3D High-Frequency Millimeter-Wave Stereo Integrated Antenna Array Based on LTCC Technology

Abstract

The present invention belongs to the technical field of high-frequency millimeter-wave wireless communication, and discloses a high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology, which includes a transition interface layer, a feeding layer, and a radiation layer stacked on top of each other in sequence from bottom to top. The radiation layer is provided with N mutually independent stepped radiation resonant cavities that are all in an inverted pyramid shape facing the free space. The feeding layer is provided with a first excitation module, a broadband H-plane SIW power divider, and a second excitation module that are connected in sequence. The transition interface layer is provided with a waveguide transition interface stepped resonant cavity that is in an inverted pyramid shape facing the metal waveguide, and the waveguide transition interface stepped resonant cavity is connected to the first excitation module; a bidirectional transmission path of electromagnetic waves is formed by the waveguide transition interface stepped resonant cavity, the first excitation module, the broadband H-plane SIW power divider, the second excitation module, and the stepped radiation resonant cavity. The present invention can achieve broadband matching and suppress high-order resonances in the cavity, and has a higher antenna gain.

Description

Technical Field

[0001] The present invention relates to the technical field of high-frequency millimeter-wave wireless communication, and particularly to a three-dimensional integrated antenna array for high-frequency millimeter waves based on LTCC technology. Background Art

[0002] Millimeter waves are electromagnetic waves with a frequency range between 30 GHz and 300 GHz. Compared with the microwave band, the beam width of millimeter waves is several times smaller than that of microwaves under the same size, so it is beneficial to achieve a narrower beam and obtain a higher spatial resolution. Compared with the infrared band, the atmospheric attenuation coefficient of communication devices operating in the millimeter-wave band is smaller, and the degree of influence by extreme climate conditions is relatively lower. In new application scenarios such as uncompressed high-definition video transmission and high-speed wireless personal area network transmission, the characteristics of millimeter waves such as short wavelength, narrow beam, and strong anti-interference ability make it regarded as one of the important ways to solve the above problems.

[0003] The main difficulty of high-frequency millimeter-wave wireless communication technology is that the devices supporting its operation need to adapt to a more compact layout while serving a larger bandwidth. Low Temperature Co-fired Ceramic (LTCC) is the current mainstream integration method and has received great attention due to its outstanding characteristics such as high dielectric constant, low dielectric loss, and laminated structure. In the microwave band, many quite mature works have proven the effectiveness of fabricating three-dimensional integrated passive devices by LTCC technology. In millimeter waves, especially in the high-frequency millimeter-wave part, the work on fabricating passive devices by LTCC technology is still in the exploration stage. Most of the existing problems are that due to the relatively high dielectric constant of LTCC under high-frequency conditions, the excitation interface structure from a conventional air waveguide to SIW and the operating bandwidth of SIW antennas are relatively narrow, and the high-frequency millimeter-wave resources cannot be effectively utilized.

[0004] Therefore, it is necessary to study a broadband LTCC three-dimensional integrated antenna suitable for high-frequency millimeter waves. Summary of the Invention

[0005] The purpose of the present invention is to provide a three-dimensional integrated antenna array for high-frequency millimeter waves based on LTCC technology to solve the problems existing in the prior art. By arranging structures such as multi-layer inverted pyramid-shaped stepped resonators, blind hole arrays, and half-wavelength resonators, the electromagnetic wave mode is regulated, and it has the advantages of small volume, high integration, and large operating bandwidth.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A three-dimensional integrated antenna array for high-frequency millimeter waves based on LTCC technology, comprising a transition interface layer, a feeding layer, and a radiation layer stacked on top of each other in sequence from bottom to top;

[0008] Among them, the radiation layer is provided with N mutually independent stepped radiation resonant cavities that are all in an inverted pyramid shape facing the free space.

[0009] The feeding layer is provided with a first excitation module, a broadband H-plane SIW power divider, and a second excitation module that are connected in sequence. The second excitation module has N excitation ports, and one stepped radiation resonant cavity is correspondingly connected to one excitation port.

[0010] The transition interface layer is provided with a waveguide transition interface stepped resonant cavity that is in an inverted pyramid shape facing the metal waveguide. The waveguide transition interface stepped resonant cavity is connected to the first excitation module; the transition interface layer is also provided with an EBG structure isolated from the waveguide transition interface stepped resonant cavity for suppressing electromagnetic leakage between the metal waveguide and the waveguide transition interface stepped resonant cavity.

[0011] The waveguide transition interface stepped resonant cavity, the first excitation module, the broadband H-plane SIW power divider, the second excitation module, and the stepped radiation resonant cavity constitute a bidirectional transmission path for electromagnetic waves.

[0012] As a possible implementation, the radiation layer sequentially includes M groups of radiation substrates from bottom to top. Each group of radiation substrates sequentially includes a radiation LTCC dielectric layer and a radiation metal layer from bottom to top; the radiation layer is provided with N radiation regions for forming N stepped radiation resonant cavities.

[0013] A radiation coupling slit is opened at the center of each radiation region, and the radiation coupling slit is located at the bottom surface of the bottom radiation substrate.

[0014] On each group of radiation substrates, a radiation metallized via hole group that is concentric with the radiation coupling slit and encloses the radiation coupling slit is opened. Each radiation metallized via hole in the radiation metallized via hole group is connected to the radiation metal layer on the radiation substrate where it is located.

[0015] Along the direction from bottom to top, the enclosed area of the radiation metallized via hole group on the radiation substrate gradually becomes larger to form an inverted pyramid-shaped stepped radiation resonant cavity.

[0016] As a possible implementation, M is greater than or equal to 1 and less than or equal to the ceiling of the result of dividing half of the medium wavelength at the lowest operating frequency by the thickness of a single-layer radiation LTCC dielectric layer.

[0017] As a possible implementation, the feeding layer sequentially includes a first feeding metal layer, a feeding LTCC dielectric layer, and a second feeding metal layer from bottom to top.

[0018] Among them, the feeding layer is provided with a first excitation region for forming a first excitation module; a first excitation coupling slot is formed on the first feeding metal layer of the first excitation region, and a first excitation metallization via hole group that simultaneously connects the first feeding metal layer and the second feeding metal layer is formed in the feeding LTCC dielectric layer of the first excitation region. The first excitation metallization via hole group encloses a half-wavelength resonant cavity with an opening, and the first excitation coupling slot is located in the half-wavelength resonant cavity; a quasi-TEM mode metallization blind hole group is formed on the second feeding metal layer below the first excitation coupling slot from the bottom surface upwards.

[0019] As a possible implementation, the quasi-TEM mode metallization blind hole group is based on the first excitation coupling slot, where 3 / 5 of the metallization blind holes are located on the side close to the opening of the half-wavelength resonant cavity, and 2 / 5 of the metallization blind holes are located on the side far from the opening of the half-wavelength resonant cavity.

[0020] As a possible implementation, the feeding layer is provided with a power divider region for forming a broadband H-plane SIW power divider; a power dividing metallization via hole group that simultaneously connects the first feeding metal layer and the second feeding metal layer is formed in the feeding LTCC dielectric layer of the power divider region; the power dividing metallization via hole group encloses a first SIW transmission channel near the opening end of the half-wavelength resonant cavity, and the first SIW transmission channel extends in the direction away from the opening end of the half-wavelength resonant cavity to form an N / 2-way SIW impedance transformer; an inductive post is arranged at one end of each SIW impedance transformer away from the first SIW transmission channel; each SIW impedance transformer extends N / 2-way second SIW transmission lines in the direction close to the second excitation module.

[0021] As a possible implementation, the feeding layer is provided with a second excitation region for forming a second excitation module;

[0022] N groups of second excitation metallization via hole groups that simultaneously connect the first feeding metal layer and the second feeding metal layer are formed in the feeding LTCC dielectric layer of the second excitation region; the opening end of each group of second excitation metallization via hole groups is connected to the second SIW transmission line; a second excitation coupling slot is formed on the first feeding metal layer in the enclosed area of each group of second excitation metallization via hole groups, which is coupled with the radiation coupling slot.

[0023] As a possible implementation, the transition interface layer is provided with a transition interface region, and a waveguide transition interface stepped resonant cavity is formed in the transition interface region;

[0024] A transition interface coupling slot is formed at the center bottom of the waveguide transition interface stepped resonant cavity;

[0025] The number of steps of the transition metallization hole group formed on the E-plane of the waveguide transition interface stepped resonant cavity is less than that of the transition metallization hole group formed on the H-plane;

[0026] The region of the transition interface area enclosing the waveguide transition interface stepped resonator is also provided with a periodic mushroom-shaped EBG structure; an isolation metallization hole group is also opened between the innermost mushroom-shaped EBG structure and the waveguide transition interface stepped resonator.

[0027] As a possible implementation, the transition interface layer sequentially includes three groups of transition substrates from bottom to top, and each group of transition substrates sequentially includes a transition metal layer and a transition LTCC dielectric layer from bottom to top;

[0028] The layout rule of the transition metallization hole group located on the E-plane is as follows: a group of transition metallization hole groups are opened on the bottom transition substrate, after extending outward a preset distance, another group of transition metallization hole groups are opened upward with the transition metal layer included in the sub-bottom transition substrate as the starting surface, and the other group of transition metallization hole groups penetrate upward through the remaining transition substrates;

[0029] The layout rule of the transition metallization hole group located on the H-plane is as follows: a group of transition metallization hole groups are opened on each group of transition substrates, and along the direction from bottom to top, the distance between the transition metallization hole groups on the transition substrates and the transition interface coupling gap gradually increases.

[0030] As a possible implementation, the mushroom-shaped EBG structure includes periodic metal sheets arranged on the lower surface of the sub-bottom transition LTCC dielectric layer and periodic metallization vias opened on the sub-bottom transition LTCC dielectric layer with the same central axis as the metal sheets.

[0031] Beneficial effects:

[0032] A kind proposed by the present invention has the following beneficial effects compared with the prior art:

[0033] 1. The high-frequency millimeter-wave three-dimensional integrated antenna array based on the LTCC process provided by the present invention designs an inverted pyramid-shaped stepped resonator, which can achieve broadband matching and suppress high-order resonances in the cavity, enabling the TE100 mode conducive to radiation to stably exist under a larger aperture surface. A larger effective radiation aperture surface means higher in-band antenna gain;

[0034] 2. The high-frequency millimeter-wave three-dimensional integrated antenna array based on the LTCC process provided by the present invention has three resonance points formed by its half-wavelength resonator, metallization blind holes, and inverted pyramid-shaped stepped radiation resonator, contributing a higher working bandwidth to the antenna unit, far exceeding the working bandwidth of the slot itself;

[0035] 3. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology provided by the present invention is provided with a periodic mushroom-shaped EBG structure around the stepped resonant cavity of the waveguide transition interface, which can effectively suppress the surface wave caused by assembly errors. Compared with adding an EBG structure to the flange through CNC technology, the EBG structure laid in the medium in the present invention can be arranged in a closer area around the waveguide, effectively avoiding the introduction of additional resonant cavities and affecting the matching. Description of the Drawings

[0036] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0037] Figure 1 is an exploded view of the high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology provided by the embodiment of the present invention;

[0038] Figure 2 is a schematic diagram of the inverted pyramid-shaped stepped resonant cavity structure in the antenna array provided by the embodiment of the present invention;

[0039] Figure 3 is a schematic diagram of the feeding layer provided with a first excitation module, a broadband H-plane SIW power divider and a second excitation module in the antenna array provided by the embodiment of the present invention;

[0040] Figure 4 is a schematic diagram of the first excitation module structure in the antenna array provided by the embodiment of the present invention;

[0041] Figure 5 is a schematic diagram of the opening position of the quasi-TEM mode metallized blind hole group in the antenna array provided by the embodiment of the present invention;

[0042] Figure 6 is a schematic diagram of the broadband H-plane SIW power divider structure in the antenna array provided by the embodiment of the present invention;

[0043] Figure 7 is a schematic diagram of the second excitation module structure in the antenna array provided by the embodiment of the present invention;

[0044] Figure 8 is a schematic diagram of the waveguide transition interface stepped resonant cavity structure in the antenna array provided by the embodiment of the present invention;

[0045] Figure 9 is a schematic diagram of the mushroom-shaped EBG structure in the antenna array provided by the embodiment of the present invention;

[0046] Figures 10 to 12 is the experimental result diagram obtained from the simulation experiment on the antenna array in the embodiment of the present invention.

[0047] Reference numerals

[0048] 1 - Transition interface layer, 10 - Waveguide transition interface stepped resonator, 100 - Transition interface coupling slot, 11 - EBG structure, 12 - Transition substrate, 120 - Transition metal layer, 121 - Transition LTCC dielectric layer, 1210 - Periodic metal sheet, 1211 - Periodic metallized via, 13 - Isolation metallized via group;

[0049] 2 - Feeding layer, 20 - First excitation module, 21 - Broadband H - plane SIW power divider, 22 - Second excitation module, 220 - Excitation port, 23 - First feeding metal layer, 230 - First excitation coupling slot, 231 - Second excitation coupling slot, 24 - Feeding LTCC dielectric layer, 240 - First excitation metallized via group, 241 - Half - wavelength resonator, 242 - Power - dividing metallized via group, 2420 - First SIW transmission channel, 2421 - SIW impedance transformer, 24210 - Inductive post, 2422 - Second SIW transmission line, 243 - Second excitation metallized via group, 25 - Second feeding metal layer, 250 - Quasi - TEM mode metallized blind - via group, 2501 - Metallized blind via;

[0050] 3 - Radiation layer, 30 - Stepped radiation resonator, 31 - Radiation substrate, 310 - LTCC dielectric layer, 311 - Radiation metal layer, 32 - Radiation region, 320 - Radiation coupling slot, 321 - Radiation metallized via group, 3210 - Radiation metallized via. Detailed implementation manners

[0051] For the convenience of clearly describing the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, terms such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and effects. For example, the first threshold and the second threshold are only used to distinguish different thresholds, and do not limit their sequence. Those skilled in the art can understand that terms such as "first" and "second" do not limit the quantity and execution order, and "first", "second", etc. do not necessarily mean different.

[0052] It should be noted that in the present invention, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the present invention should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly, using words such as "exemplary" or "for example" is intended to present relevant concepts in a specific manner.

[0053] In the present invention, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the relationship between associated objects and indicates that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. The following "at least one (item)" or its similar expressions refer to any combination of these items, including any combination of single item (s) or plural items (s). For example, at least one (item) of a, b, or c can represent: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b, and c, where a, b, and c can be single or multiple.

[0054] An embodiment of the present invention aims to provide a high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology. By arranging structures such as multi-layer inverted pyramid-shaped stepped resonators, blind hole arrays, and half-wavelength resonators, the electromagnetic wave mode is regulated. It has the advantages of small volume, high integration, and large working bandwidth. It can not only provide a reliable technical path for high-frequency millimeter-wave wireless communication, but also provide a reference application method for other processes involving high-dielectric-constant multi-layer boards, such as HTCC and MEMS.

[0055] See Figure 1 , the high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology includes a transition interface layer 1, a feeding layer 2, and a radiation layer 3 stacked on top of each other from bottom to top;

[0056] See Figures 1 to 2 , the radiation layer 3 is provided with N mutually independent stepped radiation resonators 30 that are all in an inverted pyramid shape facing the free space, and are used to transmit or receive high-frequency millimeter waves to the free space; the radiation layer 3 sequentially includes M groups of radiation substrates 31 from bottom to top.

[0057] See Figures 1 to 2, each group of radiation substrates 31 successively includes a radiation LTCC dielectric layer 310 and a radiation metal layer 311 from bottom to top. Exemplarily, the material of the LTCC dielectric layer 310 is Ferro A6M with a single-layer thickness of 0.094 mm, and the material of the radiation metal layer 311 is silver with a thickness of 0.008 mm; the radiation layer 3 is provided with N radiation regions 32 for forming N stepped radiation resonators 30; a radiation coupling slit 320 is formed at the center of each radiation region 32, and the radiation coupling slit 320 is located at the bottom surface of the bottom radiation substrate 31; a radiation metallized via hole group 321 that is concentric with the radiation coupling slit 320 and encloses the radiation coupling slit 320 is formed on each group of radiation substrates 31. Each radiation metallized via hole 3210 in the radiation metallized via hole group 321 is communicated with the radiation metal layer 311 on the corresponding radiation substrate 31. Exemplarily, the diameter of the radiation metallized via hole 3210 is 0.085 mm or 0.127 mm, the material is silver, and the distance between adjacent radiation metallized via holes 3210 is twice the hole diameter; along the direction from bottom to top, the enclosed area of the radiation metallized via hole group 321 on the radiation substrate 31 gradually increases layer by layer to form an inverted pyramid-shaped stepped radiation resonator 30, and the inverted pyramid-shaped stepped radiation resonator 30 emits or receives high-frequency millimeter waves to / from free space.

[0058] See Figure 2 , as an example, passing through the vertical direction vector, the plane perpendicular to the radiation coupling slit 320 of the stepped radiation resonator 30 is the E-plane, and the plane parallel to the radiation coupling slit 320 is the H-plane. The E-plane steps achieve broadband matching between the stepped radiation resonator 30 and free space, and the H-plane steps are used to suppress high-order modes.

[0059] See Figure 2, as an example, there are three layers of radiation substrates 31. From the bottommost radiation substrate 31 to the topmost radiation substrate 31, the enclosed area of the radiation metallized vias group 321 gradually increases layer by layer. The radiation metallized vias groups 321 on the same layer of radiation substrate 31 enclose a quadrilateral. Looking down at the stepped radiation resonator 30 in the shape of an inverted pyramid, the two sides parallel to the radiation coupling slot 320 are regarded as the length, and the two sides perpendicular to the radiation coupling slot 320 are regarded as the width. Preferably, the length of the quadrilateral enclosed by the radiation metallized vias group 321 on the bottommost radiation substrate 31 is 0.6 mm to 0.8 mm, for example, 0.6 mm, 0.7 mm, 0.8 mm; the width is 0.5 mm to 0.7 mm, for example, 0.5 mm, 0.6 mm, 0.7 mm; the length of the quadrilateral enclosed by the radiation metallized vias group 321 on the middle layer radiation substrate 31 is 1.2 mm to 1.4 mm, for example, 1.2 mm, 1.3 mm, 1.4 mm, and the width is 1.1 mm to 1.3 mm, for example, 1.1 mm, 1.2 mm, 1.3 mm; the length of the quadrilateral enclosed by the radiation metallized vias group 321 on the topmost radiation substrate 31 is 1.5 mm to 1.7 mm, for example, 1.5 mm, 1.6 mm, 1.7 mm, and the width is 1.3 mm to 1.5 mm, for example, 1.3 mm, 1.4 mm, 1.5 mm.

[0060] With such a design, the radiation port area of the stepped radiation resonator 30 can be made as large as possible. Even if the length and width of the radiation port surface are close to the size of twice the dielectric wavelength, no higher-order resonance will occur in the stepped radiation resonator 30.

[0061] As a possible implementation, M is greater than or equal to 1 and less than or equal to the ceiling of the result of dividing half of the dielectric wavelength at the lowest operating frequency by the thickness of the single-layer radiation LTCC dielectric layer.

[0062] As an example, when the dielectric wavelength at the lowest operating frequency of 120 GHz is about 1 mm and the thickness of the single-layer radiation LTCC dielectric layer is 0.094 mm, then , where represents the ceiling.

[0063] See Figure 1 and Figure 3, the feeding layer 2 is provided with a first excitation module 20, a broadband H-plane SIW power divider 21 and a second excitation module 22 that are sequentially connected. The second excitation module 22 has N excitation ports 220, and one stepped radiation resonator 30 is correspondingly connected to one excitation port 220. As a possible implementation, the feeding layer 2 sequentially includes a first feeding metal layer 23, a feeding LTCC dielectric layer 24 and a second feeding metal layer 25 from bottom to top. Exemplarily, the material of the feeding LTCC dielectric layer 24 is FerroA6M, the single-layer thickness is 0.094 mm, and the materials of the first feeding metal layer 23 and the second feeding metal layer 25 are silver, and the thickness is 0.008 mm.

[0064] See Figure 1 and Figure 4 , the feeding layer 2 is provided with a first excitation region for forming the first excitation module 20; a first excitation coupling slit 230 is formed on the first feeding metal layer 23 of the first excitation region, and a first excitation metallization via hole group 240 that simultaneously communicates with the first feeding metal layer 23 and the second feeding metal layer 25 is formed in the feeding LTCC dielectric layer 24 of the first excitation region. The first excitation metallization via hole group 240 encloses a half-wavelength resonator 241 with an opening. Exemplarily, the diameter of the metallization via holes in the first excitation metallization via hole group 240 is 0.085 mm or 0.127 mm, the material is silver, and the distance between adjacent metallization via holes is twice the hole diameter. The first excitation coupling slit 230 is located in the half-wavelength resonator 241, and a quasi-TEM mode metallization blind hole group 250 is formed on the second feeding metal layer 25 below the first excitation coupling slit 230 from the bottom surface upward. As an example, the size of the first excitation coupling slit 230 is preferably 0.4 mm in length and 0.12 mm in width, and the half-wavelength resonator 241 provides the electric field distribution required for good matching at the center frequency for the first excitation coupling slit 230.

[0065] See Figures 4 to 5 , as a possible implementation, the quasi-TEM mode metallization blind hole group 250 is composed of five metallization blind holes 2501, and the height of the metallization blind holes 2501 is preferably 0.094 mm. The quasi-TEM mode metallization blind hole group 250 is based on the first excitation coupling slit 230, and 3 / 5 of the metallization blind holes 2501 are located on the side close to the opening of the half-wavelength resonator 241, and 2 / 5 of the metallization blind holes 2501 are located on the side far from the opening of the half-wavelength resonator 241. The eigenmode excited by the metallization blind holes 2501 on the side close to the opening of the half-wavelength resonator 241 provides the electric field distribution required for good matching at low frequencies for the first excitation coupling slit 230, and the metallization blind holes 2501 on the side close to the opening of the half-wavelength resonator 241 provide the electric field distribution required for good matching at high frequencies for the first excitation coupling slit 230.

[0066] SeeFigure 1 , Figure 3 and Figure 4 , the half - wavelength resonator 241, the quasi - TEM mode metallized blind - via group 250, and the inverted - pyramid - shaped stepped - radiation resonator 30 form three resonance points, which can contribute a working bandwidth of more than 40 GHz to the antenna element in total.

[0067] See Figure 1 , Figure 3 , Figure 6 and Figure 7 , as a possible implementation, the feeding layer 2 is provided with a power - divider region for forming a broadband H - plane SIW power divider 21; the feeding LTCC dielectric layer 24 in the power - divider region is provided with a power - dividing metallized via group 242 that simultaneously connects the first feeding metal layer 23 and the second feeding metal layer 25; the power - dividing metallized via group 242 encloses a first SIW transmission channel 2420 near the open end of the half - wavelength resonator 241, and the first SIW transmission channel 2420 extends away from the open end of the half - wavelength resonator 241 to form an N / 2 - path SIW impedance transformer 2421; an inductance post 24210 is provided at one end of each SIW impedance transformer 2421 away from the first SIW transmission channel 2420; each SIW impedance transformer 2421 extends N / 2 - path second SIW transmission lines 2422 in the direction close to the second excitation module 22.

[0068] See Figure 7 , as an example, the width of the first SIW transmission channel 2420 is 0.8 mm, the width of the SIW impedance transformer 2421 is 1.06 mm, and the length is 1.06 mm; the distance of the inductance post 24210 along the direction parallel to the first SIW transmission channel 2420 from the center coordinate of the SIW impedance transformer 2421 is 0.23 mm.

[0069] See Figures 1 to 3 and Figure 7 , as a possible implementation, the feeding layer 2 is provided with a second excitation region for forming the second excitation module 22; the feeding LTCC dielectric layer 24 in the second excitation region is provided with N groups of second excitation metallized via groups 243 that simultaneously connect the first feeding metal layer 23 and the second feeding metal layer 25. Exemplarily, the diameter of the metallized vias in the second excitation metallized via group 243 is 0.085 mm or 0.127 mm, the material is silver, and the distance between adjacent metallized vias is twice the hole diameter. The open end of each group of second excitation metallized via groups 243 is connected to the second SIW transmission line 2422; a second excitation coupling slot 231 is opened in the first feeding metal layer 23 in the enclosed area of each group of second excitation metallized via groups 243, which is coupled to the radiation coupling slot 320.

[0070] See Figure 1, the transition interface layer 1 is provided with a waveguide transition interface stepped resonator 10 in an inverted pyramid shape facing the metal waveguide, and the waveguide transition interface stepped resonator 10 is communicated with the first excitation module 20; the transition interface layer 1 is also provided with an EBG structure 11 isolated from the waveguide transition interface stepped resonator 10 for suppressing electromagnetic leakage between the metal waveguide and the waveguide transition interface stepped resonator.

[0071] See Figure 1 and Figure 3 , a bidirectional transmission path of electromagnetic waves is formed by the waveguide transition interface stepped resonator 10, the first excitation module 20, the broadband H-plane SIW power divider 21, the second excitation module 22 and the stepped radiation resonator 30.

[0072] See Figure 1 and Figure 8 , as a possible implementation, the transition interface layer 1 sequentially includes three groups of transition substrates 12 from bottom to top, and each group of transition substrates 12 sequentially includes a transition metal layer 120 and a transition LTCC dielectric layer 121 from bottom to top; the transition interface layer 1 is provided with a transition interface area, and the waveguide transition interface stepped resonator 10 is formed in the transition interface area; a transition interface coupling slot 100 is opened at the center bottom of the waveguide transition interface stepped resonator 10. Exemplarily, the material of the transition LTCC dielectric layer 121 is Ferro A6M, the single-layer thickness is 0.094 mm, and the material of the transition metal layer 120 is silver, and the thickness is 0.008 mm.

[0073] See Figure 8 , as a possible implementation, the number of steps of the transition metallization hole group opened on the E-plane of the waveguide transition interface stepped resonator 10 is less than that of the transition metallization hole group opened on the H-plane; the layout rule of the transition metallization hole group located on the E-plane is: a group of transition metallization hole groups are opened on the bottom transition substrate, after extending a preset distance outward, another group of transition metallization hole groups are opened upward with the transition metal layer included in the sub-bottom transition substrate as the starting surface, and the other group of transition metallization hole groups penetrate upward through the remaining transition substrates. The layout rule of the transition metallization hole group located on the H-plane is: a group of transition metallization hole groups are opened on each group of transition substrates, and along the direction from bottom to top, the distance between the transition metallization hole group on the transition substrate and the transition interface coupling slot gradually increases.

[0074] See Figure 8, as an example, the number of steps of the transition metallization hole groups opened on the E-plane is two. From bottom to top, the distance between the first-level transition metallization hole groups on two opposite E-planes is 0.68 mm, and the distance between the second-level transition metallization hole groups is 0.8 mm; the number of steps of the transition metallization hole groups opened on the H-plane is three. From bottom to top, the distance between the first-level transition metallization hole groups on two opposite H-planes is 0.68 mm, the distance between the second-level transition metallization hole groups is 1.14 mm, and the distance between the third-level transition metallization hole groups is 1.6 mm.

[0075] See Figure 1 and Figure 8 , in the area surrounding the waveguide transition interface stepped resonator 10 of the transition interface area, a periodic mushroom-shaped EBG structure 11 is also provided; an isolation metallization hole group 13 is also opened between the innermost mushroom-shaped EBG structure 11 and the waveguide transition interface stepped resonator.

[0076] See Figure 9 , as a possible implementation, the mushroom-shaped EBG structure 11 includes a periodic metal sheet 1210 provided on the lower surface of the sub-bottom transition LTCC dielectric layer 121 and a periodic metallization via 1211 opened on the sub-bottom transition LTCC dielectric layer 121 with the same central axis as the periodic metal sheet 1210.

[0077] See Figure 9 , as an example, the upper end of the periodic metallization via 1211 is connected to the center of the periodic metal sheet 1210, and the distance between adjacent mushroom-shaped EBG structures 11 is 0.4 mm; the periodic metal sheet 1210 is square with a side length of 0.25 mm; the diameter of the periodic metallization via 1211 is 0.127 mm. When there is an assembly error, the mushroom-shaped EBG structure 11 can effectively suppress surface waves. Compared with adding an EBG structure to the flange through CNC technology, the EBG structure laid in the dielectric in this embodiment can be arranged in a closer area around the waveguide, effectively avoiding introducing additional resonators to affect the matching.

[0078] Next, the structural parameters of the array antenna are optimized multiple times using the high-frequency structure simulation software (High Frequency Structure Simulator, HFSS), and finally the simulation results of the array antenna with better performance are obtained. The simulation results are shown in Figure 10, Figure 11 , Figure 12 as shown. According to the simulation data, in the frequency band from 122 GHz to 165 GHz, the return loss of the antenna shows excellent performance, always remaining below -10 dB, and the relative bandwidth reaches more than twice that of a common end-fire LTCC antenna, fully demonstrating its broadband characteristics.

[0079] In terms of gain, through precise design, a 4×1 one-dimensional linear array structure is adopted, and a sector beam with an average maximum gain of 12.7 dBi is successfully achieved. It is worth noting that the main lobe gain of the antenna pattern remains stable throughout the frequency band, which is crucial for ensuring the stability and reliability of the millimeter-wave communication system.

[0080] Generally speaking, the optimized array antenna not only exhibits excellent performance in terms of return loss, bandwidth, and gain, but also the stability of the antenna pattern reaches an ideal level. Therefore, this antenna design is very suitable for application in the field of high-frequency millimeter-wave communication, especially in future 5G and 6G communication systems, where it can provide more reliable and efficient communication capabilities.

[0081] Although the present invention has been described in connection with various embodiments, however, in the process of implementing the claimed invention, those skilled in the art can understand and achieve other variations of the disclosed embodiments by viewing the drawings, the disclosure content, and the like. In the specification, the word "comprising" does not exclude other components or steps, and "a" or "one" does not exclude a plurality. A single processor or other unit can implement several functions listed in the specification. Certain measures are described in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0082] Although the present invention has been described in connection with specific features and their embodiments, it is obvious that various modifications and combinations can be made without departing from the spirit and scope of the present invention. Accordingly, the present specification and the drawings are merely exemplary descriptions of the present invention and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the present invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the present invention and its equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology, characterized in that It includes a transition interface layer, a feeding layer, and a radiation layer stacked on top of each other from bottom to top; Among them, the radiation layer is provided with N mutually independent stepped radiation resonant cavities that are all in an inverted pyramid shape facing the free space; The feeding layer is provided with a first excitation module, a broadband H-plane SIW power divider, and a second excitation module that are connected in sequence. The second excitation module has N excitation ports, and one stepped radiation resonant cavity is correspondingly connected to one excitation port; The transition interface layer is provided with a waveguide transition interface stepped resonant cavity in an inverted pyramid shape facing the metal waveguide. The waveguide transition interface stepped resonant cavity is connected to the first excitation module; the transition interface layer is also provided with an EBG structure isolated from the waveguide transition interface stepped resonant cavity for suppressing electromagnetic leakage between the metal waveguide and the waveguide transition interface stepped resonant cavity; The waveguide transition interface stepped resonant cavity, the first excitation module, the broadband H-plane SIW power divider, the second excitation module, and the stepped radiation resonant cavity form a bidirectional transmission path for electromagnetic waves.

2. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology according to claim 1, wherein The radiation layer sequentially includes M groups of radiation substrates from bottom to top. Each group of radiation substrates sequentially includes a radiation LTCC dielectric layer and a radiation metal layer from bottom to top; the radiation layer is provided with N radiation regions for forming N stepped radiation resonant cavities; A radiation coupling slit is opened at the center of each radiation region, and the radiation coupling slit is located on the bottom surface of the bottom radiation substrate; Each group of radiation substrates is provided with a radiation metallization via group that is concentric with the radiation coupling slit and encloses the radiation coupling slit. Each radiation metallization via in the radiation metallization via group is connected to the radiation metal layer on the corresponding radiation substrate; Along the direction from bottom to top, the enclosed area of the radiation metallization via group on the radiation substrate gradually increases layer by layer to form an inverted pyramid-shaped stepped radiation resonant cavity.

3. The three-dimensional integrated antenna array based on LTCC technology according to claim 2, wherein, M is greater than or equal to 1 and less than or equal to the ceiling of the result of dividing half of the medium wavelength at the lowest operating frequency by the thickness of a single-layer radiation LTCC dielectric layer.

4. The high-frequency millimeter-wave three-dimensional integrated antenna array based on the LTCC process according to claim 2, wherein, The feeding layer sequentially includes a first feeding metal layer, a feeding LTCC dielectric layer, and a second feeding metal layer from bottom to top; Among them, the feeding layer is provided with a first excitation region for forming the first excitation module; a first excitation coupling slit is opened on the first feeding metal layer of the first excitation region, and a first excitation metallization via group that simultaneously connects the first feeding metal layer and the second feeding metal layer is opened in the feeding LTCC dielectric layer of the first excitation region. The first excitation metallization via group encloses a half-wavelength resonant cavity with an opening, and the first excitation coupling slit is located in the half-wavelength resonant cavity; a quasi-TEM mode metallization blind hole group is opened on the second feeding metal layer below the first excitation coupling slit from the bottom surface upwards.

5. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology according to claim 4, wherein The quasi-TEM mode metallization blind hole group is based on the first excitation coupling slit. Among them, 3 / 5 of the metallization blind holes are located on the side close to the opening of the half-wavelength resonant cavity, and 2 / 5 of the metallization blind holes are located on the side far from the opening of the half-wavelength resonant cavity.

6. The three-dimensional integrated antenna array based on LTCC technology according to claim 4, characterized in that The feeding layer is provided with a power divider area for forming a broadband H-plane SIW power divider; a power dividing metallized via hole group that simultaneously connects the first feeding metal layer and the second feeding metal layer is provided in the feeding LTCC dielectric layer of the power divider area; the power dividing metallized via hole group encloses a first SIW transmission channel near the open end of the half-wavelength resonant cavity, and the first SIW transmission channel extends in the direction away from the open end of the half-wavelength resonant cavity to form an N / 2-way SIW impedance transformer; an inductance post is arranged at one end of each SIW impedance transformer away from the first SIW transmission channel; each SIW impedance transformer extends N / 2-way second SIW transmission lines in the direction close to the second excitation module.

7. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology according to claim 6, characterized in that, The feeding layer is provided with a second excitation area for forming a second excitation module; N groups of second excitation metallized via hole groups that simultaneously connect the first feeding metal layer and the second feeding metal layer are provided in the feeding LTCC dielectric layer of the second excitation area; the open end of each group of second excitation metallized via hole groups is connected to the second SIW transmission line; a second excitation coupling slot is provided in the first feeding metal layer in the enclosed area of each group of second excitation metallized via hole groups and is coupled with the radiation coupling slot.

8. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology according to claim 1, wherein The transition interface layer is provided with a transition interface area, and a waveguide transition interface stepped resonant cavity is formed in the transition interface area; A transition interface coupling slot is provided at the center bottom of the waveguide transition interface stepped resonant cavity; The number of steps of the transition metallized via hole group provided on the E-plane of the waveguide transition interface stepped resonant cavity is less than that of the transition metallized via hole group provided on the H-plane; A periodic mushroom-shaped EBG structure is further provided in the area of the transition interface area enclosing the waveguide transition interface stepped resonant cavity; an isolation metallized via hole group is further provided between the innermost mushroom-shaped EBG structure and the waveguide transition interface stepped resonant cavity.

9. The three-dimensional integrated antenna array based on LTCC technology according to claim 8, characterized in that The transition interface layer sequentially includes three groups of transition substrates from bottom to top, and each group of transition substrates sequentially includes a transition metal layer and a transition LTCC dielectric layer from bottom to top; The layout rule of the transition metallized via hole group located on the E-plane is: a group of transition metallized via hole groups is provided on the bottom transition substrate, after extending a preset distance outward, another group of transition metallized via hole groups is provided upward with the transition metal layer included in the sub-bottom transition substrate as the starting surface, and the other group of transition metallized via hole groups penetrates upward through the remaining transition substrates; The layout rule of the transition metallized via hole group located on the H-plane is: a group of transition metallized via hole groups is provided on each group of transition substrates, and along the direction from bottom to top, the distance between the transition metallized via hole group on the transition substrate and the transition interface coupling slot gradually increases.

10. The three-dimensional integrated antenna array based on LTCC technology according to claim 8, characterized in that, The mushroom-shaped EBG structure includes periodic metal sheets provided on the lower surface of the sub-bottom transition LTCC dielectric layer and periodic metallized vias provided on the sub-bottom transition LTCC dielectric layer with the same central axis as the metal sheets.

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