A dual-frequency antenna array structure

Abstract

The application discloses a kind of dual-frequency antenna array structures, the dual-frequency antenna array structure is multilayer laminated structure, from bottom to top sequentially first metal layer, first dielectric layer, second metal layer, second dielectric layer, third metal layer, third dielectric layer, fourth metal layer;Wherein, the rectangular waveguide-SIW transition structure formed by first metal layer, second metal layer, first dielectric layer, second dielectric layer;SIW power distributor and impedance matching structure formed by second metal layer, third metal layer, second dielectric layer;Antenna radiator formed by third metal layer, fourth metal layer, third dielectric layer.The dual-frequency antenna array structure provided by the application can realize dual-frequency radiation, excite the high-order mode of SIC, and has small size and can ensure high gain and high radiation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of array antenna technology, and specifically relates to a dual-frequency antenna array structure. Background Technology

[0002] Antennas are a key component in wireless communication systems, playing a crucial role in converting guided electromagnetic waves into radiated electromagnetic wave energy. Current development directions and goals for antennas include wide bandwidth, high efficiency, high gain, and small size. However, achieving both antenna performance and miniaturization is often difficult. Therefore, how to achieve miniaturization of millimeter-wave antennas while maintaining good radiation performance has become a key research focus. A significant branch of current miniaturized antennas is the substrate integrated cavity (SIC) antenna, which radiates through the resonance of the SIC and a radiation window loaded on an upper metal layer. Current research is largely limited to utilizing the fundamental mode of the resonant cavity; how to efficiently apply higher-order resonant modes to antenna radiation remains a problem to be solved.

[0003] As the electromagnetic environment becomes increasingly complex and changeable, single-frequency antennas sometimes struggle to complete transmission tasks, thus increasing the operating frequency of the antenna becomes a solution; the use of low-frequency bands is already quite crowded, requiring the design of devices suitable for higher frequency bands to solve this problem. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-frequency antenna array structure to solve one or more of the aforementioned technical problems. The dual-frequency antenna array structure provided by this invention can achieve dual-frequency radiation, excite higher-order modes of SiC, has a small size, and ensures high gain and high radiation efficiency.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The present invention provides a dual-frequency antenna array structure, wherein the dual-frequency antenna array structure is a multi-layer stacked structure, which consists of a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, a third metal layer, a third dielectric layer, and a fourth metal layer from bottom to top;

[0007] The first metal layer is provided with a rectangular waveguide feed port, which is used to input electromagnetic energy from the external rectangular waveguide into the interior of the dual-frequency antenna array structure;

[0008] The first dielectric layer is provided with a rectangular substrate integrated cavity composed of multiple metal short-circuit pillars. The rectangular substrate integrated cavity is used to resonate the electromagnetic wave energy input from the rectangular waveguide feed port and output the resonant electromagnetic wave energy.

[0009] The second metal layer is provided with a rectangular coupling window; the second dielectric layer is provided with a substrate integrated waveguide transmission structure, an impedance matching structure, and a power distribution structure, which are composed of multiple metal short-circuit pillars; the rectangular coupling window is used to couple the resonant electromagnetic wave energy to the substrate integrated waveguide transmission structure, the impedance matching structure is used to match the input impedance of the power distribution structure with the characteristic impedance in the substrate integrated waveguide transmission structure, and the power distribution structure is used to distribute and output the electromagnetic energy transmitted through the impedance matching structure;

[0010] An hourglass-shaped coupling slot is provided on the third metal layer; a rectangular substrate integrated cavity is provided in the antenna radiator composed of metal short-circuit pillars in the third dielectric layer; the hourglass-shaped coupling slot is used to couple the electromagnetic energy distributed and output by the power distribution structure to the rectangular substrate integrated cavity in the antenna radiator and to feed the antenna radiator; the rectangular substrate integrated cavity in the antenna radiator is used to generate the electromagnetic resonant mode required for antenna radiation;

[0011] A rectangular radiation window is provided on the fourth metal layer, which is used to radiate the electromagnetic energy generated by the electromagnetic resonance of the rectangular substrate integrated cavity in the antenna radiator.

[0012] A further improvement of the present invention is that the long sides of the rectangular waveguide feed port, the rectangular substrate integrated cavity, and the rectangular coupling window are parallel to each other, the short sides are parallel to each other, and the centers of the three are aligned vertically.

[0013] The size of the rectangular coupling window is less than the size of the rectangular waveguide feed port, which is less than the size of the rectangular substrate integrated cavity.

[0014] A further improvement of the present invention is that the power distribution structure is provided with four output ports for splitting the electromagnetic energy transmitted through the impedance matching structure into four outputs.

[0015] A further improvement of the present invention is that the power distribution structure in the second dielectric layer is provided with three independent metal short-circuit pillars for changing the phase of the output port.

[0016] A further improvement of the present invention is that the number of hourglass-shaped coupling slots provided on the third metal layer is four; the number of rectangular substrate integrated cavities in the antenna radiator provided on the third dielectric layer is four; and the rectangular radiation windows provided on the fourth metal layer are divided into four groups.

[0017] The centers of the four hourglass-shaped coupling slots are aligned vertically with the centers of the rectangular substrate integrated cavities in the four antenna radiators; the centers of the rectangular substrate integrated cavities in the four antenna radiators are aligned vertically with the centers of the four sets of rectangular radiation windows.

[0018] A further improvement of the present invention is that the rectangular substrate integrated cavities in the four antenna radiators together form a grid-shaped structure.

[0019] A further improvement of the present invention is that the four sets of rectangular radiating windows together form a grid-shaped structure;

[0020] Each set of rectangular radiating windows includes four rectangular holes, which are located within the four rectangular frames of the grid structure.

[0021] A further improvement of the present invention is that the substrate integrated waveguide transmission structure in the second dielectric layer is a structure of two rows of metal short-circuit pillars maintaining a preset spacing.

[0022] A further improvement of the present invention is that the multilayer stacked structure is fixed between layers using a low-temperature co-fired ceramic process.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] To address the challenge of simultaneously achieving miniaturization, high gain, and high efficiency, the dual-band antenna array structure provided by this invention employs a SiC antenna, which is fed by a rectangular waveguide and transitions to a substrate integrated waveguide (SIW). This approach features a multi-layered structure, arranging different parts of the antenna on different layers, fully utilizing vertical space, and ensuring high gain and high radiation efficiency while achieving miniaturization. To address the issue of frequency band congestion, the dual-band antenna array structure provided by this invention utilizes higher-order resonant modes of the SiC antenna instead of the fundamental modes. This method increases the antenna's operating frequency, reduces electromagnetic interference within the same frequency band during antenna use, and simultaneously reduces the complexity and requirements of signal modulation.

[0025] To address the alignment issues between layers in multilayer stacked structures, this invention employs a low-temperature co-fired ceramic (LTCC) process. This process reduces misalignment of vertical positions between layers by firing multiple layers of ceramic uniformly, resulting in smaller errors compared to PCB manufacturing processes. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below; obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0027] Figure 1This is an exploded view of a dual-frequency antenna array structure provided in an embodiment of the present invention;

[0028] Figure 2 This is a top view schematic diagram of the antenna unit radiator structure in an embodiment of the present invention;

[0029] Figure 3 This is a top view schematic diagram of the SIW power divider structure in an embodiment of the present invention;

[0030] Figure 4 This is a top view schematic diagram of the upper structure of the rectangular waveguide-SIW transition structure in an embodiment of the present invention;

[0031] Figure 5 This is a top view schematic diagram of the lower structure of the rectangular waveguide-SIW transition structure in an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the S-parameter simulation results of the antenna in an embodiment of the present invention;

[0033] Figure 7 This is a schematic diagram of the actual gain direction of the antenna at 146GHz in an embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the actual gain direction of the antenna at 166GHz in an embodiment of the present invention;

[0035] Figure 9 This is a schematic diagram of the maximum true gain of the antenna as a function of frequency in an embodiment of the present invention;

[0036] Figure 10 This is a schematic diagram of the antenna radiation efficiency versus frequency in an embodiment of the present invention;

[0037] In the figure, 1. First metal layer; 2. First dielectric layer; 3. Second metal layer; 4. Second dielectric layer; 5. Third metal layer; 6. Third dielectric layer; 7. Fourth metal layer; 8. Metal short-circuit post; 9. Rectangular radiation window; 10. Rectangular substrate integrated cavity in the antenna radiator; 11. Hourglass-shaped coupling slot; 12. Impedance matching structure; 13. Rectangular coupling window; 14. Rectangular substrate integrated cavity in the rectangular waveguide-SIW transition structure; 15. Rectangular waveguide feed port. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0040] The present invention will now be described in further detail with reference to the accompanying drawings:

[0041] Please see Figures 1 to 5 The -x direction is defined as forward, +x direction as backward, -y direction as left, +y direction as right, -z direction as down, and +z direction as up. The dual-band antenna array structure provided in this embodiment is a multi-layered structure, which, from bottom to top, includes a rectangular waveguide-SIW transition structure, an impedance matching structure, a power divider, and a 2×2 antenna array. Specifically, the dual-band antenna array structure provided in this embodiment consists of 7 layers, including 4 metal layers and 3 dielectric layers. From bottom to top, they are: first metal layer 1, first dielectric layer 2, second metal layer 3, second dielectric layer 4, third metal layer 5, third dielectric layer 6, and fourth metal layer 7. All metal layer materials can be high-conductivity metals such as gold, silver, and copper. All dielectric layer materials are insulating materials with a relative permittivity of 2 to 15 and a relative permeability of approximately 1, which can be selected according to the operating frequency.

[0042] In this embodiment of the invention, the interlayer fixing method for the multilayer stacked structure can be selected from screw fixing, conductive adhesive bonding, integrated ceramic firing, etc.; in the preferred embodiment of the invention, it is recommended to use the LTCC process and the integrated ceramic firing method for interlayer fixing, which can reduce the occurrence of interlayer misalignment to a greater extent and reduce errors.

[0043] In this embodiment of the invention, a rectangular hole is loaded in the first metal layer 1, with its long side along the front-back direction and its short side along the left-right direction. This rectangular hole serves as a rectangular waveguide feed port 15. A rectangular structure composed of several metal short-circuit pillars is disposed in the first dielectric layer 2, with its long side along the front-back direction and its short side along the left-right direction. This rectangular structure serves as a rectangular substrate integrated cavity 14 in the rectangular waveguide-SIW transition structure. A rectangular hole is loaded in the second metal layer 3, with its long side along the front-back direction and its short side along the left-right direction. This rectangular hole serves as a rectangular coupling window.A SIW transmission structure and a power distribution structure composed of several metal shorting posts are provided in the second dielectric layer 4. Among them, the SIW transmission structure includes multiple rows of two rows of metal shorting post rows that maintain a certain distance. This type of double row of metal shorting posts is called a SIW structure, which plays a role in conducting electromagnetic waves. The distance between the two rows of metal shorting posts is the width of the SIW. Specifically, for example, the structure of the SIW transmission structure from right to left can be as follows: The rightmost is a column of metal shorting posts with a length of W5 along the front-back direction; a section of SIW with a width of W5 is set to the left from the front and back ends of this column of metal shorting posts; a section of SIW with a distance between the two rows varying uniformly from W5 to W4 and W4 < W5 is set from the leftmost end of this section of SIW. The width change of this SIW structure is formed by the front and back rows of metal shorting posts moving closer to the inside. This SIW structure is an axisymmetric structure, and the axis of symmetry is along the left-right direction; a section of SIW with a width that first becomes smaller and then returns to W4 is set from the left end of this section of SIW. The width change of this SIW structure is formed by the front and back rows of metal shorting posts first moving closer to the inside and then expanding to the outside. The narrowest part of the SIW width is the center position of this section of SIW in the left-right direction. This section of SIW is an impedance matching structure 12; a SIW power divider composed of several metal shorting posts is set from the left end of the impedance matching structure 12. The front and back sides of this SIW power divider are axisymmetric, and the axis of symmetry is the axis of symmetry of the impedance matching structure 12 in the left-right direction; the front half of the structure of this SIW power divider is composed of a section of SIW with a notch and the left and right sides sealed by columns of metal shorting posts. The back side of this SIW is aligned with the leftmost metal shorting post of the front side SIW edge in the impedance matching structure 12 along the left-right direction, and its notch part is several metal shorting posts at the position slightly to the right of the center of the back side SIW edge; the back half of the structure of the SIW power divider is axisymmetric with the front half structure, and the leftmost ends of the notches of these two parts of SIW are connected by metal shorting posts in the front-back direction to form a column of shorting posts, and the right ends of the notches are not connected. Preferably, in the embodiment of the present invention, three independent metal shorting posts are provided inside the SIW power divider. These three independent metal shorting posts are respectively the first independent metal shorting post located in the front side SIW of the SIW power divider, the second independent metal shorting post located between the two SIWs, and the third independent metal shorting post located in the back side SIW. The three are aligned in the front-back direction, and the distance between the first independent metal shorting post and the front side SIW edge of the SIW power divider is S3. The second independent metal shorting post is located on the axis of symmetry of the SIW power divider in the front-back direction and on the right side of the column of metal shorting posts formed by the connection of the left ends of the front and back side SIW notches of the SIW power divider, and the distance is S4. The distance between the third independent metal shorting post and the back side SIW edge of the SIW power divider is S3.

[0044] In an embodiment of the present invention, four hourglass-shaped coupling slots 11 are loaded on the third metal layer 5. The vertical direction of the hourglass of the hourglass-shaped coupling slot 11 is along the front-back direction, and the horizontal direction of the hourglass is along the left-right direction. The distance between the centers of the front-back two groups of hourglass-shaped coupling slots 11 is W0, and the distance between the centers of the left-right two groups of hourglass-shaped coupling slots 11 is L0. Four rectangular structures composed of metal shorting posts are arranged on the third dielectric layer 6. The rectangular structure is preferably a square in the embodiment of the present invention. Its two sides are parallel to the front-back and left-right directions respectively, and the specific directions of the long side and the short side are not required. The rectangular structure is a rectangular SIC 10 in the antenna radiator, and its length and width are L0 and W0 respectively. The middle four sides of the four rectangular substrate integrated cavities 10 in the antenna radiator are common parts, jointly forming a "field" shaped structure. Sixteen rectangular holes are loaded on the fourth metal layer 7. The long side of the rectangular hole is along the front-back direction, and the short side is along the left-right direction. The rectangular hole is a rectangular radiation window 9. The sixteen rectangular radiation windows 9 can be divided into four groups, with four in each group. The four groups of rectangular radiation windows are arranged in a "field" shape and are respectively located in the four rectangular frames of the "field" shape. And the four rectangular radiation windows in each group of rectangular radiation windows are also arranged in a "field" shape and are respectively located in the four rectangular frames of the "field" shape.

[0045] In a specific exemplary embodiment of the present invention, the size of the rectangular waveguide feed port 15 located on the first metal layer 1 is the size of a standard rectangular waveguide in the antenna operating frequency band; for example, the size of the rectangular waveguide feed port 15 can be the size of a standard rectangular waveguide in the D band, with the model number WR-6.5.

[0046] In a preferred technical solution of the embodiment of the present invention, the long sides of the rectangular waveguide feed port 15 located on the first metal layer 1, the rectangular substrate integrated cavity 14 in the rectangular waveguide - SIW transition structure located in the first dielectric layer 2, and the rectangular coupling window 13 located on the second metal layer 3 are parallel to each other, the short sides are parallel to each other, and the central positions of the three are aligned in the up-down direction; and the dimensional relationship among the three is: rectangular coupling window 13 < rectangular waveguide feed port 15 < rectangular substrate integrated cavity 14 in the rectangular waveguide - SIW transition structure.

[0047] In an embodiment of the present invention, the center point of the rectangular coupling window 13 located on the second metal layer 3 is consistent with the middle position of the SIW with a width of W5 in the second dielectric layer 4 in the front-back direction, and is separated from the rightmost metal shorting post column in the second dielectric layer 4 by L5 + wf / 2 in the left-right direction.

[0048] In this embodiment of the invention, the center point of the hourglass-shaped coupling slot 11 located at the upper left corner on the third metal layer 5 is aligned with the center of the rectangular structure on the front side of the SIW power divider located on the second dielectric layer 4 in the front-back direction, and the distance from the leftmost metal short-circuit post of the SIW power divider in the left-right direction is L3+W2 / 2. The centers of the four hourglass-shaped coupling slots 11 on the third metal layer 5, the centers of the rectangular SIC10 in the four antenna radiators in the third dielectric layer 6, and the centers of each of the four sets of rectangular radiation windows 9 on the fourth metal layer 7 are aligned vertically.

[0049] The working principle of the technical solution provided in this embodiment of the invention is as follows: The rectangular waveguide feed port 15 located on the first metal layer 1 serves to input electromagnetic energy from the external rectangular waveguide into the antenna structure; the rectangular substrate integrated cavity 14 in the rectangular waveguide-SIW transition structure located in the first dielectric layer 2 serves to resonate the energy input from the external rectangular waveguide into the antenna structure, facilitating the conversion between the electromagnetic wave mode in the waveguide and the electromagnetic wave mode in the SIW; the rectangular coupling window 13 located on the second metal layer 3 serves to couple the electromagnetic energy resonating in the rectangular substrate integrated cavity 14 in the rectangular waveguide-SIW transition structure to the upper SIW transmission structure; the SIW transmission structure located in the second dielectric layer 4 serves to couple the electromagnetic energy from the lower... The electromagnetic energy input to the layer structure undergoes further transition, thereby completing the conversion between the electromagnetic wave mode in the waveguide and the electromagnetic wave mode in the SIW. The function of the impedance matching structure 12 located in the second dielectric layer 4 is to match the input impedance of the SIW power divider with the characteristic impedance in the SIW transmission structure, thereby reducing the loss caused by impedance mismatch. The function of the SIW power divider located in the second dielectric layer 4 is to distribute the electromagnetic energy transmitted through the impedance matching structure 12 into four parts, ensuring that the amplitude of the four output ports (hourglass-shaped coupling gap 11) is the same and the phase difference between the left and right sets of ports is 180°. Among them, the function of the three independent metal shorting posts is to change the phase of the left and right sets of output ports to achieve a phase difference of 180°. The hourglass-shaped coupling slot located on the third metal layer 5 couples the electromagnetic energy output from the SIW power divider to the rectangular substrate integrated cavity 10 in the upper antenna radiator. This hourglass-shaped coupling slot feeds the antenna radiator, allowing more electromagnetic energy to be coupled into the resonant cavity of the third dielectric layer compared to a traditional rectangular coupling slot, thus improving antenna efficiency. The rectangular substrate integrated cavity 10 in the antenna radiator, located in the third dielectric layer 6, generates the electromagnetic resonant modes required for antenna radiation. The rectangular radiation window 9 on the fourth metal layer 7 allows for high-gain, high-efficiency radiation of the two higher-order modes generated by the electromagnetic resonance of the rectangular substrate integrated cavity 10 in the antenna radiator.

[0050] In the technical solution provided by the embodiment of the present invention, the overall function of the rectangular waveguide - SIW transition structure composed of the first metal layer 1, the second metal layer 3, the first dielectric layer 2, and the second dielectric layer 4 is to convert the electromagnetic wave mode in the external rectangular waveguide into the electromagnetic wave mode in the SIW with low loss. The function of the SIW power divider and impedance matching structure composed of the second metal layer 3, the third metal layer 5, and the second dielectric layer 4 is to transmit the electromagnetic energy to each unit of the antenna array structure with low loss, and ensure that the amplitude of each antenna unit is the same, and the phase difference between the left and right groups of antenna units is 180°. In the antenna radiator composed of the third metal layer 5, the fourth metal layer 7, and the third dielectric layer 6, the four rectangular radiation windows 9 located on the fourth metal layer 7 and the rectangular substrate integrated cavities 10 in the four antenna radiators located in the third dielectric layer 6 work together to successfully excite two high - order resonance modes of the rectangular SIC in the antenna radiator, realizing high - gain and high - efficiency dual - band radiation, making it applicable to more and more complex application scenarios, and realizing the increase of the working frequency, effectively reducing the electromagnetic interference in the pass - band during the use of the antenna. In addition, an hourglass - shaped coupling slot, a rectangular SIC in an antenna radiator, and a group (four) of rectangular radiation windows that coincide in the center in the up - down direction form an antenna unit radiator, and the four antenna unit radiators are arranged in a "field" shape, constituting a 2×2 antenna array radiator structure.

[0051] In summary, in order to realize the mode conversion of electromagnetic waves between the rectangular waveguide and the SIW, the embodiment of the present invention designs a transition structure, realizing impedance matching and mode conversion with low insertion loss; two high - order resonance modes of SIC and four rectangular radiation windows are used in the antenna structure to realize dual - band radiation; its small size, high gain, and radiation efficiency make it a suitable choice for dual - band antennas. Aiming at the problem that the electromagnetic signal environment is becoming more and more complex and changeable, the technical solution of exciting two high - order resonance modes of SIC is adopted in the present invention. This means has the characteristics of dual - band operation and can be applied to more and more complex application scenarios.

[0052] Please refer to Figure 1 , Figure 1 which is the schematic diagram of the hierarchical structure of the embodiment of the present invention; in the embodiment of the present invention, there is a rectangular waveguide - SIW transition structure composed of the first metal layer 1, the second metal layer 3, the first dielectric layer 2, and the second dielectric layer 4; an SIW power divider and impedance matching structure composed of the second metal layer 3, the third metal layer 5, and the second dielectric layer 4; an antenna radiator composed of the third metal layer 5, the fourth metal layer 7, and the third dielectric layer 6.

[0053] Please refer to Figure 2 , Figure 2This is the radiating element of the unit antenna in this embodiment of the invention; in this embodiment of the invention, with the center of a rectangular SiC with dimensions W0×L0 located in the third dielectric layer 6 as the center of symmetry, four elements with dimensions W are loaded on the fourth metal layer 7. S ×L S A rectangular radiation window 9 is used to achieve high-efficiency radiation of energy in the resonant cavity; the rectangular radiation window is spaced S1 and S2 in the y and x directions, respectively, the spacing between adjacent metal short-circuit pillars 8 is Dp1, and the diameter of the metal pillars is d; the antenna radiator is fed through an hourglass-shaped coupling slot 11 loaded on the third metal layer 5.

[0054] Please see Figure 3 , Figure 3 This invention relates to a power divider and impedance matching structure. In this embodiment, the input is a SIW structure located on the second dielectric layer 4 on the right. Through a SIW impedance matching structure, and then a 1-to-4 SIW power divider, equal amplitude output is achieved at the four output ports (i.e., hourglass-shaped coupling slots). A 180° phase difference exists between the left and right output ports within the operating frequency band through three independent metal short-circuit pillars in the middle. Energy is then transferred to the rectangular SIC of the upper antenna radiator through the hourglass-shaped coupling slot 11 loaded on the third metal layer 5. The SIW widths at the power divider input port and in the branch section are W4 and W3, respectively. The spacing between adjacent metal short-circuit pillars is Dp2. The positions of the three independent metal short-circuit pillars in the middle are determined by S3 and S4, and their y-coordinates are the same. The size and position of the hourglass-shaped coupling window are determined by L1, L3, W1, and W2. The impedance matching structure 12 increases the bandwidth of the power divider. This structure is implemented using a gradually widening SIW with a length of L2, while maintaining a width of W4 for both the left and right ports. The alignment between the SIW power divider and the antenna radiator is such that the center of each hourglass-shaped coupling slot is aligned with the center of the upper SIC10 in the z-direction.

[0055] Please see Figure 4 and Figure 5 , Figure 4 and Figure 5This is the rectangular waveguide-SIW transition structure of the present invention. In this embodiment, a rectangular waveguide of model WR-6.5 transmits energy to a rectangular SiC with dimensions clf×cwf located in the first dielectric layer 2 through a rectangular waveguide feed port 15 loaded on the first metal layer 1. Then, the energy is coupled to a SIW with a width of W5 in the second dielectric layer 4 by a rectangular coupling window 13 with dimensions lf×wf located on the second metal layer 3. After that, through a uniform width change of length L4, the width of the SIW is converted from W5 to the width W4 used by the input port of the impedance matching structure 12. The spacing between the adjacent metal short-circuit pillars of the SIW in the second dielectric layer 4 and the rectangular SiC 14 in the first dielectric layer 2 are Dp2 and Dp3, respectively. Finally, a low-loss transition from the WR-6.5 rectangular waveguide to the SIW is achieved. Specifically, the alignment of the rectangular waveguide-SIW transition structure layers is as follows: the rectangular coupling window 13, the rectangular SiC 14, and the rectangular waveguide feed port 15 are aligned at their centers in the z direction. The position of the point of alignment in the x direction is the middle position of the SIW with a width of W5 in the second dielectric layer 4, and the position in the y direction is determined by the parameters L5 and wf.

[0056] The antenna provided in this invention excites two higher-order modes of SiC, achieving high-efficiency dual-frequency radiation by loading rectangular radiation windows onto the metal surface of the antenna structure. Taking a single-element antenna as an example, theoretical and simulation analysis shows that when four rectangular radiation windows are loaded onto the metal surface of the antenna, its TM... 130 (or TM) 310 ) and TM 230 (or TM) 320 The ) mode will realize radiation, so the resonant mode of SIC is first calculated using the following formula,

[0057]

[0058] In the formula, f represents the resonant frequency of SiC, and ε r and μ r Let L0 and W0 be the relative permittivity and relative permeability of the dielectric, respectively, and let Dp be the length and width of the SiC. W represents the distance between adjacent metal short-circuit posts. eff L eff and H eff The equivalent size of the SiC is represented by m, n, and p, which represent the resonance orders of the SiC in the y, x, and z directions, respectively. When the dielectric is thin, p is generally considered to be 0. The results were then verified through eigensimlation simulation, and the size of the SiC was adjusted to achieve its TM value. 130 (or TM) 310 ) and TM 230 (or TM) 320The mode operates in the required frequency band. After determining the resonant frequency, high-gain, high-efficiency dual-frequency radiation is achieved by adjusting the spacing and size of the rectangular radiation windows. This invention uses an hourglass-shaped coupling slot to feed the antenna radiator, which, compared to the traditional rectangular coupling slot, allows more energy to be coupled into the resonant cavity of the third dielectric layer, thereby improving the antenna efficiency.

[0059] In a preferred embodiment of the present invention, the LTCC process is to be used for processing and preparation, and the metal material is gold with an electrical conductivity of 4.52 × 10⁻⁶. 7 The antenna array has a permeability of S / m, with each layer having a thickness of approximately 6–12 μm. The dielectric material is Ferro A6M ceramic with a relative permittivity of 5.9 and a relative permeability of 1. Each layer has a thickness of approximately 192 μm (composed of two ceramic dielectric sheets with a thickness of approximately 96 μm). This resulted in a miniaturized, high-gain, and high-efficiency antenna array design.

[0060] In a specific exemplary embodiment of the present invention, the overall dimensions (in mm) are: 22 × 15.6 × 0.598, and the specific geometric parameters (in mm) are: L0 = 1.44, L1 = 0.36, L2 = 1.634, L3 = 0.334, L4 = 1.365, L5 = 0.26, L... S =0.59, W0=1.44, W1=0.13, W2=0.07, W3=0.78, W4=0.66, W5=1.04, W S =0.4, S1=0.23, S2=0.07, S3=0.27, S4=0.315, lf=0.39, wf=0.25, clf=2.55, cwf=1.5, d=0.087, Dp1=0.18, Dp2=0.182, Dp3=0.191.

[0061] Please see Figure 6 , Figure 6 The simulation results of the S-parameters of the preferred antenna array for the embodiment show that the reflection coefficient of the antenna array is less than -10 dBi in the ranges of 145 GHz to 150 GHz and 161 GHz to 169 GHz.

[0062] Please see Figure 7 , Figure 7 The preferred antenna array for this embodiment has a true gain pattern at 146 GHz; the gain pattern has good symmetry in both the xoz and yoz planes and the maximum true gain reaches 13.2 dBi.

[0063] Please see Figure 8 , Figure 8The preferred antenna array for this embodiment has a true gain pattern at 166 GHz; the gain pattern has good symmetry in both the xoz and yoz planes and the maximum true gain reaches 14.1 dBi.

[0064] Please see Figure 9 , Figure 9 The maximum true gain of the preferred antenna array in the embodiment is shown as a function of frequency. It can be seen that the maximum true gain of the antenna array is greater than 12 dBi in the 145 GHz-150 GHz and 161 GHz-169 GHz frequency bands.

[0065] Please see Figure 10 , Figure 10 The preferred embodiment shows the radiation efficiency curve of the antenna array as a function of frequency; wherein, the radiation efficiency of the antenna array is greater than 75% in the operating frequency bands of 145GHz-150GHz and 161GHz-169GHz.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A dual-frequency antenna array structure, characterized in that, The dual-frequency antenna array structure is a multi-layer stacked structure, consisting of a first metal layer (1), a first dielectric layer (2), a second metal layer (3), a second dielectric layer (4), a third metal layer (5), a third dielectric layer (6), and a fourth metal layer (7) from bottom to top. The first metal layer (1) is provided with a rectangular waveguide feed port (15), which is used to input electromagnetic energy from the external rectangular waveguide into the interior of the dual-frequency antenna array structure; The first dielectric layer (2) is provided with a rectangular substrate integrated cavity composed of multiple metal short-circuit pillars (8). The rectangular substrate integrated cavity is used to resonate the electromagnetic wave energy input from the rectangular waveguide feed port (15) and output the resonant electromagnetic wave energy. The second metal layer (3) is provided with a rectangular coupling window (13); the second dielectric layer (4) is provided with a substrate integrated waveguide transmission structure, an impedance matching structure (12) and a power distribution structure composed of multiple metal short-circuit pillars (8); the rectangular coupling window (13) is used to couple the resonant electromagnetic wave energy to the substrate integrated waveguide transmission structure, the impedance matching structure (12) is used to match the input impedance of the power distribution structure with the characteristic impedance in the substrate integrated waveguide transmission structure, and the power distribution structure is used to distribute and output the electromagnetic energy transmitted through the impedance matching structure (12); An hourglass-shaped coupling slot (11) is provided on the third metal layer (5); a rectangular substrate integrated cavity (10) is provided in the antenna radiator composed of metal short-circuit posts (8) in the third dielectric layer (6); the hourglass-shaped coupling slot (11) is used to couple the electromagnetic energy distributed and output by the power distribution structure to the rectangular substrate integrated cavity (10) in the antenna radiator and to feed the antenna radiator; the rectangular substrate integrated cavity (10) in the antenna radiator is used to generate the electromagnetic resonance mode required for antenna radiation; A rectangular radiation window (9) is provided on the fourth metal layer (7). The rectangular radiation window (9) is used to radiate the electromagnetic energy generated by the electromagnetic resonance of the rectangular substrate integrated cavity (10) in the antenna radiator. in, The long sides of the rectangular waveguide feed port (15), the rectangular substrate integrated cavity on the first dielectric layer (2) and the rectangular coupling window (13) are parallel to each other, the short sides are parallel to each other, and the centers of the three are aligned vertically. The size of the rectangular coupling window (13) is less than the size of the rectangular waveguide feed port (15) and less than the size of the rectangular substrate integrated cavity on the first dielectric layer (2); the size of the rectangular waveguide feed port (15) is the standard rectangular waveguide size for the D-band. The power distribution structure is provided with four output ports, which are used to split the electromagnetic energy transmitted through the impedance matching structure (12) into four outputs.

2. The dual-frequency antenna array structure according to claim 1, characterized in that, The power distribution structure in the second dielectric layer (4) contains three independent metal short-circuit pillars for changing the phase of the output port.

3. The dual-frequency antenna array structure according to claim 1, characterized in that, The number of hourglass-shaped coupling slots (11) provided on the third metal layer (5) is four; the number of rectangular substrate integrated cavities (10) in the antenna radiator provided on the third dielectric layer (6) is four; the rectangular radiation windows (9) provided on the fourth metal layer (7) are divided into four groups; Among them, the center of each of the four hourglass-shaped coupling gaps (11) is aligned vertically with the center of each of the four rectangular substrate integrated cavities (10) in the four antenna radiators; the center of each of the four rectangular substrate integrated cavities (10) in the four antenna radiators is aligned vertically with the center of each of the four sets of rectangular radiation windows (9).

4. The dual-frequency antenna array structure according to claim 3, characterized in that, The rectangular substrate integrated cavities (10) in the four antenna radiators together form a grid-shaped structure.

5. A dual-frequency antenna array structure according to claim 4, characterized in that, Four sets of rectangular radiating windows (9) together form a grid-shaped structure; Each set of rectangular radiation windows (9) includes four rectangular holes, which are located within the four rectangular frames of the grid structure.

6. The dual-frequency antenna array structure according to claim 1, characterized in that, The substrate integrated waveguide transmission structure in the second dielectric layer (4) is a structure of two rows of metal short-circuit pillars with a preset spacing.

7. The dual-frequency antenna array structure according to claim 1, characterized in that, The multilayer stacked structure is fixed between layers using a low-temperature co-fired ceramic process.

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