A microwave and millimeter wave high frequency ratio common aperture antenna combining MIMO technology

Abstract

The present invention discloses a microwave and millimeter wave high frequency ratio common aperture antenna combined with MIMO technology. In the microwave and millimeter wave high frequency ratio common aperture antenna, four substrate integrated waveguide back cavity patch antennas and four electric dipoles of electromagnetic dipoles are shared through structural design, forming a 2×2 MIMO antenna array to radiate millimeter wave signals, realizing the use of dual-polarized electromagnetic dipole antennas in microwave frequency bands, and combining MIMO technology in millimeter wave frequency bands, and finally realizing a high frequency ratio common aperture antenna with high integration, high isolation and other characteristics, combining MIMO technology in millimeter wave frequency bands, and covering multiple frequency bands.

Description

Technical Field

[0001] The present invention belongs to the technical field of antenna design, and in particular relates to a microwave and millimeter wave large frequency ratio co-aperture antenna structure combined with MIMO technology. Background Art

[0002] In recent years, 5G communication technology has developed rapidly, greatly improving the data transmission rate. Among them, the microwave frequency band below 6GHz has been applied to 5G mobile communication systems in China and many other countries. However, due to the lack of spectrum resources in the microwave frequency band, it cannot meet the requirements of higher speed and larger capacity transmission in the future. The millimeter wave frequency band with rich spectrum resources has gradually attracted widespread attention from scholars at home and abroad. However, communication in the millimeter wave frequency band also faces many challenges. Its transmission distance is short and it is easy to produce multipath effects, so it cannot completely replace microwave technology. In order to obtain a larger coverage range and high-speed data transmission at the same time, the integration of millimeter wave antennas and microwave antennas into a co-aperture antenna at the RF front end has become a hot research area for future 5G communication systems. Compared with the solution of independent design of microwave and millimeter wave antennas, the co-aperture antenna can realize the radiation of microwave and millimeter waves in one aperture at the same time, which can save the space occupied by the antenna and achieve miniaturization.

[0003] Due to the short wavelength of millimeter waves, the high-frequency part of the common-aperture antenna will have to face complex multipath effects and electromagnetic interference. The present invention proposes to share four substrate integrated waveguide back cavity patch antennas and four electric dipoles of the electromagnetic dipole on the microwave and millimeter-wave large frequency ratio common-aperture antenna through structural design, forming a 2×2 MIMO antenna array to radiate millimeter-wave signals, realizing the use of dual-polarized electromagnetic dipole antennas in the microwave frequency band and combining MIMO technology in the millimeter-wave frequency band, and finally realizing a high-frequency ratio common-aperture antenna with the characteristics of high integration, high isolation, etc., which is combined with MIMO technology in the millimeter-wave frequency band and can cover multiple frequency bands. Summary of the invention

[0004] The purpose of the present invention is to address the short wavelength of existing millimeter waves, and the high-frequency part of the common-aperture antenna faces complex multipath effects and electromagnetic interference. A microwave and millimeter-wave high-frequency ratio common-aperture antenna that works in two frequency bands of 3.26GHz to 5.01GHz and 26.82GHz to 29.9GHz and combines MIMO technology at high frequencies is proposed. It covers the N78, N79 frequency bands and the 28GHz millimeter-wave frequency band respectively, and adopts a structural multiplexing scheme. While realizing antenna integration, it realizes normal radiation of the two frequency bands and high port isolation. In addition, the MIMO unit of the high-frequency part adopts a miniaturized substrate integrated waveguide back cavity patch antenna, which has a high gain and a low envelope correlation coefficient.

[0005] The technical solution to achieve the purpose of the present invention is:

[0006] The microwave and millimeter wave high frequency ratio co-aperture antennas combined with MIMO technology include:

[0007] 2×2 MIMO antenna array F;

[0008] Substrate integrated waveguide fed cavity array N;

[0009] The vertical short-circuit part M of the electromagnetic dipole;

[0010] Electromagnetic dipole feeding network G;

[0011] The 2×2 MIMO antenna array F includes four centrosymmetric 2×2 cavity-backed patch antenna array units, with a certain spacing between the units.

[0012] Each 2×2 cavity-backed patch antenna array unit includes a metal patch P1, a dielectric plate S1, a metal patch P3, and a number of metal pillars M1 that are arranged in sequence from top to bottom; the several metal pillars M1, the metal patch P1, and the metal patch P3 form four interconnected square substrate integrated waveguide cavities of the same size, with a conduction window left at the center of the cavity and no metal pillar M1 set.

[0013] A square groove V1 is etched on the metal patch P1 at the center of the corresponding position of each substrate integrated waveguide cavity, and a metal patch P2 is laid at the center of each square groove V1, with a certain distance between the metal patch P2 and the square groove.

[0014] The metal patch P2 is connected to the metal patch P3 via two metal pillars M2 penetrating the dielectric plate S1 ; the two metal pillars M2 are symmetrical about the center of the metal patch P2 .

[0015] In each 2×2 cavity-backed patch antenna array unit, a coupling slot V2 is etched on the metal patch P3 at the position of the substrate integrated waveguide cavity conduction window for coupling high-frequency signals into the cavity. The coupling slot V2 is at a certain distance from the metal pillar M1.

[0016] Preferably, the direction in which the metal pillar M2 deviates from the center of the patch (ie, the straight line where two metal pillars M2 are located in the same substrate integrated waveguide cavity) is parallel to the long side of the coupling slot V2.

[0017] Preferably, the distance that the metal pillar M2 deviates from the center of the metal patch P2 in the current substrate integrated waveguide cavity affects the impedance matching and radiation performance of the antenna.

[0018] The substrate integrated waveguide feeding cavity array N comprises four centrally symmetrical rectangular substrate integrated waveguide feeding cavities, a dielectric plate S2, and four metal pillars M4 penetrating the dielectric plate S2, and the four rectangular substrate integrated waveguide feeding cavities are respectively bonded under four 2×2 cavity-backed patch antenna array units;

[0019] The rectangular substrate integrated waveguide feeding cavity is surrounded by a metal patch P3 and a metal patch P4 shared with the 2×2 MIMO antenna array F, and a plurality of metal pillars M3 penetrating the dielectric plate S2.

[0020] A metal column M4 is provided inside the rectangular substrate integrated waveguide feeding cavity at a position away from the coupling slot V2, for adjusting the impedance matching of the feeding cavity.

[0021] A through hole Q for introducing high-frequency probe feeding is opened inside the rectangular substrate integrated waveguide feeding cavity;

[0022] Preferably, the metal patches P1 , P3 , and P4 are of the same size.

[0023] The four substrate integrated waveguide back cavity patch antenna array units and the rectangular substrate integrated waveguide feeding cavity as a whole serve as the electric dipole part of the electromagnetic dipole working at a low frequency, and the electromagnetic dipole antenna is not additionally provided with an electric dipole patch.

[0024] The electromagnetic dipole vertical short-circuit part M includes four dielectric plates S3 bent 90 degrees and placed vertically and not in contact with each other, and a metal patch P5 attached to the outer side of the dielectric plate S3.

[0025] The 90° bent dielectric plate S3 is an integrally formed structure, which is vertically connected by two vertically arranged sub-dielectric plates; the right-angle sides of the four 90° bent dielectric plates S3 are arranged inwards.

[0026] The upper end of the dielectric plate S3 is connected to the dielectric plates S1 and S2, and the lower end is connected to the dielectric plate S4, so as to play a fixing role.

[0027] The vertical short-circuit patch (ie, metal patch P5) bent 90° and placed outside the dielectric plate S3 connects the inner side of the 2×2 cavity-backed patch antenna array unit (ie, electric dipole) and the metal patch P6 to work as a magnetic dipole.

[0028] The electromagnetic dipole feeding network G contacts the lower end of the electromagnetic dipole vertical short-circuit portion M and includes a metal patch P6, a dielectric plate S4, and Y-shaped feeding microstrip lines Y1 and Y2 arranged in sequence from top to bottom.

[0029] A cross-shaped coupling gap V3 is etched at the center of the metal patch P6.

[0030] Preferably, the cross-shaped coupling gap V3 is located in the gaps between four dielectric plates S3 bent 90 degrees.

[0031] The Y-shaped feeding microstrip lines Y1 and Y2 are located below the cross-shaped coupling gap, and the Y-shaped feeding microstrip lines Y1 and Y2 are placed orthogonally to reduce coupling.

[0032] Preferably, the Y-shaped feeding microstrip lines Y1 and Y2 both adopt a one-to-two microstrip feeding structure.

[0033] Preferably, in order to shorten the length of the microstrip line, the ends of the Y-shaped feeding microstrip lines Y1 and Y2 are connected to circular metal patches.

[0034] Preferably, the Y-shaped feeding microstrip lines Y1 and Y2 have different sizes, so as to adjust the impedance matching in two different polarization directions.

[0035] Preferably, the bridging portion of the two Y-shaped microstrip lines is achieved by cutting off the portion of the Y-shaped feeding microstrip line Y2 that intersects with the Y-shaped feeding microstrip line Y1, slotting the metal patch P6 and laying the metal patch P7, and connecting the metal patch P7 and the Y-shaped feeding microstrip line Y2 using a metal column M5 that passes through the dielectric plate S4.

[0036] The principle of the antenna of the present invention is described in detail below.

[0037] When one unit in the high-frequency MIMO antenna is working, the millimeter wave signal is fed from the through hole Q into the substrate integrated waveguide feeding cavity surrounded by the metal column M3, and then transmitted to the coupling slot V2 through the feeding cavity. The coupling slot V2 excites the substrate integrated waveguide back cavity patch antenna cavity above, and finally the square slot V1 of the substrate integrated waveguide back cavity patch antenna and the metal patch P2 jointly radiate the millimeter wave signal outward. At this time, the current on the metal patch P1 is distributed in the cavity. The other three MIMO units work in the same way, and the four antenna units can work independently.

[0038] When the antenna works at low frequency, the microwave signal is input from the Y-shaped feeding microstrip lines Y1 and Y2 at the bottom, and the cross-shaped gap V3 above the Y-shaped feeding microstrip lines Y1 and Y2 couples the energy to the electromagnetic dipole radiation part above. Since only low-frequency signals are transmitted, the four high-frequency MIMO antenna units and their feeding network are equivalent to three layers of stacked patches as a whole, which can be regarded as four horizontal microstrip patches with a thickness equal to the sum of the thickness of the dielectric plates S1 and S2, working as the electric dipole of the electromagnetic dipole. The vertical short-circuit patch (i.e., metal patch P5) bent 90° connects the inner side of the above electric dipole and the metal patch P6, working as a magnetic dipole. Energy input from different Y-shaped feeding microstrip lines Y1 and Y2 will realize different polarization directions of the low-frequency part. At this time, the current on the patch is evenly distributed at the edge of the patch.

[0039] The antenna uses the cavity-backed patch antenna as a horizontal patch and shares it with the electric dipole of the electromagnetic dipole antenna. At the same time, the dual-polarized electromagnetic dipole structure itself is combined with MIMO technology in the high-frequency part, which makes the antenna have a high space utilization rate. In addition, the distance between the electromagnetic dipole units is the distance between the MIMO units. This distance can simultaneously adjust the impedance matching of the electromagnetic dipole and the isolation between the MIMO units. The antenna also obtains a lower MIMO antenna envelope correlation coefficient on the basis of ensuring low-frequency coverage of two 5G frequency bands.

[0040] Due to the high-pass characteristics of the substrate integrated waveguide, the signal cannot enter the cavity of the high-frequency radiation part when the antenna works at low frequency, ensuring good port-to-port isolation. When the antenna works at high frequency, there is a certain distance between the high-frequency substrate integrated waveguide antenna unit and the low-frequency feeding microstrip line, which makes the port isolation between high and low frequencies also high. This co-aperture antenna design does not require additional decoupling structure and achieves high isolation between high and low frequencies.

[0041] Compared with the prior art, the present invention has the following significant advantages:

[0042] 1. The present invention utilizes the characteristics of the electromagnetic dipole structure itself, integrates a high-frequency radiation structure in the electric dipole part, has high space utilization, and has a large bandwidth in both working frequency bands.

[0043] 2. The present invention fully utilizes the high-pass characteristics of the substrate integrated waveguide structure and the spacing of the radiation structure itself, and achieves high port isolation in two different operating frequency bands without using an additional decoupling structure.

[0044] 3. The present invention combines MIMO technology in the high-frequency operating band of the large-frequency ratio common-aperture antenna, and uses the spatial structure of the electromagnetic dipole itself to layout the MIMO antenna units, thereby achieving a low envelope correlation coefficient and a higher gain. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a three-dimensional view of the microwave and millimeter wave large frequency ratio common aperture antenna combined with MIMO technology of the present invention.

[0046] Figure 2 It is a side view of the microwave and millimeter wave large frequency ratio common aperture antenna combined with MIMO technology of the present invention.

[0047] Figure 3 (a) is a top view of the MIMO antenna array of the present invention.

[0048] Figure 3 (b) is a top view of the substrate integrated waveguide back cavity patch antenna array unit of the present invention.

[0049] Figure 4 (a) is a top view of the substrate integrated waveguide feeding cavity array of the present invention.

[0050] Figure 4 (b) is a top view of the substrate integrated waveguide feeding cavity of the present invention.

[0051] Figure 5 (a) is a top view of the vertical short-circuit portion of the electromagnetic dipole and the electromagnetic dipole feeding network of the present invention.

[0052] Figure 5 (b) is a bottom view of the electromagnetic dipole feeding network of the present invention.

[0053] Figure 5 (c) is a schematic diagram of the feed microstrip line jumper structure of the present invention.

[0054] Figure 6 is the reflection coefficient of the present invention when working at low frequency |S 11 |、|S 22 |, isolation degree |S 12 |Curve simulation diagram.

[0055] Figure 7 is the reflection coefficient of the present invention when it works at high frequency |S 33 |, isolation degree |S 34 |、|S 35 |、|S 36 |Curve simulation diagram.

[0056] Figure 8 It is the MIMO antenna envelope correlation coefficient when the present invention works in the high frequency band.

[0057] Fig. 9 is the antenna gain of the present invention in two working frequency bands.

[0058] Fig.10 It is the isolation between the high-frequency and low-frequency antenna ports in the two working frequency bands of the present invention.

[0059] Fig.11 (a) is the radiation pattern of the present invention at 3.5 GHz.

[0060] Fig.11 (b) is the radiation pattern of the present invention at 4.7 GHz.

[0061] Fig.12 (a) is the radiation pattern of the present invention at 26.8 GHz.

[0062] Fig.12 (b) is the radiation pattern of the present invention at 28 GHz.

[0063] Fig.12(c) is the radiation pattern of the present invention at 29.9 GHz. DETAILED DESCRIPTION

[0064] The implementation of the technical solution is further analyzed below in conjunction with the accompanying drawings:

[0065] Combination Figure 1 , Figure 3 (a) Figure 4 (a) Figure 5 (a) Figure 5 (b) The microwave and millimeter-wave high frequency ratio co-aperture antenna combined with MIMO technology consists of four parts: 2×2 MIMO antenna array F, substrate integrated waveguide feeding cavity array N, electromagnetic dipole vertical short-circuit part M, and electromagnetic dipole feeding network G.

[0066] The 2×2 MIMO antenna array F includes four 2×2 substrate integrated waveguide back cavity patch array antenna units that rotate sequentially and leave a certain distance between them. Each back cavity patch array antenna unit includes a metal patch P1, a dielectric plate S1, a metal patch P2, and metal columns M1 and M2 that pass through the dielectric plate S1, which are arranged in sequence from top to bottom.

[0067] Each 2×2 substrate integrated waveguide back cavity patch array antenna unit includes four square substrate integrated waveguide cavities surrounded by a number of metal pillars M1 and interconnected. A conduction window is left at the center of the antenna, where no metal pillar is set.

[0068] A square groove V1 is etched at the center of the corresponding position of each substrate integrated waveguide cavity of the metal patch P1, and a metal patch P2 is laid at the center of each square groove V1. The metal patch P2 has a certain distance from the square groove and is slightly smaller than the square groove.

[0069] A coupling slot V2 is etched at the center of the conductive window of each substrate integrated waveguide back cavity patch array antenna of the metal patch P3 for feeding in high frequency signals.

[0070] A pair of metal pillars M2 symmetrical about the center of the patch is provided between each metal patch P2 and P3. The metal pillars M2 are located near the edge center of the metal patch P2, and the straight line where each pair of metal pillars are located is parallel to the long side of the coupling gap V2.

[0071] The substrate integrated waveguide feeding cavity array N includes four sequentially rotated rectangular substrate integrated waveguide feeding cavities, each feeding cavity is located below the back cavity patch antenna unit, and includes a metal patch P3, a dielectric plate S2, a metal patch P4, and metal pillars M3 and M4 that pass through the dielectric plate S2.

[0072] The rectangular feeding cavity is surrounded by metal pillars M3, and a metal pillar M4 is provided inside the feeding cavity away from the gap to adjust the impedance matching of the feeding cavity. A feeding through hole Q is opened at the beginning of the rectangular feeding cavity for introducing high-frequency signals.

[0073] The electromagnetic dipole vertical short-circuit part M includes four dielectric plates S3 bent 90 degrees and placed vertically, and a metal patch P5 attached to the outside of the dielectric plate S3. The upper end of the dielectric plate S3 is connected to the dielectric plates S1 and S2, and the lower end is connected to the dielectric plate S4. The vertical short-circuit patch (i.e., the metal patch P5) is connected to the inner side of the 2×2 cavity-backed patch antenna array unit (i.e., the electric dipole) and the metal patch P6, and works as a magnetic dipole.

[0074] The electromagnetic dipole feeding network G contacts the lower end of the electromagnetic dipole vertical short-circuit portion M and includes a metal patch P6, a dielectric plate S4, and Y-shaped feeding microstrip lines Y1 and Y2 arranged in sequence from top to bottom.

[0075] A cross-shaped coupling gap V3 is etched at the center of the metal patch P6.

[0076] The Y-shaped feeding microstrip lines Y1 and Y2 are orthogonally placed under the cross-shaped coupling gap, and a one-to-two microstrip structure is adopted. A circular metal patch is connected to the end of the microstrip line, and the diameter is slightly larger than the width of the end microstrip line. The intersection of the microstrip lines Y1 and Y2 is realized by using a cross-border structure, by cutting off the part of the microstrip line Y2 that crosses the microstrip line Y1, grooving on the metal patch P6 and laying the metal patch P7, and connecting the metal patch P7 and the microstrip line Y2 by using a metal column M5 that runs through the dielectric plate S4.

[0077] The metal patches P1, P3, and P4 are of the same size, and are slightly larger than the substrate integrated waveguide cavity. The size of the metal patch P4 is consistent with that of the dielectric plate S4, and the cross-shaped coupling gap V3 is located in the center of the patch, and the end of the Y-shaped microstrip line is close to the bottom of the cross-shaped gap.

[0078] The specific size requirements for a microwave and millimeter wave high frequency ratio co-aperture antenna with high isolation are as follows:

[0079] In the MIMO antenna array F, the side length La of the dielectric plate S1 is 7.04λ g1 ~8.8λ g1 , thickness H1 is 0.813mm(0.143λ g1 ), the spacing d between adjacent MIMO antenna units (substrate integrated waveguide cavity-backed patch antenna array) is 0.704λ g1 ~1.408λ g1 , the side length Lp of the metal patch P1 is 2.59λ g1 ~2.77λ g1In each substrate integrated waveguide back cavity patch antenna array, the diameter ds of the metal column M1 is 0.105λ g1 ~0.175λ g1 , the spacing dp between adjacent metal pillars is 0.105λ g1 ~0.112λ g1 , the cavity side length Lsiw of the cavity-backed patch antenna array is 2.24λ g1 ~2.43λ g1 , the side length Lq of the four interconnected cavities is 0.32λ g1 ~0.73λ g1 , the side length Lw of the square slot above the cavity is 0.58λ g1 ~0.7λ g1 , the side length Lr of the square metal patch in the square slot is 0.352λ g1 ~0.422λ g1 The distance dpg between the metal pillars M2 and P3 is 0.211λ. g1 ~0.281λ g1 The length Lsh of the coupling gap V2 on the metal patch P3 is 55λ g1 ~0.62λ g1 , width wsh is 0.035λ g1 ~0.069λ g1 .

[0080] In the substrate integrated waveguide feeding cavity array N, the side length La of the dielectric plate S2 is 7.04λ g1 ~8.8λ g1 , thickness H2 is 0.813mm(0.143λ g1 ), the spacing d between adjacent feeding cavity units is 0.704λ g1 ~1.408λ g1 , the side length Lp of the metal patch P2 is 2.59λ g1 ~2.77λ g1 The diameter ds of the metal column M1 in each substrate integrated waveguide feeding cavity is 0.105λ g1 ~0.175λ g1 , the spacing between adjacent metal pillars is din 0.11λ g1 ~0.13λ g1 , the length xin of the rectangular feeding cavity is 1.5λ g1 ~1.7λ g1 , width yin is 0.79λ g1 ~0.92λ g1 The distance ys between the coupling gap V2 and the left edge of the rectangular feeding cavity is 0.14λ g1 ~0.21λ g1The distance db between the metal column M4 and the center of the coupling gap is 0.51λ g1 ~0.58λ g1 The diameter of the input through hole Q is 0.15mm (0.026λ g1 )

[0081] In the vertical short-circuit part M of the electromagnetic dipole, the width La of the dielectric plate S3 is 0.39λ g2 ~0.41λ g2 , thickness Hv is 0.813mm(0.021λ g2 ), the vertical height Hm is 0.344λ g2 ~0.397λ g2 The spacing d between adjacent dielectric substrates is 0.11λ g2 ~0.21λ g2 The width and height of the metal patch P5 are the same as those of the dielectric plate S3.

[0082] In the electromagnetic dipole feeding network G, the side length L of the dielectric plate S4 is 1.98λ g2 ~2.26λ g2 , the length of the cross gap Ls on the metal patch P6 is 0.92λ g2 ~1.19λ g2 , width Ws is 0.021λ g2 ~0.032λ g2 In the Y-shaped feeding microstrip line, the input microstrip line width Wi of Y1 and Y2 is 0.079λ g2 ~0.092λ g2 The input microstrip line lengths Li1 and Li2 of Y1 and Y2 are 0.345λ g2 ~0.371λ g2 The length of the branch Lb is 0.47λ g2 ~0.6λ g2 , the width Wb is 0.032λ g2 ~0.036λ g2 The widths of the two output branches Wd1 and Wd2 are 0.032λ g2 ~0.039λ g2 The length of the open circuit part at the end of the two output branches is Lu 0.13λ g2 ~0.17λ g2 The diameter dr of the circular patch at the end of the two output branches is 0.083λ g2 ~0.128λ g2 In the crossover section of the microstrip line Y2, the length of the truncated section Gc is 0.092λ g2 ~0.119λ g2 , the length Lv of the rectangular slot V4 is 0.145λ g2~0.171λ g2 , width Wv is 0.039λ g2 ~0.066λ g2 , the length of the jumper microstrip line P7 is 0.137λ g2 ~0.164λ g2 , width Wc is 0.015λ g2 ~0.026λ g2 , the diameter drp of the metal column M5 is 0.008λ g2 ~0.013λ g2 .

[0083] The details and working conditions of the device of the present invention are described in detail below in conjunction with the embodiments.

[0084] Combination Figure 2 , 2×2 MIMO antenna array F, substrate integrated waveguide feeding cavity array N, electromagnetic dipole vertical short-circuit part M, and electromagnetic dipole feeding network G constitute the high frequency ratio common aperture antenna of the present invention from top to bottom.

[0085] Combination Figure 3 The 2×2 MIMO antenna array consists of four sequentially rotated cavity-backed patch antenna array units, and the spacing d between adjacent MIMO antenna units is 5.8 mm (1.02λ g1 ), a single cavity-backed patch antenna array unit is composed of metal patch P1, metal patch P2, dielectric plate S1, and metal patch P3 in order from top to bottom. The dielectric plate has a relative dielectric constant of 3.55 and a thickness of 0.813 mm (0.143 λ g1 ), side length La is 44mm (7.75λ g1 The side length of the metal patch P1 is 15 mm (2.64λ g1 ), the side length of the metal patch P2 is 15mm (2.64λ g1 The side length Lsiw of the four interconnected substrate integrated waveguide cavities surrounded by the metal pillars M1 is 13.2 mm (2.32λ g1 ), the diameter ds of the metal column M1 is 0.8 mm (0.14λ g1 ), the spacing dp between adjacent metal pillars is 0.66mm (0.12λ g1 The length Lq of the connection between two adjacent cavities in the antenna unit is 1.98 mm (0.35λ g1 ). A square slot is opened on the metal patch P1 corresponding to the center of each antenna cavity, and the side length Lw of each square slot is 3.6mm (0.63λ g1 ), a metal patch P2 is laid in the square groove, and the side length Lr of the metal patch P2 is 2.2mm (0.387λ g1), the spacing dpg between the metal pillars M2 connecting the metal patch P2 and the metal patch P3 is 1.4mm (0.25λ g1 ), the diameter of the metal column M2 is the same as the diameter of the metal column M1. A coupling gap V2 is opened at the position corresponding to the metal patch P3 below the center of the cavity, and the length of the coupling gap Lsh is 3.3mm (0.58λ g1 ), width Wsh is 0.3mm(0.05λ g1 ). where λ g1 is the dielectric wavelength at the center operating frequency of 28 GHz of the high frequency part of the common aperture antenna.

[0086] Combination Figure 4 The substrate integrated waveguide feeding cavity array N consists of four rectangular substrate integrated waveguide feeding cavities rotated sequentially, and the distance d between adjacent feeding cavities is 5.8mm (1.02λ g1 ), each substrate integrated waveguide feeding cavity is composed of a metal patch P3, a dielectric plate S2, and a metal patch P4 in order from top to bottom. The dielectric plate S2 has a relative dielectric constant of 3.55 and a thickness H2 of 0.813 mm (0.065λ g1 ), side length La is 44mm (7.75λ g1 The side length of metal patch P1 and metal patch P3 is 15mm (2.64λ g1 The rectangular substrate integrated waveguide feeding cavity surrounded by the metal column M3 has a length of 9.1 mm (1.6λ g1 ), width yin is 4.9mm(0.86λ g1 ), the diameter ds of the metal column M3 is 0.8 mm (0.14λ g1 ), the spacing between adjacent metal pillars is 0.7mm (0.12λ g1 The distance ys between the coupling gap V2 on the metal patch P3 and the left metal column is 1 mm (0.176λ g1 ), the distance db between the matching metal column M4 and the center of the coupling gap V2 is 3.1 mm (0.55λ g1 The diameter din of the feed hole Q in the cavity is 0.15 mm (0.026λ g1 ).

[0087] Combination Figure 2 and Figure 5 (a), the electromagnetic dipole vertical short circuit part M is composed of four dielectric plates S3 bent 90° and placed vertically and a metal patch P5 attached to the outside of the dielectric plate S3. The dielectric plate S3 has a relative dielectric constant of 3.55 and a thickness Hv of 0.813 mm (0.021λ g2), the upper end of the bent part is in contact with the inner edge of the metal patch P1, metal patch P3, and metal patch P4, and the width is consistent with them. The height Hm is 14mm (0.37λ g2 The width and height of the bent metal patch P5 are the same as those of the dielectric plate S3, and the distance d between adjacent bent metal patches is 5.8 mm (0.154λ g2 ). where λ g2 is the dielectric wavelength at the center operating frequency of 4.2 GHz of the low-frequency part of the co-aperture antenna.

[0088] Combination Figure 5 (b) The Y-shaped feeding microstrip lines Y1 and Y2 are placed orthogonally below the cross-shaped gap. In the Y-shaped feeding microstrip line, the input end microstrip line width Wi of the microstrip lines Y1 and Y2 is 3.31 mm (0.088λ g2 ), the input microstrip line length Li1 of microstrip line Y1 is 13.5mm (0.36λ g2 ), the input microstrip line length Li2 of Y2 is 13.3mm (0.35λ g2 The lengths of the two branches of Y1 and Y2 are both 20 mm (0.53λ g2 ), width Wb is 1.3mm(0.035λ g2 ), the output microstrip line width Wd1 of Y1 is 1.3mm (0.035λ g2 ), the output microstrip line width Wd2 of Y2 is 1.5mm (0.04λ g2 The length Lu of the open-circuit end portion (part beyond the gap) of Y1 and Y2 is 5.5 mm (0.146λ g2 The diameter dr of the circular metal patch at the end of Y1 and Y2 is 4 mm (0.106λ g2 ).

[0089] Combination Figure 6 , it can be seen from the given reflection coefficient curve that when the antenna works in the microwave frequency band, the working frequency band with a reflection coefficient lower than -10dB is 3.26GHz~5.01GHz, and the relative bandwidth is 41.7%. The working frequency bands and relative bandwidths of the two polarizations are basically the same. The working frequency bands meet the required N78 band of 3.4GHz~3.6GHz and the N79 band of 4.4GHz~5GHz. In addition, the antenna's |S 12 |In the working frequency band, it is lower than -25dB, indicating that the isolation between the two polarization directions of the electromagnetic dipole is good. Ports 1 and 2 are the input ports of the two polarization directions of the electromagnetic dipole antenna.

[0090] Combination Figure 7, it can be seen from the given reflection coefficient curve that when the antenna works in the millimeter wave band, the working frequency band below -10dB is 26.82GHz~29.89GHz, the relative bandwidth is 10.96%, and the working frequency band meets the required millimeter wave band of 24.25GHz~27.5GHz. For the convenience of representation, only the reflection coefficient of one MIMO unit is given in the figure, and the working frequency band and relative bandwidth of other MIMO units are the same as in the figure. In addition, as shown in the figure, the antenna's |S 34 |、|S 35 |、|S 36 |In the working frequency band, they are all lower than -40dB, indicating that the isolation between MIMO units is good. Ports 3, 4, 5, and 6 are the input ports of the four MIMO antenna units.

[0091] Combination Figure 8 ,The envelope correlation coefficient of the MIMO antenna is lower than 0.0001 within the working frequency band.

[0092] Combination Fig. 9 The maximum gain of the antenna in the low-frequency working band is greater than 8.6dBi, and the gain curve in the band is relatively stable. The maximum gain of the antenna in the high-frequency working band is greater than 12.5dBi, and the gain curve in the band is relatively stable.

[0093] Combination Fig.10 , the antenna is in the low frequency working band, |S 13 |、|S 14 |、|S 15 |、|S 16 | are all lower than -95dB, the antenna is in the high frequency working band, |S 13 |、|S 14 |、|S 15 |、|S 16 | are both lower than -40dB, which shows that the antenna has good isolation between the high and low frequency ports in both working frequency bands.

[0094] Combination Fig.11 When the antenna works at 3.5GHz and 4.7GHz, a relatively symmetrical radiation pattern can be obtained in both the E plane and the H plane. And the cross polarization of the E plane and the H plane is less than -25dB, which shows that the antenna has good radiation characteristics in the microwave working frequency band.

[0095] Combination Fig.12 When the antenna works at 26.8GHz, 28GHz and 29.9GHz, a relatively symmetrical radiation pattern can be obtained in both the E plane and the H plane. In addition, the cross-polarization of the E plane and the H plane is less than -25dB, which shows that the antenna has good radiation characteristics in the millimeter wave operating frequency band.

Claims

1. A microwave and millimeter wave high frequency ratio common aperture antenna combining MIMO technology, characterized in that include: 2×2 MIMO antenna array F; Substrate integrated waveguide fed cavity array N; The vertical short-circuit part M of the electromagnetic dipole; Electromagnetic dipole feeding network G; The 2×2 MIMO antenna array F includes four centrosymmetric 2×2 cavity-backed patch antenna array units, with a certain spacing between the units; Each 2×2 cavity-backed patch antenna array unit includes a metal patch P1, a dielectric plate S1, a metal patch P3, and a plurality of metal pillars M1 that penetrate the dielectric plate S1, which are arranged in sequence from top to bottom; the plurality of metal pillars M1, the metal patch P1, and the metal patch P3 form four interconnected square substrate integrated waveguide cavities of the same size, with a conduction window left at the center of the cavity and no metal pillar M1 arranged; A square groove V1 is etched on the metal patch P1 at the center of the corresponding position of each substrate integrated waveguide cavity, and a metal patch P2 is laid at the center of each square groove V1, and a certain distance is left between the metal patch P2 and the square groove; The metal patch P2 is connected to the metal patch P3 via two metal pillars M2 that penetrate the dielectric plate S1; the two metal pillars M2 are symmetrical about the center of the metal patch P2; In each 2×2 cavity-backed patch antenna array unit, a coupling slot V2 is etched on the metal patch P3 at the position of the substrate integrated waveguide cavity conduction window, for coupling high-frequency signals into the cavity; the coupling slot V2 is at a certain distance from the metal pillar M1; The substrate integrated waveguide feeding cavity array N comprises four centrally symmetrical rectangular substrate integrated waveguide feeding cavities, a dielectric plate S2, and four metal pillars M4 penetrating the dielectric plate S2, and the four rectangular substrate integrated waveguide feeding cavities are respectively bonded under four 2×2 cavity-backed patch antenna array units; The rectangular substrate integrated waveguide feeding cavity is surrounded by a metal patch P3 and a metal patch P4 shared with the 2×2 MIMO antenna array F, and a plurality of metal pillars M3 penetrating the dielectric plate S2; A metal column M4 is provided at a position away from the coupling gap V2 inside the rectangular substrate integrated waveguide feeding cavity, for adjusting the impedance matching of the feeding cavity; A through hole Q for introducing high-frequency probe feeding is opened inside the rectangular substrate integrated waveguide feeding cavity; The four substrate integrated waveguide back cavity patch antenna array units and the rectangular substrate integrated waveguide feeding cavity as a whole serve as the electric dipole part of the electromagnetic dipole operating at a low frequency, and the electromagnetic dipole antenna is not additionally provided with an electric dipole patch; The electromagnetic dipole vertical short-circuit part M comprises four dielectric plates S3 bent 90 degrees and placed vertically and not in contact with each other, and a metal patch P5 attached to the outer side of the dielectric plate S3; The upper end of the dielectric plate S3 is connected to the dielectric plates S1 and S2, and the lower end is connected to the dielectric plate S4, playing a fixing role; The metal patch P5 is connected to the inner side of the 2×2 cavity-backed patch antenna array unit and the metal patch P6 to work as a magnetic dipole; The electromagnetic dipole feeding network G is in contact with the lower end of the electromagnetic dipole vertical short-circuit part M, and includes a metal patch P6, a dielectric plate S4, and Y-shaped feeding microstrip lines Y1 and Y2 arranged in sequence from top to bottom; A cross-shaped coupling gap V3 is etched at the center of the metal patch P6.

2. A microwave and millimeter wave high frequency ratio common aperture antenna combined with MIMO technology as claimed in claim 1, characterized in that The straight line where the two metal pillars M2 are located in the same substrate integrated waveguide cavity is parallel to the long side of the coupling slot V2.

3. A microwave and millimeter wave high frequency ratio common aperture antenna combined with MIMO technology as claimed in claim 1, characterized in that The distance that the metal pillar M2 deviates from the center of the metal patch P2 in the current substrate integrated waveguide cavity affects the impedance matching and radiation performance of the antenna.

4. A microwave and millimeter wave high frequency ratio common aperture antenna combined with MIMO technology as claimed in claim 1, characterized in that The metal patches P1, P3, and P4 have the same size.

5. A microwave and millimeter wave high frequency ratio common aperture antenna combined with MIMO technology as claimed in claim 1, characterized in that The 90°-bent dielectric plate S3 is an integrally formed structure, which is vertically connected by two vertically arranged sub-dielectric plates; the right-angle sides of the four 90°-bent dielectric plates S3 are arranged inwards.

6. A microwave and millimeter wave high frequency ratio common aperture antenna combined with MIMO technology as claimed in claim 1, characterized in that The cross-shaped coupling gap V3 is located in the gaps between four dielectric plates S3 bent 90 degrees.

7. The microwave and millimeter wave high frequency ratio common aperture antenna combined with MIMO technology as claimed in claim 1, characterized in that The Y-shaped feeding microstrip lines Y1 and Y2 are located below the cross-shaped coupling gap, and the Y-shaped feeding microstrip lines Y1 and Y2 are placed orthogonally to reduce coupling.

8. The microwave and millimeter wave high frequency ratio common aperture antenna combined with MIMO technology as claimed in claim 1, characterized in that The Y-shaped feeding microstrip lines Y1 and Y2 both adopt a one-to-two microstrip feeding structure.

9. The microwave and millimeter wave high frequency ratio common aperture antenna combined with MIMO technology as claimed in claim 1, characterized in that The Y-shaped feeding microstrip lines Y1 and Y2 have different sizes and are used to adjust the impedance matching of two different polarization directions.

10. The microwave and millimeter wave high frequency ratio common aperture antenna combined with MIMO technology as claimed in claim 1, characterized in that When the antenna works at high frequency, the millimeter wave signal is fed from the through hole Q into the substrate integrated waveguide feeding cavity surrounded by the metal column M3, and then transmitted to the coupling slot V2 through the feeding cavity. The coupling slot V2 excites the substrate integrated waveguide back cavity patch antenna cavity above, and finally the square slot V1 of the substrate integrated waveguide back cavity patch antenna and the metal patch P2 jointly radiate the millimeter wave signal outward. At this time, the current on the metal patch P1 is distributed in the cavity; When the antenna works at low frequency, the microwave signal is input from the Y-shaped feeding microstrip lines Y1 and Y2 at the bottom, and the cross-shaped gap V3 above the Y-shaped feeding microstrip lines Y1 and Y2 couples the energy to the electromagnetic dipole radiation part above. Since only low-frequency signals are transmitted, the four high-frequency MIMO antenna units and their feeding network are equivalent to three-layer stacked patches as a whole, and are regarded as four horizontal microstrip patches with a thickness equal to the sum of the thicknesses of the dielectric plates S1 and S2, working as electric dipoles of electromagnetic dipoles. The metal patch P5 connects the inner side of the above electric dipole and the metal patch P6, working as a magnetic dipole. The energy input from different Y-shaped feeding microstrip lines Y1 and Y2 will realize different polarization directions of the low-frequency part. At this time, the current on the patch is evenly distributed at the edge of the patch.

Images