in Figure 8 At t = T / 4 and t = 3T / 4, the current on the metal patch is maximum and is distributed along the ±x direction, indicating that the electric dipole is effectively excited; at this time, the slot electric field also reaches the maximum value, and the direction is along the ±y axis, indicating that the magnetic dipole is also effectively excited, and its spatial position is orthogonal to the electric dipole. It should be noted that the electric field directions in the far field direction of the two remain parallel after excitation, so this structure only radiates linearly polarized waves and cannot form circular polarization.

[0061] Figure 9 The simulation results of S11 and gain of the antenna are given. The results show that the antenna has good impedance matching (S11 ≤ -10 dB) in the frequency band of 26.5 GHz to 42 GHz, and the relative bandwidth reaches 45.26%; at the same time, the gain remains good flatness (fluctuation less than 1 dB) in the entire bandwidth, indicating that the magnetic and electric dipole antenna has excellent wideband and stability characteristics.

[0062] The E-plane and H-plane normalized patterns at 28 GHz and 34 GHz frequency points are shown in Figure 10) to further verify that the unit has good radiation directivity. Therefore, the linearly polarized magneto-electric dipole antenna unit can be used as an ideal array feed source for millimeter wave three-beam lens antenna, meeting the application requirements of wide frequency and high gain. Theta represents the elevation angle of the medium lens antenna pattern, and E represents the plane of the electric field direction and the maximum radiation direction, which is the xoz plane here. H represents the plane of the magnetic field direction and the maximum radiation direction, which is the yoz plane here.

[0063] In some embodiments, in order to fully exert the advantages of the designed linearly polarized magneto-electric dipole antenna unit in terms of bandwidth coverage capability and gain stability, the present application further designs a feed network structure capable of achieving one-to-four equal power feeding to meet the needs of multi-unit array excitation. At the same time, in order to reduce the overall antenna profile height, the feed network structure is realized by using a microstrip line structure, which takes into account the structural compactness and processing process compatibility. Considering that the dielectric loss and radiation loss of the microstrip transmission line at the millimeter wave frequency band have a significant impact on the system efficiency, a thin dielectric plate with a thickness of only 0.127 mm is selected in the network design, thereby significantly reducing the transmission loss and improving the feed efficiency.

[0064] As shown in Figure 11 As shown in (a), the designed feed network structure realizes the four-equal power distribution function by combining the T-junction power divider with the 1 / 4 wavelength impedance transformer. This feed network structure not only effectively ensures the power balance between the four output ports, but also has the advantages of low loss and easy integration, providing a solid foundation for efficient driving of antenna arrays and further improving the overall performance of the millimeter wave lens antenna system.

[0065] The T-junction power divider is a passive device commonly used for power combining and power distribution in radio frequency systems and can be implemented based on almost any type of transmission line structure. The feed network structure described in this specification is realized based on a dielectric substrate and integrates the T-junction power divider into the millimeter wave feed network using a microstrip line structure, which facilitates compact integration with the millimeter wave front-end circuit.

[0066] The 1 / 4 wavelength impedance transformer is a simple and effective circuit that can realize real number load impedance matching. From the perspective of impedance analysis, the transmission line impedance equation

[0067] (5)

[0068] wherein Z in represents the input impedance, Z L represents the load impedance, Z0 represents the characteristic impedance, and βl represents the electrical length, i.e. the phase length of the transmission line; wherein: β is the phase constant (β=2π / λ, λ is the wavelength), and l is the physical length of the transmission line.

[0069] Let the impedance of the 1 / 4 wavelength transformer be Z1, and the load resistance be R L Then

[0070] (6)

[0071] In order to make the reflection coefficient Γ = 0, it must be that Z in = Z0; and substituting = We obtain

[0072] (7)

[0073] The disadvantage of this impedance matching method is that complete matching can only be achieved at one frequency point, and mismatching occurs at other frequency points. The 1 / 4 wavelength impedance transformer can also be analyzed from the perspective of multiple reflections, that is, by selecting a suitable matching line length and characteristic impedance, the superposition result of all reflected waves on the matching line can be zero.

[0074] In some embodiments, the transmission impedance of the microstrip line is uniformly set to 50 Ω to simplify the matching and reduce the reflection. When the radio frequency signal enters the T-junction branch structure, its power is equally distributed to the two output branches at the branch point. Ideally, the equivalent input impedance of the T-shaped structure should be the parallel of the input impedance of the two branches. Thus, when the characteristic impedance of each branch is set to 100 Ω, the input end presents 50 Ω, effectively realizing minimum reflection. In order to further ensure impedance continuity and suppress standing wave reflection, a 1 / 4 wavelength impedance transformation section is introduced in each output branch, which is used to gradually transition the 100 Ω branch impedance to 50 Ω, thereby realizing good matching with the antenna element port. According to equation (7), the impedance of the 1 / 4 wavelength transformer is Since subsequent tests need to be performed through a tablet joint for signal excitation and measurement, in order to ensure that the simulation results are consistent with the actual test conditions, the tablet joint is introduced into the simulation model in this specification, and is connected with the designed four-equal-part microstrip line feeding network. The three-dimensional structural model of the tablet joint is shown in Figure 11 (b).

[0075] In some embodiments, the magnetoelectric dipole array antenna is obtained by equally spacing and copying the linearly polarized magnetoelectric dipole antenna element in the horizontal plane along the X and Y axis directions, and finally forming a 2x2 planar array structure. The antenna array realizes unified excitation and uniform power distribution of the array elements by being integrated with the four-equal-part feeding network. The specific array arrangement mode of the antenna array and the structure of the band joint are shown in Figure 12 .

[0076] The reflection coefficient (S11) simulation results of the 2x2 magnetoelectric dipole antenna array are shown inFigure 13 (a) shows. It can be seen that there is a certain difference in the reflection coefficient between the case of considering the joint structure and the case of not considering the joint structure. This is mainly due to the introduction of additional metal structure and the expansion of the substrate size by the joint, resulting in changes in the input matching of the antenna. Nevertheless, the array still maintains good broadband characteristics. In the required working frequency range of 26.5 GHz to 40.0 GHz, S11 is always below -10 dB, and the corresponding relative bandwidth reaches 45.26%.

[0077] The gain simulation results of the 2x2 magnetic electric dipole antenna array are shown in FIG. 2 (b), and the maximum gain of 13.38 dBi is obtained at 34 GHz. Figure 13 Figure 14 (a)-(f) show the E-plane and H-plane normalized far-field radiation patterns of the antenna array at three typical frequency points of 28 GHz, 34 GHz and 40 GHz. The results show that the antenna has good directivity and low sidelobe level, indicating that it is suitable as a feed source for a wideband millimeter wave lens antenna.

[0078] In some embodiments, the millimeter wave three-beam all-dielectric lens antenna provided by the application comprises: a set of 2x2 Ka-band magnetic electric dipole array antennas as a feed source for radiating a spherical wave signal; and an all-dielectric circular lens structure composed of 384 dielectric units for converting the spherical wave into a plurality of directional plane waves through phase compensation and focusing functions, thereby realizing three-beam directional radiation; wherein the focal length F=102.41mm (which can be approximated as 103mm), the focal ratio F / D=0.95, and the dielectric unit size is 4.9mmx4.9mm. The dielectric unit is composed of a square dielectric column, and eight square holes are uniformly distributed in the column for realizing anti-reflection and phase control functions. Through systematic scanning and optimization of parameters such as the size of the square hole, the opening position and the unit height, a unit library meeting the design target is constructed. The finally selected structure is verified by full-wave simulation in HFSS, showing excellent transmission efficiency and complete 2π phase control capability. According to the design method of superimposing the path compensation phase and the periodic phase, the phase distribution of the aperture surface of the all-dielectric circular lens structure is planned. After considering the beam width and radiation direction of the feed source, the overall size of the all-dielectric circular lens structure and the corresponding phase distribution are determined, so as to obtain the required phase response characteristics of each dielectric unit.

[0079] ​The full-dielectric circular lens structure adopts high-performance 3D printing material TP20280, effectively improving the efficiency and stability of the lens antenna. At the same time, the high dielectric constant property makes the lens thickness reduced, thereby realizing further compression of the antenna profile. Manufactured by Bambu Lab X1-Carbon high-precision 3D printing equipment, the fine forming capability of the equipment ensures the structural consistency and processing precision of the dielectric unit, meeting the strict control requirements of size tolerance in the millimeter wave frequency band.

[0080] Subsequently, electromagnetic performance simulation analysis was carried out in HFSS. The antenna works in the frequency band of 26.5 GHz to 40 GHz, has three-beam radiation capability, and the simulation results are as follows:

[0081] 1 dB gain bandwidth is 40.60% (30.5 GHz to 38.5 GHz);

[0082] The highest aperture efficiency is 32.41%;

[0083] In the frequency band of 26.5 GHz to 40 GHz, the gain of the feed antenna is 11.5 dBi to 13.57 dBi, and after loading the dielectric lens, the gain of the antenna is greater than 17.5 dBi;

[0084] In the entire frequency band, the highest gain reaches 22.2 dBi at 35 GHz.

[0085] The lowest gain in the entire frequency band is higher than 17.5 dBi, indicating that the antenna has stable gain performance in a wide frequency band.

[0086] Figure 15 The E-plane far-field radiation patterns of the lens antenna at 28 GHz, 34 GHz and 40 GHz are shown. Especially at 34 GHz, the radiation pattern clearly shows three beams pointing to -28°, 0° and +28°, which is highly consistent with the theoretical design goal. Figure 16 Further, the gain and aperture efficiency performance of the lens antenna in the frequency band of 26.5 GHz to 40 GHz is shown. At 35 GHz, the gains of the three beams are 22.2 dBi, 20.98 dBi and 22.2 dBi respectively, and the cross level of the center beam and the adjacent beam is about 1.3 dB. The cross level between beams at other frequency points is better than 2 dB, indicating that the beams have good isolation and less mutual interference. The overall gain fluctuation is controlled within 3 dB, verifying that the antenna system has good stability and consistency in a wide frequency range.

[0087] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "setting", "connecting", "fixing", "rotating" and other terms should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited, the above terms in the present application can be understood according to the specific meaning of the above terms by the person skilled in the art according to the specific circumstances.

[0088] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A millimeter-wave three-beam all-dielectric lens antenna, characterized in that, The millimeter-wave three-beam all-dielectric lens antenna includes a set of 2×2 magnetoelectric dipole array antennas and an all-dielectric circular lens structure; the 2×2 magnetoelectric dipole array antennas are used as feed sources and are set on the planar side of the all-dielectric circular lens structure, with the feed source facing the geometric center of the all-dielectric circular lens structure; the all-dielectric circular lens structure has a directionally controllable three-beam radiation capability; The feed consists of four linearly polarized magnetoelectric dipole antenna elements. Each linearly polarized magnetoelectric dipole antenna element comprises, from top to bottom, an upper substrate, a prepreg, and a lower substrate. Two metal patches are arranged on the upper surface of the upper substrate, each with rectangular chamfered corners. A rectangular metal sheet is arranged on the lower surface of the upper substrate, with coupling slots on the sheet. The two metal patches are located on either side of the coupling slots, and each metal patch is connected to the rectangular metal sheet via three metallized vias. Microstrip lines are arranged on the lower surface of the lower substrate. The all-dielectric circular lens structure includes multiple dielectric units, each dielectric unit including a square dielectric pillar and an impedance matching structure disposed at both ends of the square dielectric pillar; the impedance matching structure includes 4 square holes, and the 4 square holes are arranged at equal intervals in a 2×2 matrix.

2. The millimeter-wave three-beam all-dielectric lens antenna according to claim 1, characterized in that, A four-part microstrip feed network is constructed by connecting four linearly polarized magnetoelectric dipole antenna elements via a T-junction power divider and a quarter-wavelength converter. This network operates in the Ka-band. The four-part microstrip feed network also includes a transmission microstrip line. The tail end of the transmission microstrip line is connected to the input terminal of a first T-junction power divider. The two output terminals of the first T-junction power divider are each connected to a 1 / 4 wavelength converter. The tail end of one 1 / 4 wavelength converter is connected to the input terminal of a second T-junction power divider, and the tail end of the other 1 / 4 wavelength converter is connected to the input terminal of a third T-junction power divider. The two output terminals of the second T-junction power divider are each connected to the microstrip line of a linearly polarized magnetoelectric dipole antenna element through a 1 / 4 wavelength converter. The two output terminals of the third T-junction power divider are each connected to the microstrip line of a linearly polarized magnetoelectric dipole antenna element through a 1 / 4 wavelength converter.

3. The millimeter-wave three-beam all-dielectric lens antenna according to claim 1, characterized in that, The all-dielectric circular lens structure comprises 384 dielectric units, each with a length and width of 4.9 mm and a height of 3.7 to 12.6 mm.

4. The millimeter-wave three-beam all-dielectric lens antenna according to claim 1, characterized in that, The square hole has a side length of 1.75mm and a height of 1.5mm.

5. A millimeter-wave three-beam all-dielectric lens antenna according to claim 1, characterized in that, The phase distribution of an all-dielectric circular lens structure is a superposition of path-compensated phase and periodic phase, wherein the calculation formula for the path phase compensation of the dielectric unit is: ， This represents the path compensation phase of the i-th dielectric cell, (x m ,y n ) represents the center coordinates of the i-th dielectric element, k0 represents the free space wavenumber, and R i φ represents the distance from the feed phase center to the i-th dielectric element. i θ represents the beam azimuth angle, and θ represents the elevation angle.

6. A millimeter-wave three-beam all-dielectric lens antenna according to claim 1, characterized in that, A circular lens structure made entirely of dielectric material was fabricated using 3D printing technology. The material used was PREPERM® TP20280, which has a dielectric constant of 4.4 and a loss tangent of 0.

004.

7. A millimeter-wave three-beam all-dielectric lens antenna according to claim 1, characterized in that, The focal length of the millimeter-wave three-beam all-dielectric lens antenna is set at 102.41 mm, corresponding to a focal diameter ratio of 0.

95.

8. A millimeter-wave three-beam all-dielectric lens antenna according to claim 1, characterized in that, The millimeter-wave three-beam all-dielectric lens antenna operates in the 26.5 GHz to 40.0 GHz frequency band, achieving a three-beam radiation mode with beam pointing at -28°, 0°, and +28° respectively.

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