Dual-band microstrip antenna array with different feeding modes and design method thereof

Abstract

The application discloses a dual-frequency microstrip antenna array with different feeding modes and relates to the technical field of antennas. The dual-frequency microstrip antenna array comprises N*N antenna array elements, each of the antenna array elements comprises four antenna units, the four antenna units are arranged in a 2*2 matrix form, and the four antenna units are fed in the same direction; in any four adjacent antenna array elements arranged in the 2*2 matrix form, the horizontal feeding directions of two adjacent antenna array elements in the vertical direction are the same, and the vertical feeding directions are opposite; the horizontal feeding directions of two adjacent antenna array elements in the horizontal direction are opposite, and the vertical feeding directions are the same. The antenna array is divided into four kinds of antenna array elements, and different feeding is conducted, so that cross polarization is greatly improved. Meanwhile, the reverse sparse array and the reverse amplitude weighting technology are adopted, so that the sidelobe of the gain pattern of the antenna is uniform, and the optimization of cross polarization and gain is realized.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a dual-frequency microstrip antenna array employing different feeding methods and its design method. Background Technology

[0002] Satellite communication typically requires high cross-polarization of antennas to reduce interference with nearby satellites. Microstrip antenna arrays are increasingly popular due to their miniaturization, lightweight design, and ease of integration with other microwave components. However, a drawback of microstrip antennas is poor cross-polarization. Even for microstrip slot antennas, although the cross-polarization of a single element can be excellent, achieving below -30dB, when assembled into an array antenna, the cross-polarization deteriorates sharply due to mutual coupling between elements, and the more elements there are, the more severe the deterioration. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a dual-frequency microstrip antenna array with different feeding methods and its design method.

[0004] To solve the above technical problems, the technical solution of the present invention is as follows:

[0005] A dual-frequency microstrip antenna array employing different feeding methods includes N*N antenna array elements, each antenna array element comprising four antenna elements, the four antenna elements being arranged in a 2*2 row and column configuration, and all four antenna elements being fed in the same direction.

[0006] In any four adjacent antenna elements arranged in a 2x2 matrix, the horizontal feeding directions of two adjacent antenna elements in the vertical direction are the same and their vertical feeding directions are opposite. The horizontal feeding directions of two adjacent antenna elements in the horizontal direction are opposite and their vertical feeding directions are the same.

[0007] As a preferred embodiment of the dual-frequency microstrip antenna array with different feeding methods described in this invention, wherein: in any two adjacent antenna array elements, the center distance between the two adjacent antenna elements is 1.2 to 1.25 times the wavelength corresponding to the highest frequency of the antenna design.

[0008] As a preferred embodiment of the dual-frequency microstrip antenna array employing different feeding methods described in this invention, the power of the antenna elements located around the antenna array elements is greater than the power of the antenna elements located inside the antenna array elements.

[0009] As a preferred embodiment of the dual-frequency microstrip antenna array with different feeding methods described in this invention, the power difference between the antenna elements located around the antenna array elements and the antenna elements located inside the antenna array elements is 0.5 dBW.

[0010] This invention also provides a design method for a dual-frequency microstrip antenna array employing different feeding methods, including:

[0011] An antenna array is established, comprising N*N antenna elements, each antenna element comprising four antenna units. The four antenna units are arranged in a 2*2 matrix, and all four antenna units are fed in the same direction. Among any four adjacent antenna elements arranged in a 2*2 matrix, the horizontal feeding directions of two adjacent antenna elements in the vertical direction are the same, and their vertical feeding directions are opposite. The horizontal feeding directions of two adjacent antenna elements in the horizontal direction are opposite, and their vertical feeding directions are the same.

[0012] Adjust the sparsity of the antenna array to optimize the antenna gain;

[0013] An inverse amplitude weighting method is used to make the power of the antenna elements located around the antenna array elements greater than the power of the antenna elements located inside the antenna array elements.

[0014] As a preferred embodiment of the design method for a dual-frequency microstrip antenna array employing different feeding methods described in this invention, adjusting the sparsity of the antenna array to optimize the antenna gain includes:

[0015] In any two adjacent antenna elements, the center distance between the two adjacent antenna elements is 1.2 to 1.25 times the wavelength corresponding to the highest frequency of the antenna design.

[0016] As a preferred embodiment of the design method for a dual-frequency microstrip antenna array employing different feeding methods described in this invention, the step of employing inverse amplitude weighting to ensure that the power of the antenna elements located around the antenna array elements is greater than the power of the antenna elements located inside the antenna array elements includes:

[0017] The power difference between the antenna elements located around the antenna array element and the antenna elements located inside the antenna array element is 0.5 dBW.

[0018] The beneficial effects of this invention are:

[0019] This invention divides the antenna array into four types of antenna elements and feeds them differently, which greatly improves cross-polarization. At the same time, it employs inverse sparse array and inverse amplitude weighting techniques to make the sidelobes of the antenna gain pattern uniform, thus achieving optimization of cross-polarization and gain. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of a dual-frequency microstrip antenna array using different feeding methods provided in Example 1;

[0022] Figure 2 Gain cross-polarization pattern of a 16*16 dual-frequency microstrip antenna array with different feeding methods provided in Example 1;

[0023] Figure 3 This is a schematic diagram illustrating the adjustment of antenna array sparsity in the design method of dual-frequency microstrip antenna arrays using different feeding methods provided in Example 2;

[0024] Figure 4 This is a schematic diagram showing that all antenna elements in the antenna array are fed in the same direction.

[0025] Figure 5 The calculated gain cross-polarization pattern of a 16×16 element antenna array composed of all antenna elements fed in the same direction;

[0026] Figure 6 This is a schematic diagram showing the anti-phase feeding of adjacent antenna elements in an antenna array;

[0027] Figure 7 Gain cross-polarization pattern calculated for a 16×16 array element composed of adjacent antenna elements fed in opposite phases;

[0028] Figure 8 The gain pattern obtained by calculation and simulation of the 16×16 element antenna array after adjustment in step S102 in Example 2;

[0029] Figure 9 The gain pattern is obtained by calculating and simulating the 16×16 element antenna array after adjustment in step S103 in Example 2. Implementation

[0030] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. Example

[0031] Embodiment 1 of this application provides a dual-frequency microstrip antenna array employing different feeding methods. The antenna array comprises N*N antenna elements. Each antenna element includes four antenna components arranged in a 2*2 row and column configuration, and all four antenna components are fed in the same direction.

[0032] See Figure 1 In this embodiment, the antenna array includes four antenna elements: the first element, the second element, the third element, and the fourth element. Each element includes four antenna units, and all four antenna units in each element are fed in the same direction. Taking the first element as an example, the horizontal and vertical feeding directions of the four antenna units in the first element are the same.

[0033] Of these four antenna elements, for horizontal feeding, the first and second elements are the same, and the third and fourth elements are the same. However, the first and second elements are opposite to the third and fourth elements. For vertical feeding, the first and third elements are the same, and the second and fourth elements are the same. However, the first and third elements are opposite to the second and fourth elements.

[0034] Expanding the antenna array from 4x4 elements to 16x16 elements, the calculated gain cross-polarization pattern is as follows: Figure 2 As shown. By Figure 2 It can be seen that the axial cross-polarization of the antenna has been greatly improved, reaching below -35dB, and the antenna gain is relatively high. However, the left and right sidelobes of the main beam are very low, the beamwidth is severely widened, and the gain does not reach the expected level.

[0035] Therefore, the center distance d between two adjacent antenna elements is changed, see [reference]. Figure 3 To achieve optimal antenna gain, the gain of the antenna should be 1.2 to 1.25 times the wavelength corresponding to the highest frequency in the antenna design. Taking a 16×16 array element as an example, the antenna gain should be increased by approximately 1.5 dB based on the above.

[0036] Simultaneously, inverse amplitude weighting is employed to ensure that the power of antenna elements located around the antenna array elements is greater than the power of antenna elements located inside the antenna array elements. Figure 1 For example, the 12 antenna elements arranged in a rectangular circle around the perimeter of the antenna array are given greater power, while the four antenna elements arranged in a rectangular circle inside the antenna array are given less power, thus further increasing the antenna gain.

[0037] In this embodiment, the power difference between the antenna elements located around the antenna array element and the antenna elements located inside the antenna array element is 0.5 dBW. Example

[0038] This embodiment provides a design method for a dual-frequency microstrip antenna array using different feeding methods. The design method includes steps S101 to S103, which are described in detail below:

[0039] Step S101: Establish an antenna array, which includes N*N antenna elements. Each antenna element includes four antenna units. The four antenna units are arranged in a 2*2 matrix, and all four antenna units are fed in the same direction. Among any four adjacent antenna elements arranged in a 2*2 matrix, the horizontal feeding directions of two adjacent antenna elements in the vertical direction are the same, and the vertical feeding directions are opposite. The horizontal feeding directions of two adjacent antenna elements in the horizontal direction are opposite, and the vertical feeding directions are the same.

[0040] Specifically, when designing the feeding of an antenna array, all antenna elements are first fed in the same direction, see [reference needed]. Figure 4 When a 16x16 element antenna array is formed, the calculated gain cross-polarization pattern is as follows: Figure 5 As shown, the axial cross-polarization is only -27.5dB.

[0041] The usual technical solution is then adopted, namely, adjacent antenna elements are fed in opposite phases, see [link to relevant documentation]. Figure 6 When assembled into a 16x16 element antenna array, the calculated gain cross-polarization pattern is as follows: Figure 7 As shown, by Figure 7 It can be observed that axial cross-polarization is significantly improved, reaching below -35dB. However, the sidelobe distribution of the radiation pattern is relatively poor, and the gain is about 4.5dB lower than that of uniformly fed in the same direction, indicating that conventional reverse feeding is not suitable for this type of antenna.

[0042] This embodiment divides the antenna array into four antenna elements and feeds them differently. See [link to documentation]. Figure 1 Of these four antenna elements, for horizontal feeding, the first and second elements are the same, and the third and fourth elements are the same. However, the first and second elements are opposite to the third and fourth elements. For vertical feeding, the first and third elements are the same, and the second and fourth elements are the same. However, the first and third elements are opposite to the second and fourth elements.

[0043] Expanding the antenna array from 4x4 elements to 16x16 elements, the calculated gain cross-polarization pattern is as follows. Figure 2 As shown. By Figure 2 It can be seen that the axial cross-polarization of the antenna has been greatly improved, reaching below -35dB, and the gain has also improved by more than 2.5dB compared to the above arrangement. However, the left and right sidelobes of the main beam are very low, the beam is severely widened, and the gain has not reached the expected level.

[0044] Step S102: Adjust the sparsity of the antenna array to optimize the antenna gain.

[0045] For details, see Figure 3 The second and fourth array elements are moved upwards or downwards as a whole, changing the center distance *d* between adjacent antenna elements. As *d* increases, meaning the array becomes sparser in the middle with reverse density weighting, the antenna gain increases significantly. The antenna gain is optimal when *d* is 1.2 to 1.25 times the wavelength corresponding to the highest frequency in the antenna design. Taking a 16×16 array element as an example, the antenna gain increases by approximately 1.5 dB on top of the above. The gain pattern obtained from the simulation calculation for a 16×16 array element is shown in Figure 8.

[0046] Step S103: Use inverse amplitude weighting to make the power of the antenna elements located around the antenna array elements greater than the power of the antenna elements located inside the antenna array elements.

[0047] For details, see Figure 8 The sidelobes of the antenna are not evenly distributed. Therefore, this step uses inverse amplitude weighting to make the power of the antenna elements located around the antenna array elements greater than the power of the antenna elements located inside the antenna array elements, thereby further increasing the antenna gain.

[0048] In this embodiment, the power difference between the antenna elements located around the antenna array element and the antenna elements located inside the antenna array element is 0.5 dBW, thus further increasing the antenna gain by more than 0.5 dB. A calculation simulation is performed using a 16×16 array element as an example, and the resulting gain direction... Figure 9 As shown.

[0049] Therefore, the technical solution of this application divides the antenna array into four types of antenna elements and feeds them differently, which greatly improves the cross-polarization. At the same time, the use of anti-sparse array and anti-amplitude weighting techniques makes the sidelobes of the antenna gain pattern uniform, thus achieving optimization of cross-polarization and gain.

[0050] In addition to the above embodiments, the present invention may have other implementation methods; all technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A dual-frequency microstrip antenna array employing different feeding methods, comprising N×N antenna array elements, characterized in that: Each of the antenna array elements includes four antenna elements, which are arranged in a 2×2 row and column configuration, and all four antenna elements are fed in the same direction. In any four adjacent antenna elements arranged in a 2×2 matrix, the horizontal feeding directions of two adjacent antenna elements in the vertical direction are the same and the vertical feeding directions are opposite, and the horizontal feeding directions of two adjacent antenna elements in the horizontal direction are opposite and the vertical feeding directions are the same. In any two adjacent antenna elements, the center distance between the two adjacent antenna elements is 1.2 to 1.25 times the wavelength corresponding to the highest frequency of the antenna design; The power of the antenna elements located around the antenna array element is greater than the power of the antenna elements located inside the antenna array element; The power difference between the antenna elements located around the antenna array element and the antenna elements located inside the antenna array element is 0.5 dBW.

2. A design method for a dual-frequency microstrip antenna array employing different feeding methods, characterized in that: include: An antenna array is established, comprising N×N antenna elements, each antenna element comprising four antenna units. The four antenna units are arranged in a 2×2 matrix, and all four antenna units are fed in the same direction. Among any four adjacent antenna elements arranged in a 2×2 matrix, the horizontal feeding directions of two adjacent antenna elements in the vertical direction are the same, and their vertical feeding directions are opposite. The horizontal feeding directions of two adjacent antenna elements in the horizontal direction are opposite, and their vertical feeding directions are the same. Adjust the sparsity of the antenna array to optimize the antenna gain; An inverse amplitude weighting method is used to make the power of the antenna elements located around the antenna array elements greater than the power of the antenna elements located inside the antenna array elements.

3. The design method for a dual-frequency microstrip antenna array using different feeding methods according to claim 2, characterized in that: Adjusting the sparsity of the antenna array to optimize the antenna gain includes: In any two adjacent antenna elements, the center distance between the two adjacent antenna elements is 1.2 to 1.25 times the wavelength corresponding to the highest frequency of the antenna design.

4. The design method for a dual-frequency microstrip antenna array using different feeding methods according to claim 2, characterized in that: The method of employing inverse amplitude weighting to ensure that the power of the antenna elements located around the antenna array element is greater than the power of the antenna elements located inside the antenna array element includes: The power difference between the antenna elements located around the antenna array element and the antenna elements located inside the antenna array element is 0.5 dBW.

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