CN118095006A - Antenna radiation field calculation method based on electromagnetic dipole array - Google Patents
Antenna radiation field calculation method based on electromagnetic dipole array Download PDFInfo
- Publication number
- CN118095006A CN118095006A CN202410264122.5A CN202410264122A CN118095006A CN 118095006 A CN118095006 A CN 118095006A CN 202410264122 A CN202410264122 A CN 202410264122A CN 118095006 A CN118095006 A CN 118095006A
- Authority
- CN
- China
- Prior art keywords
- magnetic
- antenna
- electric
- field
- dipole
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000005855 radiation Effects 0.000 title claims abstract description 124
- 238000004364 calculation method Methods 0.000 title claims abstract description 60
- 238000004422 calculation algorithm Methods 0.000 claims abstract description 15
- 230000002068 genetic effect Effects 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 12
- 238000005070 sampling Methods 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 49
- 230000005684 electric field Effects 0.000 claims description 24
- 238000004088 simulation Methods 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 5
- 230000005484 gravity Effects 0.000 claims description 3
- 239000008186 active pharmaceutical agent Substances 0.000 claims description 2
- 239000000306 component Substances 0.000 description 12
- 230000003071 parasitic effect Effects 0.000 description 9
- 230000014509 gene expression Effects 0.000 description 7
- 238000004458 analytical method Methods 0.000 description 6
- 238000005457 optimization Methods 0.000 description 5
- 238000013461 design Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000005284 excitation Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- 239000002184 metal Substances 0.000 description 2
- 230000005405 multipole Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 208000000044 Amnesia Diseases 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 230000011218 segmentation Effects 0.000 description 1
Landscapes
- Variable-Direction Aerials And Aerial Arrays (AREA)
Abstract
The invention discloses an antenna radiation field calculation method based on an electromagnetic dipole array, which comprises the following steps: dividing the surface of an antenna of a radiation field to be calculated into a plurality of parts according to materials and structures, taking points on each part, and obtaining equivalent electric and magnetic current densities at the points by utilizing a Huygens principle; placing an electric (magnetic) dipole at a point with non-zero electric (magnetic) current density, wherein the electric (magnetic) current density on the electric (magnetic) dipole is equal to the electric (magnetic) current density at the point, and the direction of the electric (magnetic) dipole is the direction of the electric (magnetic) current at the point, so as to obtain an equivalent dipole array model of the antenna; determining the weighting coefficient of each part according to the area proportion of each part and the number of the sampling points, multiplying the field excited by each part of infinitesimal electric dipole and magnetic dipole by the weighting coefficient of the part, and then summing to obtain the antenna radiation field calculation result; and optimizing the weighting coefficient by adopting a genetic algorithm to obtain a final calculation result of the antenna radiation field.
Description
Technical Field
The invention relates to the field of antenna design and wireless communication, in particular to an antenna radiation field calculation method based on an electromagnetic dipole array.
Background
Antennas are important devices for radiating and receiving electromagnetic signals and are a core component of wireless systems such as radar, communication and navigation, so the radiation characteristics of the antennas have a significant impact on the performance of these systems. The radiation characteristics of the antenna are different in near-field areas and far-field areas, and although a large number of traditional applications work in the far-field areas of the antenna, such as a communication base station, a broadcasting station and the like, along with the development of wireless technology, near-field application scenes of the antenna are also increasing, such as a large-scale MIMO array, a stealth aircraft, non-contact charging and the like. Thus, accurately and efficiently obtaining the far and near field radiation characteristics of an antenna is critical to the design and performance analysis of these systems.
The antenna radiation characteristics can be studied from three aspects of theoretical analysis, numerical calculation and experimental test. In the aspect of theoretical analysis, through solving maxwell's equation set of corresponding boundary conditions, the radiation field analysis solution of simple and regular antennas such as line antennas, loop antennas and slot antennas can be obtained, but is difficult to be directly applied to microstrip and waveguide antennas with complex boundaries and structures.
In terms of numerical computation, typical numerical computation methods include a moment Method (Method of Moments, moM), a Finite Element Method (FEM), a Multi-layer fast multipole algorithm (Multi LEVEL FAST Multipole Method, MLFMM), etc., and these methods solve the problem of solving the radiation field, but they are too large in computation amount, especially for antennas with high complexity and large size, and are often performed by means of antenna simulation software. In the far field simulation, software simulation only calculates the angular distribution of the radiation field, and if the radiation field on any area such as a line segment or a surface at a position far from the antenna is wanted, the simulation process is limited by the memory of the computer, and the conditions of overlong running time, incapability of solving even and the like occur.
In the aspect of experimental test, the radiation characteristics of the antenna can be tested by utilizing environments such as a microwave darkroom and the like and by means of instruments such as a network analyzer, a turntable and the like, but the near-field radiation characteristics and the far-field radiation characteristics of the antenna are obtained through the test, so that time and labor are wasted, and the direct connection between the radiation characteristics of the antenna and the structure of the antenna cannot be obtained. In addition, due to the limitation of the test field, it is difficult to obtain a radiation field in any region at a position far from the antenna.
In summary, the numerical calculation is an important way to obtain the antenna radiation field, but the main drawbacks of the existing numerical calculation method include:
(1) The essential link between the radiation characteristics and the antenna structure cannot be represented.
(2) And cannot be applied to the solution of the near field region and the far field region at the same time.
(3) The amount of computation grows exponentially with the antenna size and spatial distance, and cannot be calculated for radiation fields of complex structure, large scale and long distance.
Through searching, at present, a method for searching an infinite small electric dipole model of an antenna with a known near field by adopting a particle swarm optimization algorithm exists, and the method is simultaneously suitable for radiation field calculation of a near field region and a far field region, is small in calculation amount, and has good consistency with a simulation result. However, the equivalent electric dipole array model of the method is distributed in the antenna, so that the essential relation between the radiation characteristic and the antenna structure cannot be represented, and the method has more iteration times and larger calculated amount in the stage of obtaining the equivalent electric dipole model of the antenna.
Therefore, it is highly desirable to provide a method for calculating and analyzing the radiation characteristics of an antenna, which can embody the relationship between the radiation characteristics and the antenna structure, is suitable for antennas with complex structures, can be applied to far fields and near fields, and is efficient, rapid and small in calculation amount.
Disclosure of Invention
The invention aims to: the invention provides an electromagnetic dipole array-based antenna radiation field calculation method, which aims to solve the defects that the existing antenna radiation field calculation method is large in calculation amount, is not suitable for antennas with different structures, cannot be simultaneously suitable for solving near-field areas and far-field areas, cannot reflect essential relations between radiation characteristics and antenna structures and the like.
The technical scheme is as follows: an antenna radiation field calculation method based on an electromagnetic dipole array comprises the following steps:
dividing the antenna surface of a radiation field to be calculated according to materials and structures, dividing the antenna surface into a plurality of parts, taking points on each part, and obtaining equivalent electric and magnetic current densities at the points by utilizing a Huygens principle and magnetic and electric field intensities at the points;
Placing an electric dipole at a point with non-zero current density, wherein the current density of the electric dipole is equal to the current density of the point, the direction of the electric dipole is the direction of the current of the point, and placing a magnetic dipole at a point with non-zero magnetic current density, the magnetic current density of the magnetic dipole is equal to the magnetic current density of the point, and the direction of the magnetic dipole is the direction of the magnetic current of the point, so that an equivalent dipole array model of the antenna is obtained;
Determining the weighting coefficients of the radiation fields of the electric dipole array and the magnetic dipole array of each part in the total radiation field of the antenna according to the area proportion of each part and the number of the sampling points, multiplying the field excited by each part of infinitesimal electric dipole and the field excited by each magnetic dipole by the weighting coefficient of the part, and then summing to obtain the calculation result of the radiation field of the antenna;
and optimizing and adjusting the weighting coefficients of the electric dipoles and the magnetic dipoles of each part by adopting a genetic algorithm to obtain a final calculation result of the antenna radiation field.
Further, the method divides the antenna surface of the radiation field to be calculated into a plurality of parts according to materials and structures, takes points on each part, and obtains equivalent electric and magnetic current densities at the points by utilizing the Huygens principle and the magnetic and electric field intensities at the points, which comprises the following steps:
Dividing the antenna surface of the radiation field to be calculated according to the material and structure, dividing the antenna surface into a plurality of parts, taking points on each part, assuming that the antenna surface is divided into Y parts, sequentially numbering the Y parts with y=1, 2, … and Y, the number of points taken by the Y part is N y, uniformly distributing the points, sequentially numbering the points with (Y, 1), (Y, 2), …, (Y, N y), DS (y,k) represents the area of the grid where the point (y, k) is located;
The area of each part is denoted by S y:
S y is regarded as the coefficient of the specific gravity of the electric dipole and the magnetic dipole of each part in the generated antenna radiation field;
a discrete format based on huygens principle, expressed as:
HJ,r,n＝HJ,θ,n＝0
EJ,φ,n＝0
EM,r,n＝EM,θ,n＝HM,φ,n＝0
En＝EJ,n+EM,n
Hn＝HJ,n+HM,n
Wherein:
Er,n＝EJ,r,n+EM,r,n,Hr,n＝HJ,r,n+HM,r,n
Eφ,n＝EJ,φ,n+EM,φ,n,Hφ,n＝HJ,φ,n+HM,φ,n
Eθ,n＝EJ,θ,n+EM,θ,n,Hθ,n＝HJ,θ,n+HM,θ,n
Wherein H J,r,n,HJ,θ,n,HJ,φ,n sequentially represents the r, theta and phi components of the magnetic field strength H generated by the equivalent current at the nth observation point under the spherical coordinate system;
j s,(y,z) denotes the equivalent current density at the (y, z) th point of the antenna surface;
θ (y,z),n represents the included angle formed by the electromagnetic dipole direction at the (y, z) th point of the antenna surface and the connection line between the nth observation point and the point;
R (y,z),n represents the distance between the (y, z) th point and the nth observation point of the antenna surface;
k represents wave number;
E J,r,n,EJ,θ,n,EJ,φ,n sequentially represents the r, theta and phi components of the electric field strength E excited by the equivalent current at the nth observation point under the spherical coordinate system;
η represents the wave impedance;
E M,r,n,EM,θ,n,EM,φ,n represents the r, θ, phi components of the electric field strength E of the field excited by the equivalent magnetic current at the nth observation point under the spherical coordinate system;
M s,(y,z) represents the equivalent magnetic current density at the (y, z) th point of the antenna surface;
H M,r,n,HM,θ,n,HM,φ,n represents the r, θ, phi components of the magnetic field strength H of the field excited by the equivalent magnetic current at the nth observation point in the spherical coordinate system;
E J,n、EM,n represents the electric field strength excited by the equivalent current and the equivalent magnetic current at the nth observation point respectively;
H J,n、HM,n represents the magnetic field strength excited by the equivalent current and the equivalent magnetic current at the nth observation point, respectively;
E n,Hn denotes the field excited by the equivalent electromagnetic current at the nth observation point.
Further, the method determines the weighting coefficients of the radiation fields of the electric dipole array and the magnetic dipole array of each part in the total radiation field of the antenna according to the area proportion of each part and the number of the sampling points, and sums the weighted coefficients of the parts after the fields excited by the infinitesimal electric dipoles and the magnetic dipoles of each part are multiplied to obtain the calculation result of the radiation field of the antenna, and specifically comprises the following steps:
In the method, in the process of the invention, Representing the calculation result of the electric field excited by the electric dipole array of the y-th part at the nth observation point,/>Representing the calculation result of the electric field excited by the magnetic dipole array of the y-th part at the nth observation point,/>Representing the calculation result of the magnetic field excited by the electric dipole array of the y-th part at the nth observation point,/>Representing the calculation result of the magnetic field excited by the magnetic dipole array of the y-th part at the n-th observation point; /(I)Wherein the symbols/>Representing an upward rounding.
Further, the genetic algorithm is adopted to perform optimization adjustment on the weighting coefficients of the electric dipole and the magnetic dipole of each part, so as to obtain a final calculation result of the antenna radiation field, and the method specifically comprises the following steps:
Constructing an objective function:
find χ＝[C1 C2 … CY]
s.t.Cy≥0
In the method, in the process of the invention, Simulating simulation results obtained by simulating electric field intensity and magnetic field intensity excited by an antenna of a radiation field to be calculated at a plurality of points in space by adopting full-wave simulation software;
Solving an objective function by adopting a genetic algorithm to obtain χ corresponding to the minimum F, and obtaining the area proportion of each part of the antenna of the radiation field to be calculated based on the χ corresponding to the minimum F;
And determining the weighting coefficients of the radiation fields of the electric dipole array and the magnetic dipole array of each part in the total radiation field of the antenna according to the area proportion of each part of the antenna of the radiation field to be calculated and the number of the taking points, multiplying the field excited by each part of the infinitesimal electric dipole and the magnetic dipole by the weighting coefficient of the part, and then summing to obtain the calculation result of the radiation field of the antenna.
Further, the method for solving the objective function by adopting the genetic algorithm to obtain χ corresponding to the minimum F specifically includes:
Step 1: initialization of The value of each element in χ 0 is determined by the area ratio of each part; let i=0, and determine the threshold value threshold, max_for, calculate the value of F i, if F i < threshold, stop the calculation, output the/>, corresponding to the minimum F i yOtherwise give Y variants of χ i/>Select three/>, with the minimum F i y valueIs marked as/>
Step 2: according to the givenCalculating F i 1,Fi 2,Fi 3;
Step 3: if F i y < threshold exists or the number of loops reaches Max_for, stopping calculation and outputting the corresponding minimum F i y Otherwise give Y variants of χ i/>Selecting three with minimum F i y valueAssignment to/>, from small to largeLet i=i+1, return to step 2.
The beneficial effects are that: compared with the prior art, the invention has the following advantages:
(1) The method focuses on the calculation of the antenna radiation field, provides a discrete format of the Huygens principle, and further obtains an equivalent electromagnetic dipole array model of the antenna; the step of obtaining the equivalent electromagnetic dipole array model of the antenna from the discrete format of the Huygens principle is to simplify the discrete format first and then optimize the proportionality coefficient by using a genetic algorithm; wherein the simplification of the discrete format includes: the antenna surface is divided into a plurality of parts according to materials and positions, points are uniformly taken in each part, and compared with the calculation directly performed by using a discrete format, the memory loss of one multiplication calculation can be saved at each point; according to the existing knowledge and observation of the electromagnetic current distribution on the surface of the antenna, electric dipoles or magnetic dipoles in some parts are removed, so that the calculated amount is reduced;
(2) Compared with the method for directly utilizing the particle swarm optimization algorithm to obtain the equivalent electric dipole array model, the method for obtaining the equivalent electromagnetic dipole array model and the radiation field of the antenna can intuitively embody the connection between the antenna structure and the radiation field and guide the design and optimization of the antenna. Since the distribution rule of the equivalent electromagnetic dipoles in various antenna structures such as a patch, a dielectric plate, a ground plane and the like can be obtained from the equivalent electromagnetic dipole model, the radiation field of the infinitesimal electromagnetic dipoles is known, how each part of the structure of the antenna contributes to the whole radiation field can be obtained through the contribution of each electromagnetic dipole to the whole radiation field, and the relation between the antenna structure and the radiation field is obtained; in addition, in the method, the determination of the initial value of the parameter (each part of the proportionality coefficient) of the optimization problem has a theoretical basis, so that the error between the initial value and the optimal parameter is small, and the optimal parameter can be obtained with a small number of iteration times;
(3) Compared with a complete numerical method, the method is a semi-analytic method, after a dipole array model is obtained by a numerical method, the radiation field of a single electric (magnetic) dipole is calculated by using the radiation field expression of the electric (magnetic) dipole, and then the radiation fields of the dipole array are overlapped to obtain an antenna radiation field; the calculation amount is not increased when calculating the radiation field of the line segment and the plane far away from the antenna;
(4) Compared with a complete resolution method, the half resolution method is applicable to antennas with known arbitrary design parameters.
Drawings
FIG. 1 is a block diagram of an antenna radiation field calculation concept;
FIG. 2 is a schematic diagram of a Huygens principle discrete format;
FIG. 3 is a schematic diagram of a three-polarized antenna structure;
Fig. 4 is a three-polarized antenna S parameter;
FIG. 5 is a schematic diagram of a radiation field calculation position;
FIG. 6 is a graph of the radiation field component at face1 when PORT1 is excited;
FIG. 7 is a graph of the radiated field component at face2 when PORT1 is energized;
FIG. 8 is a radiation field component on face1 when PORT2 is excited;
FIG. 9 is a graph of the radiation field components at face2 when PORT2 is excited;
FIG. 10 is a plot of the radiated field component at face1 when PORT3 is energized;
FIG. 11 is a plot of the radiation field component at face2 when PORT3 is energized;
FIG. 12 is a comparison of PORT1 excitation far field radiation patterns; wherein (a) in fig. 12 is an XOY plane, (b) in fig. 12 is an XOZ plane, and (c) in fig. 12 is a YOZ plane;
FIG. 13 is a comparison of PORT2 excitation far field radiation patterns; wherein (a) in fig. 13 is an XOY plane, (b) in fig. 13 is an XOZ plane, and (c) in fig. 13 is a YOZ plane;
fig. 14 is a comparison of PORT3 excitation far-field radiation patterns, where (a) in fig. 14 is the XOY plane, (b) in fig. 14 is the XOZ plane, and (c) in fig. 14 is the YOZ plane.
Detailed Description
The technical scheme of the invention is further described with reference to the accompanying drawings and the embodiments.
In the antenna theory, huyghen's principle is a method for calculating an antenna radiation field by using equivalent electricity and magnetic current of an antenna surface, and the equivalent current J s and the equivalent magnetic current M s can be obtained by the following formula:
Wherein, Assuming that the surface of the antenna is S, the electric field strength and the magnetic field strength on the outer surface of S are E, H, respectively, for the antenna surface unit external normal vector.
The electric field E and the magnetic field H excited by the antenna in space are calculated using the following electromagnetic flow radiation field calculation formula:
E＝EA+EF
H＝HA+HF
where ω denotes the angular frequency of the equivalent electric (magnetic) current at the antenna surface, μ denotes the permeability of the medium, ε denotes the dielectric constant of the medium, A denotes the vector potential of the magnetic induction B, i.e F represents the vector potential of the displacement current D, i.eR represents the distance between the equivalent electric (magnetic) current source of the antenna surface and the observation point in space; /(I)Representing the gradient of a scalar,/>Representing the divergence of the vector,/>The rotation of the vector is represented by H A, the magnetic field strength generated by the current, E A, the electric field strength generated by the current, E F, the magnetic field strength generated by the magnetic current, H F, and j, the imaginary unit.
According to the Huygens principle and the electromagnetic radiation field calculation formula, the radiation field calculation formulas of various antennas such as a patch antenna, a slot antenna, a horn antenna and the like are obtained, and the radiation field of the antenna can be calculated by using the parameters of the antenna. However, for antennas with more complex structures, it is difficult to obtain expressions of J s and M s with respect to antenna parameters, and it is more difficult to obtain expressions of radiation fields with respect to antenna parameters.
The values of J s and M s at discrete points are obtained by a numerical method, which is feasible for any antenna, so this embodiment proposes a huyghen principle discrete format according to the following: the in-plane electric (magnetic) flow can be equivalent to an array excitation field consisting of an infinite number of infinitesimal electric (magnetic) dipoles. Specifically, for any antenna, the antenna model surface may be meshed into a limited number of small meshes, numbered i=1, 2, …, P in sequence, and the area is dS i in sequence. A point is taken at the geometric center of each grid, the number of which is the grid number containing the point, so that P points are taken on the antenna surface. Only the equivalent electric (magnetic) current density J s,i(Ms,i at the P points is obtained, it can be approximately assumed that in the ith grid, the equivalent electric (magnetic) current density at any point is J s,i(Ms,i, and the distance between the observation point and any point in the grid is equal to the distance between the observation point and the center point of the grid, so that the approximation value of the electric (magnetic) current radiation field can be calculated by only using the values of J s and M s at discrete points.
With the above notation, the discrete format expression is as follows:
HJ,r,n＝HJ,θ,n＝0
EJ,φ,n＝0
EM,r,n＝EM,θ,n＝HM,φ,n＝0
En＝EJ,n+EM,n
Hn＝HJ,n+HM,n
Wherein H J,r,n,HJ,θ,n,HJ,φ,n sequentially represents the r, theta and phi components of the magnetic field strength H generated by the equivalent current at the nth observation point under the spherical coordinate system; θ i,n represents an included angle formed by the direction of an electric (magnetic) dipole at the ith point of the model surface and the connecting line of the nth observation point and the ith point; r i,n represents the distance between the i-th point and the n-th observation point taken by the model surface; k represents wave number, and the relation between the wave number and angular frequency omega of source electromagnetic (magnetic) flow, dielectric constant epsilon of medium and magnetic permeability mu of medium is E J,r,n,EJ,θ,n,EJ,φ,n sequentially represents the r, theta and phi components of the electric field strength E excited by the equivalent current at the nth observation point under the spherical coordinate system; η represents the wave impedance; similarly, E M,r,n,EM,θ,n,EM,φ,n,HM,r,n,HM,θ,n,HM,φ,n represents the field excited by the equivalent magnetic current at the nth observation point; e J,n、EM,n represents the electric field strength excited by the equivalent current and the equivalent magnetic current at the nth observation point respectively; h J,n、HM,n represents the magnetic field strength excited by the equivalent current and the equivalent magnetic current at the nth observation point, respectively; e n,Hn denotes the field excited by the equivalent electromagnetic current at the nth observation point. A schematic of the discrete format is shown in fig. 2.
In the above expression, let the expression of p→infinity, dS i→0,En,Hn be equal to the expression of the equivalent electric, magnetic current excited radiation field obtained by huyghen's principle, so theoretically, when the grid division is infinitely dense, the radiation field calculated by the discrete format is equal to the equivalent electric, magnetic current excited radiation field obtained by huyghen's principle.
When the simulation software performs grid segmentation on the surface of the antenna model, the antenna materials are the same, the geometric rule is adopted, and the size of the grid is uniform. The above discrete format can be further simplified.
Depending on the material and structure of the antenna pattern, the antenna surface may be divided into Y parts, each of which is substantially uniformly distributed at points taken inside, the Y parts being numbered y=1, 2, …, Y in sequence. Assuming that the number of points taken in the y-th part is N y, the points taken are sequentially numbered (y, 1), (y, 2), …, (y, N y), thenThe area of each part is denoted by S y, and it can be seen that:
At this time, the above formula can be further simplified as:
HJ,r,n＝HJ,θ,n＝0
EJ,φ,n＝0
EM,r,n＝EM,θ,n＝HM,φ,n＝0
En＝EJ,n+EM,n
Hn＝HJ,n+HM,n
Wherein:
Er,n＝EJ,r,n+EM,r,n,Hr,n＝HJ,r,n+HM,r,n
Eφ,n＝EJ,φ,n+EM,φ,n,Hφ,n＝HJ,φ,n+HM,φ,n
Eθ,n＝EJ,θ,n+EM,θ,n,Hθ,n＝HJ,θ,n+HM,θ,n
Placing an electric dipole at a point with non-zero current density, wherein the current density of the electric dipole is equal to the current density of the point, the direction of the electric dipole is the direction of the current of the point, and placing a magnetic dipole at a point with non-zero magnetic current density, the magnetic current density of the magnetic dipole is equal to the magnetic current density of the point, and the direction of the magnetic dipole is the direction of the magnetic current of the point, so that an equivalent dipole array model of the antenna is obtained; determining the weighting coefficients of the radiation fields of the electric dipole array and the magnetic dipole array of each part in the total radiation field of the antenna according to the area proportion of each part and the number of the sampling points, multiplying the field excited by each part of infinitesimal electric dipole and the field excited by each magnetic dipole by the weighting coefficient of the part, and then summing to obtain the calculation result of the radiation field of the antenna; where S y can be regarded as a coefficient representing the specific gravity of the dipoles of the different parts in the generated place. Since the present embodiment focuses on only the normalized field in the final generated field, it can be used Instead of S y, where the symbol/>Representing an upward rounding.
It can be seen that the radiation field of the antenna is not related to the micro-element dS (y,i) of each partial grid area, but only related to the area S y of each partial grid area, and only the uniform grid division on each partial grid is required to be ensured. Since the above defines that the point to be fetched is at the geometric center of the mesh, it can be considered that the mesh division is uniform in each part as long as the point to be fetched is uniform in that part. Therefore, in the actual step of discretizing the equivalent electric and magnetic current of the antenna surface, the mesh division is not needed on the antenna model surface, the antenna model surface is only needed to be divided into a plurality of parts according to the materials and the structures, the points are evenly taken on each part, and then the equivalent electric and magnetic current density at the points is only obtained, so that the subsequent step can be carried out.
Converting the values of the field of the antenna in a spherical coordinate system into values in a rectangular coordinate system:
The result of the obtained field will have some errors due to the previous approximation, and then the electric field strength and the magnetic field strength obtained by the full wave simulation software at K (K < N) points in the space will be selected as ideal values, respectively It is indicated that C y is adjusted with a genetic algorithm to make the difference between the calculation result and the simulation result smaller.
For ease of representation, these points are still numbered with n=1, 2, …, K. By usingRepresenting the calculation result of the electric field excited by the electric dipole array of the y-th part at the nth observation point,/>Representing the calculation result of the electric field excited by the magnetic dipole array of the y-th part at the nth observation point,/>Representing the calculation result of the magnetic field excited by the electric dipole array of the y-th part at the nth observation point,/>Representing the calculation result of the magnetic field excited by the magnetic dipole array of the y-th portion at the n-th observation point, then:
This translates the problem of finding the optimal parameter C y into the following minimum problem:
find χ＝[C1 C2 … CY]
s.t.Cy≥0.
Adopting a genetic algorithm to adjust C y, wherein the specific steps comprise:
Step 1: give an initial value The values of the elements in χ 0 are determined by the area ratio of the parts, i.e./>Let i=0 and determine the threshold, max_for the maximum number of cycles. The value of F i was calculated. If F i < threshold exists, stopping calculation and outputting/>, corresponding to the minimum F i y Otherwise give Y variants of χ i/>
Step 2: according to the givenCalculate F i 1,Fi 2,Fi 3.
Step 3: if F i y < threshold exists or the number of loops has reached Max_for, stopping calculation and outputting the corresponding minimum F i y Otherwise give Y variants of χ i/>
Step 4: handle variantsAnd substituting the value of (3) into F to calculate to obtain F i y. If the individuals in F i y meet F i y < threshold, stopping calculation and outputting the/>, corresponding to the minimum F i y Otherwise, select the three/>, with the smallest F i y valueAssignment to/>, from small to largeLet i=i+1, return to step 2.
In order to verify the correctness of the method and the applicability of the method to the antenna with the complex structure, a tripolar antenna with the complex structure is selected for radiation field calculation.
The three-polarization antenna with complex structure selected in this embodiment is composed of a main radiation patch, a parasitic radiation patch, an inner and outer ring via hole and a metal grounding plate, and the structure is as shown in fig. 3. The dielectric plate is made of two layers of FR4 (epsilon r =4.4) materials, the main radiation patch is positioned on the upper surface of the upper dielectric plate, the parasitic radiation patch is positioned between the two layers of dielectric plates, the main radiation patch and the parasitic radiation patch are parallel to the XOY plane, and the bottom of the lower dielectric plate is a rectangular metal grounding plate. The antenna structure is provided with an inner ring of via holes and an outer ring of via holes, the outer ring of 8 via holes is connected with the grounding plate and the main radiation patch, the angle between the adjacent via holes is 45 degrees, the inner ring of 12 via holes is connected with the main radiation patch and the parasitic radiation patch, and the angle between the adjacent via holes is 30 degrees. The three PORTs are all fed by adopting coaxial probes, the coaxial lines are connected with the main radiation patch and the grounding plate, the PORT1 is positioned at the center of a circle, the PORT2 and the PORT3 are respectively positioned on the x axis and the y axis, and because the PORT1 needs to pass through the parasitic radiation patch, a small hole with the diameter of d 3 is formed in the middle of the parasitic radiation patch, and therefore, the parasitic radiation patch can also be regarded as an annular patch. The parasitic radiation patch and the inner and outer ring via holes play a role in adjusting the resonant frequency and reducing the coupling between ports.
The S parameters of the triple polarized antenna are shown in fig. 4. When PORT1 is excited, the antenna is well matched at 3.47-3.58GHz, the bandwidth is 110MHz, when PORT2 is excited, the antenna is well matched at 3.47-3.57GHz, the bandwidth is 100MHz, and when PORT3 is excited, the antenna is well matched at 3.47-3.57GHz, and the bandwidth is 100MHz. The center frequency of the antenna is 3.5GHz, the public bandwidth is 100MHz (3.47-3.57 GHz), and the relative bandwidth is 2.9%.
According to the method provided by the embodiment, an equivalent electromagnetic dipole array model of the three-polarization antenna is provided: the three-pole antenna is equivalent to an infinitesimal electric and magnetic dipole array, and the positions, directions and amplitudes of the infinitesimal electric and magnetic dipoles are determined by the current on the surfaces of the main radiation patch, the parasitic radiation patch and the inner and outer ring through holes and the magnetic current distribution on the surface of the dielectric plate.
By using the method provided by the embodiment, the radiation field of the tri-polarization antenna is calculated and compared with the simulation result of the full-wave numerical simulation software FEKO. For convenience of displaying the near field result, the near field computing position is selected from two planes parallel to the XOY plane, and the distances d between the near field computing position and the XOY plane are respectively 0.5λ and 2λ. The position of the two planes can be expressed in coordinates as:
face1:x＝-2.3λ～2.3λ,y＝-2.3λ～2.3λ,z＝0.5λ
face2:x＝-2.3λ～2.3λ,y＝-2.3λ～2.3λ,z＝2λ
Where λ=85.7 mm, as shown in fig. 5.
As can be seen from fig. 6 to 11, the near field result of the analysis of the triple polarized antenna by the method of the present embodiment is substantially identical to the FEKO simulation result. For far field results, far field patterns of the tri-polarized antennas XOY, XOZ, YOZ were calculated. Comparing the calculation result with the far field pattern result obtained by simulation in the FEKO software, the results are shown in fig. 12-14, and it can be seen that the calculation result and the far field pattern result are basically consistent, so that the effectiveness and the correctness of the method of the embodiment are verified.
Claims (5)
1. An antenna radiation field calculation method based on an electromagnetic dipole array is characterized by comprising the following steps of: comprising the following steps:
dividing the antenna surface of a radiation field to be calculated according to materials and structures, dividing the antenna surface into a plurality of parts, taking points on each part, and obtaining equivalent electric and magnetic current densities at the points by utilizing a Huygens principle and magnetic and electric field intensities at the points;
Placing an electric dipole at a point with non-zero current density, wherein the current density of the electric dipole is equal to the current density of the point, the direction of the electric dipole is the direction of the current of the point, and placing a magnetic dipole at a point with non-zero magnetic current density, the magnetic current density of the magnetic dipole is equal to the magnetic current density of the point, and the direction of the magnetic dipole is the direction of the magnetic current of the point, so that an equivalent dipole array model of the antenna is obtained;
Determining the weighting coefficients of the radiation fields of the electric dipole array and the magnetic dipole array of each part in the total radiation field of the antenna according to the area proportion of each part and the number of the sampling points, multiplying the field excited by each part of infinitesimal electric dipole and the field excited by each magnetic dipole by the weighting coefficient of the part, and then summing to obtain the calculation result of the radiation field of the antenna;
and optimizing and adjusting the weighting coefficients of the electric dipoles and the magnetic dipoles of each part by adopting a genetic algorithm to obtain a final calculation result of the antenna radiation field.
2. The method for calculating the radiation field of the antenna based on the electromagnetic dipole array according to claim 1, wherein: dividing the antenna surface of the radiation field to be calculated into a plurality of parts according to materials and structures, taking points on each part, and obtaining equivalent electric and magnetic current densities at the points by utilizing a Huygens principle and magnetic and electric field intensities at the points, wherein the method specifically comprises the following steps of:
Dividing the antenna surface of the radiation field to be calculated according to the material and structure, dividing the antenna surface into a plurality of parts, taking points on each part, assuming that the antenna surface is divided into Y parts, sequentially numbering the Y parts with y=1, 2, … and Y, the number of points taken by the Y part is N y, uniformly distributing the points, sequentially numbering the points with (Y, 1), (Y, 2), …, (Y, N y), DS (y,k) represents the area of the grid where the point (y, k) is located;
The area of each part is denoted by S y:
S y is regarded as the coefficient of the specific gravity of the electric dipole and the magnetic dipole of each part in the generated antenna radiation field;
a discrete format based on huygens principle, expressed as:
HJ,r,n＝HJ,θ,n＝0
EJ,φ,n＝0
EM,r,n＝EM,θ,n＝HM,φ,n＝0
En＝EJ,n+EM,n
Hn＝HJ,n+HM,n
Wherein:
Er,n＝EJ,r,n+EM,r,n,Hr,n＝HJ,r,n+HM,r,n
Eφ,n＝EJ,φ,n+EM,φ,n,HJ,φ,n＝HJ,φ,n+HM,φ,n
Eθ,n＝EJ,θ,n+EM,θ,n,Hθ,n＝HJ,θ,n+HM,θ,n
wherein H J,r,n,HJ,θ,n,HJ,φ,n sequentially represents the r, theta and phi components of the magnetic field strength H generated by the equivalent current at the nth observation point under the spherical coordinate system;
j s,(y,z) denotes the equivalent current density at the (y, z) th point of the antenna surface;
θ (y,z),n represents the included angle formed by the electromagnetic dipole direction at the (y, z) th point of the antenna surface and the connection line between the nth observation point and the point;
R (y,z),n represents the distance between the (y, z) th point and the nth observation point of the antenna surface;
k represents wave number;
E J,r,n,EJ,θ,n,EJ,φ,n sequentially represents the r, theta and phi components of the electric field strength E excited by the equivalent current at the nth observation point under the spherical coordinate system;
η represents the wave impedance;
e M,r,n,EM,θ,n,EM,φ,n represents the r, θ, phi components of the electric field strength E of the field excited by the equivalent magnetic current at the nth observation point under the spherical coordinate system;
M s,(y,z) represents the equivalent magnetic current density at the (y, z) th point of the antenna surface;
H M,r,n,HM,θ,n,HM,φ,n represents the r, θ, phi components of the magnetic field strength H of the field excited by the equivalent magnetic current at the nth observation point in the spherical coordinate system;
E J,n、EM,n represents the electric field strength excited by the equivalent current and the equivalent magnetic current at the nth observation point respectively;
H J,n、HM,n represents the magnetic field strength excited by the equivalent current and the equivalent magnetic current at the nth observation point, respectively;
E n,Hn denotes the field excited by the equivalent electromagnetic current at the nth observation point.
3. The method for calculating the radiation field of the antenna based on the electromagnetic dipole array according to claim 2, wherein: the method comprises the steps of determining the weighting coefficients of the radiation fields of the electric dipole array and the magnetic dipole array of each part in the total antenna radiation field according to the area proportion of each part and the number of the sampling points, multiplying the field excited by each part of infinitesimal electric dipole and the field excited by each magnetic dipole by the weighting coefficient of the part, and then summing to obtain the antenna radiation field calculation result, and specifically comprises the following steps:
In the method, in the process of the invention, Representing the calculation result of the electric field excited by the electric dipole array of the y-th portion at the n-th observation point,Representing the calculation result of the electric field excited by the magnetic dipole array of the y-th part at the nth observation point,/>Representing the calculation result of the magnetic field excited by the electric dipole array of the y-th part at the nth observation point,/>Representing the calculation result of the magnetic field excited by the magnetic dipole array of the y-th part at the n-th observation point; /(I)Wherein the symbols/>Representing an upward rounding.
4. A method of calculating an antenna radiation field based on an electromagnetic dipole array according to claim 3 and wherein: the genetic algorithm is adopted to optimize and adjust the weighting coefficients of the electric dipole and the magnetic dipole of each part to obtain the final calculation result of the antenna radiation field, and the method specifically comprises the following steps:
Constructing an objective function:
find χ＝[C1 C2 … CY]
s.t. Cy≥0
In the method, in the process of the invention, Simulating simulation results obtained by simulating electric field intensity and magnetic field intensity excited by an antenna of a radiation field to be calculated at a plurality of points in space by adopting full-wave simulation software;
Solving an objective function by adopting a genetic algorithm to obtain χ corresponding to the minimum F, and obtaining the area proportion of each part of the antenna of the radiation field to be calculated based on the χ corresponding to the minimum F;
And determining the weighting coefficients of the radiation fields of the electric dipole array and the magnetic dipole array of each part in the total radiation field of the antenna according to the area proportion of each part of the antenna of the radiation field to be calculated and the number of the taking points, multiplying the field excited by each part of the infinitesimal electric dipole and the magnetic dipole by the weighting coefficient of the part, and then summing to obtain the calculation result of the radiation field of the antenna.
5. The method for calculating the radiation field of the antenna based on the electromagnetic dipole array according to claim 4, wherein: the method for solving the objective function by adopting the genetic algorithm to obtain χ corresponding to the minimum F comprises the following steps:
Step 1: initialization of The value of each element in χ 0 is determined by the area ratio of each part; let i=0, and determine the threshold value threshold, max_for, calculate the value of F i, if F i < threshold, stop the calculation, output the/>, corresponding to the minimum F i y Otherwise give Y variants of χ i/>Select three/>, with the minimum F i y valueIs marked as/>
Step 2: according to the givenCalculating F i 1,Fi 2,Fi 3;
Step 3: if F i y < threshold exists or the number of loops reaches Max_for, stopping calculation and outputting the corresponding minimum F i y Otherwise give Y variants of χ i/>Select three/>, with the minimum F i y valueAssignment to/>, from small to largeLet i=i+1, return to step 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410264122.5A CN118095006A (en) | 2024-03-08 | 2024-03-08 | Antenna radiation field calculation method based on electromagnetic dipole array |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410264122.5A CN118095006A (en) | 2024-03-08 | 2024-03-08 | Antenna radiation field calculation method based on electromagnetic dipole array |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118095006A true CN118095006A (en) | 2024-05-28 |
Family
ID=91143719
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410264122.5A Pending CN118095006A (en) | 2024-03-08 | 2024-03-08 | Antenna radiation field calculation method based on electromagnetic dipole array |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118095006A (en) |
-
2024
- 2024-03-08 CN CN202410264122.5A patent/CN118095006A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Tong et al. | A broad-band U-slot rectangular patch antenna on a microwave substrate | |
| Chen et al. | HF band shipboard antenna design using characteristic modes | |
| Wu et al. | Machine-learning-assisted optimization and its application to antenna designs: Opportunities and challenges | |
| Zhang et al. | Automatic AI-driven design of mutual coupling reducing topologies for frequency reconfigurable antenna arrays | |
| Yan et al. | Synthesis of pattern reconfigurable sparse arrays with multiple measurement vectors FOCUSS method | |
| Yoo et al. | Analytic model of a coax-fed planar cavity-backed metasurface antenna for pattern synthesis | |
| Laurin et al. | Near-field diagnostics of small printed antennas using the equivalent magnetic current approach | |
| WO2019118025A1 (en) | Earth-ionosphere waveguide power transfer | |
| Song et al. | Performance of planar slotted waveguide arrays with surface distortion | |
| Karaova et al. | Design, fabrication, and measurement of efficient beam-shaping reflectors for 5G applications | |
| CN108959806A (en) | A kind of equivalent radiated power modeling method based on spherical surface near field measurement and ball mode source | |
| Schröder et al. | Fast evaluation of electromagnetic fields using a parallelized adaptive cross approximation | |
| Kusiek et al. | Resonance frequency calculation of a multilayer and multipatch spherical microstrip structure using a hybrid technique | |
| Yang et al. | Alternative method for obtaining antenna current Green’s function based on infinitesimal dipole modeling | |
| CN112034264A (en) | Multi-probe compact range antenna test system and generation method | |
| Gao et al. | Equivalent model built with limited information: Predicting installed performance of slotted waveguide antennas | |
| CN118095006A (en) | Antenna radiation field calculation method based on electromagnetic dipole array | |
| Dahl et al. | Efficient simulation of substrate-integrated waveguide antennas using a hybrid boundary element method | |
| Chen et al. | A periodic microstrip radial antenna array with a conical beam | |
| Zhao et al. | Applicability Extension and Calculation Acceleration of Pattern-Multiplication Principle in Far-Field Analysis of Conformal Arrays | |
| Hyun et al. | 3-D thin-wire FDTD analysis of coaxial probe fed in asymmetric microwave components | |
| Zhang et al. | Radiation analysis of large antenna array by using periodic equivalence principle algorithm | |
| Malek | 3-D antenna array analysis using the induced EMF method | |
| Andriychuk et al. | Synthesis of Plane Waveguide Array Based on a Strict Solution of Analysis Problem | |
| Perera | Physical Knowledge Based Scalable Phased Array Antenna Modeling for Radar Systems |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication |