阅读说明：本技术 一种通过均匀面阵发射多模复用信号的天线选择方法 (Antenna selection method for transmitting multimode multiplexing signals through uniform area array ) 是由 刘程翔 周斌 琚诚 赵宇 于 2021-09-18 设计创作，主要内容包括：本发明涉及一种通过均匀面阵发射多模复用信号的天线选择方法,包括：选择基础面阵；确定中心阵元以及可生成的UCA的最大半径；计算基础面阵中任一阵元到中心阵元的距离,结合可生成的UCA的最大半径,确定基础面阵可生成的UCA的半径序列；确定对应不同UCA半径的阵元集合序列；给定OAM涡旋电磁波束的最大发散角度,计算基础面阵可发射的OAM模式,以及可发射的OAM模式所需的最小UCA半径；从对应不同UCA半径的阵元集合序列中提取出可发射的OAM模式所需的阵元集合,并计算出每一阵元所需的激励相位。本发明可以在均匀面阵上产生不同半径UCA,使得在应用中可以实现波束的灵活调整。本发明可以降低开发成本,加快项目开发速度。(The invention relates to an antenna selection method for transmitting multimode multiplexing signals through a uniform area array, which comprises the following steps: selecting a basic area array; determining the maximum radius of the central array element and the UCA which can be generated; calculating the distance from any array element in the basic area array to the central array element, and determining the radius sequence of UCA which can be generated by the basic area array by combining the maximum radius of the UCA which can be generated; determining array element set sequences corresponding to different UCA radiuses; the maximum divergence angle of the OAM vortex electromagnetic wave beam is given, and an OAM mode which can be transmitted by a basic area array and the minimum UCA radius required by the OAM mode which can be transmitted are calculated; and extracting an array element set required by the transmittable OAM mode from the array element set sequences corresponding to different UCA radiuses, and calculating an excitation phase required by each array element. The invention can generate UCAs with different radiuses on a uniform area array, so that the beam can be flexibly adjusted in application. The invention can reduce the development cost and accelerate the project development speed.)

1. An antenna selection method for transmitting a multimode multiplexed signal through a uniform area array, comprising:

step S1, selecting a rectangular grid array, a hexagonal grid array or a triangular grid array as a basic area array;

step S2, extracting a candidate central array element set from the basic area array, and determining the central array elements and the maximum radius of UCA which can be generated by the basic area array according to the candidate central array element set;

step S3, calculating the distance from any array element in the basic area array to the central array element, and determining the radius sequence of UCA which can be generated by the basic area array by combining the maximum radius of UCA which can be generated by the basic area array;

step S4, according to the radius sequence of UCA which can be generated by the basic area array, determining array element set sequences corresponding to different UCA radii;

step S5, the maximum divergence angle of the OAM vortex electromagnetic wave beam is given, and the OAM mode which can be emitted by the basic area array and the minimum UCA radius r required by the emitting OAM mode are calculated according to the UCA radius sequence which can be generated by the basic area array_l，min；

Step S6, according to the minimum UCA radius r required by the transmittable OAM mode_l，minAnd extracting an array element set required by the transmittable OAM mode from the array element set sequences corresponding to different UCA radiuses, and calculating an excitation phase required by each array element in the array element set required by the transmittable OAM mode.

2. The method for selecting antennas to transmit multimode multiplexed signals over a uniform area array as claimed in claim 1, wherein the method for extracting the candidate central array element set in step S2 comprises:

step S21, determining a set S of candidate intermediate rows and a set T of candidate intermediate columns of the basic area array according to the row number and the column number of the basic area array;

step S22, calculating a candidate central array element set H ═ T × S ═ S{ (T, S) | T ∈ T ^ S ∈ S }, T is the row number of the candidate intermediate row, S is the column number of the candidate intermediate column, and the element in the set H is the candidate central array element H_iI belongs to I, and I represents a set of candidate central array element sequence numbers.

3. The method for selecting antennas to transmit multimode multiplexed signals over a uniform area array as claimed in claim 1, wherein in step S2, if the candidate central array element set H has only one element, the central array element of the basic area array is the only element of the candidate central array element set H; if the candidate central array element set H has two or more elements, determining the central array element of the basic area array comprises the following steps:

step S23, determining all edge array elements in the basic area array;

step S24, calculating each candidate central array element h_iDistance D to all edge array elements_iFrom D, and_ifind each candidate central array element h in the set_iMinimum distance min (D) to edge array element_i)；

Step S25, from each candidate central array element h_iMinimum distance min (D) to edge array element_i) Find the maximum value max_i∈I(min(D_i) Max) will be satisfied_i∈I(min(D_i) Candidate central array element h of (c)_iAs a central array elementAnd will max_i∈I(min(D_i) Maximum radius r of UCA that can be generated as a base area array_max。

4. The antenna selection method for transmitting multi-mode multiplexed signals by a uniform area array as claimed in claim 1, wherein the step S3 comprises:

step S31, using central array elementEstablishing coordinate system for origin, initializing basic area arrayThe generated radius sequence R of the UCA is an empty set, and j is initialized to be 1; j represents the sequence number of the array elements in the basic area array, j belongs to {1, 2, 3 … N }, and N is the number of the array elements;

step S32, calculating any array element p in the basic area array_jTo the central array elementDistance d of_j；

Step S33, determining the distance d_jWhether it is larger than the maximum radius r of UCA that the basic area array can generate_maxIf yes, it indicates that the array element is not available for transmitting the multi-mode multiplexing signal, let j equal to j +1, go to step S32; if not, go to step S34;

step S34, judging whether d already exists in the sequence R_jIf not, d is added_jInserting the sequences into the sequence R from small to large;

step S35, let j equal j +1, repeat steps S32-S34 until j equal N, finally generate the increment sequence R (R ═ N)₁，r₂...r_k...r_n)。

5. The antenna selection method for transmitting multi-mode multiplexed signals by a uniform area array as claimed in claim 4, wherein the step S4 comprises:

step S41, initializing an array element set sequence C corresponding to different UCA radii as an empty set, and initializing j to 1; j represents the sequence number of the array elements in the basic area array, j belongs to {1, 2, 3 … N }, and N is the number of the array elements;

step S42, any array element p in the basic area array is calculated again_jTo the central array elementDistance d of_j；

Step S43, judging whether d exists in the radius sequence R of UCA which can be generated by the basic area array_jIf yes, find d equal to_jR of_kAnd the array element p is combined_jAdding with r_kArray element set C of corresponding different UCA radiuses_k；

Step S44, let j equal j +1, repeat steps 42-S43 until j equal N, and finally generate array element set sequence C (C ═ N)₁，C₂...C_k...C_n)。

6. The method as claimed in claim 4 or 5, wherein any element p in the basic area array is selected from a group consisting of a plurality of elements_jTo the central array elementDistance d of_jCalculated according to the following formula:

wherein 2a represents the array element spacing, x 'of the triangular grid array'_jRepresents p_jIn a central array elementAbscissa, y 'in a coordinate system of origin'_jRepresents p_jIn a central array elementIs the ordinate of the coordinate system of the origin.

7. The antenna selection method for transmitting multi-mode multiplexed signals by a uniform area array as claimed in claim 1, wherein the step S5 comprises:

step S51, the OAM modes l' to be verified are respectively 1, 2 and 3, and the minimum UCA radius r required when the maximum divergence angle of the OAM vortex electromagnetic wave beam is beta is calculated_i，min；

Step S52, when judging that l is 1, 2, 3, the calculated minimum UCA radius r_l，minWhether it is less than the maximum value in the radius sequence R of UCA generated by the basic area array, if soIf so, indicating that the OAM mode which can be transmitted by the basic area array comprises the current OAM mode l' to be verified, and transmitting r_l’，minMinimum UCA radius r required to join into a transmittable OAM mode_l，minSet R of_minIn (1), L is added to a set L of transmittable OAM modes L.

8. The method of claim 7, wherein the minimum UCA radius r required for the maximum divergence angle of the OAM vortex electromagnetic beam to be β is the minimum UCA radius r_l，minCalculated according to the following formula:

in the formula, l represents an OAM mode to be verified, and f represents the frequency of an OAM vortex electromagnetic wave.

9. The antenna selection method for transmitting multi-mode multiplexed signals by a uniform area array as claimed in claim 4, wherein the step S6 comprises:

step S61, finding the minimum UCA radius R needed by the OAM mode which can be transmitted or more from the radius sequence R of UCA which can be generated by the basic area array_i，minAnd is less than or equal to r_l+1，minAnd find the smallest r among them_k，r_kCorresponding array element set C_kI.e. the required set of array elements C'_k。

Step S62, calculating an array element set C'_kIn each array element p_m＝(x_m，y_m) Desired excitation phase θ_m。

10. The method of claim 9, wherein the set of array elements C 'are selected by the antenna for transmitting the multi-mode multiplexing signal through the uniform area array'_kIn each array element p_m＝(x_m，y_m) Desired excitation phase θ_mCalculated according to the following formula:

wherein l represents an OAM mode that can be transmitted, (x)_m，y_m) Representing array elements p_mThe coordinates of (a).

Technical Field

The present invention relates to a wireless communication system, and more particularly, to an antenna selection method for transmitting a multimode multiplexing signal through a uniform area array, which is suitable for an Orbital Angular Momentum (OAM) based multimode multiplexing communication system in microwave and millimeter wave bands.

Background

Multiplexing refers to the process and technique of transmitting multiple signals or data streams over one channel, and currently, commonly used multiplexing techniques include frequency division multiplexing, time division multiplexing, space division multiplexing, and the like. The multimode multiplexing technology is to use the orthogonality of electromagnetic wave transmission modes to realize multiplexing of multiple signals. Specifically, the electromagnetic waves radiated by the antenna have a wave-particle duality and can carry OAM like moving particles. So that each photon can carry(Representing reduced Planck constant, l is called topological load and l is an integer), different topological loads correspond to different OAM modes, the different OAM modes are orthogonal to each other, and multimode multiplexing transmission can be realized by utilizing the orthogonality of the OAM modes. The OAM of the electromagnetic wave is related to its phase space distribution, and when the phase plane of the electromagnetic wave is spiral, the electromagnetic wave is also called an OAM vortex electromagnetic wave.

At present, an OAM vortex electromagnetic wave is mainly emitted by using a uniform circular array (UCA, an antenna array composed of antenna units arranged at equal intervals on a circle). When the UCA transmits OAM vortex electromagnetic waves with the mode of l, the phase difference of adjacent UCA antenna units needs to meet the requirementWherein M is the number of UCA antenna units. Fig. 1 is a schematic diagram of an UCA with M-8 and l-1, where the antenna excitation phases are represented numerically. By changing the excitation phase difference of adjacent antennas, the UCA can emit OAM vortex electromagnetic waves in different modes.

However, the UCA is used as special hardware for transmitting OAM vortex electromagnetic waves, and customization cost is high, so that the cost for transmitting OAM multimode multiplexing signals by using the UCA is expensive, and the system development period is long. In addition, when the OAM vortex electromagnetic wave is generated by using the UCA, the beam divergence angle of the vortex electromagnetic wave is related to the UCA radius, the OAM vortex electromagnetic wave mode number and the transmission signal frequency:

2πr/f>1.02l+1.874

in the formula, β represents a beam divergence angle, l represents an absolute value of a number of modes of transmitting OAM vortex electromagnetic waves, f represents a signal frequency, and r represents a radius of UCA.

From the above equation, the beam divergence angle is proportional to the OAM vortex electromagnetic wave pattern number and inversely proportional to the transmission signal frequency and UCA radius. That is, the smaller the UCA radius, the larger the beam divergence angle of the generated OAM vortex electromagnetic wave. However, the radius of the UCA is fixed after the UCA is manufactured, and the beam divergence angle of the OAM vortex electromagnetic wave is also determined, so that the beam adjustment is not flexible. And, the OAM beam divergence angle is related to the OAM transmission distance, and the larger the beam divergence angle is, the smaller the transmission distance is. Thus, a fixed beam divergence angle of the OAM swirling electromagnetic wave means a fixed and unchangeable transmission distance, i.e. the OAM swirling electromagnetic wave can only be received by the receiving antenna within a distance range. These problems greatly limit the wide application of OAM communication systems, and it is necessary to develop a technology that is low in cost, short in period, and capable of flexibly adjusting beams.

The prior art has a uniform area array which has mature production and manufacturing technology, complete matching devices and low production and manufacturing cost and comprises a rectangular grid array, a hexagonal grid array and a triangular grid array. Fig. 2(a) -2 (c) show schematic diagrams of these three uniform area arrays, in which a rectangular grid array divides a plane into several rectangular grids, each antenna occupying the intersection of one grid; the hexagonal grid array divides a plane into a plurality of regular hexagonal grids, and each array element occupies the intersection point of one grid; the triangular grid array divides the plane into a plurality of regular triangular grids, and each array element occupies the intersection point of one grid. The three arrays are widely applied to the fields of military use, civil use, scientific research and the like, and if the three antenna arrays are used for emitting OAM vortex electromagnetic waves and realizing multimode multiplexing, the development period can be greatly shortened and the development cost can be reduced. However, the OAM vortex electromagnetic wave cannot be emitted on the above uniform area array using the prior art, and the flexible adjustment of the beam cannot be realized.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides an antenna selection method for transmitting multimode multiplexing signals through a uniform area array, which can reduce the cost and shorten the development period, and simultaneously can generate UCAs with different radiuses on the uniform area array, thereby controlling the divergence angle of OAM vortex electromagnetic waves through the change of the radius of the UCAs and realizing the function of adjusting the transmission distance of the OAM vortex electromagnetic waves.

An antenna selection method for transmitting a multimode multiplexed signal through a uniform area array, comprising:

step S1, selecting a rectangular grid array, a hexagonal grid array or a triangular grid array as a basic area array;

step S2, extracting a candidate central array element set from the basic area array, and determining the central array elements and the maximum radius of UCA which can be generated by the basic area array according to the candidate central array element set;

step S3, calculating the distance from any array element in the basic area array to the central array element, and determining the radius sequence of UCA which can be generated by the basic area array by combining the maximum radius of UCA which can be generated by the basic area array;

step S4, according to the radius sequence of UCA which can be generated by the basic area array, determining array element set sequences corresponding to different UCA radii;

step S5, the maximum divergence angle of the OAM vortex electromagnetic wave beam is given, and the OAM mode which can be emitted by the basic area array and the minimum UCA radius r required by the emitting OAM mode are calculated according to the UCA radius sequence which can be generated by the basic area array_l，min；

Step S6, according to the minimum UCA radius r required by the transmittable OAM mode_l，minFrom sets of array elements corresponding to different UCA radiiAnd extracting an array element set required by the transmittable OAM mode from the combined sequence, and calculating an excitation phase required by each array element in the array element set required by the transmittable OAM mode.

Further, the method for extracting the candidate central array element set in step S2 includes:

step S21, determining a set S of candidate intermediate rows and a set T of candidate intermediate columns of the basic area array according to the row number and the column number of the basic area array;

step S22, calculating a candidate central array element set H { (T, S) | T ∈ T ^ S ∈ S }, where T is a row number of a candidate intermediate row, S is a column number of a candidate intermediate column, and an element in the set H is a candidate central array element H_iI belongs to I, and I represents a set of candidate central array element sequence numbers.

Further, in the step S2, if the candidate central array element set H has only one element, the central array element of the basic area array is the only element of the candidate central array element set H; if the candidate central array element set H has two or more elements, determining the central array element of the basic area array comprises the following steps:

step S23, determining all edge array elements in the basic area array;

step S24, calculating each candidate central array element h_iDistance D to all edge array elements_iFrom D, and_ifind each candidate central array element h in the set_iMinimum distance min (D) to edge array element_i)；

Step S25, from each candidate central array element h_iMinimum distance min (D) to edge array element_i) Find the maximum value max_i∈I(min(D_i) Max) will be satisfied_i∈I(min(D_i) Candidate central array element h of (c)_iAs a central array elementAnd will max_i∈I(min(D_i) Maximum radius r of UCA that can be generated as a base area array_max。

Further, the step S3 includes:

step S31, using central array elementEstablishing a coordinate system for an origin, initializing a radius sequence R of UCA which can be generated by a basic area array as an empty set, and initializing j to 1; j represents the sequence number of the array elements in the basic area array, j belongs to {1, 2, 3 … N }, and N is the number of the array elements;

step S32, calculating any array element p in the basic area array_jTo the central array elementDistance d of_j；

Step S33, determining the distance d_jWhether it is larger than the maximum radius r of UCA that the basic area array can generate_maxIf yes, it indicates that the array element is not available for transmitting the multi-mode multiplexing signal, let j equal to j +1, go to step S32; if not, go to step S34;

step S34, judging whether d already exists in the sequence R_jIf not, d is added_jInserting the sequences into the sequence R from small to large;

step S35, let j equal j +1, repeat steps S32-S34 until j equal N, finally generate the increment sequence R (R ═ N)₁，r₂…r_k…r_n)。

Further, the step S4 includes:

step S41, initializing an array element set sequence C corresponding to different UCA radii as an empty set, and initializing j to 1; j represents the sequence number of the array elements in the basic area array, j belongs to {1, 2, 3 … N }, and N is the number of the array elements;

step S42, any array element p in the basic area array is calculated again_jTo the central array elementDistance d of_j；

Step S43, judging whether d exists in the radius sequence R of UCA which can be generated by the basic area array_jIf yes, find d equal to_jR of_kAnd the array element p is combined_jAdding with r_kArray element set C of corresponding different UCA radiuses_k；

Step S44, let j equal j +1, repeat steps 42-S43 until j equal N, and finally generate array element set sequence C (C ═ N)₁，C₂…C_k…C_n)。

Any array element p in the basic area array_jTo the central array elementDistance d of_jCalculated according to the following formula:

wherein 2a represents the array element spacing, x 'of the triangular grid array'_jRepresents p_jIn a central array elementAbscissa, y 'in a coordinate system of origin'_jRepresents p_jIn a central array elementIs the ordinate of the coordinate system of the origin.

Further, the step S5 includes:

step S51, the OAM modes l' to be verified are respectively 1, 2 and 3, and the minimum UCA radius r required when the maximum divergence angle of the OAM vortex electromagnetic wave beam is beta is calculated_l，min；

Step S52, when judging that l is 1, 2, 3, the calculated minimum UCA radius r_l，minIf the value is less than the maximum value in the radius sequence R of the UCA which can be generated by the basic area array, if so, the OAM mode which can be transmitted by the basic area array is shown to comprise the current OAM mode l' to be verified, and R is compared with the maximum value_l’，minMinimum UCA radius r required to join into a transmittable OAM mode_l，minSet R of_minIn (1), L is added to a set L of transmittable OAM modes L.

The above-mentionedMinimum UCA radius r required when maximum divergence angle of OAM vortex electromagnetic wave beam is beta_l，minCalculated according to the following formula:

in the formula, l represents an OAM mode to be verified, and f represents the frequency of an OAM vortex electromagnetic wave.

Further, the step S6 includes:

step S61, finding the minimum UCA radius R needed by the OAM mode which can be transmitted or more from the radius sequence R of UCA which can be generated by the basic area array_l，minAnd is less than or equal to r_l+1，minAnd find the smallest r among them_k，r_kCorresponding array element set C_kI.e. the required set of array elements C'_k。

Step S62, calculating an array element set C'_kIn each array element p_m＝(x_m，y_m) Desired excitation phase θ_m。

The array element set C'_kIn each array element p_m＝(x_m，y_m) Desired excitation phase θ_mCalculated according to the following formula:

wherein l represents an OAM mode that can be transmitted, (x)_m，y_m) Representing array elements p_mThe coordinates of (a).

The invention selects array elements in the uniform area array of the rectangular grid array, the hexagonal grid array or the triangular grid array and determines the excitation phase required by the array elements so as to generate UCAs with different radiuses on the uniform area array, thereby quickly adjusting the divergence angle of the OAM multi-mode multiplexing signals in application and realizing the flexible adjustment of beams. In addition, the invention can reduce the development cost of the OAM multimode multiplexing communication system, the OAM detection system and other systems and accelerate the project development speed.

Drawings

Fig. 1 is a schematic diagram of a uniform circular array having 8 antenna elements and 1 transmission mode.

Fig. 2(a) is a schematic diagram of a rectangular grid array, fig. 2(b) is a schematic diagram of a hexagonal grid array, and fig. 2(c) is a schematic diagram of a triangular grid array.

Fig. 3 is a flowchart of an antenna selection method for transmitting a multimode multiplexed signal through a uniform area array according to the present invention.

FIG. 4 is a schematic diagram of candidate intermediate and edge elements.

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 3, the method for selecting an antenna for transmitting a multimode multiplexed signal through a uniform area array according to the present invention includes the following steps:

step S1, selecting a rectangular grid array, a hexagonal grid array, or a triangular grid array as a basic area array, where the set of all array elements in the basic area array is P ═ P₁，p₂…p_N}，p_j＝(x_j，y_j) Representing any element, x, of the underlying area array_jLine number, y representing the array element_jThe array element is represented by a column number, j represents the sequence number of the array element in the basic area array, j belongs to {1, 2, 3 … N }, and N is the number of the array element. For convenience of illustration, the present embodiment describes the method of the present invention in detail by taking a triangular grid array as an example. It should be understood that the steps described with reference to the present embodiment may be used when selecting a rectangular grid array or a hexagonal grid array. Triangular grid array referring to fig. 2(c), the array element pitch is 2 a. Assuming a triangular grid array with s number of rows_numThe number of columns is t_num。

Step S2, extracting candidate central array element set H from the basic area array, and determining the central array element of the selected basic area array according to the candidate central array element setAnd the maximum radius r of UCA that the base area array can generate_max。

The method for extracting the candidate central array element set comprises the following steps:

and step S21, determining a set S of candidate intermediate rows and a set T of candidate intermediate columns of the basic area array according to the row number and the column number of the basic area array. The elements in set S represent the row numbers of the candidate intermediate rows and the elements in set T represent the column numbers of the candidate intermediate columns.

According to the number of rows s of the triangular grid array_numThe values are different, and there are two cases for the set S of candidate intermediate rows of the triangular grid array:

s_numwhen the number of the odd numbers is taken,s_numwhen the number of the even numbers is taken,

according to the number t of triangular grid array columns_numThe value of the set T of candidate intermediate columns of the triangular grid array is different from that of the candidate intermediate columns of the triangular grid array, and the set T has two conditions:

t_numwhen the number of the odd numbers is taken,t_numwhen the number of the even numbers is taken,

step S22, calculating a candidate central array element set H { (T, S) | T ∈ T ^ S ∈ S }, where T is a row number of a candidate intermediate row, S is a column number of a candidate intermediate column, and an element in the set H is a candidate central array element H_iI belongs to I, and I represents a set of candidate central array element sequence numbers. According to the above-mentioned s_numAnd t_numWith different values, triangular gridsH, I for the lattice array has several cases:

1)t_numis odd number, s_numIs odd, H ═ H₁}，I＝{1}；

2)t_numIs odd number, s_numIs even, H ═ H₁，h₂}，I＝{1，2}；

3)t_numIs an even number, s_numIs odd, H ═ H₁，h₂}，I＝{1，2}；

4)t_numIs an even number, s_numIs even, H ═ H₁，h₂，h₃，h₄}，I＝{1，2，3，4}。

If the candidate central array element set H only has one element, the element is the central array element; if the candidate central array element set H has two or more than two elements, the step of determining the central array element of the basic area array comprises the following steps:

and step S23, determining all edge array elements in the basic area array. Specifically, as shown in fig. 4, for any array element p in the basic area array_j＝(x_j，y_j) If (x)_j-1，y_j)、(x_j+1，y_j)、(x_j，y_j+1)、(x_j，y_j-1)、(x_j+1，y_j-1) and (x)_j-1，y_j+1) there is one or more array element in the position, and the array element is the edge array element.

Step S24, calculating each candidate central array element h_iDistance D to all edge array elements_iFrom D, and_ifind each candidate central array element h in the set_iMinimum distance min (D) to edge array element_i)。

Step S25, from each candidate central array element h_iMinimum distance min (D) to edge array element_i) Find the maximum value max_i∈I(min(D_i) Max) will be satisfied_i∈I(min(D_i) Candidate central array element h of (c)_iAs a central array elementMaximum radius r of UCA that can be generated by base area array_maxI.e. max_i∈I(min(D_i))。

Step S3, calculating any array element p in the basic area array_jTo the central array elementDistance d of_jAnd combining the maximum radius r of UCA generated by the basic area array_maxAnd determining the radius sequence R of UCAs which can be generated by the base area array. The method specifically comprises the following steps:

step S31, using central array elementEstablishing a coordinate system for an origin, initializing a radius sequence R of UCA which can be generated by a basic area array as an empty set, and initializing j to 1; wherein, the central array element is usedThe coordinate system of the origin is a coordinate system with the base vector at 60 deg., as shown in fig. 4.

Step S32, calculating any array element p in the basic area array according to the following formula_jTo the central array elementDistance d of_j：

Wherein 2a represents the array element spacing, x 'of the triangular grid array'_jRepresents p_jIn a central array elementAbscissa, y 'in a coordinate system of origin'_jRepresents p_jIn a central array elementIs the ordinate of the coordinate system of the origin.

Step S33, determining the distance d_jWhether it is larger than the maximum radius r of UCA that the basic area array can generate_maxIf yes, it indicates that the array element is not available for transmitting the multi-mode multiplexing signal, let j equal to j +1, go to step S32; if not, the process proceeds to step S34.

Step S34, judging whether d already exists in the sequence R_jIf not, d is added_jInserted into the sequence R in order from small to large.

Step S35, let j equal j +1, repeat steps S32-S34 until j equal N, finally generate the increment sequence R (R ═ N)₁，r₂…r_k…r_n)。

And step S4, determining array element set sequences C corresponding to different UCA radiuses according to the radius sequences R of UCAs which can be generated by the basic area array. The method specifically comprises the following steps:

step S41, initializing an array element set sequence C corresponding to different UCA radii as an empty set, and initializing j to 1;

step S42, any array element p in the basic area array is calculated again according to the following formula_jTo the central array elementDistance d of_j：

Step S43, judging whether d exists in the radius sequence R of UCA which can be generated by the basic area array_jIf yes, find d equal to_jR of_kAnd the array element p is combined_jAdding with r_kArray element set C of corresponding different UCA radiuses_k；

Step S44, let j equal j +1, repeat steps 42-S43 until j equal N, and finally generate array element set sequence C (C ═ N)₁，C₂…C_k…C_n)。

Step S5, giving the maximum divergence angle of the OAM vortex electromagnetic wave beamRadius sequence R of UCA which can be generated by the base area array, OAM mode which can be transmitted by the base area array and minimum UCA radius R required by the transmittable OAM mode are determined_l，min. The method specifically comprises the following steps:

step S51, the OAM modes l' to be verified are respectively 1, 2 and 3, and the minimum UCA radius r required by the OAM modes to be verified when the maximum divergence angle of the OAM vortex electromagnetic wave beam is beta is calculated according to the following formula_l′，min：

In the formula, l' represents an OAM mode to be verified, and f represents the frequency of an OAM vortex electromagnetic wave.

Step S52, when the OAM mode l' to be verified is judged to be 1, 2 and 3 respectively, the calculated minimum UCA radius r_l，minIf the value is less than the maximum value in the radius sequence R of the UCA which can be generated by the basic area array, if so, the OAM mode which can be transmitted by the basic area array is shown to comprise the current OAM mode l' to be verified, and R is compared with the maximum value_l′，minMinimum UCA radius r required to join into a transmittable OAM mode_l，minSet R of_minIn (2), L' is added to the set L of transmittable OAM modes L.

Step S5 may calculate the OAM mode that can be transmitted and the minimum UCA radius of each mode in the case where the beam maximum divergence angle is β. When the mode of transmitting the OAM vortex electromagnetic wave is changed, the UCA radius may be quickly adjusted according to the result of step S5 to ensure the alignment between the transceiving antennas. R can also be recalculated by changing beta when the transmission distance changes_minAnd L, ensuring the alignment between the transmitting and receiving antennas.

Step S6, according to the minimum UCA radius r required by the transmittable OAM mode_l，minExtracting an array element set C 'required by an OAM mode capable of being transmitted from array element set sequences C corresponding to different UCA radiuses'_kAnd calculating an array element set C'_kThe required excitation phase for each array element. The method specifically comprises the following steps:

step S61, generating from the basic area arrayFinding a radius sequence R of UCA which satisfies R or more_l，minAnd is less than or equal to r_l+1，minAnd find the smallest r among them_k，r_kCorresponding array element set C_kI.e. the required set of array elements C'_k. Wherein r is_l+1，minIndicating the minimum UCA radius required for the previous mode of the OAM mode l that can be transmitted.

In step S62, an array element set C 'is calculated according to the following formula'_kIn each array element P_m＝(x_m，y_m) Desired excitation phase θ_m：

Wherein l represents an OAM mode that can be transmitted, (x)_m，y_m) Representing array elements P_mIn a central array elementCoordinates in a coordinate system as origin.

The method for transmitting the multimode multiplexing signal by using the uniform area array can be applied to microwave and millimeter wave band OAM multimode multiplexing communication systems. The invention utilizes the uniform area array to transmit the multi-mode multiplexing signals and provides the excitation phase required by each array element when transmitting the multiplexing signals of different modes. The method can generate UCAs with different radiuses, so that the divergence angle of the OAM multimode multiplexing signals can be quickly adjusted in application, and compared with the traditional UCAs, the method is more flexible. The method makes full use of the prior art and devices, can reduce the development cost of an OAM multimode multiplexing communication system, an OAM detection system and other systems, and accelerates the project development speed.

The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.