A compact dual-band Van Atta array antenna for dual-band backward RCS enhancement

Abstract

The invention discloses a compact dual-band Van Atta array antenna for dual-band backward RCS enhancement, and relates to the technical field of RCS backward enhancement and dual-band antennas. In the present invention, all single-port single-band antennas and single-port dual-band antennas are provided with a corresponding power divider in the dual-band feeding network, and the two output ends of each power divider are connected to the antenna through metal through holes. Each antenna is fed through a port. Thanks to the above-mentioned hybrid array and the design of single-port feeding of all antennas, the number of transmission lines in the antenna unit and the feeding network is effectively reduced. The present invention reduces the number of transmission lines in the antenna unit and the feeding network by using these two antenna hybrid array methods, solves the problem of the large size and complex design of the dual-band Van Atta array, and realizes the compact design of the dual-band Van Atta array.

Description

Technical Field

[0001] The invention relates to the technical field of RCS backward enhancement and dual-frequency antenna, and in particular to a compact dual-frequency radar reflection cross-section backward enhancement array antenna designed based on the Van Atta principle. Background Art

[0002] The passive Van Atta array is a low-cost, highly integrated rearward RCS enhancement structure. Within the scanning range of the antenna array, the antenna array receives the incident wave, and after being transmitted by the feed network, the antenna array radiates in the incident direction. It has many applications in radar detection, autonomous driving, and wireless communications.

[0003] Traditional backward RCS enhancement structures are unable to meet the current application requirements of communication and radar detection systems due to their large size, complex design and manufacturing, and inability to be integrated in a planar manner. Passive Van Atta arrays can better solve the above problems. In recent years, broadband, wide-angle, high RCS passive Van Atta arrays have gradually become the focus of research.

[0004] However, due to the size and design difficulty of the dual-band antenna array and dual-band feeding network, many current research works on the Van Atta array can only achieve backward RCS enhancement in a single frequency band. Increasing the operating frequency band of the Van Atta array can further improve its integration and reduce application costs, meeting more application scenarios and needs. Therefore, it is crucial to solve the design difficulties of the dual-band Van Atta array and realize a compact dual-band Van Atta array. Summary of the invention

[0005] The purpose of the present invention is to design a compact dual-band Van Atta array for dual-band backward RCS enhancement, to achieve a compact design of the dual-band Van Atta array, to achieve backward RCS enhancement of two frequency bands, and to reduce the size of the dual-band Van Atta array. Compared with the traditional dual-band antenna array, the present invention designs and uses a new dual-band antenna array, which is composed of a single-port single-frequency antenna and a single-port dual-frequency antenna. They have similar structures and have the same performance in the same operating frequency band. The present invention reduces the number of antenna units and transmission lines in the feeding network by using these two types of antenna hybrid arrays, solves the problem of the dual-band Van Atta array being too large in size and complex in design, and achieves a compact design of the dual-band Van Atta array.

[0006] The technical solution adopted by the present invention to solve the above-mentioned problem is: a compact dual-frequency Van Atta array antenna for dual-frequency backward RCS enhancement, the antenna comprising: a plurality of single-port single-frequency antennas (1), a plurality of single-port dual-frequency antennas (2), a dual-frequency feeding network (3), and a substrate; the number of the single-port single-frequency antennas (1) and the single-port dual-frequency antennas (2) differs by 1; the single-port single-frequency antennas (1) and the single-port dual-frequency antennas (2) are arranged on the upper surface of the substrate in pairs, forming a one-dimensional array antenna, and the antenna structures at both ends of the one-dimensional array antenna are the same; the dual-frequency feeding network (3) is arranged on the lower surface of the substrate, and the dual-frequency feeding network (3) is connected to the single-port single-frequency antenna (1) or the single-port dual-frequency antenna (2) through a metal through hole;

[0007] The single-port single-frequency antenna (1) comprises: two metal strips (13), each metal strip passing through a substrate through a metal through hole (14) to connect to a dual-frequency feeding network (3); the single-port dual-frequency antenna (2) comprises two metal strips (17) and a metal patch (16), the metal strips (17) being located on both sides of the metal patch (16), and the metal strips (17) passing through the substrate through a metal through hole to connect to the dual-frequency feeding network (3); the metal strips in all the single-port single-frequency antennas (1) and the single-port dual-frequency antennas (2) have the same size and are in the same direction, which is the one-dimensional array direction composed of all the single-port single-frequency antennas (1) and the single-port dual-frequency antennas (2);

[0008] The two metal strips of the single-port single-frequency antenna (1) serve as the radiation structure of the high-frequency antenna, and both operate in a monopole mode; the two metal strips of the single-port dual-frequency antenna (2) serve as the radiation structure of the high-frequency antenna, and the middle metal patch serves as the excitation structure at low frequencies;

[0009] Each single-port single-frequency antenna (1) and single-port dual-frequency antenna (2) corresponds to a one-to-two power divider in the dual-frequency feeding network (3), and the dual output ends of the power divider are respectively connected to two metal strips in the single-port single-frequency antenna (1) or the single-port dual-frequency antenna (2); all antennas in the dual-frequency Van Atta array antenna are arranged in order, the single input ends of the power dividers corresponding to the first antenna and the last antenna are connected to each other, the single input end of the power divider corresponding to the second antenna and the second to last antenna are connected to each other, the single input end of the power divider corresponding to the third antenna and the third to last antenna are connected to each other, ..., until only the single input end of the power divider corresponding to the middle antenna is left hanging.

[0010] Furthermore, the distance between the metal strips of the adjacent antennas is λ H0 / 2, the metal patch spacing between the two single-port dual-band antennas (2) is λ L0 / 2,λ H0 is the vacuum wavelength at high frequencies, λ L0is the vacuum wavelength at low frequencies.

[0011] The dual-frequency feeding network is composed of several microstrip lines of equal length, and a one-to-two geometric microstrip power divider (20) is set at the beginning and end of the microstrip transmission line. Since the number of units in the array is an odd number, the unit at the center position is not connected to other antennas, and the length of the microstrip line connected to it is half the length of the remaining microstrip lines, and the microstrip line only contains one set of power dividers. The two output ends of the microstrip power divider are connected to the antenna through metal through holes, and each antenna is fed through a port. Thanks to the above-mentioned hybrid array and the design of single-port feeding of all antennas, the number of antenna units and transmission lines in the feeding network is effectively reduced. According to the principle of the Van Atta array, the microstrip line in the feeding network connects two antenna units at symmetrical positions (21), thereby achieving conjugation of the phase difference of adjacent units in the array. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a structural perspective view of a compact dual-frequency Van Atta array for dual-frequency backward RCS enhancement according to the present invention;

[0013] Figure 2 The design principle of the compact dual-frequency Van Atta array in the present invention is compared with the design principle of the conventional dual-frequency Van Atta array.

[0014] Figure 3 It is a single-port single-frequency antenna designed by the present invention;

[0015] Figure 4 It is a single-port dual-frequency antenna designed by the present invention;

[0016] Figure 5 It is a dual-frequency antenna array that uses a hybrid array of a single-port single-frequency antenna and a single-port dual-frequency antenna;

[0017] Figure 6 It is a dual-frequency feeding network of a dual-frequency Van Atta array designed by the present invention;

[0018] Figure 7 This is the single-station RCS result at 5.8 GHz for the compact dual-band Van Atta array designed by the present invention;

[0019] Figure 8 This is the single-station RCS result of the compact dual-band Van Atta array designed by the present invention at 10.6 GHz. Specific implementation plan

[0020] The following is a further description of the specific embodiments of the present invention in conjunction with the accompanying drawings.

[0021] According to the different unit structures and array formation methods in the dual-frequency antenna array, the design principles of the dual-frequency Van Atta array can be divided into three types. The first type is a dual-frequency Van Atta array that uses a co-aperture design of a low-frequency antenna (4) and a high-frequency antenna (5). Two feed ports realize an antenna array that works at two frequencies, and a co-aperture design is used to reduce the size of the antenna array. However, the dual-frequency Van Atta array designed using this principle has a large number of antenna units and a large number of transmission lines in the feed network (6)(7), which increases the design difficulty and overall size. The second type is a dual-frequency VanAtta array that only uses a single-port dual-frequency antenna (8). A dual-frequency antenna array composed of only a single-port dual-frequency antenna can effectively reduce the number of transmission lines in the feed network (9). However, since only one antenna is used, when forming an array, the antenna arrays of the two frequencies have the same unit spacing, which is not conducive to wide-angle scanning. In addition, common single-port dual-frequency antennas usually use multi-mode, slotted and stacked patch structures. The dual-frequency antennas realized by these structures also have the problem of small frequency intervals. Based on the above two principles, the present invention uses a mixed array method of a single-port single-frequency antenna (10) and a single-port dual-frequency antenna (11), which can reduce the number of antenna units and transmission lines in the feeding network (12) and reasonably control the unit spacing of antenna arrays of different frequencies.

[0022] like Figure 1 As shown, a compact dual-band Van Atta array for dual-band backward RCS enhancement includes a 1×9 dual-band antenna array, five geometric microstrip power dividers and a dual-band feeding network composed of five microstrip lines. The 1×9 dual-band antenna array consists of five single-port dual-band antennas and four single-port single-band antennas. The five geometric microstrip power dividers are respectively connected to the top metal strip through metal through holes to feed the antenna array. The dual-band feeding network consists of five microstrip lines, four of which have the same length, and the other open-circuit microstrip line has a length half the length of the remaining microstrip lines. In the Van Atta array composed of an odd number of antenna units, the antenna unit at the center position is not connected to other units, and the length of the transmission line connected to it is half the length of the remaining transmission lines.

[0023] like Figure 3 As shown in the figure, the single-port single-frequency antenna consists of two long metal strips, two metal through holes and a microstrip power divider. The two output ports of the microstrip power divider are connected to the two top metal strips through metal through holes to feed the antenna. The length L1 of the metal strip is , the width W1 is , and the spacing OS1 is . According to the mirror principle, its working mode is the planar monopole mode.

[0024] like Figure 4As shown in the figure, the single-port dual-frequency antenna consists of a rectangular patch, two long metal strips, two metal through holes and a microstrip power divider. Compared with the single-port single-frequency antenna, it has an additional rectangular patch with a length of L2 and a width of W2. At high frequencies, the metal strip radiates as a monopole; at low frequencies, the metal strip feeds the low-frequency rectangular patch and reuses it as the excitation structure of the low-frequency antenna.

[0025] like Figure 2 As shown in FIG. 1 , the present invention uses a method of hybrid arraying of single-frequency antennas and dual-frequency antennas, combined with a single-port design of the antenna, to effectively reduce the number of transmission lines in the antenna unit and the feed network, and realize a compact design of a dual-frequency Van Atta array. The final structure is shown in FIG. Figure 5 and Figure 6 As shown in the figure, the high-frequency antenna array is 1×9 in scale; the low-frequency antenna array is 1×5 in scale. The unit spacing in the high-frequency array is , and the unit spacing in the low-frequency array is . The transmission lines in the feed network connect the antenna units at symmetrical positions, and the unit at the center position uses an open microstrip line.

[0026] For electromagnetic waves incident from any direction within the scanning range, after receiving the incident wave, the antenna array can achieve the conjugation of the incident wave phase gradient through the phase conjugation network, thereby achieving re-radiation in the incident direction. The actual test results of the compact dual-frequency Van Atta array designed by the present invention at 5.8 GHz and 10.6 GHz are shown in Figure 2. Figure 7 and Figure 8 As shown in the figure, within the range of ±30 degrees, the single-station RCS is relatively stable, and has a good rearward RCS enhancement effect.

Claims

1. A compact dual-band Van Atta array antenna for dual-band backward RCS enhancement, the antenna comprising: A plurality of single-port single-frequency antennas (1), a plurality of single-port dual-frequency antennas (2), a dual-frequency feeding network (3), and a substrate; The number of the single-port single-frequency antenna (1) and the single-port dual-frequency antenna (2) differs by 1; the single-port single-frequency antenna (1) and the single-port dual-frequency antenna (2) are arranged on the upper surface of the substrate in pairs, forming a one-dimensional array antenna, and the antenna structures at both ends of the one-dimensional array antenna are the same; the dual-frequency feeding network (3) is arranged on the lower surface of the substrate, and the dual-frequency feeding network (3) is connected to the single-port single-frequency antenna (1) or the single-port dual-frequency antenna (2) through a metal through hole; The single-port single-frequency antenna (1) comprises: two metal strips (13), each metal strip passing through a substrate through a metal through hole (14) to connect to a dual-frequency feeding network (3); the single-port dual-frequency antenna (2) comprises two metal strips (17) and a metal patch (16), the metal strips (17) being located on both sides of the metal patch (16), and the metal strips (17) passing through the substrate through a metal through hole to connect to the dual-frequency feeding network (3); the metal strips in all the single-port single-frequency antennas (1) and the single-port dual-frequency antennas (2) have the same size and are in the same direction, which is the one-dimensional array direction composed of all the single-port single-frequency antennas (1) and the single-port dual-frequency antennas (2); The two metal strips of the single-port single-frequency antenna (1) serve as the radiation structure of the high-frequency antenna, and both operate in a monopole mode; the two metal strips of the single-port dual-frequency antenna (2) serve as the radiation structure of the high-frequency antenna, and the middle metal patch serves as the excitation structure at low frequencies; Each single-port single-frequency antenna (1) and single-port dual-frequency antenna (2) corresponds to a one-to-two power divider in the dual-frequency feeding network (3), and the dual output ends of the power divider are respectively connected to two metal strips in the single-port single-frequency antenna (1) or the single-port dual-frequency antenna (2); all antennas in the dual-frequency Van Atta array antenna are arranged in order, the single input ends of the power dividers corresponding to the first antenna and the last antenna are connected to each other, the single input end of the power divider corresponding to the second antenna and the second to last antenna are connected to each other, the single input end of the power divider corresponding to the third antenna and the third to last antenna are connected to each other, ..., until only the single input end of the power divider corresponding to the middle antenna is left hanging.

2. A compact dual-frequency Van Atta array antenna for dual-frequency backward RCS enhancement as claimed in claim 1, characterized in that: The distance between the metal strips of adjacent antennas is λ H0 / 2, the metal patch spacing between the two single-port dual-band antennas (2) is λ L0 / 2,λ H0 is the vacuum wavelength at high frequencies, λ L0 is the vacuum wavelength at low frequencies.

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