Radome antenna combination response rapid evaluation method based on spherical domain generalized transmission line model

Abstract

The invention provides an antenna housing and antenna combination response rapid evaluation method based on a spherical domain generalized transmission line model. The method comprises the following steps: constructing a unified ball domain mode interface space, enabling an antenna housing to be equivalent to a bidirectional ball domain generalized transmission line, representing an antenna radiation behavior as a ball domain multi-port response matrix, and describing the position and attitude change of an antenna in the housing by using an analyzed ball domain geometric transformation operator. The two parts are combined in a cascade mode in a mode space, a directional diagram, gain and scattering sectional area under different installation conditions can be rapidly calculated without repeating full-wave simulation, and the method is suitable for radome design and antenna installation optimization.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic field numerical analysis and antenna engineering technology. It relates to a method for rapidly evaluating the combined response of a radome and an antenna inside the radome using a spherical generalized transmission line model. This method can be used for radome design, optimization of the installation position and attitude of the antenna inside the radome, and integrated performance analysis of the radome. Background Technology

[0002] Radomes are widely used in radar, communication, guidance, and detection systems. Their functions include protecting the internal antenna, improving aerodynamic shape, and reducing the radiometric cross-section (RCS). The material, electromagnetic thickness, curved surface shape, and multi-layered structure of the radome all significantly affect the radiation characteristics of the antenna inside the radome.

[0003] In engineering applications, the installation position and orientation (including translation, rotation, and polarization) of the antenna inside the radome have a critical impact on system performance. For example, to achieve integrated stealth of the radome, it is necessary to reduce the overall scattering of the radome while ensuring the antenna's radiation performance; however, different installation methods will result in different incident angle spectra, phase distributions, and propagation paths, thereby changing the radiation pattern, gain, beam shift, and RCS.

[0004] Traditional methods involve simulating the radome and antenna as a whole, which is computationally intensive. When exploring multiple installation locations and attitudes, repeated modeling and solving are required, resulting in extremely low efficiency. Therefore, a method is needed that allows the radome and antenna to be simulated only once, enabling rapid prediction of the combined system performance at any location and attitude. Summary of the Invention

[0005] This invention proposes a fast evaluation method for the response of radome-antenna combinations based on a spherical domain generalized transmission line model. This method involves:

[0006] 1. The radome is equivalent to a bidirectional spherical generalized transmission line;

[0007] 2. Represent the antenna radiation behavior as a spherical multiport response matrix;

[0008] 3. An analytical spherical geometric transformation operator is introduced to describe the changes in antenna position and attitude;

[0009] 4. Solve the cascaded antennas of the radome in the spherical mode space;

[0010] Therefore, different installation conditions can be quickly evaluated without repeating full-wave simulations.

[0011] The technical solution of the present invention includes the following steps:

[0012] 1. Construct the spherical domain pattern base and interface space

[0013] Within the free space regions outside and inside the radome, the electromagnetic field satisfies the homogeneous Helmholtz equation. This invention selects two linearly independent spherical vector modes as angular expansion bases:

[0014] ,

[0015] in This is a model index. This family of models constitutes the spherical interface space, which can be used to uniformly describe the field distribution of the outer and inner domains.

[0016] 2. Spherical Generalized Transmission Line Model of the Radome

[0017] set up:

[0018] • : Mode coefficients incident from the outside of the enclosure to the spherical interface;

[0019] • : Mode coefficients radiated outward from the enclosure;

[0020] • : Mode coefficients incident from inside the enclosure to the inner spherical interface;

[0021] • : Mode coefficients radiating from the internal interface of the enclosure back to the internal region.

[0022] The spherical generalized transmission line model of the enclosure is defined as follows:

[0023] , .

[0024] Matrices A, B, C, and D describe the outer self-response, the coupling of the inner incident ...

[0025] 3. Spherical Multiport Response Model of Antenna

[0026] Let the antenna port excitation vector be... After performing a full-wave simulation on the antenna, its radiation field on the reference sphere is expanded into spherical mode coefficients. :

[0027] ,

[0028] in Let be the spherical multiport response matrix of the antenna.

[0029] Since the interface between the reference sphere and the inner spherical region of the housing is consistent. Can be used directly as One of the inputs.

[0030] 4. Spherical Geometric Transformation Operator for Antenna Position and Orientation

[0031] The actual installation location and orientation of the antenna are usually different from the reference coordinate system used in modeling. This invention introduces a spherical domain geometric transformation operator:

[0032] ,

[0033] in This represents the translational position of the antenna relative to the center of the radome. For attitude angles (such as Euler angles).

[0034] By applying the transformation operator, the original mode coefficients can be transformed into mode coefficients in the newly installed state:

[0035] .

[0036] 5. Solving the spherical cascade of radome antenna systems

[0037] When the antenna is operating in transmit mode, it can be taken as follows: The incident radiation inside the shroud is:

[0038] .

[0039] Substituting the generalized transmission line relation:

[0040] .

[0041] therefore:

[0042] .

[0043] The external radiation pattern, gain, or scattering parameters are obtained. The entire calculation requires only matrix operations and does not require repeated simulations. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the algorithm flow given in the embodiment of the present invention.

[0045] Figure 2 This is a schematic diagram of any radome antenna given in the embodiments of the present invention.

[0046] Figure 3 This is a comparison chart of xoz surface gain at 8.625 GHz in an embodiment of the present invention.

[0047] Figure 4 This is a comparison chart of yoz plane gain at 8.625 GHz in an embodiment of the present invention.

[0048] Figure 5 This is a schematic diagram of the multi-antenna co-cover analysis in the implementation of this invention. Detailed Implementation

[0049] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0050] Example 1: Radiation Pattern Optimization

[0051] Figure 1 This is a flowchart of the method described in the patent. Figure 2 The radome antenna is an example of this embodiment. Figure 3 , Figure 4 for Figure 2 A gain comparison chart of the radome antenna obtained through HFSS simulation and using the method described in the patent is presented. An example is demonstrated using Ansys Electronics Desktop 2021 simulation software and MATLAB. The specific steps are as follows:

[0052] Step 1, create the following in HFSS: Figure 2 The antenna in the radome.

[0053] Step two: Construct a spherical mode interface, equating the radome to a bidirectional spherical generalized transmission line. Perform a full-wave simulation of the radome to obtain far-field data, from which the spherical mode coefficients can be calculated. Finally, the... .

[0054] Step three: After performing a full-wave simulation on the antenna, the spherical mode coefficients of its radiation field expansion on the reference sphere can be obtained. Therefore, we can obtain That is, to represent the antenna radiation behavior as a spherical multiport response matrix.

[0055] Step four: Use the spherical domain geometric transformation operator to describe the antenna's position and attitude changes within the enclosure, and apply this to the installation location. With attitude angle Perform analytic transformations and concatenations, using This allows for rapid evaluation of the gain, and the results are as follows: Figure 3 , Figure 4 As shown.

[0056] Step 5: Perform a full-wave simulation of the radome antenna at this location in HFSS to obtain... Figure 3 , Figure 4 The result.

[0057] Example 2: Multi-antenna co-shading analysis

[0058] Construct multiple antennas separately and Superimpose all antennas on the spherical interface Input, then pass Obtaining the combined system response eliminates the need for resimulation; full-wave simulation always takes longer than computation. A schematic diagram of multiple antennas sharing a radome is shown below. Figure 4 As shown.

[0059] The effects of the present invention are as follows Figure 3 , Figure 4 As shown, simulating a radome antenna using HFSS on an Intel® Core™ i7-10700 CPU@2.90GHz processor takes about 110 seconds. This method, through matrix operations, takes about 1 second, thus speeding up the simulation while maintaining accuracy, and is particularly effective for radome antennas.

[0060] The above description is merely a specific example of the present invention. Obviously, those skilled in the art, after understanding the content and principles of the present invention, may make various modifications and changes in form and details without departing from the principles and structure of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A fast evaluation method for the response of an antenna combination with a radome based on a spherical generalized transmission line model, comprising: (1) Construct an interface pattern space consisting of M-type and N-type sphere patterns; (2) Perform a full-wave simulation of the radome and project it onto the mode space to obtain the spherical generalized transmission line operator; (3) Perform a full-wave simulation of the antenna and construct the spherical multi-port response matrix; (4) Construct a spherical geometric transformation operator to describe antenna translation and rotation; (5) The antenna response, geometric transformation and radome transmission line operator are cascaded to obtain the external radiation mode coefficients of the combined system.

2. The method according to claim 1, wherein the spherical domain generalized transmission line operator of the radome is represented as: ； in, These are the mode coefficients incident from the outside of the enclosure to the spherical interface; These are the mode coefficients radiated outwards from the cover; These are the mode coefficients incident from inside the enclosure to the inner spherical interface; These are the mode coefficients radiating from the internal interface of the enclosure back to the internal region. Matrices A, B, C, and D respectively describe the outer self-response, the coupling of the inner incident to the outer side, the coupling of the outer incident to the inner side, and the inner self-response.

3. The method according to claim 1, wherein the spherical domain geometric transformation operator is: ； The spherical mode coefficients are obtained by expanding the radiation field of the antenna on the reference sphere after a full-wave simulation. For geometric transformation operators in the sphere domain, This represents the translational position of the antenna relative to the center of the radome. For attitude angles (such as Euler angles). This refers to the mode coefficient in the newly installed state.

4. The method according to any one of claims 1 to 3, wherein only the geometric transformation operator is updated during the optimization process, while the radome transmission line operator and the antenna response matrix remain unchanged.

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