High-gain dual-beam circularly polarized antenna array for 5g band based on enz feeding network

Abstract

This invention belongs to the field of antenna technology and discloses a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network. The invention uses a SIW (Single Induction Wave) operating at its cutoff frequency, equivalent to an ENZ medium, and designs a two-dimensional feed network. Utilizing the wave uniformity in the ENZ medium, an approximately equal-amplitude and in-phase excitation is applied to the radiating elements with a simple structure, overcoming the complexity and high loss problems of traditional feed networks. Furthermore, due to the boundary conditions of the SIW-equivalent ENZ medium, dual-beam radiation is naturally formed. Subsequently, a polarization conversion structure is added to the surface of the ENZ radiating elements to achieve circularly polarized radiation. Experimental measurements show that the antenna can form two symmetrical radiating beams pointing at 23 degrees respectively at 8.253 GHz, with gains of [missing information] and an antenna efficiency of up to 90%. This antenna array is effectively applicable to satellite communication, base station terminals, and other scenarios, possessing characteristics such as integration and high gain.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and particularly relates to a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network. Background Technology

[0002] With the development of 5G millimeter-wave communication, low-orbit satellite internet, and high-capacity multi-point access systems, antenna arrays not only need to have high gain, but also need to simultaneously meet requirements such as multi-directional coverage, low-loss feeding, and polarization stability within limited installation space. Dual-beam antennas can form effective radiation coverage in two spatial directions, which is beneficial to improving spatial multiplexing capabilities; circularly polarized antennas can reduce polarization mismatch caused by changes in the attitude of the transmitter and receiver, and improve the impact of multipath fading in complex propagation environments. Therefore, high-gain array antennas that combine dual-beam radiation and circularly polarized radiation capabilities have become an important research direction in 5G and subsequent communication systems.

[0003] Existing dual-beam circularly polarized arrays typically rely on multi-stage power dividers, phase shifters, Butler matrices, or series phase feed networks to achieve amplitude and phase distribution, and then obtain circularly polarized radiation through orthogonal feeding, sequential rotation, or special radiating elements. While this approach can form a predetermined beam, it suffers from long feed paths, numerous network nodes, and strong coupling between power distribution and phase control, easily leading to problems such as transmission loss, sensitivity to manufacturing errors, and difficulties in inter-layer integration. Especially in the case of 5G band array size constraints, complex feed networks occupy a large planar area, making it difficult to achieve a compact and coordinated design of radiating elements, feed structures, and polarization conversion structures.

[0004] In recent years, SIW structures based on the near-zero epsilon characteristics have been used in array feeding and slot antenna design. These structures typically utilize the near-zero equivalent dielectric constant of SIWs in the TE10 near-cutoff state to reduce phase changes within the waveguide and create an approximately uniform electric field within a certain region. Feeding the slot radiation structure using this uniform field simplifies traditional power divider networks and improves aperture field distribution. However, existing ENZ / SIW-fed antennas mostly focus on single-layer or single-channel slot radiation, primarily achieving linearly polarized single-beam or directional high-gain radiation. Their structural design focuses on near-cutoff resonance, impedance matching, and slot gain enhancement, without establishing a complete structural relationship around a dual-beam circularly polarized array, involving bottom-layer feeding, interlayer uniform coupling, upper-layer multi-column SIW frequency response, and the coordinated operation of the polarization conversion layer.

[0005] When a uniform electric field is formed only in a single-layer SIW, it is difficult to directly extend this uniform field into a consistent feed for multiple radiation channels. When using a multi-row SIW or multi-slot radiation structure, if the ENZ resonant frequency band, equivalent width, and via parameters of each SIW row are inconsistent, amplitude and phase inhomogeneity can easily occur between different radiation regions, affecting the stability of dual-beamforming. When the linearly polarized slot radiation and the circular polarization conversion structure are designed independently, it is difficult for the polarization conversion layer to effectively correspond with the slot field direction of the lower layer, making it difficult to simultaneously guarantee the circular polarization axial ratio and dual-beam direction. Therefore, the existing technology still requires a stacked ENZ-fed antenna array that generates a uniform electric field through a single-row SIW at the bottom layer, couples this uniform electric field to a multi-row SIW structure in the same ENZ resonant frequency band at the upper layer, forms a linearly polarized dual beam through the surface radiation slots, and finally converts it into a circularly polarized dual-beam radiation through the polarization conversion layer, in order to reduce the dependence on complex feed networks and improve array integration. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network.

[0007] The present invention is implemented as follows: a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network, comprising a feed terminal, a first SIW structure, a second SIW structure, and a polarization conversion layer coupled sequentially from bottom to top;

[0008] The feed terminal is a coaxial probe feed structure, and the feed position of the coaxial probe corresponds to the input impedance matching position of the first layer SIW structure.

[0009] The first layer SIW structure is a single-row SIW structure. When the frequency of the input high-frequency current meets its ENZ resonant frequency, the first layer SIW structure generates a uniform electric field distributed along the Z-axis inside the structure.

[0010] The second layer SIW structure is formed by four columns of SIW structures arranged side by side. The four columns of SIW structures have the same metal via radius, center distance between adjacent metal vias, center distance between two rows of metal vias, and wide side of the rectangular waveguide region as the first layer SIW structure, so that the first layer SIW structure and the second layer SIW structure have the same ENZ resonant frequency band.

[0011] The second-layer SIW structure receives the uniform electric field coupled from the first-layer SIW structure and forms a uniform electric field in the four columns of SIW structures, providing a uniform feed field to the surface radiation slots of the second-layer SIW structure to form a linearly polarized dual beam.

[0012] The polarization conversion layer consists of a dielectric substrate and a metal patch covering the dielectric substrate. The polarization conversion layer receives the linearly polarized dual beams output from the second-layer SIW structure and converts them into circularly polarized dual beam radiation.

[0013] Furthermore, the first SIW structure includes two rows of metal vias, each with a radius of R, an adjacent center-to-center distance of w, and a center-to-center distance between the two rows of metal vias. A rectangular waveguide region is formed between two rows of metal through holes, and the rectangular waveguide region has a wide side a.

[0014] Furthermore, the wide side a is... The diameter of the metal through-hole and the center distance w between adjacent metal through-holes are obtained as input parameters; the width a is based on... Based on the base value, subtract the ratio of 1.08 times the square of the metal via diameter to the center distance w of adjacent metal vias, and add 0.1 times the square of the metal via diameter to the ratio of... The ratio; the center distance w between adjacent metal vias is not greater than 1 / 20 of the waveguide wavelength in SIW; the wide side a is used as the downstream input parameter for calculating the ENZ resonant frequency.

[0015] Furthermore, in TE10 mode, the first layer SIW structure obtains the effective dielectric constant according to the Drude dispersion model, using the substrate relative permittivity, light speed, operating frequency, and width a as inputs; when the effective dielectric constant is 0, the corresponding operating frequency is determined as the ENZ resonant frequency; the ENZ resonant frequency is obtained according to the TE10 mode cutoff frequency relationship, using the light speed, substrate relative permittivity, and width a as inputs.

[0016] Furthermore, the four SIW structures in the second layer SIW structure each have the same ENZ resonant frequency as the first layer SIW structure, and receive the uniform electric field coupled from the first layer SIW structure through the same ENZ resonant frequency band, providing a uniform electric field of the same frequency band to the surface radiation groove.

[0017] The present invention also provides a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network, comprising a feed end, a first SIW structure, a second SIW structure and a polarization conversion layer coupled sequentially from bottom to top;

[0018] The feed terminal is a coaxial probe feed structure, and the feed position of the coaxial probe corresponds to the input impedance matching position of the first layer SIW structure.

[0019] The first layer SIW structure is a single-row SIW structure. When the frequency of the input high-frequency current meets its ENZ resonant frequency, the first layer SIW structure generates a uniform electric field distributed along the Z-axis inside the structure.

[0020] The second layer SIW structure is formed by four columns of identical SIW structures arranged side by side. The structural parameters of each column of SIW structure are the same as those of the first layer SIW structure, so that the first layer SIW structure and the second layer SIW structure have the same ENZ resonant frequency band.

[0021] The second-layer SIW structure receives the uniform electric field coupled from the first-layer SIW structure and forms a uniform electric field in the four-column SIW structure, providing a uniform feed field to the surface radiation slots of the second-layer SIW structure to form a linearly polarized dual beam.

[0022] The polarization conversion layer consists of a dielectric substrate and a metal patch covering the dielectric substrate. The polarization conversion layer receives the linearly polarized dual beams output from the second-layer SIW structure and converts them into circularly polarized dual beam radiation.

[0023] Furthermore, the first SIW structure includes two rows of metal vias, each with a radius of R, an adjacent center-to-center distance of w, and a center-to-center distance between the two rows of metal vias. Two rows of metal vias form an equivalent rectangular waveguide region, which has a wide side a.

[0024] Furthermore, the wide side a is... The diameter of the metal through-hole and the center distance w between adjacent metal through-holes are obtained as input parameters; the width a is based on... Based on the base value, subtract the ratio of 1.08 times the square of the metal via diameter to the center distance w of adjacent metal vias, and add 0.1 times the square of the metal via diameter to the ratio of... The ratio; the center distance w between adjacent metal vias is not greater than one-twentieth of the waveguide wavelength in SIW; the wide side a is used as the downstream input parameter for calculating the ENZ resonant frequency.

[0025] Furthermore, in TE10 mode, the first layer SIW structure obtains the effective dielectric constant according to the Drude dispersion model, using the substrate relative permittivity, light speed, operating frequency, and width a as inputs; when the effective dielectric constant is zero, the corresponding operating frequency is determined as the ENZ resonant frequency; the ENZ resonant frequency is obtained according to the TE10 mode cutoff frequency relationship, using the light speed, substrate relative permittivity, and width a as inputs.

[0026] Furthermore, the four columns of SIW structures in the second layer SIW structure have the same metal via radius, center distance between adjacent metal vias, center distance between two rows of metal vias, equivalent rectangular waveguide wide side, and ENZ resonant frequency as the first layer SIW structure.

[0027] This invention also provides a control method for a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network. The antenna array includes a first layer of single-column SIW structure, a second layer of SIW structure formed by four identical SIW structures arranged side by side, a polarization conversion layer, and a coaxial probe feed terminal located at the bottom of the antenna. The control method includes:

[0028] Step 1: Input a high-frequency current into the coaxial probe feed terminal and match the input impedance of the first layer SIW structure by the feed position of the coaxial probe.

[0029] Step 2: When the frequency of the input high-frequency current satisfies the ENZ resonant frequency of the first-layer SIW structure, the first-layer SIW structure generates a single-column uniform electric field distributed along the Z-axis.

[0030] Step 3: Couple the single-column uniform electric field to the second-layer SIW structure. Utilize the same structural parameters of the four SIW structures in the second-layer SIW structure as the first-layer SIW structure to make the four SIW structures be in the same ENZ resonant frequency band and form a uniform electric field.

[0031] Step 4: The surface radiation groove of the second-layer SIW structure receives a uniform electric field and forms a linearly polarized dual beam.

[0032] Step 5: The linearly polarized dual beams are received by the polarization conversion layer and converted into circularly polarized dual beams for outward radiation by the metal patch on the dielectric substrate.

[0033] Furthermore, step 2 includes a parameter calculation step: using the radius R of the metal through-hole, the center distance w between adjacent metal through-holes, and the center distance between the two rows of metal through-holes. As input, the diameter of the metal via is first determined by the radius R of the metal via, and then the width a is output according to the SIW equivalent rectangular waveguide width correction relationship; the center distance w between adjacent metal vias is constrained to be no greater than one-twentieth of the waveguide wavelength in SIW; the width a enters the ENZ resonant frequency calculation step.

[0034] Furthermore, the ENZ resonant frequency calculation step includes: taking the speed of light, the relative permittivity of the substrate, and the width a as inputs, outputting the ENZ resonant frequency according to the TE10 mode cutoff frequency relationship; taking the relative permittivity of the substrate, the speed of light, the operating frequency, and the width a as inputs, outputting the effective permittivity according to the Drude dispersion model; when the effective permittivity is zero, the corresponding operating frequency is taken as the ENZ operating frequency of the first layer SIW structure.

[0035] Furthermore, in step 3, the four columns of SIW structures in the second layer of the SIW structure respectively receive the uniform electric field coupled from the first layer of the SIW structure, and maintain the same ENZ resonant frequency band according to the same structural parameters as the first layer of the SIW structure, so that the four columns of SIW structures provide a uniform feed field to the radiation slots on their respective surfaces.

[0036] Furthermore, in step 5, the polarization conversion layer takes the linearly polarized dual beam output from the second SIW structure as input and the metal patch on the dielectric substrate as the polarization conversion unit to convert the linearly polarized dual beam into a circularly polarized dual beam, which serves as the final radiation output of the antenna array.

[0037] This invention also provides a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network, comprising:

[0038] The first layer is a single-row SIW structure. When this structure operates at the ENZ frequency, a uniform electric field distributed along the Z-axis will be generated inside the structure.

[0039] The second layer consists of four identical SIW structures arranged side by side, and the structural parameters of each column are exactly the same as those of the first layer SIW, which ensures that the first and second layers have the same ENZ resonant frequency band.

[0040] The third layer is the polarization conversion layer; it is formed by adding a metal patch on a dielectric substrate; the feed end is located at the bottom of the antenna and is fed by a coaxial probe, and impedance matching is achieved by adjusting the position of the probe.

[0041] Furthermore, the first layer is a single-column SIW structure:

[0042] The radius of the metal through-hole is R, the distance between the centers of adjacent metal through-holes (cylinders) is w, and the spacing between two rows of metal through-holes (cylinders) is [missing information]. The SIW structure can be equivalent to a rectangular waveguide. Assuming the width of the equivalent rectangular waveguide is 'a', then... The equivalent relationship with a is (w≤1 / 20λg, where λg is the guided wave wavelength in SIW):

[0043]

[0044]

[0045] In TE10 mode, the effective permittivity of the waveguide It can be characterized by the Drude dispersion model, expressed as:

[0046]

[0047] Where c is the speed of light and f is the operating frequency of SIW. It is the relative permittivity of the substrate; when When SIW operates in ENZ mode, it exhibits a near-zero propagation constant and an infinite wavelength; its operating frequency f can be calculated as the cutoff frequency.

[0048] .

[0049] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0050] This invention, in analyzing the equivalent ENZ medium of a substrate waveguide (SIW) within a surface slot, discovered an interesting equal-amplitude, anti-phase electric field distribution characteristic within the slot and analyzed its physical formation mechanism. This finding had not been previously reported. Subsequently, to address the design challenges of ENZ-fed circularly polarized dual-beam antennas, a novel dual-beam circularly polarized antenna array based on equivalent ENZ feeding using a substrate integrated waveguide (SIW) was designed based on this electric field distribution characteristic. First, using a SIW operating at its cutoff frequency as an equivalent ENZ medium, a two-dimensional feeding network was designed. Utilizing the wave homogeneity in the ENZ medium, an approximately equal-amplitude, in-phase excitation was applied to the radiating elements with a simple structure, overcoming the complexity and high loss problems of traditional feeding networks. Furthermore, due to the boundary conditions of the SIW equivalent ENZ medium, dual-beam radiation is naturally formed. Subsequently, a polarization conversion structure was added to the surface of the ENZ radiating elements to achieve circularly polarized radiation. Actual measurements show that the antenna can form two symmetrical radiating beams pointing at 23 degrees each at 8.253 GHz, with gains of [missing values] and an antenna efficiency of up to 90%. This antenna array is effectively applicable to scenarios such as satellite communication and base station terminals, possessing characteristics such as integration and high gain. This invention provides a good approach for the integration and miniaturization of circularly polarized dual-beam antenna design.

[0051] This invention, based on the interesting finding that the electric field within a slotted substrate waveguide (SIW) is equally and out of phase when it is equivalent to an ENZ medium, proposes a novel dual-beam circularly polarized antenna array based on the equivalent epsilon-near-zero (ENZ) medium of a SIW. Simulation calculations and experimental tests demonstrate that this antenna, while successfully achieving a circular design, can form two independent radiating beams. This work provides a new design approach for miniaturized circularly polarized multi-beam antennas. Attached Figure Description

[0052] Figure 1 This is a structural diagram of a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network, provided in an embodiment of the present invention.

[0053] Figure 2 This is a schematic diagram of the overall appearance of the antenna provided in an embodiment of the present invention.

[0054] Figure 3 This is a schematic diagram of the first layer SIW structure provided in the embodiment of the present invention; (a) four grooves are equally spaced on the SIW surface. (b) Schematic diagram of partial dimensions of SIW.

[0055] Figure 4 This is a diagram showing the current distribution and electric field distribution of the first feed network layer provided in an embodiment of the present invention.

[0056] Figure 5 This is the S11 curve diagram of the SIW power supply network provided in the embodiment of the present invention.

[0057] Figure 6 The embodiments of the present invention provide a planar radiation pattern (E-plane) and a three-dimensional radiation pattern of the far-field radiation gain of the SIW feed network in ENZ mode.

[0058] Figure 7 This is a polarization conversion-radiation layer provided in an embodiment of the present invention. (a) Schematic diagram of surface unit distribution of the polarization conversion-radiation layer. (b) Schematic diagram of parameters of a single unit.

[0059] Figure 8 This is a schematic diagram of the polarization conversion effect provided in the embodiment of the present invention, (a) the polarization conversion-reflection and transmission coefficient curve of the radiation layer; (b) the polarization conversion phase curve.

[0060] Figure 9 This is the S11 curve of the entire antenna after the polarization-conversion-radiation layer is covered, as provided in the embodiment of the present invention.

[0061] Figure 10 This is the S11 curve of the entire antenna after the polarization-conversion-radiation layer is covered, as provided in the embodiment of the present invention.

[0062] Figure 11 These are the front overall view and the back feed port view of the antenna provided in the embodiments of the present invention.

[0063] Figure 12 This is a comparison chart of actual measurement data and policy data provided in the embodiments of the present invention.

[0064] Figure 13 This is a flowchart of a 5G high-gain dual-beam circularly polarized antenna array based on an ENZ feed network, provided in an embodiment of the present invention. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0066] like Figure 1 As shown, an embodiment of the present invention provides a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network, comprising:

[0067] The antenna is divided into three layers along the z-axis. The first layer is a single-column SIW structure. When this structure operates at the ENZ frequency, a uniform electric field distributed along the Z-axis is generated inside the structure. The second layer consists of four identical SIW structures arranged side by side, with each column having the same structural parameters as the first layer SIW, ensuring that the first and second layers have the same ENZ resonant frequency band. The third layer is a polarization conversion layer, formed by adding metal patches to a dielectric substrate. The feed end is located at the bottom of the antenna and is fed by a coaxial probe; impedance matching is achieved by adjusting the probe position. The working principle of the structure is as follows: when the frequency of the input high-frequency current meets the ENZ resonant frequency of the SIW, the first layer structure first achieves ENZ characteristics, generating a single-column uniform longitudinal electric field, which is then coupled to the second layer structure, forming a uniform electric field in the four columns of the second layer structure. This achieves uniform in-phase feeding of each radiating slot on the surface of the second layer and forms a linearly polarized dual beam in space. Finally, this linearly polarized dual beam passes through the polarization conversion and radiating layer, and is tuned to a circularly polarized dual beam for outward radiation.

[0068] See the overall appearance of the antenna. Figure 2 Specific parameters are shown in Table 1. The dielectric substrate used for each layer is Rogersdurid 6002, with a loss tangent of 0. .

[0069] 2. Design of ENZ Feed Network Based on SIW

[0070] Table 1. Detailed parameters of the omnidirectional antenna array

[0071]

[0072] Figure 3 This is a schematic diagram of the first layer of SIW; the radius of the metal through-hole is R, the distance between the centers of adjacent metal through-holes (cylinders) is w, and the spacing between two rows of metal through-holes (cylinders) is... The SIW structure can be equivalent to a rectangular waveguide. Assuming the width of the equivalent rectangular waveguide is *a*, then... The equivalent relationship with a is (w≤1 / 20λg, where λg is the guided wave wavelength in SIW):

[0073]

[0074]

[0075] In TE10 mode, the effective permittivity of the waveguide It can be characterized by the Drude dispersion model, expressed as:

[0076]

[0077] Where c is the speed of light and f is the operating frequency of SIW. It is the relative permittivity of the substrate. When When SIW operates in ENZ mode, it exhibits a near-zero propagation constant and an infinite wavelength. Its operating frequency f can be calculated as the cutoff frequency.

[0078]

[0079] Subsequently, four identical radiating slots were formed on the surface of the SIW; the shape and size of each radiating slot are as follows: Figure 2 As shown; when the SIW is excited by a coaxial probe, the electric field distribution in the ENZ mode is as follows. Figure 1 As shown on the left side of b. Since the wavelength is infinitely large in the ENZ medium and the internal electric field is uniformly distributed, the phase change is negligible, thus achieving in-phase radiation at the four radiation slots.

[0080] Then, another SIW structure is applied on top of this layer. This structure consists of four rows of slotted structures identical to the first layer, but its orientation is orthogonal to that of the first layer. Figure 3 As shown; the idea behind this combination is to utilize the uniform electric field characteristics of the ENZ medium to first achieve a uniform field distribution in the first layer of SIW. At this point, the four slots are equivalent to equal-amplitude, co-directional feed sources. Since the first and second layers of SIW have identical structures, impedance matching between layers is achieved. Through coupling, a uniform field distribution is ultimately formed in the four rows of parallel slotted structures in the second layer, as shown. Figure 4 As shown in b), a final array of 16 equal-amplitude, co-directional feed sources is formed; Figure 4 (c) shows that all electric fields perpendicular to the slots in the second layer are uniform. Interestingly, the present invention observed the phenomenon of anti-symmetry of the horizontal electric field on the inner surface of the slot. Figure 4 In (d), the electric field on the surface of each slot exhibits perfect reverse symmetry. Analysis suggests that at a frequency of 8.233 Hz, the SIW achieves ENZ characteristics, at which point it can be considered equivalent to an ENZ medium encasing a metallic conductor. When the SIW operates in TE10 mode, the electric field along the z-direction within this ENZ medium is uniformly distributed, while the electric field along the x-direction should be zero (PEC tangential electric field). When slots much smaller than the wavelength are cut into the PEC, to maintain a zero electric field within the slots (forced boundary condition), the electric field within the slots must be distributed with equal amplitude and opposite directions to ensure the total field within the slots is zero. This reverse distribution of the electric field within the slots under forced boundary conditions is a physical phenomenon that has not yet been publicly reported. This reverse distribution of the electric field within the slots under forced boundary conditions can be viewed as a pair of parallel, fundamental oscillators carrying opposite magnetic currents, producing a dual-beam radiation effect. Figure 4 As shown in (d), a very simple dual-beam radiation characteristic was achieved based on this physical phenomenon.

[0081] Figure 5 This is the S11 curve of the SIW feeder network; from Figure 4 As can be seen, the feeder network has two resonant frequencies, namely 8.233GHz and 8.51GHz. The 8.233GHz frequency is the resonant frequency when the network is operating in the ENZ state, while the 8.51GHz frequency is the resonant frequency when the network is in the inherent FP state. It can be seen that when the feeder network is operating in the ENZ state, it can effectively radiate electromagnetic waves.

[0082] Figure 6 The far-field radiation gain planar (E-plane) and stereo pattern of the SIW feed network in ENZ mode are shown. The pattern reveals a clearly symmetrical dual beam, but the two lobes are not very independent, each with a half-power lobe width of 23 degrees and linear polarization, with a maximum gain of 7.83 dBi.

[0083] 3-polarization conversion-radiation structure design

[0084] To further enhance the gain of the two beams and achieve circular polarization, a polarization conversion unit is then added over the feed network layer.

[0085] The parameters are as follows:

[0086] Table 2. Detailed Parameters of Omnidirectional Antenna Array

[0087]

[0088] By introducing asymmetry in surface impedance, polarization torsion of reflected or transmitted waves can be achieved. For example... Figure 6 (b) is a polarization-torsional metasurface (PRMS) structure. It consists of a dielectric substrate and an upper metasurface metal patch. Here, the metasurface patch is a square metal patch with a 45° bevel in the middle. Its polarization-torsional characteristics can be observed by the amplitude and phase of the reflection coefficient. Assuming that a TM wave along the z-axis is incident perpendicularly to the PRMS surface (ΓTE / TMTE / TM represents the polarization-torsional ratio, i.e., the ratio of the reflected electric field TE to TM, which is orthogonal to the incident electric field TM), it is found that the magnitude of the reflection coefficient ΓTM / TMTM / TM is less than -10dB (from 7.5GHz to 8.8GHz), and ΓTE / TMTE / TM

[0089] Above -1 dB, the incident wave TM is primarily converted into the orthogonally reflected wave TE. Furthermore, at the center frequency of 8.253 GHz, the phase of ΓTE / TMTE / TM is close to -90°, meaning the TM incident wave leads the TE reflected wave by 90°. In other words, the incident and reflected waves have a 90° polarization twist and a 90° phase difference, forming a left-handed circularly polarized wave (LHCP).

[0090] Figure 8 Schematic diagram of polarization conversion effect: (a) Polarization conversion-reflection and transmission coefficient curves of the radiative layer; (b) Polarization conversion phase curve.

[0091] Figure 9 The S11 curve of the entire antenna after the upper polarization-conversion radiation layer is covered. Figure 9 The results show that at 8.253 GHz, the antenna can still radiate effectively when it is in ENZ mode, effectively suppressing the inherent FP resonance effect of SIW.

[0092] Figure 10 To show the far-field radiation gain planar (E-plane) and stereoscopic radiation patterns of the antenna in ENZ mode after covering the upper polarization-conversion-radiating layer. Compared to Figure 6 The independence of the two beams in this pattern is significantly enhanced, with their respective half-power beamwidths reduced to 20 degrees, exhibiting circular polarization, and the gain increased to a maximum of 9.1 dBi.

[0093] 4. Testing Experiment

[0094] Subsequently, comparative experiments were conducted. An experimental antenna was designed and fabricated based on the simulation model, such as… Figure 11 As shown.

[0095] Figure 12 For the comparison curves of S11 and E-plane radiation patterns between measured and simulated data, from... Figure 12 It can be seen that the test curves and the simulation curves have a good agreement. In the S11 curve, the experimental results demonstrate that the feeding network designed in this invention achieves ENZ resonant matching feeding. The test and simulation radiation pattern curves show the same trend and consistent gain, proving that the design of this embodiment is reasonable and successful.

[0096] like Figure 13 Another objective of this invention is to provide a control method for a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network, as follows:

[0097] S101, when the frequency of the input high-frequency current satisfies the ENZ resonant frequency of SIW, the first layer structure first realizes the ENZ characteristics and generates a single-column uniform longitudinal electric field.

[0098] S102 is coupled to the second layer structure and forms a uniform electric field in the four columns of the second layer structure, realizing uniform in-phase feeding of each radiation slot on the surface of the second layer and forming a linearly polarized dual beam in space.

[0099] S103, this linearly polarized dual-beam antenna, after polarization conversion and radiation layer, is adjusted to have the overall appearance of a circularly polarized dual-beam outward radiating antenna.

[0100] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network, characterized in that, It includes a feed terminal coupled sequentially from bottom to top, a first SIW structure, a second SIW structure, and a polarization conversion layer; The feed terminal is a coaxial probe feed structure, and the feed position of the coaxial probe corresponds to the input impedance matching position of the first layer SIW structure. The first layer SIW structure is a single-row SIW structure. When the frequency of the input high-frequency current meets its ENZ resonant frequency, the first layer SIW structure generates a uniform electric field distributed along the Z-axis inside the structure. The second layer SIW structure is formed by four columns of SIW structures arranged side by side. The four columns of SIW structures have the same metal via radius, center distance between adjacent metal vias, center distance between two rows of metal vias, and wide side of the rectangular waveguide region as the first layer SIW structure, so that the first layer SIW structure and the second layer SIW structure have the same ENZ resonant frequency band. The second-layer SIW structure receives the uniform electric field coupled from the first-layer SIW structure and forms a uniform electric field in the four columns of SIW structures, providing a uniform feed field to the surface radiation slots of the second-layer SIW structure to form a linearly polarized dual beam. The polarization conversion layer consists of a dielectric substrate and a metal patch covering the dielectric substrate. The polarization conversion layer receives the linearly polarized dual beams output from the second-layer SIW structure and converts them into circularly polarized dual beam radiation.

2. The 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network according to claim 1, characterized in that, The first SIW structure includes two rows of metal vias, each with a radius of R and a center-to-center distance of w between adjacent vias. The center-to-center distance between the two rows of metal vias is [missing information]. A rectangular waveguide region is formed between two rows of metal through holes, and the rectangular waveguide region has a wide side a.

3. The 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network according to claim 2, characterized in that, The width a is The diameter of the metal through-hole and the center distance w between adjacent metal through-holes are obtained as input parameters; the width a is based on... Based on the base value, subtract the ratio of 1.08 times the square of the metal via diameter to the center distance w of adjacent metal vias, and add 0.1 times the square of the metal via diameter to the ratio of... The ratio; the center distance w between adjacent metal vias is not greater than 1 / 20 of the waveguide wavelength in SIW; the wide side a is used as the downstream input parameter for calculating the ENZ resonant frequency.

4. The 5G band high-gain dual-beam circularly polarized antenna array based on the ENZ feed network according to claim 3, characterized in that, In the TE10 mode, the first layer SIW structure uses the substrate relative permittivity, light speed, operating frequency, and width a as inputs to obtain the effective permittivity according to the Drude dispersion model. When the effective permittivity is 0, the corresponding operating frequency is determined as the ENZ resonant frequency. The ENZ resonant frequency is obtained using the light speed, substrate relative permittivity, and width a as inputs according to the TE10 mode cutoff frequency relationship.

5. The 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network according to claim 1, characterized in that, The four SIW structures in the second layer SIW structure have the same ENZ resonant frequency as the first layer SIW structure, and receive the uniform electric field coupled from the first layer SIW structure through the same ENZ resonant frequency band, providing a uniform electric field of the same frequency band to the surface radiation groove.

6. A control method for a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network, characterized in that, The antenna array includes a first layer of single-row SIW structure, a second layer of SIW structure formed by four rows of identical SIW structures arranged side by side, a polarization conversion layer, and a coaxial probe feed terminal located at the bottom of the antenna. The control method includes: Step 1: Input a high-frequency current into the coaxial probe feed terminal and match the input impedance of the first layer SIW structure by the feed position of the coaxial probe. Step 2: When the frequency of the input high-frequency current satisfies the ENZ resonant frequency of the first-layer SIW structure, the first-layer SIW structure generates a single-column uniform electric field distributed along the Z-axis. Step 3: Couple the single-column uniform electric field to the second-layer SIW structure. Utilize the same structural parameters of the four SIW structures in the second-layer SIW structure as the first-layer SIW structure to make the four SIW structures be in the same ENZ resonant frequency band and form a uniform electric field. Step 4: The surface radiation groove of the second-layer SIW structure receives a uniform electric field and forms a linearly polarized dual beam. Step 5: The linearly polarized dual beams are received by the polarization conversion layer and converted into circularly polarized dual beams for outward radiation by the metal patch on the dielectric substrate.

7. The control method for a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network according to claim 6, characterized in that, Step 2 includes parameter calculation steps: using the radius R of the metal through-hole, the center distance w between adjacent metal through-holes, and the center distance between the two rows of metal through-holes. As input, the diameter of the metal via is first determined by the radius R of the metal via, and then the width a is output according to the SIW equivalent rectangular waveguide width correction relationship; the center distance w between adjacent metal vias is constrained to be no greater than one-twentieth of the waveguide wavelength in SIW; the width a enters the ENZ resonant frequency calculation step.

8. The control method for a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network according to claim 7, characterized in that, The ENZ resonant frequency calculation steps include: taking the speed of light, the relative permittivity of the substrate, and the width a as inputs, outputting the ENZ resonant frequency according to the TE10 mode cutoff frequency relationship; taking the relative permittivity of the substrate, the speed of light, the operating frequency, and the width a as inputs, outputting the effective permittivity according to the Drude dispersion model; when the effective permittivity is zero, the corresponding operating frequency is taken as the ENZ operating frequency of the first layer SIW structure.

9. The control method for a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network according to claim 6, characterized in that, In step 3, the four columns of SIW structures in the second layer receive the uniform electric field coupled from the first layer SIW structure, and maintain the same ENZ resonant frequency band according to the same structural parameters as the first layer SIW structure, so that the four columns of SIW structures provide a uniform feed field to the radiation slots on their respective surfaces.

10. The control method for a 5G band high-gain dual-beam circularly polarized antenna array based on an ENZ feed network according to claim 6, characterized in that, In step 5, the polarization conversion layer takes the linearly polarized dual beam output from the second SIW structure as input and uses the metal patch on the dielectric substrate as the polarization conversion unit to convert the linearly polarized dual beam into a circularly polarized dual beam, which serves as the final radiation output of the antenna array.

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