Millimeter wave broadband quasi-planar end-fire antenna

Abstract

This invention provides a millimeter-wave broadband quasi-planar end-fire antenna, comprising a dielectric substrate, a metal patch, a metal ground plane, and a feed transmission line. The metal patch is fixed to a first sidewall of the dielectric substrate, which is parallel to the YZ plane. The metal ground plane and the metal patch are spaced apart, and both the metal ground plane and the feed transmission line are embedded within the dielectric substrate. The metal ground plane has dielectric vias. One end of the feed transmission line is connected to an external circuit, and the other end of the feed transmission line extends along the X direction through the dielectric via towards the metal patch. The millimeter-wave broadband quasi-planar end-fire antenna provided by this invention allows the metal patch, metal ground plane, and feed transmission line to be integrally 3D printed with the dielectric substrate, avoiding the performance degradation caused by traditional structures such as metallized vias and metal conductors. By rationally setting the feed structure, the antenna operating bandwidth is significantly increased. Antenna gain compensation is achieved by selectively "removing" dielectric blocks from the dielectric substrate.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and more specifically, relates to a millimeter-wave broadband quasi-planar end-fire antenna. Background Technology

[0002] With the development of 5G wireless communication technology, the trend of applying millimeter-wave frequency band wireless communication systems to mobile terminal devices is becoming increasingly significant. For next-generation mobile terminals and wearable devices, the antenna's radiation range needs to cover the user's environment from above, as well as from the front, back, left, and right. This requires these devices to integrate both side-fire and end-fire antennas. A side-fire antenna is a type of antenna whose maximum radiation direction is perpendicular to the antenna element; its main characteristic is that the antenna's radiation range covers directly above the antenna element. An end-fire antenna is a type of antenna whose maximum radiation direction is parallel to the antenna element; its main characteristic is that the antenna's radiation range covers the sides of the antenna element. The most representative side-fire antenna is the patch antenna, which has a planar structure, and its theoretical basis and manufacturing process are mature. End-fire antennas are mostly cavity or quasi-planar structures, with relatively complex structures, and further research on the theory and manufacturing process of end-fire antennas is urgently needed.

[0003] In traditional technologies, the main types of radiating elements for end-fire antennas include planar Yagi antennas, horn antennas, folded antennas, and grid antennas. Planar Yagi antennas are typical end-fire antennas, consisting of a director, an active element, and a reflector. This type of antenna can only achieve end-fire performance in horizontal polarization and has a narrow bandwidth. Horn antennas can achieve end-fire performance in both horizontal and vertical polarization, but their large size makes them difficult to integrate into small mobile devices. Folded antennas use two parallel metal plates, feeding a probe or radiating patch between the plates to induce a vertically polarized electric field, thus achieving vertically polarized end-fire performance. However, the induced electric field is constrained by the parallel metal plate structure, making it difficult to radiate outwards, resulting in a significant decrease in the antenna's radiation efficiency. Grid antennas use several metallized vias and metal conductors to form an equivalent planar radiating element. Grid antennas can achieve both end-fire and side-fire, offering advantages such as wide bandwidth, low profile, and miniaturization. Therefore, lattice antennas are a type of planar end-fire antenna suitable for next-generation mobile terminals and wearable devices, and their flexible design and manufacturing processes have always been a key focus of the industry. However, vertically polarized lattice antennas have the following technical problems: First, the lattice antenna structure requires the lamination of multiple layers of printed circuit boards (PCBs) for fabrication, and the PCB layer thickness needs to be sufficiently fine to obtain a good feed point. This poses a significant technical challenge and high manufacturing cost for traditional PCB processes. Second, to achieve a vertically polarized lattice antenna, i.e., the normal of the equivalent planar radiating element is along the horizontal direction, more PCB layers need to be laminated to ensure the size of the radiating element (mainly determined by the operating frequency), resulting in higher costs and larger cumulative errors during manufacturing. This makes it difficult to guarantee the antenna's RF performance and poses a significant processing risk.

[0004] PCB (Printed Circuit Board) and Low-Temperature Co-fired Ceramic (LTCC) processes are currently the mainstream manufacturing processes for planar antennas, and both can be used to manufacture lattice antennas. When using these two processes to manufacture multilayer high-density interconnect transmission line circuit structures, the processing difficulty of metallized vias is high, and the processing cost is directly related to the complexity of the circuit structure and the number of lamination layers. If these two processes are used to manufacture end-fire antennas with vertical polarization, the antenna's RF performance will be severely limited by the circuit board structure, layer thickness, and number of lamination layers. Specifically, fewer lamination layers on the circuit board result in lower processing costs and smaller cumulative errors, but it is difficult to obtain an antenna feed point with good impedance matching. Increasing the number of lamination layers and reducing the layer thickness of the circuit board helps to obtain an antenna feed point with better impedance matching, but the processing cost increases significantly, and the process becomes more complex. More importantly, end-fire antenna structures with vertical polarization are incompatible with these two processes, and the RF performance of such antennas manufactured using these processes is difficult to optimize.

[0005] In recent years, 3D printing technology has provided a new approach for manufacturing microwave and millimeter-wave front-end antennas and passive components. Antennas and passive components based on planar transmission line architectures can also be integrated using 3D printing, significantly improving the flexibility of their structural design and manufacturing efficiency, and contributing to further improvements in their radio frequency performance. Therefore, end-fire antenna structures with vertical polarization can be designed using 3D printing principles and rapidly integrated using 3D printing technology. Summary of the Invention

[0006] The purpose of this invention is to provide a millimeter-wave broadband quasi-planar end-fire antenna, aiming to resolve the compatibility conflict between this type of antenna structure and traditional PCB, LTCC and other processing technologies without sacrificing the antenna's broadband radiation performance and in-band gain.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a millimeter-wave broadband quasi-planar end-fire antenna with pairwise orthogonal X, Y, and Z directions is provided. The antenna comprises a dielectric substrate, a metal patch, a metal ground plane, and a feed transmission line. The metal patch is fixed to a first sidewall of the dielectric substrate, the first sidewall being parallel to the YZ plane. The metal ground plane is spaced apart from the metal patch, and both the metal ground plane and the feed transmission line are embedded within the dielectric substrate. The metal ground plane has a dielectric aperture. One end of the metal conductor of the feed transmission line is connected to an external circuit, and the other end of the metal conductor extends along the X direction through the dielectric aperture toward the metal patch. The grounding conductor plate of the feed transmission line is connected and conductive to the metal ground plane.

[0008] Optionally, a first groove is formed on the dielectric substrate, the first groove is disposed between the metal patch and the metal ground plane, the first groove extends through both sides of the dielectric substrate in the Z direction, and two second grooves are formed on the first sidewall of the dielectric substrate, the two second grooves are respectively disposed on opposite sides of the metal patch in the Y direction, and the second grooves extend through both sides of the dielectric substrate in the Z direction.

[0009] Optionally, the dielectric substrate has two third grooves on the first sidewall, the two third grooves are respectively disposed on opposite sides of the metal patch in the Y direction, and the third grooves penetrate one side of the dielectric substrate in the Z direction.

[0010] Optionally, the dielectric substrate has two fourth grooves on the second sidewall, the second sidewall is parallel to the XY plane, the two fourth grooves are respectively disposed on opposite sides of the metal patch in the Y direction, and the fourth grooves penetrate one side of the dielectric substrate in the Z direction.

[0011] Optionally, on one side of the metal patch, the distance from the second groove, the third groove, and the fourth groove to the metal patch gradually increases.

[0012] Optionally, the first groove, the second groove, the third groove, and the fourth groove are all rectangular grooves; or, the first groove, the second groove, the third groove, and the fourth groove are all trapezoidal grooves, and the second groove, the third groove, and the fourth groove are interconnected; or, at least one of the first groove, the second groove, the third groove, and the fourth groove is a rectangular groove, and at least one is a trapezoidal groove.

[0013] Optionally, the power supply structure has a central symmetry plane parallel to the XZ plane, the first slot is symmetrically arranged about the central symmetry plane, the two second slots are symmetrically arranged about the central symmetry plane, the two third slots are symmetrically arranged about the central symmetry plane, and the two fourth slots are symmetrically arranged about the central symmetry plane.

[0014] Optionally, the power supply transmission line includes an L-shaped probe and a grounded coplanar waveguide. The L-shaped probe and the grounded coplanar waveguide are respectively disposed on opposite sides of the metal ground plane, and the metal conductor strips of the L-shaped probe and the grounded coplanar waveguide are connected and conductive at the dielectric aperture. The grounding conductor plate of the grounded coplanar waveguide is connected and conductive to the metal ground plane.

[0015] Optionally, the L-shaped probe includes a first metal conductor strip and a metal post connected to each other, wherein the length direction of the first metal conductor strip is the X direction and the length direction of the post is the Z direction, and the first metal conductor strip and the metal conductor strip of the grounded coplanar waveguide are connected and conductive at the dielectric aperture.

[0016] Optionally, the metal patch, the metal floor, the power supply transmission line, and the dielectric substrate are integrally 3D printed.

[0017] The beneficial effects of the millimeter-wave broadband quasi-planar end-fire antenna provided by this invention are as follows: First, by flexibly designing the structure of the feed transmission line, the vertical polarization mode of the metal patch is excited, achieving broadband and stable end-fire performance in the millimeter-wave band; Second, by selectively "removing" the dielectric block on the dielectric substrate, the in-band gain of the antenna is significantly compensated without sacrificing the broadband radiation performance of the antenna; Third, the physical structure of this antenna is highly compatible with 3D printing technology, enabling integrated 3D printing molding. Compared with similar antennas under traditional PCB or LTCC processes, the antenna has better RF performance, greater design flexibility, and a more convenient manufacturing process. Specifically, the metal patch can be integrally 3D printed onto the first sidewall of the dielectric substrate, eliminating the need for traditional structures such as metallized vias and metal conductors. This ensures the continuity of the surface current of the metal patch and effectively improves the antenna gain. The metal ground plane and feed transmission line can be integrally 3D printed inside the dielectric substrate. By rationally setting the feed structure, the operating bandwidth of the antenna is significantly increased. The dielectric and metal parts of the antenna can be integrally 3D printed. The dielectric part can be selectively "removed" to effectively improve the antenna's radiation pattern, ensure the consistency of the in-band radiation pattern, and compensate for the in-band gain. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a three-dimensional structural diagram of a millimeter-wave quasi-planar end-fire antenna using traditional PCB manufacturing processes.

[0020] Figure 2 A three-dimensional structural diagram of a millimeter-wave broadband quasi-planar end-fire antenna provided for the first embodiment of the present invention;

[0021] Figure 3 for Figure 2 A three-dimensional structural diagram of the metal part of the antenna;

[0022] Figure 4 for Figure 2 The simulated port reflection coefficients (S0) of the antenna and three other similar antennas (vertically polarized direct-fed grid antenna, vertically polarized direct-fed patch antenna, and vertically polarized coupled-fed patch antenna) are compared. 11 Curve comparison chart;

[0023] Figure 5 for Figure 4 A comparison of the simulated gain curves of four antennas;

[0024] Figure 6(a) shows Figure 2 The E-plane radiation patterns of the mid-band antenna at 26, 30, and 34 GHz are shown in Figure 6(b). Figure 2 H-plane radiation patterns of the central antenna at 26, 30, and 34 GHz;

[0025] Figure 7 A three-dimensional structural diagram of a millimeter-wave broadband quasi-planar end-fire antenna provided in the second embodiment of the present invention;

[0026] Figure 8 for Figure 7 Cross-sectional view of the antenna;

[0027] Figure 9 for Figure 7 A three-dimensional structural diagram of the fabrication model of the antenna used for radio frequency performance measurement;

[0028] Figure 10 for Figure 9 Simulated port reflection coefficient (S) of the antenna 11 )curve;

[0029] Figure 11 for Figure 9 The simulated gain curve of the antenna;

[0030] Figure 12(a) shows Figure 9 The E-plane radiation patterns of the mid-band antenna at 26, 30, and 34 GHz are shown in Figure 12(b). Figure 9 H-plane radiation patterns of the central antenna at 26, 30, and 34 GHz.

[0031] Figure 13 A three-dimensional structural diagram of a millimeter-wave broadband quasi-planar end-fire antenna provided in the third embodiment of the present invention;

[0032] Figure 14 for Figure 13 Cross-sectional view of the antenna;

[0033] Figure 15 for Figure 13 A three-dimensional structural diagram of the fabrication model of the antenna used for radio frequency performance measurement;

[0034] Figure 16 for Figure 15 Simulation and measurement of port reflection coefficient (S) of the antenna 11 )curve;

[0035] Figure 17 for Figure 15 The gain curves of the antenna in simulation and measurement;

[0036] Figure 18(a) is Figure 15 The E-plane radiation pattern of the antenna at 30 GHz; Figure 18(b) shows... Figure 15 The H-plane radiation pattern of the antenna at 30 GHz is shown in Figure 18(c). Figure 15 The E-plane radiation pattern of the antenna at 34 GHz; Figure 18(d) shows... Figure 15 H-plane radiation pattern of the central antenna at 34 GHz.

[0037] The following are the labeling elements in the figure:

[0038] 91-Dielectric substrate; 92-Metal mesh; 93-Metal ground plane;

[0039] 1-Dielectric substrate; 11-First groove; 12-Second groove; 13-Third groove; 14-Fourth groove; 2-Metal patch; 3-Metal ground plane; 31-Dielectric via; 4-Feed transmission line; 41-L-shaped probe; 411-First metal conductor; 412-Metal pillar; 42-Grounding coplanar waveguide; 421-Metal conductor; 422-Grounding conductor plate; 5-Assembly hole. Detailed Implementation

[0040] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0041] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0042] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0044] Please see Figure 1 , Figure 1 This is a three-dimensional structural diagram of a millimeter-wave quasi-planar end-fire antenna using conventional PCB manufacturing processes. The antenna includes a dielectric substrate 91, a metal mesh 92, and a metal ground plane 93. The metal mesh 92 is disposed on the side surface of the dielectric substrate 91 and is composed of alternating stacks of metallized vias in the vertical direction and metal conductive strips in the horizontal direction, serving as the radiating patch for an equivalent patch antenna in the vertical direction. The metal ground plane 93 consists of metallized vias in the vertical direction and metal conductive strips on its upper and lower surfaces, serving as the ground plane for an equivalent patch antenna in the vertical direction. Striplines pass through the metal ground plane 93 to directly feed the metal mesh 92 to excite the vertical polarization mode and achieve end-fire performance. Figure 1 The millimeter-wave quasi-planar end-fire antenna shown, constructed from a metal mesh 92, has very limited bandwidth and gain, failing to meet practical application requirements. Furthermore, in vertical polarization, to ensure the size of the radiating element (primarily determined by the operating frequency), a large number of PCB layers are required, resulting in high costs and significant accumulated errors during manufacturing. This makes it difficult to guarantee the antenna's RF performance and poses a substantial processing risk.

[0045] The millimeter-wave broadband quasi-planar end-fire antenna provided in the embodiments of the present invention will now be described.

[0046] Please see Figure 2 and Figure 3 , Figure 2 This is a three-dimensional structural diagram of a millimeter-wave broadband quasi-planar end-fire antenna provided in the first embodiment of the present invention. Figure 3 for Figure 2A three-dimensional structural diagram of the metal portion of the antenna. The millimeter-wave broadband quasi-planar end-fire antenna includes a dielectric substrate 1, a metal patch 2, a metal ground plane 3, and a feed transmission line 4. The dielectric substrate 1 has a first sidewall and a second sidewall disposed opposite to each other, and the first and second sidewalls can be parallel to each other. Both the first and second sidewalls are parallel to the YZ plane. The metal patch 2 is fixed to the first sidewall of the dielectric substrate 1, and the metal ground plane 3 and the feed transmission line 4 are both embedded in the dielectric substrate 1. The metal ground plane 3 is spaced apart from the metal patch 2. Specifically, the metal ground plane 3 can be parallel to the metal patch 2, that is, both the metal patch 2 and the metal ground plane 3 are parallel to the YZ plane. One end of the metal conductor of the feed transmission line 4 is connected to an external circuit, and the other end of the metal conductor of the feed transmission line 4 passes through the metal ground plane 3 and extends toward the metal patch 2, coupling and feeding the metal patch 2 to excite the vertical polarization mode, causing the metal patch 2 to induce a surface current in the vertical direction (Z direction), thereby realizing the end-fire performance of the vertical polarization mode. A dielectric hole 31 is correspondingly provided on the metal floor 3 for one end of the power supply transmission line 4 to pass through. The dielectric hole 31 is filled with a dielectric material to isolate the outer periphery of the power supply transmission line 4 from the wall of the dielectric hole 31. The grounding conductor plate 422 of the power supply transmission line 4 is connected and conductive to the metal floor 3.

[0047] The millimeter-wave broadband quasi-planar end-fire antenna in the above embodiments, firstly, by flexibly designing the structure of the feed transmission line 4, excites the vertical polarization mode of the metal patch 2, achieving broadband and stable end-fire performance in the millimeter-wave band; secondly, the physical structure of this antenna is highly compatible with 3D printing technology, enabling integrated 3D printing molding. Compared with similar antennas using traditional PCB or LTCC processes, this antenna offers better RF performance, greater design flexibility, and a more convenient manufacturing process. Specifically, the metal patch 2 can be integrated into the first sidewall of the dielectric substrate 1 using 3D printing, eliminating the need for equivalent replacements using traditional structures such as metallized vias, ensuring the continuity of the surface current of the metal patch 2, and effectively improving the antenna gain; the feed transmission line 4 can be integrated into the interior of the dielectric substrate 1 using 3D printing, and by reasonably setting the spacing between the metal patch 2 and the metal ground plane 3, the operating bandwidth of the antenna is significantly increased.

[0048] In one embodiment of the present invention, please refer to Figure 2A first groove 11 is formed on the dielectric substrate 1, positioned between the metal patch 2 and the metal ground plane 3, extending through opposite sides of the dielectric substrate 1 along the Z-direction. The first groove 11 alters the electric field distribution in the antenna dielectric, thus contributing to improved gain in the high-frequency band of the antenna's operating frequency band. Two second grooves 12 are formed on the first sidewall of the dielectric substrate 1, extending through the first sidewall. These two second grooves 12 are positioned on opposite sides of the metal patch 2 along the Y-direction, extending through opposite sides of the dielectric substrate 1 along the Z-direction. Introducing the two second grooves 12 effectively suppresses radiation pattern distortion induced by sidelobe radiation, thereby maintaining good consistency in the antenna's radiation pattern within the operating frequency band. By selectively "removing" dielectric blocks from the dielectric substrate 1 to form dielectric grooves, significant compensation for the antenna's in-band gain is achieved without sacrificing its broadband radiation performance. The dielectric and metal portions of the antenna can be integrally 3D printed.

[0049] Optionally, both the first groove 11 and the second groove 12 are rectangular grooves; or, both the first groove 11 and the second groove 12 are trapezoidal grooves; or, one of the first groove 11 and the second groove 12 is a rectangular groove and the other is a trapezoidal groove.

[0050] In one embodiment of the present invention, please refer to Figure 3 The feed transmission line 4 includes an L-shaped probe 41 and a grounding coplanar waveguide 42. The grounding coplanar waveguide 42 includes a metal conductor strip 421 and a grounding conductor plate 422. The L-shaped probe 41 and the grounding coplanar waveguide 42 are respectively disposed on opposite sides of the metal ground plane 3 in the X direction. The L-shaped probe 41 is disposed close to the metal patch 2, and the metal conductor strip 421 of the L-shaped probe 41 and the grounding coplanar waveguide 42 are connected and conductive at the dielectric aperture 31. The grounding conductor plate 422 of the grounding coplanar waveguide 42 is connected and conductive to the metal ground plane 3. By introducing the L-shaped probe 41 to couple and feed the metal patch 2, the bandwidth of the antenna is significantly increased.

[0051] Please see Figure 3 The L-shaped probe 41 includes a first metal conductor strip 411 and a metal post 412 connected to each other. The connection angle between the first metal conductor strip 411 and the metal post 412 can be 90 degrees or close to 90 degrees. The length direction of the first metal conductor strip 411 is the X direction, and the length direction of the metal post 412 is the Z direction. The first metal conductor strip 411 and the metal conductor strip 412 are connected and conductive at the medium hole 31.

[0052] In one embodiment of the present invention, please refer to Figure 2 and Figure 3The feeding structure has a central symmetry plane parallel to the XZ plane, and the two second slots 12 are symmetrically arranged about the central symmetry plane. The first slot 11 is symmetrically arranged about the central symmetry plane, so that the radiation pattern of the antenna can maintain good symmetry and consistency within the band.

[0053] Please see Figure 4 To Figure 6, Figure 4 for Figure 2 The simulated port reflection coefficients (S0) of the antenna and three other similar antennas (vertically polarized direct-fed grid antenna, vertically polarized direct-fed patch antenna, and vertically polarized coupled-fed patch antenna) are compared. 11 Curve comparison chart, Figure 5 for Figure 4 Figure 6(a) shows a comparison of the simulated gain curves of several antennas. Figure 2 The E-plane radiation patterns of the mid-band antenna at 26, 30, and 34 GHz are shown in Figure 6(b). Figure 2 The H-plane radiation patterns of the antenna at 26, 30, and 34 GHz are shown in the figures. As can be seen, replacing the grid antenna with a patch antenna significantly improves the antenna gain; the operating bandwidth of the antenna is significantly improved under coupled feeding; selectively "removing" rectangular dielectric blocks from the dielectric substrate 1 to form the second slot 12 and the first slot 11 can significantly improve the antenna's radiation pattern. Compared to the antenna before "removing" the rectangular dielectric blocks, Figure 2 The radiation pattern of the antenna in the in-band high-frequency band was significantly improved.

[0054] Figure 2 and Figure 3 The key dimensions of the antenna simulation model are as follows: the dielectric substrate 1 has a thickness of 2.9 mm in the Z direction; the metal patch 2 is rectangular, with lengths of 2.9 mm and 1.8 mm in the Z and Y directions, respectively; the first slot 11 and the second slot 12 are both rectangular slots, with lengths of 2.2 mm and 0.4 mm in the Y and X directions, respectively, and lengths of 2 mm and 0.4 mm in the X and Y directions, respectively; the metal conductor 421 has a width of 0.39 mm, a gap distance of 0.25 mm between the metal conductor 421 and the ground conductor plate 422, and a distance of 0.175 mm between the metal conductor 421 and the ground conductor plate 422 below it in the Z direction; the dielectric aperture 31 has lengths of 0.2 mm, 0.89 mm, and 0.385 mm in the X, Y, and Z directions, respectively; the length of the first metal conductor 411 and the height of the metal post 412 are 1 mm and 0.8 mm, respectively. To increase the mechanical strength of the overall antenna structure, a rectangular dielectric block is protruding on the side of the dielectric substrate 1 perpendicular to the first sidewall. The lengths of the rectangular dielectric block in the X, Y and Z directions are 3.65 mm, 0.5 mm and 1.45 mm, respectively.

[0055] In one embodiment of the present invention, please refer to Figure 7 and Figure 8 , Figure 7 This is a three-dimensional structural diagram of a millimeter-wave broadband quasi-planar end-fire antenna provided in the second embodiment of the present invention. Figure 8 for Figure 7 A cross-sectional view of the antenna. Two third slots 13 are formed in the first sidewall of the dielectric substrate 1, penetrating the first sidewall. The two third slots 13 are respectively located on opposite sides of the metal patch 2 in the Y direction, and penetrate one side of the dielectric substrate 1 in the Z direction. The two third slots 13 can effectively suppress radiation pattern distortion induced by sidelobe radiation, thereby enabling the antenna to maintain good consistency in its radiation pattern within the operating frequency band.

[0056] Optionally, both the second groove 12 and the third groove 13 are rectangular grooves, and the third groove 13 and the second groove 12 have the same dimensions in the X direction and the same dimensions in the Y direction. Of course, in other embodiments, the dimensions of the third groove 13 and the second groove 12 in the X and Y directions may be different. Alternatively, please refer to... Figure 13 The second groove 12 and the third groove 13 are both trapezoidal grooves, and the second groove 12 and the third groove 13 are interconnected.

[0057] Optionally, two fourth slots 14 are also formed on the dielectric substrate 1. The two fourth slots 14 are respectively disposed on opposite sides of the metal patch 2 in the Y direction. The fourth slots 14 penetrate one side of the dielectric substrate 1 in the Z direction, that is, the third slot 13 and the fourth slot 14 are closed at one end and open at the other end. The open ends of the third slot 13 and the fourth slot 14 face the same direction. The two fourth slots 14 can effectively suppress the radiation pattern distortion induced by sidelobe radiation, thereby enabling the antenna to maintain good consistency in radiation pattern within the operating frequency band.

[0058] Optionally, the first groove 11, the second groove 12, the third groove 13, and the fourth groove 14 are all rectangular grooves; or, the first groove 11, the second groove 12, the third groove 13, and the fourth groove 14 are all trapezoidal grooves, and the second groove 12, the third groove 13, and the fourth groove 14 are interconnected; or, at least one of the first groove 11, the second groove 12, the third groove 13, and the fourth groove 14 is a rectangular groove, and at least one is a trapezoidal groove.

[0059] Optionally, on one side of the metal patch 2, the distances from the second groove 12, the third groove 13, and the fourth groove 14 to the metal patch 2 gradually increase. That is, in the Y direction, one fourth groove 14, one third groove 13, one second groove 12, the metal patch 2, another second groove 12, another third groove 13, and another fourth groove 14 are arranged in sequence.

[0060] In one embodiment of the present invention, please refer to Figure 7 and Figure 8 The feeding structure has a central symmetry plane parallel to the XZ plane. The first slot 11 is symmetrical about the central symmetry plane, the two second slots 12 are symmetrical about the central symmetry plane, the two third slots 13 are symmetrical about the central symmetry plane, and the two fourth slots 14 are symmetrical about the central symmetry plane, so that the radiation pattern of the antenna can maintain good symmetry and consistency within the band.

[0061] Please see Figure 9 , Figure 9 for Figure 7 A three-dimensional structural diagram of the fabrication model of the antenna used for radio frequency performance measurement, for experimental verification. Figure 7 The RF performance of the mid-millimeter-wave broadband quasi-planar end-fire antenna is achieved by extending and connecting the antenna's grounded coplanar waveguide 42 and dielectric substrate 1 to a coaxial connector. The extended section of dielectric substrate 1 has mounting holes 5 for assembling the coaxial connector. (See also...) Figures 10 to 1 2, Figure 10 for Figure 9 Simulated port reflection coefficient (S) of the antenna 11 )curve, Figure 11 for Figure 9 The simulated gain curve of the antenna is shown in Figure 12(a). Figure 9 The E-plane radiation patterns at 26, 30, and 34 GHz of the central antenna are shown in Figure 12(b). Figure 9 The H-plane radiation patterns of the central antenna at 26, 30, and 34 GHz. As can be seen from the figure, compared to... Figure 2 Compared to the antenna structure in the previous one, selectively "removing" dielectric blocks on the dielectric substrate 1 to form the third slot 13 and the fourth slot 14 can further improve the radiation pattern of the antenna and significantly compensate for the in-band gain of the antenna without sacrificing the antenna bandwidth.

[0062] Figures 7 to 9The key dimensions of the antenna simulation model are as follows: the dielectric substrate 1 has a thickness of 2.9 mm in the Z direction; the metal patch 2 is rectangular, with lengths of 2.9 mm and 1.8 mm in the Z and Y directions, respectively; the first slot 11, the second slot 12, the third slot 13, and the fourth slot 14 are all rectangular slots. The first slot 11 has lengths of 2.2 mm and 0.4 mm in the Y and X directions, the second slot 12 has lengths of 2 mm and 0.4 mm in the X and Y directions, the third slot 13 has lengths of 2 mm, 0.4 mm, and 1 mm in the X, Y, and Z directions, respectively, and the fourth slot 14 has... The lengths in the X, Y, and Z directions are 1 mm, 0.4 mm, and 1.47 mm, respectively; the width of the metal guide strip 421 of the grounding coplanar waveguide 42 is 0.39 mm, the distance from the metal guide strip 421 to the grounding conductor plate 422 is 0.25 mm, and the distance between the metal guide strip 421 and the grounding conductor plate 422 below it in the Z direction is 0.175 mm; the lengths of the dielectric aperture 31 in the X, Y, and Z directions are 0.2 mm, 0.89 mm, and 0.385 mm, respectively; the length of the first metal guide strip 411 and the height of the metal post 412 in the L-shaped probe 41 are 1 mm and 0.8 mm, respectively. To increase the mechanical strength of the overall antenna structure, a rectangular dielectric block is protruding from the side of the dielectric substrate 1 perpendicular to the first sidewall. The lengths of the rectangular dielectric block in the X, Y, and Z directions are 3.65 mm, 0.5 mm, and 1.45 mm, respectively.

[0063] In one embodiment of the present invention, please refer to Figure 13 and Figure 14 , Figure 13 This is a three-dimensional structural diagram of a millimeter-wave broadband quasi-planar end-fire antenna provided in the third embodiment of the present invention. Figure 14 for Figure 13 A cross-sectional view of the antenna. In this embodiment, the second slot 12, the third slot 13, and the fourth slot 14 are all trapezoidal slots and are interconnected. Setting multiple trapezoidal slots can change the electric field distribution in the medium, thereby suppressing radiation pattern distortion induced by sidelobe radiation, thus enabling the antenna to maintain good consistency in its radiation pattern within the operating frequency band. Simultaneously, the interconnected structure of the multiple trapezoidal slots significantly enhances the compatibility of the slot structure with 3D printing processes.

[0064] Please see Figure 15 , Figure 15 for Figure 13 A three-dimensional structural diagram of the fabrication model of the antenna used for radio frequency performance measurement, for experimental verification. Figure 13 The RF performance of the mid-millimeter-wave broadband quasi-planar end-fire antenna is achieved by extending and connecting the antenna's grounded coplanar waveguide 42 and dielectric substrate 1 to a coaxial connector. The extended section of dielectric substrate 1 has mounting holes 5 for assembling the coaxial connector. (See also...) Figures 16 to 1 8, Figure 16 for Figure 15 Simulation and measurement of port reflection coefficient (S) of the antenna 11 )curve, Figure 17 for Figure 15 The simulation and measurement gain curves of the antenna are shown in Figures 18(a) and 18(b), respectively. Figure 15 The radiation patterns of the antenna in the E-plane and H-plane at 30 GHz are shown in Figures 18(c) and 18(d), respectively. Figure 15 The radiation patterns of the antenna in the E-plane and H-plane at 34 GHz. As shown in the figure, compared to... Figure 2 and Figure 7 Compared to the antenna structure in the previous example, selectively "removing" dielectric blocks from the dielectric substrate 1 to form trapezoidal slots can also significantly compensate for the antenna's in-band gain without sacrificing bandwidth. Furthermore, the interconnected trapezoidal slots are more compatible with 3D printing processes, helping to reduce dimensional errors in the 3D-printed slots. In this embodiment, the simulated operating frequency range of the antenna is 26.23–38.10 GHz, the simulated in-band reflection coefficient is less than -10 dB, the simulated relative bandwidth reaches 36.9%, the simulated in-band gain is 2.3–3.9 dBi, and the simulated total in-band efficiency is better than 86%. Within the operating frequency band, the antenna's radiation pattern shows no severe distortion.

[0065] Figures 13 to 15The key dimensions of the antenna simulation model are as follows: the dielectric substrate 1 has a thickness of 2.9 mm in the Z direction; the metal patch 2 is rectangular, with lengths of 2.9 mm and 1.8 mm in the Z and Y directions, respectively; the bottom surface of the second slot 12 has lengths of 2 mm and 0.4 mm in the X and Y directions, respectively; the top surface of the second slot 12 has lengths of 2 mm and 1.1 mm in the X and Y directions, respectively; and the height of the second slot 12 in the Z direction is 1.45 mm; the top surface of the third slot 13 is coplanar with the bottom surface of the second slot 12; the bottom surface of the third slot 13 has lengths of 2 mm and 1.3 mm in the X and Y directions, respectively; and the height of the third slot 13 in the Z direction is 1.45 mm; the top surface of the fourth slot 14... The lengths of the bottom surface of the fourth groove 14 in the X and Y directions are 1 mm and 0.625 mm, respectively. The lengths of the bottom surface of the fourth groove 14 in the X and Y directions are 1 mm and 0.7 mm, respectively. The height of the fourth groove 14 in the Z direction is 0.9 mm. The width of the metal conductor strip 421 is 0.39 mm. The distance from the metal conductor strip 421 to the ground conductor plate 422 is 0.25 mm. The distance between the metal conductor strip 421 and the ground conductor plate 422 below it in the Z direction is 0.175 mm. The lengths of the dielectric hole 31 in the X, Y, and Z directions are 0.2 mm, 0.89 mm, and 0.385 mm, respectively. The length of the first metal conductor strip 411 and the height of the metal pillar 412 are 1 mm and 0.8 mm, respectively. To increase the mechanical strength of the overall antenna structure, a rectangular dielectric block is hollowed out on the side of the dielectric substrate 1 perpendicular to the first sidewall. The lengths of the rectangular dielectric block in the X, Y, and Z directions are 3.65 mm, 0.5 mm, and 1.45 mm, respectively.

[0066] The millimeter-wave broadband quasi-planar end-fire antenna in this embodiment of the invention achieves the following: First, by flexibly designing the structure of the feed transmission line 4, the vertical polarization mode of the metal patch 2 is excited, resulting in broadband and stable end-fire performance in the millimeter-wave band. Second, by selectively removing dielectric blocks from the dielectric substrate 1, the in-band gain of the antenna is significantly compensated without sacrificing its broadband radiation performance. Third, the physical structure of this antenna is highly compatible with 3D printing technology, enabling integrated 3D printing. Compared with similar antennas using traditional PCB or LTCC processes, this antenna offers better RF performance, greater design flexibility, and a more convenient manufacturing process. Specifically, the metal patch 2 can be integrally 3D printed onto the first sidewall of the dielectric substrate 1, eliminating the need for equivalent replacements using traditional structures such as metallized vias. This ensures the continuity of the surface current of the metal patch 2 and effectively improves the antenna gain. The feed transmission line 4 can be integrally 3D printed inside the dielectric substrate 1, and by appropriately setting the spacing between the metal patch 2 and the metal ground plane 3, the antenna's operating bandwidth is significantly increased. The dielectric and metal parts of the antenna can be integrally 3D printed, and the dielectric part can be selectively "removed," thereby effectively improving the antenna's radiation pattern, ensuring the consistency of the in-band radiation pattern, and compensating for in-band gain. These are all antenna functional structures that are difficult to achieve using traditional processes.

[0067] To experimentally verify the radio frequency performance of the millimeter-wave broadband quasi-planar end-fire antenna in this embodiment of the invention, a high-precision multi-nozzle inkjet 3D printing process was used to integrally additively manufacture the antenna in the third embodiment of the invention. The dielectric portion of the antenna was 3D printed using photosensitive resin, and the metal portion was 3D printed using nano-silver paste. During the printing process, the antenna model moved along... Figure 15 The Z-direction layers are layered and printed as shown. It is important to note and emphasize that the "selective 'removal' of the medium block" does not refer to mechanically or manually "removing" the medium block after the complete 3D printed medium portion, but rather to pre-designing and modeling the trapezoidal groove structure to form... Figure 15 The processing model is then integrally additively manufactured using the aforementioned 3D printing process.

[0068] Depend on Figures 16 to 1As shown in Figure 8, within the 28.8–37.0 GHz range, the measured reflection coefficient of the antenna is less than -10 dB, the measured relative bandwidth is 24.8%, and the measured in-band gain is 2.5–5.0 dBi. Compared with the simulation results, the antenna bandwidth is slightly reduced, mainly due to manufacturing errors in the key antenna structure; the antenna's in-band gain is slightly increased, primarily because the metal housing of the 2.92 mm coaxial connector increases the equivalent ground plane area of ​​the antenna after the antenna substrate is connected. Within the operating frequency band, the measured radiation pattern of the antenna is basically consistent with the simulation results, with the main difference stemming from manufacturing errors such as deformation of the 3D-printed key antenna structure.

[0069] In the embodiments provided by this invention, it should be understood that: First, how to shape a traditional vertically polarized planar end-fire antenna structure according to the principles of 3D printing and design an antenna structure compatible with multi-nozzle inkjet technology is the primary technical problem to be solved by this invention; Second, how to fully utilize the principles of multi-nozzle inkjet technology to achieve flexible design of the antenna dielectric and metal parts, significantly improving the antenna's radiation performance, is a significant feature that distinguishes this invention from related traditional technologies; Third, the structure and dimensions of the metal patch 2, the feed transmission line 4, and the dielectric block "cut out" in the dielectric substrate 1 are only schematic and not unique, but merely a relatively optimal and achievable structure. Other superior structures can be achieved based on the antenna design principles and optimization criteria; Fourth, based on this antenna unit, a vertically polarized quasi-planar end-fire antenna array can be designed and implemented, and this antenna structure can also be scaled up and applied to other millimeter-wave frequency bands; Fifth, the design concept that integrates the principles of 3D printing technology is also applicable to other microwave and millimeter-wave planar transmission line structures and devices. In the description of the embodiments of the present invention, the structural dimensions given are preferred parameters. Referring to one embodiment of the present invention, the dimensions of each component can be modified to further obtain the actual required performance.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A millimeter-wave broadband quasi-planar end-fire antenna, having pairwise orthogonal X, Y, and Z directions, characterized in that: The device includes a dielectric substrate, a metal patch, a metal ground plane, and a power transmission line. The metal patch is fixed to a first sidewall of the dielectric substrate, which is parallel to the YZ plane. The metal ground plane is spaced apart from the metal patch, and both the metal ground plane and the power transmission line are embedded in the dielectric substrate. The metal ground plane has a dielectric hole. One end of the metal conductor of the power transmission line is connected to an external circuit, and the other end of the metal conductor of the power transmission line extends along the X direction through the dielectric hole toward the metal patch. The grounding conductor plate of the power transmission line is connected and conductive to the metal ground plane. The power supply transmission line includes an L-shaped probe and a ground coplanar waveguide. The ground coplanar waveguide includes a metal conductor strip and a ground conductor plate. The L-shaped probe and the ground coplanar waveguide are respectively disposed on opposite sides of the metal ground plane in the X direction. The L-shaped probe is disposed close to the metal patch, and the metal conductor strip of the L-shaped probe and the ground coplanar waveguide are connected and conductive at the dielectric aperture. The ground conductor plate of the ground coplanar waveguide is connected and conductive to the metal ground plane.

2. The millimeter-wave broadband quasi-planar end-fire antenna as described in claim 1, characterized in that: A first groove is formed on the dielectric substrate, which is disposed between the metal patch and the metal ground plane. The first groove extends through both sides of the dielectric substrate along the Z direction. Two second grooves are formed on the first sidewall of the dielectric substrate. The two second grooves are respectively disposed on opposite sides of the metal patch in the Y direction. The second grooves extend through both sides of the dielectric substrate along the Z direction.

3. The millimeter-wave broadband quasi-planar end-fire antenna as described in claim 2, characterized in that: The dielectric substrate has two third grooves formed on the first sidewall. The two third grooves are respectively disposed on opposite sides of the metal patch in the Y direction, and the third grooves penetrate one side of the dielectric substrate in the Z direction.

4. The millimeter-wave broadband quasi-planar end-fire antenna as described in claim 3, characterized in that: The dielectric substrate has two fourth grooves on its second sidewall, which is parallel to the XY plane. The two fourth grooves are respectively located on opposite sides of the metal patch in the Y direction, and the fourth grooves penetrate one side of the dielectric substrate in the Z direction.

5. The millimeter-wave broadband quasi-planar end-fire antenna as described in claim 4, characterized in that: On one side of the metal patch, the distances from the second groove, the third groove, and the fourth groove to the metal patch gradually increase.

6. The millimeter-wave broadband quasi-planar end-fire antenna as described in claim 4, characterized in that: The first, second, third, and fourth grooves are all rectangular grooves; or, the first, second, third, and fourth grooves are all trapezoidal grooves, and the second, third, and fourth grooves are interconnected; or, at least one of the first, second, third, and fourth grooves is a rectangular groove, and at least one is a trapezoidal groove.

7. The millimeter-wave broadband quasi-planar end-fire antenna as described in claim 4, characterized in that: The power supply transmission line has a central symmetry plane parallel to the XZ plane. The first slot is symmetrically arranged about the central symmetry plane, the two second slots are symmetrically arranged about the central symmetry plane, the two third slots are symmetrically arranged about the central symmetry plane, and the two fourth slots are symmetrically arranged about the central symmetry plane.

8. The millimeter-wave broadband quasi-planar end-fire antenna as described in any one of claims 1-7, characterized in that: The L-shaped probe includes a first metal conductor strip and a metal post connected to each other. The length direction of the first metal conductor strip is the X direction, and the length direction of the metal post is the Z direction. The first metal conductor strip and the metal conductor strip of the grounded coplanar waveguide are connected and conductive at the dielectric aperture.

9. The millimeter-wave broadband quasi-planar end-fire antenna as described in any one of claims 1-7, characterized in that: The metal patch, the metal floor, the power supply transmission line, and the dielectric substrate are integrally 3D printed.

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