Method for estimating electrical curve parameters of spherical inflatable antenna

Abstract

The invention discloses a method for estimating electrical curve parameters of a spherical inflatable antenna, and belongs to the technical field of microwave communication. On the basis of analysis of structural characteristics and electrical curve characteristics of the spherical inflatable antenna, an electrical curve parameter estimation method of the type of antenna is established, the distance value from the focal point of the electrical curve to the outer surface of a sphere is used as a constraint condition, and all parameter values of the electrical curve of the antenna are determined; recommended values of electrical curve focal diameter ratio parameters are given, constraint conditions and target values can be correspondingly adjusted according to needs, and analytic method support is provided for electrical curve parameter estimation of the spherical inflatable antenna.

Description

Technical Field

[0001] The invention belongs to the technical field of microwave communications, and in particular relates to a method for estimating electrical curve parameters of a spherical inflatable antenna. Background Art

[0002] Spherical inflatable antennas are used in satellite communications, battlefield reconnaissance and jamming, and can achieve high sensitivity and precise radiation / reception of electromagnetic signals. Compared with conventional hard reflector antennas, they have the advantages of fast movement, efficient deployment and collection, and large storage ratio, and have great development potential.

[0003] At present, inflatable antennas are widely used in foreign military and civilian fields. The antennas have calibers of 1.2 meters, 1.8 meters, 2.4 meters and 4 meters, and operate in frequency bands such as C, X, Ku and Ka.

[0004] According to public information, inflatable antennas have not yet been maturely applied in China, and their key technologies are still in the development process. Summary of the invention

[0005] In view of this, the present invention proposes a method for estimating electrical curve parameters of a spherical inflatable antenna, which provides analytical method support for estimating electrical curve parameters of a spherical inflatable antenna.

[0006] A method for estimating electrical curve parameters of a spherical inflatable antenna comprises the following steps:

[0007] Step 1, determine the basic parameters, including the diameter of the antenna sphere is Φ, the distance between the focus of the electrical curve and the outer surface of the sphere is L, and L is set as a constraint condition;

[0008] Step 2, according to the basic parameters obtained in step 1, determine that the electrical curve equation of the reflector is a standard parabola equation, calculate its focal diameter ratio q, and set it as the target estimated value;

[0009] Step 3, combining the electrical curve of the reflective surface with the central section of the sphere, and setting the upper and lower vertices of the electrical curve at the longitudinal center line of the central section of the sphere;

[0010] Step 4, establishing a unified coordinate system according to the electrical curve and the central section of the sphere, thereby establishing a mathematical model of the electrical curve parameters; wherein the central axis of the parabola and the transverse central axis of the sphere are both the X-axis of the coordinate system, the Y-axis of the coordinate system passes through the vertex of the electrical curve, and the origin of the coordinate system coincides with the vertex of the electrical curve;

[0011] Mathematical model of electrical curve parameters:

[0012]

[0013] In the formula, y2 =4×q×Φ×x is the parabolic equation of the electrical curve;

[0014] Step 5: Obtain an estimated value of the q parameter of the antenna electrical curve according to the mathematical model.

[0015] Furthermore, the spherical inflatable antenna includes an antenna sphere and a flexible reflecting surface; the flexible reflecting surface is located inside the antenna sphere and divides the antenna sphere into an upper cavity and a lower cavity that are independent of each other, and the flexible reflecting surface is formed by inflating the upper cavity and the lower cavity respectively and maintaining a pressure difference.

[0016] Compared with the prior art, the present invention provides an analytical method support for estimating the electrical curve parameters of the spherical inflatable antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to describe this patent more clearly, the following drawings are provided to assist in explaining the background technology, technical principles and / or certain specific implementation plans of this patent.

[0018] Figure 1 Spherical inflatable antenna system composition diagram;

[0019] Figure 2 Antenna electrical curve schematic diagram;

[0020] Figure 3 Antenna electrical curve parameter corresponding diagram;

[0021] Figure 4 The corresponding diagram of the electrical curve parameters of the antenna with a sphere diameter of 2.4 meters;

[0022] The meanings of the numbers in the figure are:

[0023] The frame box 1, the servo drive device 2, the expansion and contraction support mechanism 3, the flexible reflection surface 4, the inflatable ball 5, and the feed network 6. DETAILED DESCRIPTION

[0024] The technical solution of this patent is described in detail below in the form of specific cases in conjunction with the accompanying drawings.

[0025] like Figure 1 The figure shows the composition diagram of the spherical inflatable antenna system. The antenna mount is of azimuth-pitch type, and its bottom is a mount box 1. A servo drive device 2 is arranged inside the mount box to realize the azimuth drive and pitch drive of the antenna. The antenna's expansion and contraction support mechanism 3 constrains and supports the inflatable sphere 5. The center position of the inflatable sphere is a flexible reflective surface 4. The flexible reflective surface separates the antenna sphere into an upper cavity and a lower cavity that are independent of each other. The two cavities are inflated separately and maintain a pressure difference. The shaping of the reflective surface is realized by the pressure difference. A feed network 6 is arranged on the top of the inflatable sphere.

[0026] like Figure 2 The figure shows the principle diagram of the electrical curve of the spherical inflatable antenna, and a method for estimating the electrical curve parameters of the spherical inflatable antenna is established based on the principle diagram. The electrical curve parameters of the spherical inflatable antenna using a standard parabolic reflector are estimated. The method includes the following steps:

[0027] a. Determine the basic parameters: the diameter of the antenna sphere is Φ, the distance between the focus of the electrical curve and the outer surface of the sphere is L, and L is used as a constraint condition (in the figure, L = AF, point A is the intersection of the sphere curve and the X-axis, and point F is the intersection of the parabola);

[0028] b. Further determine additional parameters: The electrical curve equation of the reflector is the standard parabolic equation, and its focal diameter ratio q is calculated and set as the target estimated value.

[0029] c. Combine the electrical curve with the spherical curve, and set the upper and lower vertices of the electrical curve at the longitudinal center line of the spherical curve;

[0030] d. Unify the electrical curve and the sphere section into a unified coordinate system to establish a mathematical model. The X-axis of the coordinate system is the central axis of the parabola, which is also the horizontal central axis of the sphere. The Y-axis of the coordinate system passes through the vertex of the electrical curve, and the origin of the coordinate system coincides with the origin of the electrical curve.

[0031] d. Establish a mathematical model to estimate electrical curve parameters:

[0032]

[0033] e. Based on the mathematical model established in step d, the estimated values ​​of various parameters of the antenna electrical curve are obtained and can be accurately adjusted.

[0034] like Figure 3 The figure shows the corresponding diagram of the antenna electrical curve parameters. The horizontal axis value is the focal diameter ratio q value of the electrical curve parameter, and the vertical axis is the distance coefficient (q-1 / 16q-1 / 2) value of the focal point from the sphere surface.

[0035] According to the mathematical model, let (q-1 / 16q-1 / 2) be the distance coefficient value of the focal point of the electrical curve from the surface of the sphere, then the distance from the focal point to the surface of the sphere is the product of the diameter of the sphere and the coefficient value. Therefore, for an antenna of a specific diameter, the distance from the focal point to the surface of the sphere is determined by the coefficient value.

[0036] When the coefficient value (q-1 / 16q-1 / 2) is negative, it means that the focus is inside the sphere; when the coefficient value is positive, it means that the focus is outside the sphere. According to the structural characteristics of the inflatable antenna, the feed source needs to be set outside the sphere, so the coefficient value needs to be positive, thereby determining the focal diameter ratio q value of the electrical curve.

[0037] Further, according to the mathematical model, it is required that q-1 / 16q-1 / 2>0, that is, the electrical curve focal diameter ratio q>0.604. Figure 3 It can be seen that when the focal ratio increases (q>

[0038] 0.604), the coefficient value increases, and the distance between the focus of the electrical curve and the surface of the sphere increases.

[0039] According to the estimation method, a recommended value of the focal diameter ratio of the spherical inflatable antenna can be given as being between 0.6 and 0.7, that is, 0.6<q<0.7.

[0040] like Figure 4 As shown in the figure, it is an example of the corresponding graph of the electrical curve parameters of the antenna with a sphere diameter of 2.4 meters. Its horizontal axis value is the focal diameter ratio q value of the electrical curve parameter, and its vertical axis is the distance value L of the focus from the surface of the sphere. According to the aforementioned recommended q value, q = 0.65 can be taken, and the distance from the focus of the electrical curve to the surface of the sphere is 129.2mm. Then, the structural design of the feed network is carried out according to this value, and then the design and implementation of the antenna electrical and structural scheme are completed.

Claims

1. A method for estimating electrical curve parameters of a spherical inflatable antenna, characterized in that: The following steps are involved: Step 1, determine the basic parameters, including the diameter of the antenna sphere is Φ, the distance between the focus of the electrical curve and the outer surface of the sphere is L, and L is set as a constraint condition; Step 2, according to the basic parameters obtained in step 1, determine that the electrical curve equation of the reflector is a standard parabola equation, calculate its focal diameter ratio q, and set q as the target estimated value; Step 3, combining the electrical curve of the reflective surface with the central section of the sphere, and setting the upper and lower vertices of the electrical curve at the longitudinal center line of the central section of the sphere; Step 4, establishing a unified coordinate system according to the electrical curve and the central section of the sphere, thereby establishing a mathematical model of the electrical curve parameters; wherein the central axis of the parabola and the transverse central axis of the sphere are both the X-axis of the coordinate system, the Y-axis of the coordinate system passes through the vertex of the electrical curve, and the origin of the coordinate system coincides with the vertex of the electrical curve; Mathematical model of electrical curve parameters: In the formula, y 2 =4×q×Φ×x is the parabolic equation of the electrical curve; Step 5: Obtain an estimated value of the q parameter of the antenna electrical curve according to the mathematical model.

2. The method for estimating electrical curve parameters of a spherical inflatable antenna according to claim 1, characterized in that: The spherical inflatable antenna includes an antenna sphere and a flexible reflecting surface; the flexible reflecting surface is located inside the antenna sphere and divides the antenna sphere into an upper cavity and a lower cavity that are independent of each other, and the flexible reflecting surface is formed by inflating the upper cavity and the lower cavity respectively and maintaining a pressure difference.

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