A dual-frequency slot antenna array with high aperture efficiency and high aperture multiplexing rate

Abstract

The application discloses a dual-frequency slot antenna array with high aperture efficiency and high aperture multiplexing rate, which comprises a lower dielectric substrate, an upper dielectric substrate, a substrate integrated waveguide structure surrounded by metal through holes, a slot structure in the area surrounded by the substrate integrated waveguide, and a feeding structure; the feeding structure is arranged on the upper surfaces of the upper dielectric substrate and the lower dielectric substrate, and the two feeding structures are respectively arranged at the positions on the two sides. The application adopts a planar feeding structure, and the high-frequency and low-frequency feeding structures do not affect each other, so that very high port isolation can be achieved, the profile height of the antenna is reduced, and the antenna is more compact and miniaturized.

Description

Technical Field

[0001] This invention relates to the field of antenna array technology, and in particular to a dual-frequency slot antenna array with high aperture efficiency and high aperture multiplexing rate. Background Technology

[0002] With the development of fifth-generation (5G) communication technology and radar communication, more and more spectrum resources are being put into use. For example, in 5G mobile communication technology, the communication frequency bands cover the range of microwaves and millimeter waves. Therefore, a communication system often needs to be able to support multiple frequency bands. In the past, the solution to this problem was to use multiple antennas of different frequency bands. This design is the simplest, but it brings some problems, such as: poor isolation between antennas, which will degrade antenna performance; increasing the number of antennas means a larger space occupation, which is not conducive to the miniaturization of the equipment; and increasing the number of antennas will increase costs. To address the problems caused by using discrete antennas, scholars at home and abroad have proposed the concept of aperture multiplexing antennas. The main purpose is to realize multiple operating frequencies on a single antenna, while having high isolation between different frequencies, thereby reducing size and cost. Xi'an University of Electronic Science and Technology has announced a dual-band antenna with a high frequency ratio based on structural reuse (Xi'an University of Electronic Science and Technology, A dual-band antenna with a high frequency ratio based on structural reuse, application number CN202110821341.5, application date 2021.10.22). It adopts the reuse of dipoles and "V" type resonant units in the structure to realize the application requirements of 35.5GHz and 28.5GHz dual-band, and forms end-to-end radiation in the millimeter wave band, which has more diverse functions.

[0003] In some applications, such as satellite communication and radar scanning, antennas require advantages such as high gain, low profile, and small size. To achieve these goals, antenna arrays are designed and applied. Simultaneously, the emergence of multiple communication frequency bands has placed demands on antenna arrays for multi-frequency operation, high isolation, miniaturization, and high aperture efficiency. To achieve high gain, the element topology and arrangement of the antenna array are crucial, directly determining the feasible array size and affecting the antenna's maximum gain, radiation pattern, and aperture efficiency. One approach to achieve multiple operating frequencies is to use multi-frequency antenna radiating elements arranged in an array with the same aperture. Since the radiating elements themselves possess multi-frequency characteristics, it is easy to make the array operate in multiple frequency bands. However, this approach restricts the adjustability of the antenna array due to the structural limitations of multi-frequency antenna elements. The University of Electronic Science and Technology of China (UESTC) has published a substrate-integrated antenna machine array antenna for the millimeter-wave band (UESTC, Substrate-integrated Antenna and its Array Antenna for Millimeter-Wave Band, Application No. CN201310598107.6, Application Date 2014.2.19). By setting two slots of different lengths in the substrate-integrated waveguide unit, two resonant points are introduced. The frequencies of the two resonant points are far apart, resulting in weak coupling, which is beneficial for improving the antenna's standing wave characteristics, thus achieving wide bandwidth and high gain. However, in this invention, the spacing of the radiating elements is limited by the size of the substrate-integrated waveguide unit, which is not conducive to suppressing the grating lobes of the radiation pattern. A second approach is to use nested different antenna arrays within the same aperture plane to achieve multiple operating frequencies. The key issue with this method is how to design unique radiating element structures so that they can be nested together without interfering with each other. Chengdu Jinjiang Electronic System Engineering Co., Ltd. has disclosed a dual-band composite antenna element and antenna array (Chengdu Jinjiang Electronic System Engineering Co., Ltd. A dual-band composite antenna element and antenna array: CN202120092755.4 [P]. 2022-02-18.). The array radiating element consists of a central cross-shaped L-band patch and four surrounding C-band patches. Through the nesting of the L-band cross-shaped patch and the C-band patch, the final array operates in two frequency bands. However, because the two band patches are on the same plane, this scheme is not conducive to improving the array's aperture efficiency, and the operating frequencies of the two bands will mutually restrict each other, resulting in low frequency adjustability.Scheme 3 involves stacking antenna arrays operating at different frequencies within the same aperture, which can significantly improve aperture utilization (see:

[12] D.-J.Wei, J.Li, G.Yang, J.Liu, and J.-J.Yang, “Design of compact dual-band SIW slottedarray antenna,” IEEE Antennas Wireless Propag. Lett., vol.17, no.6, pp.1085-1089, Jun.2018.). However, since the upper array will block the lower array, the aperture efficiency of the lower array will often deteriorate. Therefore, for Scheme 3, the most critical issue is how to reasonably design the structure of the upper array and the arrangement of the array elements. Summary of the Invention

[0004] To address the aforementioned background needs and existing technical problems, this invention, combining substrate integrated waveguide and antenna array theory, designs a dual-frequency stacked substrate integrated waveguide slot antenna array. The two operating frequencies are 28 GHz and 35 GHz, respectively, achieved by two layers of 8×8 substrate integrated waveguide slot arrays. By loading a grid structure onto the slot elements, the array's aperture efficiency reaches 75% and 81% at 28 GHz and 35 GHz, respectively. By stacking the arrays at the two operating frequencies, with array elements of different operating frequencies staggered vertically, the structural reuse rate is almost at the theoretical maximum, and it does not affect the antenna's radiation performance and scattering characteristics as the array size increases. Through careful design of the feed network, the port isolation of both frequency bands is greater than 50 dB. The maximum gain of the array antenna at 28.5 GHz and 35.5 GHz is 20.4 dBi and 22.6 dBi, respectively, and the antenna profile height is 0.071 wavelengths of the lowest operating frequency in vacuum.

[0005] This invention can be achieved through the following technical solutions:

[0006] A dual-band antenna array with high aperture efficiency and high aperture multiplexing rate includes two dielectric substrates, a substrate integrated waveguide structure surrounded by metal vias, a slot structure in the region enclosed by the substrate integrated waveguide, and a feeding structure. The dielectric substrate is made of Rogers 6002, with the upper dielectric substrate having a thickness of 0.254 mm and the lower dielectric substrate having a thickness of 0.508 mm.

[0007] The upper and lower surfaces of the lower dielectric substrate are covered with metal patches. The upper surface is mainly used for the antenna structure, while the lower surface serves as a ground plane, which is also the antenna structure on the upper surface of the lower dielectric substrate. Metallized vias running through the upper and lower surfaces form parallel rectangular substrate integrated waveguide cavity structures, a total of eight of which are closely connected. Eight longitudinal slots are evenly spaced at the centerline of each substrate integrated waveguide structure, thereby forming an 8×8 slot array antenna operating at low frequencies on the lower dielectric substrate.

[0008] The upper dielectric substrate has metal patches on both its top and bottom surfaces. The upper surface is primarily used for the antenna structure, while the lower surface serves as the ground plane. Eight parallel rectangular substrate-integrated waveguide cavities are formed by metallized vias penetrating both surfaces. Adjacent substrate-integrated waveguide structures are spaced apart, exposing the radiating slot structure of the lower dielectric substrate. A grid structure is loaded onto the upper dielectric substrate within this spaced area. Eight longitudinal slots are evenly spaced along the centerline of each rectangular substrate-integrated waveguide structure, thus forming an 8×8 slot array antenna operating at high frequencies on the upper dielectric substrate without obstructing the radiated energy from the lower surface.

[0009] The feeding structure is mainly distributed on the upper surface of each substrate layer and consists of three parts. The first part is a 50Ω microstrip line structure, mainly for facilitating the connection of the feeding connector. The second part is the transition structure from the microstrip line to the substrate integrated waveguide, which is the main feed line. The third part is a series feeding network of the substrate integrated waveguide, with the main feed line on one side and eight ports connected to the substrate integrated waveguide on the other side. There are feeding structures on the upper surface of both the upper and lower dielectric substrates, with the two feeding structures located on opposite sides.

[0010] Compared with existing technologies, the advantages of this invention are:

[0011] 1. Aperture multiplexing efficiency close to the theoretical maximum. This invention achieves near-perfect overlap between two slot antenna arrays with the same number of elements through the stacking of two slot antenna arrays and the staggered distribution of slot elements. Furthermore, the antenna arrays are implemented using a slot antenna based on a substrate-integrated waveguide, achieving extremely low profile height—0.071 wavelengths (a relatively low operating frequency in vacuum) and extremely high port isolation—greater than 50 dB.

[0012] 2. Compared with traditional slotted array antennas, this invention improves the current distribution on the upper surface of the upper dielectric substrate by loading a grating structure between the substrate-integrated waveguide structures on the upper surface of the upper dielectric substrate, without affecting the radiation of the lower dielectric substrate, thus greatly improving the antenna's aperture radiation efficiency. It achieves 75% at 28 GHz and 81% at 35 GHz.

[0013] 3. Compared with conventional aperture multiplexing antenna arrays, this invention uses a series-feed type feeding structure. In addition, the array elements are evenly distributed and the aperture multiplexing rate of the upper and lower substrates is high. Therefore, it is very suitable for the arrangement of a large number of array elements, further expanding the array size and obtaining higher gain. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the aperture multiplexing slot antenna array substrate structure in this invention;

[0015] Figure 2 This is a schematic diagram of the stacked arrangement of two substrate integrated waveguide slot arrays operating in different frequency bands in this invention;

[0016] Figure 3 This is a planar schematic diagram of the slot array antenna structure in this invention;

[0017] Figure 4 (a) is a schematic diagram of the high-frequency feed port in this invention;

[0018] Figure 4 (b) is a schematic diagram of the low-frequency feed port in this invention;

[0019] Figure 5 This is a schematic diagram of the grid structure loaded in this invention;

[0020] Figure 6 (a) is a schematic diagram of the planar structure of the high-frequency slot antenna array in this invention;

[0021] Figure 6 (b) is a schematic diagram of the planar structure of the low-frequency slot antenna array in this invention;

[0022] Figure 7 (a) is a graph of S11 and S21 of the array antenna in the low frequency band;

[0023] Figure 7 (b) is a graph of S11 and S21 of the array antenna in the high-frequency band;

[0024] Figure 8 (a) shows the radiation pattern of the array antenna in the common polarization and cross polarization E-plane at 28.5 GHz;

[0025] Figure 8 (b) shows the radiation pattern of the array antenna in the common polarization and cross polarization H-plane at 28.5 GHz;

[0026] Figure 9 (a) shows the radiation pattern of the array antenna in the common polarization and cross polarization E-plane at 35.5 GHz;

[0027] Figure 9(b) shows the radiation pattern of the array antenna in the common polarization and cross polarization H-plane at 35.5 GHz. Detailed Implementation

[0028] The purpose of this invention is to achieve a dual-frequency slot antenna array with high aperture radiation efficiency and high aperture utilization. To make the above-mentioned objectives, advantages and features of this invention more apparent and understandable, the specific embodiments of this invention will be described in detail below with reference to the accompanying drawings.

[0029] Figure 1 This is a schematic diagram of the aperture multiplexing slot antenna array substrate structure in this invention. The upper dielectric substrate 4 is made of Rogers 6002 substrate with a dielectric constant of 2.94 and a thickness of 0.254 mm. The lower dielectric substrate 5 is also made of Rogers 6002 substrate with a thickness of 0.508 mm. Metal layers 1, 2, and 3 are made of copper. The high-frequency antenna structure is implemented on metal layer 1, the low-frequency antenna structure is implemented on metal layer 2, and metal layer 3 serves as the antenna ground plane.

[0030] Figure 2 This diagram illustrates the stacking arrangement of two substrate-integrated waveguide slot arrays operating at different frequency bands in this invention. Slot 6 radiates high-frequency energy, while slot 7 radiates low-frequency energy. Metallized vias 8 are installed in the upper dielectric substrate to form a substrate-integrated waveguide cavity. Each pair of metallized vias forms a group, with gaps between groups to accommodate the low-frequency slot 7, achieving multiplexing of the two frequency structures without affecting low-frequency radiation. Metallized vias 9 are installed in the lower dielectric substrate to form a substrate-integrated waveguide cavity for transmitting low-frequency energy. The width of the substrate-integrated waveguide cavity in the lower dielectric substrate is smaller than that in the upper dielectric substrate, thus allowing for a lower frequency in the lower dielectric substrate and creating conditions for improving aperture multiplexing efficiency.

[0031] Figure 3 This is a schematic planar view of the aperture multiplexing slot antenna array structure in this invention. The antenna array mainly consists of three parts: a high-frequency feed network 10, a low-frequency feed network 11, and a slot antenna array 12. The two feed networks 10 and 11 employ similar structures and are located at opposite ends of the substrate. The slot antenna array 12 includes both an upper dielectric substrate and a lower dielectric substrate. Through substrate-integrated waveguide design, the two structures almost completely overlap, achieving an aperture multiplexing rate of nearly 1, a compact structure, and miniaturization.

[0032] Figure 4(a) is a schematic diagram of the high-frequency feed port structure of the dual-frequency slot array antenna in this invention, mainly composed of four parts: a microstrip feed line 13, a microstrip line-substrate integrated waveguide transition structure 14, a cylindrical metallized via 15, and a first elongated metallized via 16, with the elongated metallized via forming a substrate integrated waveguide cavity 17. The microstrip feed line 13 and the microstrip line-substrate integrated waveguide transition structure 14 are located on the upper surface of the upper dielectric substrate, i.e., the metal layer 1. The substrate integrated waveguide cavity 17 formed by the cylindrical metallized via 15, the first elongated metallized via 16, and the elongated metallized via is loaded in the upper dielectric substrate 4. The working mechanism of this structure is explained in detail below. The impedance of the microstrip feed line 13 is 50Ω, which facilitates connection with the SMA RF connector. Since the impedances of the microstrip feed line and the substrate integrated waveguide transmission line are inconsistent, the transition structure 14 is required to achieve a smooth impedance transition, thereby achieving good return loss characteristics. The microstrip line-substrate integrated waveguide transition structure 14 begins with a gradually decreasing transmission line connecting the 50Ω microstrip line to the substrate integrated waveguide. At the beginning of the substrate integrated waveguide transmission line, the spacing between the metallized vias on both sides gradually decreases until it reaches the operating frequency required for high-frequency transmission. These two transmission lines not only have different impedances but also different operating modes. In the microstrip line, the quasi-TEM mode is mainly transmitted; in the substrate integrated waveguide, the TE10 mode is mainly transmitted. This transition structure achieves impedance transition and mode conversion, exhibiting excellent transmission characteristics and return loss characteristics. The advantages of this structure are verified using an 8×8 array arrangement in this slotted array antenna. Therefore, after converting the quasi-TEM mode of the microstrip line to the TE10 mode of the substrate integrated waveguide, this feeding structure forms eight substrate integrated waveguide cavities through elongated metallized vias, dividing the energy at the feeding end into eight uniform portions for transmission into the substrate integrated waveguide cavities. To achieve even energy distribution and optimize return loss, nine cylindrical metallized vias 15 are introduced into the feed structure. Adjusting the position of the metallized vias will disturb the field distribution in the feed structure. When the via is in a suitable position, it can significantly improve energy transmission and distribution.

[0033] Figure 4(b) is a schematic diagram of the low-frequency feed port structure of the dual-frequency slot array antenna in this invention, mainly composed of four parts: a microstrip line feed line 21, a microstrip line-substrate integrated waveguide transition structure 20, a cylindrical metallized via 19, a second elongated metallized via 18, and a substrate integrated waveguide cavity 22 surrounded by the elongated metallized via. The microstrip line feed line 21 and the microstrip line-substrate integrated waveguide transition structure 20 are located on the upper surface of the lower dielectric substrate, i.e., the metal layer 2. The substrate integrated waveguide cavity 22 surrounded by the cylindrical metallized via 19, the second elongated metallized via 18, and the elongated metallized via is loaded in the substrate 5. Similar to the high-frequency feed structure, the impedance of the microstrip line feed line 21 is 50Ω, which facilitates connection with the SMA RF connector. The microstrip line-substrate integrated waveguide transition structure 20 realizes the conversion and impedance transition from the quasi-TEM mode of the microstrip line to the TE10 mode of the substrate integrated waveguide. This feed structure, after converting the quasi-TEM mode of the microstrip line into the TE10 mode of the substrate integrated waveguide, forms eight substrate integrated waveguide cavities 22 through elongated metallized vias, distributing the energy from the feed end evenly into eight parts within the substrate integrated waveguide cavities. To achieve even energy distribution and optimize return loss, nine cylindrical metallized vias 19 are also introduced into the feed structure. Adjusting the position of these vias disturbs the field distribution within the feed structure; when the vias are positioned appropriately, energy transmission and distribution can be significantly improved. Simultaneously, by adjusting... Figure 4 (a) and Figure 4 The width of the substrate integrated waveguide cavities 17 and 22, enclosed by the cylindrical metallized vias 15 and 19 and the elongated metallized vias in (b), can make the phase difference between the output ends of two adjacent substrate integrated waveguide cavities 180° and the energy equal. This is necessary for the realization of the slot array, so the next step of array design can be carried out.

[0034] Figure 5This is a schematic diagram of the grid structure of the dual-frequency slot array antenna in this invention. It mainly consists of five parts: a second elongated metallized via 18 loaded on the lower dielectric substrate and the substrate integrated waveguide cavity 22 enclosed by it; a low-frequency radiation slot 25 on the metal layer 2; a metallized via 16 loaded on the upper dielectric substrate and the substrate integrated waveguide cavity 17 enclosed by it; and a high-frequency radiation slot 23 on the metal layer 1. The last part is a grid-like structure 24 loaded on the upper surface of the upper dielectric substrate 4, on the metal layer 1. The grid-like structure 24 is located above the low-frequency radiation slot 25. Low-frequency energy is first radiated through the slots on the low-frequency substrate integrated waveguide, and then radiated into free space from the grid-like slots. Since the thickness of the upper dielectric substrate 4 is much smaller than the operating wavelength, the low-frequency energy can pass through the grid structure with almost no loss. Comparison with simulation results shows that whether or not a grid structure is loaded has almost no impact on the aperture efficiency of low-frequency radiation, confirming the correctness of the theoretical analysis. Furthermore, due to the good isolation between adjacent sets of high-frequency substrate integrated waveguide cavities, the grid structure 24 will not have a deteriorating effect on the high-frequency radiation characteristics. On the contrary, the loading of the grid structure makes the high-frequency current on the surface of the metal layer 1 more complete, which can significantly improve the radiation efficiency and is one of the main means of improving the aperture radiation efficiency in this invention.

[0035] Figure 6 (a) is a schematic diagram of the planar structure of the high-frequency slot antenna array in this invention. The slot antenna array structure consists of... Figure 4 (a) consists of a high-frequency feeding structure, a high-frequency radiation slot 23, and a grid-like structure 24. Figure 6 As shown in (a), the substrate integrated waveguide cavity 17 is a cavity with a short-circuited termination, thus forming a standing wave structure, and the slot radiating element is also a standing wave antenna element. To achieve impedance matching of the slot structure antenna, the slots are staggered off-center, and eight equally spaced elements are arranged along the center line, forming an 8×8 array arrangement in the eight substrate integrated waveguide cavities. At the same time, a grid structure is loaded between every two substrate integrated waveguide cavities, which can make the high-frequency current on the surface more complete and continuous, improving the aperture radiation efficiency.

[0036] Figure 6 (b) is a schematic diagram of the low-frequency slot antenna array planar structure in this invention, which consists of... Figure 4(b) consists of a low-frequency feed structure and a low-frequency radiation slot 25. Similarly, the elongated metallized via surrounds the substrate integrated waveguide cavity 22 with a short-circuited terminal, mainly forming the energy distribution of the standing wave field. The slot radiation elements are staggered off-center, with eight elements loaded at equal intervals along the center line, forming an 8×8 array arrangement. Unlike the high-frequency slot antenna array, in the low-frequency antenna array, two adjacent substrate integrated waveguides share a long, elongated metallized via, maximizing space utilization.

[0037] The scattering characteristics test results of this dual-frequency slot antenna array are as follows: Figure 7 As shown, Figure 7 (a) shows the S11 curve and the isolation between the two ports when the low-frequency port is fed and the high-frequency port is connected to a matched load. As can be seen from the figure, the low-frequency of the antenna array is 28.5 GHz, and the isolation between the low-frequency port and the high-frequency port is greater than 60 dB. Figure 7 (b) shows the S11 curve and the isolation between the two ports when the low-frequency port is fed and the high-frequency port is connected to a matched load. As can be seen from the figure, the antenna array operates at a high frequency of around 35.5 GHz, and the isolation between the low-frequency port and the high-frequency port is greater than 50 dB. Figure 8 The test results of the antenna array's radiation pattern at 28.5 GHz are illustrated. First, the maximum gain of the antenna at this frequency was measured to be 20.4 dBi. Then, based on the test results, the following diagram was plotted. Figure 8 The normalized co / cross polarization patterns are shown in (a) and (b). The sidelobe suppression in the E plane is approximately 12 dB, and the cross polarization isolation is greater than 30 dB; the sidelobe suppression in the H plane is approximately 18 dB, and the cross polarization isolation is greater than 30 dB. Figure 9 The test results of the antenna array's radiation pattern at 35.5 GHz are illustrated. First, the maximum gain of the antenna at this frequency was measured to be 22.6 dBi. Then, the results were plotted as follows. Figure 9 The normalized co / cross polarization patterns are shown in (a) and (b). The sidelobe suppression in the E plane is approximately 13 dB, and the cross polarization isolation is greater than 35 dB; the sidelobe suppression in the H plane is approximately 12 dB, and the cross polarization isolation is greater than 30 dB.

[0038] The advantages of this invention are: (1) By stacking and staggering the double-layer slot antenna array, the aperture reuse rate almost reaches the theoretical maximum value. (2) By loading a grid-like structure on the surface of the upper slot antenna array, the aperture radiation efficiency is greatly improved. (3) Thanks to the uniformity of the dual-frequency array antenna arrangement and the advantage of almost overlapping in structural aperture, the array unit can be further increased, which is beneficial to the integration and realization of large array antennas. (4) The planar feeding structure is adopted, and the high and low frequency feeding structures do not affect each other, which can achieve a very high port isolation, which is beneficial to reducing the antenna profile height and making the antenna more compact and miniaturized.

[0039] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the scope of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A dual-frequency slot antenna array with high aperture efficiency and high aperture multiplexing ratio, characterized in that: The substrate integrated waveguide structure is surrounded by a lower dielectric substrate, an upper dielectric substrate, a metal via, a slot structure in the area surrounded by the substrate integrated waveguide, and a feed structure, and the feed structure is arranged on the upper surface of the upper dielectric substrate and the lower dielectric substrate, and the two feed structures are arranged on the two sides, respectively. The upper and lower surfaces of the lower dielectric substrate are covered with metal patches, the upper surface is loaded with an antenna structure, and the lower surface is a ground plate, which is also the antenna structure on the upper surface of the lower dielectric substrate, and the metalized via penetrating the upper and lower surfaces surrounds a parallel rectangular substrate integrated waveguide cavity structure, a total of eight and closely arranged in a row. The upper and lower surfaces of the upper dielectric substrate are covered with metal patches, the upper surface is mainly loaded with an antenna structure, and the lower surface is a ground plate, which is also the antenna structure on the upper surface of the lower dielectric substrate, and the metalized via penetrating the upper and lower surfaces surrounds a parallel rectangular substrate integrated waveguide cavity structure, a total of eight, and the adjacent substrate integrated waveguide structures are separated by a distance, exposing the radiation slot structure of the lower dielectric substrate, and a grid structure is loaded on the upper dielectric substrate in the range of the distance. The feed structure is distributed on the upper surface of each substrate and consists of three parts, the first part is an impedance microstrip line structure, the second part is a microstrip line to substrate integrated waveguide transition structure, which is a main feed line, and the third part is a series feed network of substrate integrated waveguide, one side of which is a main feed line and the other side is eight ports connected to the substrate integrated waveguide. Eight longitudinal slots are loaded at equal intervals at the centerline position in each substrate integrated waveguide structure, thereby forming an 8x8 slot array antenna operating at low frequency on the lower dielectric substrate. Eight longitudinal slots are loaded at equal intervals at the centerline position in each rectangular substrate integrated waveguide structure, thereby forming an 8x8 slot array antenna operating at high frequency on the upper dielectric substrate and not blocking the radiation energy of the lower surface.

2. The dual-frequency slot antenna array with high aperture efficiency and high aperture multiplexing ratio according to claim 1, characterized in that: The materials of the lower dielectric substrate and the upper dielectric substrate are Rogers 6002.

3. The dual-frequency slot antenna array with high aperture efficiency and high aperture multiplexing ratio of claim 1, wherein: The thickness of the upper dielectric substrate is 0.254 mm.

4. The dual-frequency slot antenna array with high aperture efficiency and high aperture multiplexing ratio of claim 1, wherein: The thickness of the lower dielectric substrate is 0.508 mm.

5. The dual-frequency slot antenna array with high aperture efficiency and high aperture multiplexing ratio of claim 1, wherein: The first part is a microstrip line structure with an impedance of 50Ω.

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