Dual-frequency splicable passive reflection array and design method thereof

Abstract

This invention discloses a dual-frequency splicable passive reflector array and its design method, mainly addressing the problems of large size of passive transponders and difficulty in achieving simultaneous aperture beam adjustment in existing blind zone coverage technologies. The designed dual-frequency splicable passive reflector array consists of an array of multiple reflector array elements, including two types of subarrays: "0" and "1". Based on the principle of average phase gradient, M... s A subarray of "0"s and N s The "1" subarrays are arranged in an orderly manner to form the smallest periodic row vector V in the reflection array. min By changing V min M s and N s The number of subarrays and their arrangement order determine beam reconfigurability, using the minimum periodic row vector V. min By extending the array in both the elevation and azimuth planes, different apertures of the splicable reflective arrays can be obtained, achieving aperture reconfigurability and enabling its use in millimeter-wave blind spot filling in wireless communication.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic communication technology, specifically relating to a dual-frequency splicable passive reflector array and its design method. Background Technology

[0002] 5G millimeter wave technology has gained favor in the industry due to its high communication capacity and low latency. However, the low penetration, poor diffraction ability, and significant reflection attenuation of millimeter waves have hindered their widespread adoption, especially in indoor environments with many obstacles, where millimeter wave signals can create large coverage blind spots. Current technologies address this issue by deploying more active base stations or repeaters, but this increases costs and energy consumption. Therefore, how to increase indoor millimeter wave signal coverage without increasing costs is a major technical challenge.

[0003] In 2008, MCTKastelijn et al. proposed a planar passive deflector operating in the millimeter-wave band. This planar passive deflector has a pyramidal structure and can deflect the incident wave from the feed source in a specified direction. By deploying this passive deflector, the communication distance of the feed source can be extended, achieving the purpose of covering signal dead zones. However, this passive deflector has a large size, which is not conducive to assembly and integration in indoor scenarios.

[0004] In 2019, Fang Yao et al. proposed a passive reflective array operating at 29 GHz, which has good millimeter wave characteristics and can effectively fill blind spots in millimeter wave indoor environments. However, this passive reflective array has a fixed angle in its design, which makes it unsuitable for scenarios with larger angles.

[0005] In summary, current millimeter-wave indoor coverage methods face a contradiction: blind spot filling methods that can effectively cover indoor blind spots are large in size and complex in structure; while passive reflector arrays with simple structures cannot be applied to all scenarios and all frequencies. Summary of the Invention

[0006] The purpose of this invention is to address the problems of large size of passive transponders and difficulty in achieving simultaneous aperture beam adjustment in existing blind zone coverage technologies. It provides a dual-frequency, splicable passive reflector array based on 1-bit digital coding and its design method to reduce antenna size, achieve simultaneous aperture beam adjustment, and meet the requirements of different scenarios. The splicable passive reflector array designed in this invention can be used for millimeter-wave blind zone coverage in wireless communication.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On the one hand, the present invention provides a design method for a dual-frequency splicable passive reflective array, comprising the following steps:

[0008] 1) Determine the scanning range of the main beam θ of the dual-frequency splicable passive reflector array as θ0 < θ < θ1; determine the operating frequency f of the dual-frequency splicable passive reflector array, where f is equal to f1 or f2, and f1 < f2;

[0009] 2) Based on the scanning range of the main beam θ, θ0 < θ < θ1, and the operating frequencies f1 and f2, two types of subarrays, "0" and "1", are designed. The first type, the "0" subarray, is an m0×n0 array composed of several planar reflection array elements. At the frequency f1, the beam direction is θ. s10 When the frequency is f2, the beam direction is θ. s20 θ s10 and θ s20 All approach θ0; the second type of "1" subarray is an m1×n1 array composed of several planar reflection array elements, with a beam pointing at θ at frequency f1. s11 When the frequency is f2, the beam direction is θ. s21 θ s11 and θ s21 All approach θ1;

[0010] 3) Select the main beam θ and operating frequency f required for the specific application scenario, and based on the principle of average phase gradient, set M... s A subarray of "0"s and N s The "1" subarrays are arranged in an orderly manner to form the smallest periodic row vector V in the reflection array. min M s and N s The integers greater than or equal to 0 are such that the minimum periodic row vector V min At frequency f, the main beam points to θ.

[0011] 4) Based on the specific application scenario, use the minimum periodic row vector V min The array is expanded in both the elevation and azimuth planes to obtain the desired dual-frequency splicable passive reflector array.

[0012] Furthermore, in 1), 0°≤θ0<60°, 0°<θ1≤60°.

[0013] Furthermore, m0 mentioned in 2) is the number of planar reflection array elements in the azimuth plane of the "0" subarray within a 360° phase period, which is calculated using the following formula:

[0014]

[0015] Where d is the period of the planar reflection array element, P g0 It is the phase gradient, where k 02Let f2 be the space wavenumber, and θ0 be the desired beam pointing of the designed "0" subarray. The selection principle for m0 is to choose an integer value that allows the beam pointing to be closest to the value of θ0.

[0016] The number n0 is the number of planar reflection array elements of the "0" subarray along the elevation plane, which is set according to the actual application scenario and processing conditions;

[0017] The θ s10 The beam direction of the "0" subarray at frequency f1 is obtained by substituting m0 into the following formula:

[0018]

[0019] Where k 01 Let f1 be the space wavenumber at frequency f1.

[0020] The θ s20 The beam direction of the "0" subarray at frequency f2 is obtained by substituting m0 into the following formula:

[0021]

[0022] Furthermore, m1 mentioned in 2) is the number of planar reflection array elements in the azimuth plane of the "1" subarray within a 360° phase period, which can be calculated using the following formula:

[0023]

[0024] Where d is the period of the planar reflection array element, P g1 It is the phase gradient, where k 02 Let f2 be the space wavenumber, and θ1 be the desired beam pointing of the designed “1” subarray. The selection principle for m1 is to choose an integer value that allows the beam pointing to be closest to the value of θ1.

[0025] The number n1 is the number of planar reflection array elements of the "1" subarray along the elevation plane, which is set according to the actual application scenario and processing conditions;

[0026] The θ s11 The beam direction of the "1" subarray at frequency f1 is obtained by substituting m1 into the following formula:

[0027]

[0028] Where k 01 Let f1 be the space wavenumber at frequency f1.

[0029] The θ s21 The beam direction of the "1" subarray at frequency f2 is obtained by substituting m1 into the following formula:

[0030]

[0031] Furthermore, M as described in 3) s and N s The following calculation is performed using the average phase gradient principle:

[0032] Assume the total phase shift of array V, formed by splicing M "0" subarrays and N "1" subarrays, is ψ. all :

[0033] ψ all =2π(M+N)

[0034] The average phase gradient is defined as follows:

[0035]

[0036] Where m0 and m1 are the number of planar reflection array elements in the azimuth plane within the 360° phase period of the "0" subarray and the "1" subarray, respectively, and d is the period of the planar reflection array element. To make the beam of V point towards θ... i To approximate the target beam θ, the average phase gradient of V is required. Phase gradient P approximating the target beam θ gi ,Right now:

[0037]

[0038] ε can be made equivalent to ε′:

[0039]

[0040] If ε′ approaches 0, then the beam pointing of V approximates the target beam pointing θ. When ε′ is sufficiently small, there exists a solution M. s and N s Then kM must exist. s and kN s Take M s +N s The minimum value is the final solution, M. s A subarray of "0"s and N s The "1" subarray can be arranged in various ways. The array pattern of each arrangement is calculated, and the arrangement with the smallest beam pointing error and the smallest sidelobes is selected as the minimum periodic row vector V. min .

[0041] Furthermore, the minimum periodic row vector V described in 4) min Extending to the azimuth and pitch planes as a unit refers to splicing together any number of minimum periodic row vectors V along the azimuth and pitch directions according to the actual application scenario. min This forms a reflection array:

[0042] On the other hand, the present invention provides a dual-frequency splicable passive reflective array, which is designed by any of the above-described dual-frequency splicable passive reflective array design methods.

[0043] Compared with the prior art, the present invention has the following advantages:

[0044] First, the "0" subarray and "1" subarray designed based on the 1-bit concept of this invention can achieve beam reconfiguration through different arrangements. Compared with the passive reflection arrays with fixed aperture and beam direction proposed in the prior art, this invention is easier to produce and promote.

[0045] Secondly, the splicable reflector array of the present invention achieves beam reconfiguration by changing the splicing method of the "0" subarray and the "1" subarray, without the need for additional power supply. Compared with the complex active reflector array used by the prior art to achieve beam reconfiguration, the present invention avoids the complex power supply network design, simplifies the installation complexity, saves costs, and reduces the difficulty of installation for workers.

[0046] Third, the splicable reflective array of the present invention can be spliced ​​into arrays of appropriate sizes according to different scenarios and needs, so as to achieve reconfigurable aperture.

[0047] Fourth, the splicable reflective array of the present invention achieves the function of dual-frequency reflective array by using a double-layer patch method, which can adapt to more complex environments. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0049] Figure 2 This is a schematic diagram of the planar reflection array unit in this invention;

[0050] Figure 3 For an aperture of 320mm × 304mm, the minimum periodic row vector V min =

[00010] Reflection array structure diagram;

[0051] Figure 4 For an aperture of 320mm × 304mm, the minimum periodic row vector V min =Full-wave simulation radiation pattern of the reflection array

[00010] ;

[0052] Figure 5 For an aperture of 320mm × 304mm, the minimum periodic row vector V min A comparison of the measured radiation pattern and the theoretical radiation pattern of the

[00010] reflection array at 24.5 GHz;

[0053] Figure 6 For an aperture of 320mm × 304mm, the minimum periodic row vector Vmin A comparison of the measured radiation pattern and the theoretical radiation pattern of the

[00010] reflection array at 29.5 GHz;

[0054] Figure 7 The aperture is 80mm × 128mm, and the minimum periodic row vector is V. min = [0] reflection array pattern;

[0055] Figure 8 For an aperture of 80mm × 120mm, the minimum periodic row vector V min =[1] reflection array pattern;

[0056] Among them, 1. Metal ground, 2. Lower dielectric substrate, 3. Lower cross-shaped patch, 4. Upper dielectric substrate, 5. Upper cross-shaped patch. Detailed Implementation

[0057] To better understand the content of this invention, the following description, in conjunction with the accompanying drawings and specific implementation methods, will further illustrate the content of this invention. However, the scope of protection of this invention is not limited to the following embodiments.

[0058] This invention discloses a dual-frequency splicable passive reflector array and its design method, primarily addressing the problems of large size of passive transponders and the difficulty in achieving simultaneous aperture beam adjustment in existing blind zone coverage technologies. The designed dual-frequency splicable passive reflector array consists of an array of multiple reflector array elements, including two types of subarrays: "0" and "1". Based on the principle of average phase gradient, M... s A subarray of "0"s and N s The "1" subarrays are arranged in an orderly manner to form the smallest periodic row vector V in the reflection array. min By changing V min M s and N s The number of subarrays and their arrangement order determine beam reconfigurability, using the minimum periodic row vector V. min By extending the array in both the elevation and azimuth planes, different apertures of the splicable reflective arrays can be obtained, achieving aperture reconfigurability and enabling its use in millimeter-wave blind spot filling in wireless communication.

[0059] The dual-frequency splicable reflective array of this invention consists of an array of multiple planar reflective array elements, as shown in the schematic diagram below. Figure 1 As shown. A schematic diagram of the planar reflector array unit structure used in the following embodiments is shown below. Figure 2As shown, each planar reflector array unit is composed of a metal ground 1, a lower dielectric substrate 2, a lower cross-shaped patch 3, an upper dielectric substrate 4, and an upper cross-shaped patch 5, wherein the lower dielectric substrate 2 is located above the metal ground 1; the lower cross-shaped patch 3 is located above the lower dielectric substrate 2; the upper dielectric substrate 4 is located above the lower cross-shaped patch 3; and the upper cross-shaped patch 5 is located above the upper dielectric substrate 4.

[0060] Both the lower dielectric substrate 2 and the upper dielectric substrate 4 are made of dielectric substrates with a dielectric constant of 3.66 and a loss tangent of 0.004.

[0061] Example 1: Design of a dual-frequency splicable reflective array for a specific application scenario where the main beam θ is 45° and the operating frequency f is 24.5GHz and 29.5GHz.

[0062] The design method of the dual-frequency splicable reflection array in this embodiment includes the following steps:

[0063] Step 1: Determine the scanning range of the main beam θ of the dual-frequency splicable passive reflector array as 40 < θ < 60; determine the operating frequencies of the dual-frequency splicable passive reflector array as f1 = 24.5 GHz and f2 = 29.5 GHz;

[0064] Step 2: Based on the scanning range of the main beam θ (40 < θ < 60) and the operating frequencies f1 = 24.5 GHz and f2 = 29.5 GHz, design two types of subarrays, "0" and "1".

[0065] 2.1) The first type of "0" subarray is an m0×n0 array composed of several planar reflection array elements, with a beam pointing at θ at frequency f1. s10 When the frequency is f2, the beam direction is θ. s20 θ s10 and θ s20 All are close to 40°. m0 is the number of planar reflection array elements in the azimuth plane of the "0" subarray within a 360° phase period, calculated using the following formula:

[0066]

[0067] Where d is the period of the planar reflection array element, P g0 It is the phase gradient, where k 02 Let f2 be the space wavenumber, and θ0 be the desired beam pointing of the designed "0" subarray. The selection principle for m0 is to choose an integer value that allows the beam pointing to be closest to the value of θ0.

[0068] m0 takes the integer value 4;

[0069] The number n0 is the number of planar reflection array elements of the "0" subarray along the elevation plane. It is set according to the actual application scenario and processing conditions. In this embodiment, it is set to 20, and the resulting "0" subarray is a 4*20 array. The beam pointing of the "0" subarray tends to 41.7° at both 24.5GHz and 29.5GHz.

[0070] 2.2) The second type of "1" subarray is an m1×n1 array composed of several planar reflection array elements, with a beam pointing at θ at frequency f1. s11 When the frequency is f2, the beam direction is θ. s21 θ s11 and θ s21 All are close to 60°. m1 is the number of planar reflection array elements in the azimuth plane of the "1" subarray within a 360° phase period, calculated using the following formula:

[0071]

[0072] Where d is the period of the planar reflection array element, P g1 It is the phase gradient, where k 02 Let f2 be the space wavenumber, and θ1 be the desired beam pointing of the designed “1” subarray. The selection principle for m1 is to choose an integer value that allows the beam pointing to be closest to the value of θ1.

[0073] m1 takes the integer value 3;

[0074] The n1 is the number of planar reflection array elements of the "1" subarray along the elevation plane. It is set according to the actual application scenario and processing conditions. In this example, it is set to 20, and the resulting "1" subarray is a 3*20 array. The beam pointing of the "1" subarray tends to 62° at both 24.5GHz and 29.5GHz.

[0075] Step 3: Select a main beam θ of 45° for the specific application scenario. Based on the principle of average phase gradient, assume that the total phase shift of array V, which is composed of M "0" subarrays and N "1" subarrays, is ψ. all :

[0076] ψ all =2π(M+N)

[0077] The average phase gradient is defined as follows:

[0078]

[0079] Where m0 and m1 are the number of planar reflection array elements in the azimuth plane within the 360° phase period of the "0" subarray and the "1" subarray, respectively, and d is the period of the planar reflection array element. To make the beam of V point towards θ... i To approximate the target beam θ, the average phase gradient of V is required. Phase gradient P approximating the target beam θ gi ,Right now:

[0080]

[0081] ε can be made equivalent to ε′:

[0082]

[0083] If ε′ approaches 0, then the beam pointing of V approximates the target beam pointing θ. When ε′ is sufficiently small, there exists a solution M. s and N s Then kM must exist. s and kN s Take M s +N s The minimum value is the final solution, M. s A subarray of "0"s and N s The "1" subarray can be arranged in various ways. The array pattern of each arrangement is calculated, and the arrangement with the smallest beam pointing error and the smallest sidelobes is selected as the minimum periodic row vector V. min The minimum periodic row vector is V. min =

[00010] , where 0 represents a subarray of "0" and 1 represents a subarray of "1", that is, the subarrays of "0" and "1" are arranged in the order of 00010 to form the minimum periodic row vector V. min .

[0084] Step 4) Based on the specific application scenario, use the minimum periodic row vector V min By extending the array in both the elevation and azimuth planes, a dual-frequency, modular passive reflector array with a diameter of 320mm × 304mm is obtained. The structural diagram is shown below. Figure 3 As shown.

[0085] The effects of this invention can be further illustrated by the following simulations and tests:

[0086] I. Simulation Conditions

[0087] The simulation software is HFSS.

[0088] II. Simulation Content

[0089] Simulation 1: A full-wave simulation of Example 1 was performed in HFSS software, and the full-wave radiation pattern was obtained as follows. Figure 4 As shown. From Figure 4 As can be seen, the main beam pointing in this example is 44.8°, which is only 0.2° off from the design requirement of 45°, thus meeting the design requirements.

[0090] Simulation 2: The "0" subarray was simulated in HFSS software, and the radiation pattern was obtained as follows. Figure 7 As shown. From Figure 7 It can be seen that the main beam pointing is 41.9°, which is only 0.2° off from the design requirement of 41.7°, thus meeting the design requirements.

[0091] Simulation 3: The "1" subarray was simulated in HFSS software, and the simulation radiation pattern was obtained as follows. Figure 8 As shown. From Figure 8 It can be seen that the main beam direction is 62°, which meets the design requirements.

[0092] III. Measurement Conditions and Content

[0093] Test 1: Using a small horn antenna as the feed, the radiation pattern of the reflector array of Example 1 at 24.5 GHz was tested in an anechoic chamber. The obtained radiation pattern at 24.5 GHz is as follows. Figure 5 As shown.

[0094] from Figure 5 It can be seen that the measured radiation pattern of the spliced ​​reflector array is in good agreement with the theoretical calculation, with the main beam pointing at 44.8° in both cases. Since the theoretical calculation does not consider the mutual coupling between array elements and the reduced efficiency of the reflector array due to dielectric and metallic losses in the millimeter-wave band, there are some differences between the theoretical and actual radiation patterns. In blind spot coverage applications, the blind spots are mainly covered by multiple reflections of the main beam of the reflector array; therefore, these errors will not affect the blind spot coverage effect, and the design requirements are met.

[0095] Test 2: Using a small horn antenna as the feed, the radiation pattern of the reflector array of Example 1 at 29.5 GHz was tested in an anechoic chamber. The obtained radiation pattern at 29.5 GHz is shown below. Figure 6 As shown, from Figure 6 It can be seen that the measured results of the spliced ​​reflection array pattern are in good agreement with the theoretical calculation results, and the main beam direction is 44.8°. This meets the design requirements.

[0096] In summary, the reflector array of the present invention can be spliced ​​into passive reflector arrays with different beams by changing the arrangement of the two subarrays.

[0097] The above description is only a specific embodiment of the present invention and not all embodiments. Any equivalent modifications made by those skilled in the art to the technical solutions of the present invention by reading the present invention specification shall be covered by the claims of the present invention.

Claims

1. A method for designing a dual-frequency splicable passive reflection array, characterized in that, The method comprises the following steps: 1) determining the scanning range of the main beam θ of the double-frequency splicable passive reflection array to be θ0< θ < θ1; determining the working frequency f of the double-frequency splicable passive reflection array, f being equal to f1 or f2, f1 < f2; 2) Design two types of sub-arrays, "0" and "1", according to the scanning range θ0< θ < θ1 of the main beam θ and the operating frequencies f1 and f2, where the first type "0" sub-array is an m0 x n0 array of planar reflectarray elements, with the beam pointing at θ s10 at frequency f1 and at θ s20 at frequency f2, both θ s10 and θ s20 tending to θ0; the second type "1" sub-array is an m1 x n1 array of planar reflectarray elements, with the beam pointing at θ s11 at frequency f1 and at θ s21 at frequency f2, both θ s11 and θ s21 tending to θ1; 3) Select the main beam θ and the operating frequency f required by the specific application scene, and arrange M s "0" subarrays and N s "1" subarrays in order according to the average phase gradient principle to form a minimum period row vector V min in the reflective array, where M s and N s are integers greater than or equal to 0, so that the minimum period row vector V min points to θ at a frequency of f. 4) Row vectors V with minimum period according to the specific application scenario min The size of the dual-frequency splicable passive reflective array is obtained by extending the unit in the elevation plane and the azimuth plane of the array, respectively.

2. The design method of a dual-frequency splicable passive reflection array according to claim 1, wherein, In 1), 0°≤ θ0< 60°, 0°< θ1≤ 60°.

3. The design method of a dual-frequency splicable passive reflection array according to claim 1, wherein, In 2), m0 is the number of planar reflection array units of the "0" subarray in the azimuth plane within a 360° phase period, and is calculated according to the following formula: where d is the planar reflectarray unit period, P g0 is the phase gradient, where k 02 is the spatial wave number at frequency f2, θ0is the desired beam pointing of the "0" subarray at design; the principle of choosing m0is to select an integer value that makes the beam pointing as close as possible to the value of θ0; n0 is the number of planar reflection array units of the "0" subarray along the elevation plane, and is set according to the actual application scenario and processing conditions; The θ s10 is the beam pointing of the "0" subarray at a frequency of f1, which is obtained by substituting m0 into the following equation: where k 01 is the spatial wave number at frequency f1; The θ s20 is the beam pointing of the "0" subarray at a frequency of f2, which is obtained by substituting m0 into the following equation:

4. The design method of a dual-frequency splicable passive reflection array according to claim 1, wherein, In 2), m1 is the number of planar reflection array units of the "1" subarray in the azimuth plane within a 360° phase period, and is calculated according to the following formula: where d is the planar reflectarray unit period, P g1 is the phase gradient, where k 02 is the spatial wave number at frequency f2, θ1is the desired beam pointing of the "1" subarray by design; the selection principle of m1is: select an integer value that makes the beam pointing as close as possible to the value of θ1; n1 is the number of planar reflection array units of the "1" subarray along the elevation plane, and is set according to the actual application scenario and processing conditions; The θ s11 is the beam pointing of the "1" subarray at a frequency of f1, which is obtained by substituting m1 into the following equation: where k 01 is the spatial wave number at frequency f1; The θ s21 is the beam pointing of the "1" subarray at a frequency of f2, which is obtained by substituting m1 into the following equation:

5. The design method of a dual-frequency splicable passive reflection array according to claim 1, wherein, 3) M described in the M s and N s are calculated by the average phase gradient principle described below: Assume that the total phase shift of the array V after the M "0" sub-arrays and the N "1" sub-arrays are spliced is ψ all : Ψ all = 2π(M + N) The average phase gradient is then defined as where m0and m1are the number of planar reflectarray elements of the "0" subarray and "1" subarray in the azimuth plane within the 360° phase period, d is the planar reflectarray element period, and θ is the target beam direction i The average phase gradient of V that approximates the target beam θ is The phase gradient P of V that approximates the target beam θ is gi i.e.: ε can be equivalent to ε': Let ε' approach 0, then the beam pointing of V approaches the target beam pointing θ, when ε' is small enough, there is a solution M s and N s , there is kM s and kN s , take M s +N s minimum as the final solution, M s "0" sub-matrix and N s "1" sub-matrix can have various arrangements, calculate the array pattern of various arrangements, select the arrangement with the minimum beam pointing error and the minimum sidelobe as the minimum period row vector V min .

6. The design method of a dual-frequency splicable passive reflection array according to claim 1, wherein, 4) in the minimum period row vector V min To expand the azimuth and elevation planes as units, it means to splice any multiple minimum period row vectors V min , to form a reflection array:

7. A dual-frequency splicable passive reflection array, characterized in that, The double-frequency splicable passive reflection array is designed by the design method of any one of claims 1-6.

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