High-frequency millimeter wave three-dimensional integrated antenna array based on LTCC technology

Abstract

The 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 an LTCC (Low Temperature Co-Fired Ceramic) process, which comprises a transition interface layer, a feed layer and a radiation layer which are sequentially stacked together from bottom to top, the radiation layer is provided with N step radiation resonant cavities which are mutually independent and face a free space and are in an inverted pyramid shape, the feed layer is provided with a first excitation module, a broadband H-face SIW power divider and a second excitation module which are communicated in sequence, and the transition interface layer is provided with a waveguide transition interface step resonant cavity which faces a metal waveguide and is in an inverted pyramid shape. The waveguide transition interface stepped resonant cavity is communicated with the first excitation module; 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 of electromagnetic waves. According to the invention, broadband matching can be realized, high-order resonance in the cavity can be suppressed, and the antenna gain is higher.

Description

Technical Field

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

[0002] Millimeter waves are electromagnetic waves with a frequency range of 30GHz to 300GHz. Compared with microwave frequency bands, the beam width of millimeter waves of the same size is several times smaller than that of microwaves, which is conducive to achieving narrower beams and higher spatial resolution. Compared with infrared frequency bands, communication equipment working in millimeter wave bands has a smaller atmospheric attenuation coefficient and is relatively less affected by extreme climatic conditions. In new application scenarios such as uncompressed high-definition video transmission and high-speed transmission of wireless personal area networks, millimeter waves are considered to be one of the important ways to solve the above problems due to their short wavelength, narrow beam and strong anti-interference ability.

[0003] The main difficulty of high-frequency millimeter-wave wireless communication technology is that the devices that support its operation need to adapt to a more compact layout while providing services for a larger bandwidth. Low Temperature Co-fired Ceramic (LTCC) is the current mainstream integration method. It has received great attention due to its outstanding features such as high dielectric constant, low dielectric loss and stacked structure. In the microwave frequency band, there have been many fairly mature works that have proved the effectiveness of LTCC process in preparing three-dimensional integrated passive devices. In the millimeter wave, especially the high-frequency millimeter wave part, the work on the preparation of passive devices by LTCC process is still in the exploratory stage. Most of the problems are due to the high dielectric constant of LTCC under high-frequency conditions, which makes the conventional air waveguide to SIW excitation interface structure and SIW antenna have a narrow working bandwidth, and cannot effectively utilize high-frequency millimeter wave resources.

[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 address the problems existing in the prior art and provide a high-frequency millimeter-wave three-dimensional integrated antenna array based on the LTCC process. The electromagnetic wave mode is regulated by the arrangement of multi-layer inverted pyramid stepped resonant cavities, blind hole arrays, and half-wavelength resonant cavities. The antenna array has the advantages of small size, high integration, and large working bandwidth.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme: A high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology, comprising a transition interface layer, a feeding layer and a radiation layer stacked sequentially from bottom to top; The radiation layer is provided with N mutually independent stepped radiation resonant cavities which are in the shape of inverted pyramids 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 which are connected in sequence, the second excitation module has N excitation ports, and one step radiation resonance cavity is connected to one excitation port correspondingly; The transition interface layer is provided with a waveguide transition interface ladder resonant cavity in an inverted pyramid shape facing the metal waveguide, and the waveguide transition interface ladder 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 ladder resonant cavity, which is used to suppress electromagnetic leakage between the metal waveguide and the waveguide transition interface ladder resonant cavity; A bidirectional transmission path of electromagnetic waves is formed by a waveguide transition interface ladder resonant cavity, a first excitation module, a broadband H-plane SIW power divider, a second excitation module and a ladder radiation resonant cavity.

[0007] As a possible implementation, the radiation layer includes M groups of radiation substrates from bottom to top, and each group of radiation substrates 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 slot is provided at the center of each radiation area, and the radiation coupling slot is located at the bottom surface of the bottom radiation substrate; Each group of radiation substrates is provided with a radiation metallized through hole group that is co-centered with the radiation coupling slot and surrounds the radiation coupling slot, and each radiation metallized through hole in the radiation metallized through hole group is connected to the radiation metal layer on the radiation substrate; From bottom to top, the enclosed area of ​​the radiation metallized through hole group on the radiation substrate increases layer by layer to form an inverted pyramid-shaped stepped radiation resonant cavity.

[0008] As a possible implementation, M is greater than or equal to 1 and less than or equal to half of the lowest operating frequency medium wavelength divided by the thickness of a single-layer radiation LTCC medium layer, rounded up.

[0009] As a possible implementation, the feeding layer includes, from bottom to top, a first feeding metal layer, a feeding LTCC dielectric layer, and a second feeding metal layer; Among them, the feeding layer is provided with a first excitation area for forming a first excitation module; a first excitation coupling slot is opened on the first feeding metal layer of the first excitation area, a first excitation metallized through hole group is opened on the feeding LTCC dielectric layer of the first excitation area and simultaneously connects the first feeding metal layer and the second feeding metal layer, the first excitation metallized through 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 metallized blind hole group is opened from the bottom surface to the top on the second feeding metal layer below the first excitation coupling slot.

[0010] As a possible implementation method, the quasi-TEM mode metallized blind hole group is based on the first excitation coupling gap, wherein 3 / 5 of the metallized blind holes are located on the opening side close to the half-wavelength resonant cavity, and 2 / 5 of the metallized blind holes are located on the opening side away from the half-wavelength resonant cavity.

[0011] As a possible implementation, the feeding layer is provided with a power divider region for forming a broadband H-plane SIW power divider; the feeding LTCC dielectric layer of the power divider region is provided with a power division metallized through hole group that simultaneously connects the first feeding metal layer and the second feeding metal layer; the power division metallized through hole group is enclosed near the opening end of the half-wavelength resonant cavity to form a first SIW transmission channel, and the first SIW transmission channel extends in a direction away from the opening end of the half-wavelength resonant cavity to form N / 2 SIW impedance transformers; an inductor column is provided at one end of each SIW impedance transformer away from the first SIW transmission channel; and each SIW impedance transformer extends N / 2 second SIW transmission lines in a direction close to the second excitation module.

[0012] As a possible implementation manner, the feed layer is provided with a second excitation region for forming a second excitation module; The feeding LTCC dielectric layer of the second excitation area is provided with N groups of second excitation metallized through-hole groups which are connected to the first feeding metal layer and the second feeding metal layer at the same time; the opening end of each group of second excitation metallized through-hole groups is connected to the second SIW transmission line; the first feeding metal layer of the enclosed area of ​​each group of second excitation metallized through-hole groups is provided with a second excitation coupling gap which is coupled with the radiation coupling gap.

[0013] As a possible implementation, the transition interface layer is provided with a transition interface region, and the waveguide transition interface step resonant cavity is formed in the transition interface region; A transition interface coupling gap is provided at the center bottom of the waveguide transition interface ladder resonant cavity; The number of steps of the transition metallization hole group opened on the E surface of the waveguide transition interface step resonant cavity is less than the number of steps of the transition metallization hole group opened on the H surface; A periodic mushroom-shaped EBG structure is also arranged in the transition interface region enclosing the waveguide transition interface step resonant cavity; an isolation metallized hole group is also opened between the innermost mushroom-shaped EBG structure and the waveguide transition interface step resonant cavity.

[0014] As a possible implementation method, the transition interface layer includes three groups of transition substrates from bottom to top, and each group of transition substrates includes a transition metal layer and a transition LTCC dielectric layer from bottom to top; The layout rule of the transition metallization hole group located on the E surface is as follows: a group of transition metallization hole groups is opened on the bottom transition substrate, and after extending outward by a preset distance, another group of transition metallization hole groups is opened upward with the transition metal layer included in the next bottom transition substrate as the starting surface, and the other group of transition metallization hole groups penetrates the remaining transition substrate upward; The layout rule of the transition metallization hole group located on the H surface is: each group of transition substrates has a group of transition metallization hole groups, and the distance between the transition metallization hole group on the transition substrate and the transition interface coupling gap gradually increases from bottom to top.

[0015] As a possible implementation, the mushroom-shaped EBG structure includes a periodic metal sheet disposed on the lower surface of the sub-bottom transition LTCC dielectric layer and a periodic metallized via opened on the sub-bottom transition LTCC dielectric layer coaxially with the metal sheet.

[0016] Beneficial effects: Compared with the prior art, the invention has the following beneficial effects: 1. The high-frequency millimeter-wave three-dimensional integrated antenna array based on the LTCC process provided by the present invention is designed with an inverted pyramid-shaped stepped resonant cavity, which can achieve broadband matching and suppress high-order resonance in the cavity, so that the TE100 mode that is beneficial to radiation can exist stably under a larger aperture surface. A larger effective radiation aperture surface means that the in-band antenna gain will be higher; 2. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology provided by the present invention has three resonance points formed by the half-wavelength resonant cavity, the metallized blind hole and the inverted pyramid-shaped step radiation resonance, which contributes to a higher working bandwidth for the antenna unit, far exceeding the working bandwidth of the slot itself; 3. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology provided by the present invention has a periodic mushroom-shaped EBG structure around the stepped resonant cavity of the waveguide transition interface, which can effectively suppress the surface waves caused by assembly errors. Compared with adding an EBG structure on the flange through CNC technology, the EBG structure laid in the medium adopted by the present invention can be arranged in a closer area around the waveguide, effectively avoiding the introduction of additional resonant cavities to affect matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary 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: Figure 1 An exploded diagram of a high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology provided by an embodiment of the present invention; Figure 2A schematic diagram of an inverted pyramid-shaped stepped resonant cavity structure in an antenna array provided by an embodiment of the present invention; Figure 3 A schematic diagram of a first excitation module, a broadband H-plane SIW power divider and a second excitation module in a feed layer of an antenna array provided in an embodiment of the present invention; Figure 4 A schematic diagram of the structure of a first excitation module in an antenna array provided in an embodiment of the present invention; Figure 5 A schematic diagram of the locations of the quasi-TEM mode metallized blind hole group in the antenna array provided in an embodiment of the present invention; Figure 6 A schematic diagram of the structure of a broadband H-plane SIW power divider in an antenna array provided by an embodiment of the present invention; Figure 7 A schematic diagram of the structure of a second excitation module in an antenna array provided in an embodiment of the present invention; Figure 8 A schematic diagram of a stepped resonant cavity structure of a waveguide transition interface in an antenna array provided in an embodiment of the present invention; Fig. 9 A schematic diagram of a mushroom-shaped EBG structure in an antenna array provided in an embodiment of the present invention; Figures 10 to 12 This is a diagram of experimental results obtained by performing a simulation experiment on an antenna array in an embodiment of the present invention.

[0018] Reference numerals 1-transition interface layer, 10-waveguide transition interface ladder resonant cavity, 100-transition interface coupling gap, 11-EBG structure, 12-transition substrate, 120-transition metal layer, 121-transition LTCC dielectric layer, 1210-periodic metal sheet, 1211-periodic metalized via, 13-isolation metalized hole group; 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 through hole group, 241-half-wavelength resonant cavity, 242-power splitting metallized through hole group, 2420-first SIW transmission channel, 2421-SIW impedance transformer, 24210-inductor column, 2422-second SIW transmission line, 243-second excitation metallized through hole group, 25-second feeding metal layer, 250-quasi-TEM mode metallized blind hole group, 2501-metallized blind hole; 3-radiation layer, 30-step radiation resonant cavity, 31-radiation substrate, 310-LTCC dielectric layer, 311-radiation metal layer, 32-radiation region, 320-radiation coupling gap, 321-radiation metallized through hole group, 3210-radiation metallized through hole. DETAILED DESCRIPTION

[0019] In order to clearly describe the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, words 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 their order is not limited. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0020] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0021] In the present invention, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, 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 (items) or similar expressions thereof refer to any combination of these items, including any combination of single items (items) or plural items (items). For example, at least one item (items) of a, b or c can mean: 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, c can be single or multiple.

[0022] The embodiment of the present invention aims to provide a high-frequency millimeter-wave three-dimensional integrated antenna array based on the LTCC process, which regulates the electromagnetic wave mode through the arrangement of multi-layer inverted pyramid-shaped stepped resonant cavities, blind hole arrays, and half-wavelength resonant cavities. It has the advantages of small size, high integration, and large working bandwidth. It can not only provide a reliable technical path for high-frequency millimeter-wave wireless communications, but also provide a reference application method for other high dielectric constant multilayer board processes such as HTCC and MEMS.

[0023] See also Figure 1The high-frequency millimeter-wave three-dimensional integrated antenna array based on the LTCC process includes a transition interface layer 1, a feeding layer 2 and a radiation layer 3 stacked together from bottom to top; See also Figure 1 to Figure 2 The radiation layer 3 is provided with N mutually independent stepped radiation resonant cavities 30 in the shape of an inverted pyramid facing the free space, which are used to transmit or receive high-frequency millimeter waves to the free space; the radiation layer 3 includes M groups of radiation substrates 31 from bottom to top.

[0024] See also Figure 1 to Figure 2 , each group of radiation substrates 31 includes a radiation LTCC dielectric layer 310 and a radiation metal layer 311 from bottom to top. For example, the material of the LTCC dielectric layer 310 is Ferro A6M, and the single layer thickness is 0.094 mm. The material of the radiation metal layer 311 is silver, and the thickness is 0.008 mm. The radiation layer 3 is provided with N radiation regions 32 for forming N stepped radiation resonant cavities 30. A radiation coupling slot 320 is provided at the center of each radiation region 32, and the radiation coupling slot 320 is located on the bottom surface of the bottom radiation substrate 31. Each group of radiation substrates 31 is provided with a radiation metallized through hole group 321 which is concentric with the radiation coupling slot 320 and surrounds the radiation coupling slot 320. Each radiation metallized through hole 3210 is connected to the radiation metal layer 311 on the radiation substrate 31. Exemplarily, the diameter of the radiation metallized through hole 3210 is 0.085 mm or 0.127 mm, and the material is silver. The spacing between adjacent radiation metallized through holes 3210 is twice the hole diameter. From bottom to top, the enclosed area of ​​the radiation metallized through hole group 321 on the radiation substrate 31 increases layer by layer to form an inverted pyramid-shaped stepped radiation resonant cavity 30, which transmits or receives high-frequency millimeter waves into the free space.

[0025] See also Figure 2 As an example, through the vertical direction vector, the plane perpendicular to the stepped radiation resonant cavity 30 and the radiation coupling slot 320 is the E plane, and the plane parallel to the radiation coupling slot 320 is the H plane. The E plane step realizes broadband matching between the stepped radiation resonant cavity 30 and the free space, and the H plane step is used to suppress high-order modes.

[0026] See also Figure 2As an example, there are three layers of radiation substrates 31. From the bottom radiation substrate 31 to the top radiation substrate 31, the enclosed area of ​​the radiation metallized through hole group 321 increases layer by layer, and the radiation metallized through hole group 321 on the same layer of radiation substrate 31 encloses a quadrilateral. Looking down at the inverted pyramid-shaped stepped radiation resonant cavity 30, the two sides parallel to the radiation coupling slot 320 are regarded as long, and the two sides perpendicular to the radiation coupling slot 320 are regarded as wide. Preferably, the length of the quadrilateral formed by the radiation metallized through hole group 321 located at the bottom 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 formed by the radiation metallized through hole group 321 located at the middle 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 formed by the radiation metallized through hole group 321 located at the top 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. mm, 1.5mm.

[0027] Such a design can make the radiation port area of ​​the step radiation resonant cavity 30 as large as possible. Even if the length and width of the radiation port surface are close to twice the size of the medium wavelength, no high-order resonance will be generated in the step radiation resonant cavity 30.

[0028] As a possible implementation, M is greater than or equal to 1 and less than or equal to half of the lowest operating frequency medium wavelength divided by the thickness of a single-layer radiation LTCC medium layer, rounded up.

[0029] As an example, the wavelength of the lowest operating frequency 120GHz medium is about 1mm, and the thickness of the single-layer radiation LTCC medium layer is 0.094mm. ,in, Indicates rounding up.

[0030] See also Figure 1 and Figure 3The feed layer 2 is provided with a first excitation module 20, a broadband H-plane SIW power divider 21 and a second excitation module 22 which are connected in sequence, the second excitation module 22 has N excitation ports 220, and one step radiation resonant cavity 30 is connected to one excitation port 220; as a possible implementation, the feed layer 2 includes a first feed metal layer 23, a feed LTCC dielectric layer 24 and a second feed metal layer 25 from bottom to top. Exemplarily, the material of the feed LTCC dielectric layer 24 is FerroA6M, with a single layer thickness of 0.094 mm, and the material of the first feed metal layer 23 and the second feed metal layer 25 is silver, with a thickness of 0.008 mm.

[0031] See also Figure 1 and Figure 4 , the feed layer 2 is provided with a first excitation region for forming a first excitation module 20; a first excitation coupling slot 230 is provided on the first feed metal layer 23 of the first excitation region, and a first excitation metallized through hole group 240 is provided on the feed LTCC dielectric layer 24 of the first excitation region, which is connected to the first feed metal layer 23 and the second feed metal layer 25 at the same time, and the first excitation metallized through hole group 240 is enclosed to form a half-wavelength resonant cavity 241 with an opening. Exemplarily, the diameter of the metallized through hole in the first excitation metallized through hole group 240 is 0.085 mm or 0.127 mm, the material is silver, and the spacing between adjacent metallized through holes is twice the hole diameter. The first excitation coupling slot 230 is located in the half-wavelength resonant cavity 241, and the second feed metal layer 25 below the first excitation coupling slot 230 is provided with a quasi-TEM mode metallized blind hole group 250 from the bottom surface upward. As an example, the size of the first excitation coupling slot 230 is preferably 0.4 mm in length and 0.12 mm in width, and the half-wavelength resonant cavity 241 provides the first excitation coupling slot 230 with an electric field distribution required for good matching at the center frequency.

[0032] See also Figures 4 to 5 As a possible implementation, the quasi-TEM mode metallized blind hole group 250 is composed of five metallized blind holes 2501, and the height of the metallized blind holes 2501 is preferably 0.094 mm. The quasi-TEM mode metallized blind hole group 250 is based on the first excitation coupling slot 230, wherein the metallized blind holes 2501 accounting for 3 / 5 of the number are located on the opening side close to the half-wavelength resonant cavity 241, and the metallized blind holes 2501 accounting for 2 / 5 of the number are located on the opening side away from the half-wavelength resonant cavity 241. The eigenmode excited by the metallized blind holes 2501 close to the opening side of the half-wavelength resonant cavity 241 provides the first excitation coupling slot 230 with the electric field distribution required for good matching at low frequencies, and the metallized blind holes 2501 close to the opening side of the half-wavelength resonant cavity 241 provide the first excitation coupling slot 230 with the electric field distribution required for good matching at high frequencies.

[0033] See also Figure 1 , Figure 3 and Figure 4 The half-wavelength resonant cavity 241, the quasi-TEM mode metallized blind hole group 250 and the inverted pyramid-shaped stepped radiation resonant cavity 30 constitute three resonance points, which can contribute a total working bandwidth of more than 40 GHz to the antenna unit.

[0034] See also 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 of the power divider region is provided with a power division metallized through hole group 242 that simultaneously connects the first feeding metal layer 23 and the second feeding metal layer 25; the power division metallized through hole group 242 is enclosed near the opening end of the half-wavelength resonant cavity 241 to form a first SIW transmission channel 2420, and the first SIW transmission channel 2420 extends in a direction away from the opening end of the half-wavelength resonant cavity 241 to form N / 2 SIW impedance transformers 2421; an inductor column 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 second SIW transmission lines 2422 in a direction close to the second excitation module 22.

[0035] See also Figure 7 As an example, the width of the first SIW transmission channel 2420 is 0.8 mm, the width of the SIW impedance converter 2421 is 1.06 mm, and the length is 1.06 mm; the distance between the inductor column 24210 and the center coordinate of the SIW impedance converter 2421 along the direction parallel to the first SIW transmission channel 2420 is 0.23 mm.

[0036] See also Figures 1 to 3 as well as Figure 7 As a possible implementation, the feed layer 2 is provided with a second excitation region for forming a second excitation module 22; the feed LTCC dielectric layer 24 of the second excitation region is provided with N groups of second excitation metallized through-hole groups 243 that are connected to the first feed metal layer 23 and the second feed metal layer 25 at the same time. For example, the diameter of the metallized through-holes in the second excitation metallized through-hole group 243 is 0.085 mm or 0.127 mm, the material is silver, and the spacing between adjacent metallized through-holes is twice the hole diameter. The open end of each group of second excitation metallized through-hole groups 243 is connected to the second SIW transmission line 2422; the first feed metal layer 23 of each group of second excitation metallized through-hole groups 243 encloses a second excitation coupling slot 231 that is coupled to the radiation coupling slot 320.

[0037] See also Figure 1The transition interface layer 1 is provided with a waveguide transition interface ladder resonant cavity 10 in an inverted pyramid shape facing the metal waveguide, and the waveguide transition interface ladder resonant cavity 10 is connected to the first excitation module 20; the transition interface layer 1 is also provided with an EBG structure 11 isolated from the waveguide transition interface ladder resonant cavity 10, which is used to suppress electromagnetic leakage between the metal waveguide and the waveguide transition interface ladder resonant cavity.

[0038] See also Figure 1 and Figure 3 The waveguide transition interface ladder resonant cavity 10, the first excitation module 20, the broadband H-plane SIW power divider 21, the second excitation module 22 and the ladder radiation resonant cavity 30 constitute a bidirectional transmission path of electromagnetic waves.

[0039] See also Figure 1 and Figure 8 As a possible implementation, the transition interface layer 1 includes three groups of transition substrates 12 from bottom to top, and each group of transition substrates 12 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 region, and the waveguide transition interface ladder resonant cavity 10 is formed in the transition interface region; the center bottom of the waveguide transition interface ladder resonant cavity 10 is provided with a transition interface coupling gap 100. Exemplarily, the material of the transition LTCC dielectric layer 121 is Ferro A6M, and 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.

[0040] See also Figure 8 As a possible implementation method, the number of steps of the transition metallization hole group opened on the E surface of the waveguide transition interface step resonant cavity 10 is less than the number of steps of the transition metallization hole group opened on the H surface; the layout rule of the transition metallization hole group located on the E surface is: a group of transition metallization hole groups is opened on the bottom transition substrate, and after extending outward by a preset distance, another group of transition metallization hole groups is opened upward with the transition metal layer included in the second bottom transition substrate as the starting surface, and the other group of transition metallization hole groups penetrates the remaining transition substrates upward. The layout rule of the transition metallization hole group located on the H surface is: a group of transition metallization hole groups is opened on each group of transition substrates, and the distance between the transition metallization hole groups on the transition substrate and the transition interface coupling gap gradually increases from bottom to top.

[0041] See also Figure 8As an example, the number of steps of the transition metallization hole group opened on the E surface is two levels. From bottom to top, the spacing between the first-level transition metallization hole groups of two opposite E surfaces is 0.68 mm, and the spacing between the second-level transition metallization hole groups is 0.8 mm; the number of steps of the transition metallization hole group opened on the H surface is three levels. From bottom to top, the spacing between the first-level transition metallization hole groups of two opposite H surfaces is 0.68 mm, the spacing between the second-level transition metallization hole groups is 1.14 mm, and the spacing between the third-level transition metallization hole groups is 1.6 mm.

[0042] See also Figure 1 and Figure 8 A periodic mushroom-shaped EBG structure 11 is also provided in the transition interface region enclosing the waveguide transition interface step resonant cavity 10; an isolation metallized hole group 13 is also provided between the innermost mushroom-shaped EBG structure 11 and the waveguide transition interface step resonant cavity.

[0043] See also Fig. 9 As a possible implementation, the mushroom-shaped EBG structure 11 includes a periodic metal sheet 1210 disposed on the lower surface of the sub-bottom transition LTCC dielectric layer 121 and a periodic metallized via 1211 opened on the sub-bottom transition LTCC dielectric layer 121 coaxially with the periodic metal sheet 1210 .

[0044] See also Fig. 9 As an example, the upper end of the periodic metallized via 1211 is connected to the center of the periodic metal sheet 1210, and the distance between adjacent mushroom-shaped EBG structures 11 is 0.4mm; the periodic metal sheet 1210 is a square with a side length of 0.25mm; the diameter of the periodic metallized via 1211 is 0.127mm. 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 medium adopted in this embodiment can be arranged in a closer area around the waveguide, effectively avoiding the introduction of additional resonant cavities to affect matching.

[0045] Next, the structural parameters of the array antenna were optimized multiple times using the High Frequency Structure Simulator (HFSS), and finally the simulation results of the array antenna with better performance were obtained. The simulation results are shown in Figure 10. Fig.11 , Fig.12 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 maintained below -10 dB, and the relative bandwidth is more than twice that of ordinary end-fire LTCC antennas, fully demonstrating its broadband characteristics.

[0046] In terms of gain, through precise design and the use of a 4×1 one-dimensional linear array structure, a fan-shaped beam with an average maximum gain of 12.7 dBi was successfully achieved. It is worth noting that the antenna's main lobe gain in the entire frequency band maintains good stability, which is crucial to ensuring the stability and reliability of the millimeter wave communication system.

[0047] In summary, the optimized array antenna not only shows excellent performance in terms of return loss, bandwidth and gain, but also achieves an ideal stability in the directional pattern. Therefore, this antenna design is very suitable for application in the field of high-frequency millimeter-wave communications, especially in future 5G and 6G communication systems, and can provide more reliable and efficient communication capabilities.

[0048] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the drawings, etc. In the specification, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the specification. Certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0049] Although the present invention has been described in conjunction with specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present invention. Accordingly, this specification and the accompanying drawings are merely exemplary illustrations of the present invention and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present invention. Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such modifications and variations if they fall within the scope of the present invention and its equivalents.

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 feed layer and a radiation layer which are stacked together in sequence from bottom to top; The radiation layer is provided with N mutually independent stepped radiation resonant cavities which are in the shape of inverted pyramids 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 which are connected in sequence, the second excitation module has N excitation ports, and one step radiation resonance cavity is connected to one excitation port correspondingly; The transition interface layer is provided with a waveguide transition interface ladder resonant cavity in an inverted pyramid shape facing the metal waveguide, and the waveguide transition interface ladder 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 ladder resonant cavity, which is used to suppress electromagnetic leakage between the metal waveguide and the waveguide transition interface ladder resonant cavity; A bidirectional transmission path of electromagnetic waves is formed by a waveguide transition interface ladder resonant cavity, a first excitation module, a broadband H-plane SIW power divider, a second excitation module and a ladder radiation resonant cavity.

2. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology according to claim 1 is characterized in that: The radiation layer includes M groups of radiation substrates from bottom to top, and each group of radiation substrates 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 slot is provided at the center of each radiation area, and the radiation coupling slot is located at the bottom surface of the bottom radiation substrate; Each group of radiation substrates is provided with a radiation metallized through hole group that is co-centered with the radiation coupling slot and surrounds the radiation coupling slot, and each radiation metallized through hole in the radiation metallized through hole group is connected to the radiation metal layer on the radiation substrate; From bottom to top, the enclosed area of ​​the radiation metallized through hole group on the radiation substrate increases layer by layer to form an inverted pyramid-shaped stepped radiation resonant cavity.

3. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology according to claim 2 is characterized in that: M is greater than or equal to 1 and less than or equal to half of the lowest operating frequency medium wavelength divided by the thickness of a single-layer radiation LTCC medium layer, rounded up.

4. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology according to claim 2 is characterized in that: The feeding layer includes, from bottom to top, a first feeding metal layer, a feeding LTCC dielectric layer and a second feeding metal layer; Among them, the feeding layer is provided with a first excitation area for forming a first excitation module; a first excitation coupling slot is opened on the first feeding metal layer of the first excitation area, a first excitation metallized through hole group is opened on the feeding LTCC dielectric layer of the first excitation area and simultaneously connects the first feeding metal layer and the second feeding metal layer, the first excitation metallized through 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 metallized blind hole group is opened from the bottom to the top on the second feeding metal layer below the first excitation coupling slot.

5. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology according to claim 4 is characterized in that: The quasi-TEM mode metallized blind hole group is based on the first excitation coupling gap, wherein 3 / 5 of the metallized blind holes are located near the opening side of the half-wavelength resonant cavity, and 2 / 5 of the metallized blind holes are located away from the opening side of the half-wavelength resonant cavity.

6. The high-frequency millimeter-wave 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 region for forming a broadband H-plane SIW power divider; the feeding LTCC dielectric layer of the power divider region is provided with a power division metallized through hole group that simultaneously connects the first feeding metal layer and the second feeding metal layer; the power division metallized through hole group is enclosed near the opening end of the half-wavelength resonant cavity to form a first SIW transmission channel, and the first SIW transmission channel extends in a direction away from the opening end of the half-wavelength resonant cavity to form N / 2 SIW impedance converters; an inductor column is arranged at one end of each SIW impedance converter away from the first SIW transmission channel; and each SIW impedance converter extends N / 2 second SIW transmission lines in a 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 feed layer is provided with a second excitation region for forming a second excitation module; The feeding LTCC dielectric layer of the second excitation area is provided with N groups of second excitation metallized through-hole groups which are connected to the first feeding metal layer and the second feeding metal layer at the same time; the opening end of each group of second excitation metallized through-hole groups is connected to the second SIW transmission line; the first feeding metal layer of the enclosed area of ​​each group of second excitation metallized through-hole groups is provided with a second excitation coupling gap which is coupled with the radiation coupling gap.

8. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology according to claim 1, characterized in that: The transition interface layer is provided with a transition interface region, and the waveguide transition interface step resonant cavity is formed in the transition interface region; A transition interface coupling gap is provided at the center bottom of the waveguide transition interface ladder resonant cavity; The number of steps of the transition metallization hole group opened on the E surface of the waveguide transition interface step resonant cavity is less than the number of steps of the transition metallization hole group opened on the H surface; A periodic mushroom-shaped EBG structure is also arranged in the transition interface region enclosing the waveguide transition interface step resonant cavity; an isolation metallized hole group is also opened between the innermost mushroom-shaped EBG structure and the waveguide transition interface step resonant cavity.

9. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology according to claim 8, characterized in that: The transition interface layer includes three groups of transition substrates from bottom to top, and each group of transition substrates includes a transition metal layer and a transition LTCC dielectric layer from bottom to top. The layout rule of the transition metallization hole group located on the E surface is as follows: a group of transition metallization hole groups is opened on the bottom transition substrate, and after extending outward by a preset distance, another group of transition metallization hole groups is opened upward with the transition metal layer included in the next bottom transition substrate as the starting surface, and the other group of transition metallization hole groups penetrates the remaining transition substrate upward; The layout rule of the transition metallization hole group located on the H surface is: each group of transition substrates has a group of transition metallization hole groups, and the distance between the transition metallization hole group on the transition substrate and the transition interface coupling gap gradually increases from bottom to top.

10. The high-frequency millimeter-wave three-dimensional integrated antenna array based on LTCC technology according to claim 8, characterized in that: The mushroom-shaped EBG structure comprises a periodic metal sheet arranged on the lower surface of the secondary bottom transition LTCC dielectric layer and a periodic metallized via hole opened on the secondary bottom transition LTCC dielectric layer with the same central axis as the metal sheet.

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