Ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units

Abstract

The invention discloses an ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units, the antenna array arrangement mode is a square grid form, and in order to reduce the influence of an edge truncation effect on an array, an array edge unit and a middle unit adopt two structures; the edge unit is a basic conical metal Vivaldi antenna; in the middle unit, four corners of the basic unit are cut to optimize impedance matching, and meanwhile, orthogonal metal partition plates are added to the bottom to improve the isolation degree between ports. Electromagnetic energy radiates outwards at the exponential gradual change groove formed by the adjacent units; the antenna array structure comprises a bottom plate, two kinds of radiation units and a commercial standard radio frequency connector. According to the antenna array provided by the invention, the active S parameter of each port in a designed frequency band is below-10dB, and the electrical performance requirement of broadband dual polarization is met. The antenna is integrally made of metal and is high in mechanical strength, convenient to maintain and replace and wide in bandwidth.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and in particular relates to an ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units. Background Art

[0002] The Vivaldi antenna is an exponentially tapered slot-line traveling wave antenna proposed in 1979. The Vivaldi antenna satisfies the similarity principle and the proportional transformation principle. The starting width and opening width of the slot line correspond to different resonant frequencies. A wide impedance bandwidth can be achieved by adjusting the spacing between the starting end and the opening end.

[0003] The feeding structure of the common dielectric substrate Vivaldi antenna is made of printed circuit technology, which has low mechanical strength and cannot adapt to work in some special environments. The all-metal Vivaldi antenna has good structural stability and can be directly fed by a coaxial RF connector. The structure is reliable and simple. However, the conventional thin-sheet Vivaldi antenna has a complex structure and is difficult to assemble when forming a dual-polarization array. The improved conical Vivaldi antenna combines the two sheet units that originally required an orthogonal combination into a conical unit, which greatly simplifies the overall structure of the array antenna and reduces the difficulty of assembly.

[0004] When the antenna units are arrayed, the performance of the edge units will be significantly deteriorated compared to the infinite array units due to the edge truncation effect, especially when the array size is small. Common methods for dealing with the edge truncation effect of finite array antennas include: (1) loading dummy elements on the edge of the array; (2) loading metal plates on the edge units; (3) extending the outer metal arms of the edge units and loading corrugated structures. However, these methods will increase the size of the array to a certain extent. For example, for a 5*5 array, when the array edge is a circle of dummy elements, only 36% of the units participate in radiation. This causes a great waste of resources when the array installation space is limited. Summary of the invention

[0005] The present invention aims to provide an ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units. The edge units of the array are also radiating units, which can reduce the influence of edge truncation effect while maximizing the use of available aperture size; in addition, the array has a simple structure and high mechanical strength.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units, including edge units, middle units, an antenna array base plate and a radio frequency connector; the unit spacing is 0.5λ0, λ0 is the central operating wavelength; the array middle unit and the edge unit adopt different structures, and the edge unit is a radiating unit.

[0007] Furthermore, the main part of the edge unit is obtained by cutting the conical structure and the bottom cylinder; the bottom cutting leaves a rectangular column and four curved metal columns, and a threaded hole is left in the middle of the rectangular column; there are two small through holes and a large through hole in the middle of the unit bottom plate, the small through holes are used to embed the RF connector medium and the probe, and the large through hole is used to fasten the main part to the bottom plate with screws.

[0008] Furthermore, the conical structural generatrix of the edge unit is an exponential gradient curve, with the center of the circle at the intersection of the cone and the cylinder as the origin, the horizontal axis as the x-axis, and the vertical axis as the z-axis to establish a coordinate system, and the exponential curve is written as x=C1*exp(Ra*(z))+C2; wherein C1=(x2-x1) / (exp(Ra*z2)-1), C2=(x1*exp(Ra*z2)-x2) / (exp(Ra*z2)-1), (x1,0) and (x2,z2) are the initial and end coordinate points of the exponential gradient curve; x1 takes a value of 0.25λ0, x2 takes a value between 0.01λ0 and 0.02λ0, and z2 takes a value between 1.2λ0 and 1.3λ0; Ra is the curvature change coefficient of the exponential gradient curve, and takes a value between 0.01 and 0.05.

[0009] Furthermore, the bottom cylindrical structure of the edge unit has a height of 0.16λ0 to 0.2λ0, and a radius equal to x1; four arc-surface metal columns and an intermediate rectangular column are cut out of the bottom of the cylinder, and the arc-surface metal columns and the rectangular column constitute a resonant cavity; the secant of the arc-surface metal column is 0.19λ0 away from the center of the circle, and its width is the same as that of the rectangular column; the length and width of the rectangular column are both 0.12λ0, and the height is between 0.18λ0 and 0.22λ0.

[0010] Furthermore, the intermediate unit is composed of a conical main structure, a metal partition and a unit bottom plate; the conical main structure is cut at four corners based on the overall basis of the edge unit, so that it is a cross structure when viewed from above; the thickness of each arm of the cross structure is between 0.14λ0 and 0.18λ0, and the cross-intersection part is rounded; the bottom is cut to leave four arc columns, the specifications of the arc columns are consistent with those of the edge unit, the arc columns and the metal partition form a resonant cavity, and the height of the resonant cavity is between 0.16λ0 and 0.20λ0; an orthogonal metal partition embedded groove with a width consistent with the specifications of the orthogonal metal partition and a depth of 1.5 mm is cut between the four arc columns after the bottom is cut.

[0011] Furthermore, the metal partition is composed of two metal plates combined in an "X" shape perpendicular to the XOY plane. The thickness of the metal plate is 1 to 1.5 mm and the height is 6 mm. A through hole is left after the center of the "X" is cut to fix the conical main structure, the metal partition, and the bottom plate.

[0012] Furthermore, for the edge unit and the middle unit, two adjacent arc columns are selected from the four arc columns of each antenna unit, and part of the height is cut off to form a horizontal gap between the edge unit and the metal bottom plate, and the height of the horizontal gap is between 0.016λ0 and 0.024λ0.

[0013] Furthermore, the RF connector adopts a coaxial RF connector, wherein the coaxial line dielectric part and the probe are embedded in the metal bottom plate, and the feeding probe passes through the bottom plate and contacts the bottom surface of the arc column with a horizontal gap cut therein.

[0014] Compared with the prior art, the present invention has the following significant advantages:

[0015] The present invention is entirely a metal structure with high mechanical strength, and each component does not need to be connected by welding, but the various components are connected together by screws, which is convenient for the maintenance and care of the antenna array. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units proposed in the present invention.

[0017] Figure 2 This is a structural breakdown diagram of the edge unit proposed in the present invention.

[0018] Figure 3 This is a diagram of the combination of two edge units proposed by the present invention.

[0019] Figure 4 This is an exploded view of the intermediate unit structure proposed by the present invention.

[0020] Figure 5 This is a structural diagram of the orthogonal metal isolation plate of the intermediate unit proposed by the present invention.

[0021] Figure 6 This is a structural diagram of the antenna array base plate proposed in the present invention.

[0022] Figure 7 A polarization active S-parameter graph of the array proposed for the present invention.

[0023] Figure 8 The present invention proposes the same polarization port isolation of the array center port.

[0024] Fig. 9 The present invention proposes heterogeneous polarization port isolation of the array center port.

[0025] Fig.10 The present invention proposes 6 GHz XOZ and YOZ plane radiation patterns of the array.

[0026] Fig.11 The present invention proposes 12 GHz XOZ and YOZ plane radiation patterns of the array.

[0027] Fig.12 The present invention proposes 18 GHz XOZ and YOZ plane radiation patterns of the array.

[0028] Fig.13 A graph showing the maximum gain of an array varying with frequency is provided for the present invention. DETAILED DESCRIPTION

[0029] Combination Figure 1 to Figure 6 The present invention proposes an ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units, including: two metal conical antenna units, edge and middle, a metal bottom plate, and a feeding coaxial RF connector.

[0030] The middle m*n units are arranged and installed on the metal base plate at a spacing of 0.5λ0, and the edge units surround all the middle units. The final array size is (m+2)*(n+2). m and n are the numbers of the middle units in the two directions of the array arrangement. If they are equal, it is a square array, and if they are not equal, it is a rectangular array.

[0031] The edge unit also participates in radiation instead of being a dummy unit, and while reducing the edge truncation effect, it also has good radiation performance.

[0032] The conical structures of the two antenna units are obtained by rotating the exponential gradient curve. The center of the circle where the cone and the cylinder meet is taken as the origin, the horizontal direction is the x-axis, and the vertical direction is the z-axis to establish a coordinate system. The exponential curve is written as x=C1*exp(Ra*(z))+C2. Among them, C1=(x2-x1) / (exp(Ra*z2)-1), C2=(x1*exp(Ra*z2)-x2) / (exp(Ra*z2)-1), and the points (x1,0) and (x2,z2) are the initial and end coordinates of the exponential gradient curve. The value of x1 is 0.25λ0, the value of x2 is between 0.01λ0 and 0.02λ0, and the value of z2 is between 1.2λ0 and 1.3λ0. Ra is the curvature variation coefficient of the exponential gradient curve, and its value is between 0.01 and 0.05.

[0033] The resonant cavity is cut out of the bottom cylinder of the conical body of the edge unit. After cutting, four arc-surface metal columns and a middle rectangular column are left in the cylindrical structure. A screw hole is left in the middle of the rectangular column for fixing the unit conical body to the bottom plate.

[0034] The intermediate unit includes a main body of metal cones and cylinders, an orthogonal metal partition, and a bottom plate. The main body is cut at four corners to optimize impedance matching, and the bottom cylinder is cut to leave four arc-surface metal columns. The orthogonal metal partitions and the arc-surface metal columns form four resonant cavities. A partition embedded groove is left at the top of the resonant cavity, and a threaded hole is left in the center of the groove. The threaded hole, the central through hole of the metal partition, and the countersunk hole of the bottom plate are coaxial, and each component is fastened with screws.

[0035] The array is fed by a commercial coaxial RF connector, the coaxial RF connector medium and probe part are embedded in the metal bottom plate, the probe goes deep into the bottom surface of the arc column with a horizontal gap cut out, and the flange through hole of the connector is coaxial with the screw hole of the bottom plate and fixed with screws.

[0036] The array antenna and antenna unit can be cut and processed from metal materials such as brass and alloy aluminum, and gold-plated or conductively oxidized.

[0037] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0038] Example

[0039] like Figure 1 As shown, the ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units includes: an edge unit 1, a middle unit 2, an antenna array bottom plate 3 and a radio frequency connector 4.

[0040] The design frequency band of the embodiment array is 6GHz to 18GHz, the middle frequency is 12GHz, corresponding to λ0=25mm. The middle units are arranged on the antenna bottom plate in a square grid with a spacing of 0.5λ0, λ0 is the central working wavelength, the middle unit is 3*3 in scale, and the edge units surround the middle unit, finally forming a 5*5 array.

[0041] The middle units and edge units of the array adopt different structures to reduce the impact of truncation effect on the performance degradation of small arrays; at the same time, the edge units are still radiation units rather than dummy elements that do not radiate energy.

[0042] like Figure 2 As shown, the main part 5 of the edge unit is obtained by cutting the conical structure and the bottom cylinder. The bottom cutting leaves a rectangular column 6 and four curved metal columns 7, and a threaded hole is left in the middle of the rectangular column. There are two small through holes 10 and a large through hole 9 in the middle of the unit bottom plate 8. The small through holes are used to embed the RF connector medium 12 and the probe 13, and the large through hole is used to fasten the main part to the bottom plate by screws. The RF connector adopts the SMP-J type connector.

[0043] like Figure 3As shown, it is a front view of a double edge unit, and the edge unit conical curve 14 is an exponential gradient curve. The center of the circle where the cone and the cylinder intersect is taken as the origin, the horizontal direction is the x-axis, and the vertical direction is the z-axis to establish a coordinate system. The exponential curve is x=C1*exp(Ra*(z))+C2. Among them, C1=(x2-x1) / (exp(Ra*z2)-1), C2=(x1*exp(Ra*z2)-x2) / (exp(Ra*z2)-1), and the points (x1,0) and (x2,z2) are the initial and end coordinate points of the exponential gradient curve. The value of x1 is 6mm, the value of x2 is between 0.25 and 0.5mm, and the value of z2 is between 30 and 32mm. Ra is the curvature variation coefficient of the exponential gradient curve, and its value is between 0.01 and 0.05. The height of the cylinder is 4.5mm, and the radius is equal to x1. The bottom of the main body is cut to obtain a resonant cavity 15, which has a height of 5.5 mm and a length of 3.3 to 3.4 mm. A portion of the two curved metal plates is cut to leave a horizontal gap 16, which has a gap of 0.4 to 0.6 mm. The unit spacing W between the two units is 12.5 mm.

[0044] like Figure 4 As shown, it is a structural decomposition diagram of the middle unit. The main structure 17 is improved on the edge unit. The four corners are cut off to optimize impedance matching, so that it looks like a cross when viewed from above, and the corners are rounded at the intersection. On the basis of the edge unit, the height of the cylinder is changed to 5mm and the height of the resonant cavity is changed to 4.5mm. The central rectangular column is replaced with an orthogonal metal isolation plate 20. A 1.5mm deep metal groove 21 is reserved at the bottom of the main part to facilitate the embedding of the metal isolation plate into the main body. The threaded holes at the bottom of the main body, the unit bottom plate and the RF connector are consistent with the specifications of the edge unit.

[0045] like Figure 5 As shown, it is a structural diagram of orthogonal metal isolation plates. After the intersection of the isolation plates is cut, a through hole 24 is punched in the center. The two partitions 23 are 6 mm high, 1.5 mm thick and 10 mm long.

[0046] like Figure 6 The figure shows the structure of the base plate of the ultra-wideband dual-polarization all-metal Vivaldi small array antenna. There are mounting holes at the four corners and sides of the base plate for fixing the array. The base plate and the radiation part are fixed with national standard M2 screws, and the base plate and the RF connector are fixed with two national standard M1.2 screws.

[0047] like Figure 7 As shown, the active S parameters of one polarization port of the ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units are shown. Each port is less than -10dB in the frequency band of 6GHz to 18GHz. Since the two polarization ports are symmetrical, the active S parameters of the other polarization are consistent with them.

[0048] like Figure 8 , Fig. 9 As shown in the figure, the port isolation between the array center port 11 and the same polarization and different polarization is shown in the figure. The isolation between the adjacent ports at low frequencies is basically below -10dB, and the isolation between the intermediate and high frequencies is basically below -15dB.

[0049] like Figure 10 to Figure 12 The figure shows the XOZ and YOZ radiation patterns of the array at different frequencies. It can be seen from the radiation pattern that the array has good directivity within 6 to 18 GHz.

[0050] like Fig.13 As shown, it is the maximum gain of the array in the full frequency band. It can be seen that the array gain increases with increasing frequency.

[0051] The above description is only a preferred example of the present invention and is not intended to limit the present invention. Any modifications, substitutions, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0052] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. An ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units, characterized in that: It comprises an edge unit (1), a middle unit (2), an antenna array bottom plate (3) and a radio frequency connector (4); the unit spacing is 0.5λ0, λ0 being the central working wavelength; the array middle unit (2) and the edge unit (1) adopt different structures, and the edge unit (1) is a radiation unit.

2. The ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units according to claim 1, characterized in that: The main body (5) of the edge unit (1) is obtained by cutting the conical structure and the bottom cylinder; The bottom is cut to leave a rectangular column (6) and four curved metal columns (7), with a threaded hole in the middle of the rectangular column; there are two small through holes (10) and a large through hole (9) in the middle of the unit bottom plate (8), the small through holes (10) are used to embed the radio frequency connector medium (12) and the probe (13), and the large through hole (9) is used to fasten the main body (5) and the bottom plate with screws.

3. The ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units according to claim 2, characterized in that: The conical structure generatrix of the edge unit (1) is an exponential gradient curve, with the center of the intersection of the cone and the cylinder as the origin, the horizontal axis as the x-axis, and the vertical axis as the z-axis to establish a coordinate system, and the exponential curve is written as x=C1*exp(Ra*(z))+C2; wherein C1=(x2-x1) / (exp(Ra*z2)-1), C2=(x1*exp(Ra*z2)-x2) / (exp(Ra*z2)-1), (x1,0) and (x2,z2) are the initial and end coordinate points of the exponential gradient curve; x1 takes a value of 0.25λ0, x2 takes a value between 0.01λ0 and 0.02λ0, and z2 takes a value between 1.2λ0 and 1.3λ0; Ra is the curvature variation coefficient of the exponential gradient curve, and takes a value between 0.01 and 0.

05.

4. The ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units according to claim 3, characterized in that: The bottom cylindrical structure of the edge unit (1) has a height of 0.16λ0 to 0.2λ0, and a radius equal to x1; four arc-surface metal columns (7) and an intermediate rectangular column (6) are cut from the bottom of the cylinder, and the arc-surface metal columns (7) and the rectangular column (6) form a resonant cavity; the distance between the secant of the arc-surface metal column (7) and the center of the circle is 0.19λ0, and the width is the same as that of the rectangular column; the length and width of the rectangular column are both 0.12λ0, and the height is between 0.18λ0 and 0.22λ0.

5. The ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units according to claim 4, characterized in that: The intermediate unit (2) is composed of a conical main structure (17), a metal partition (20) and a unit bottom plate; the conical main structure (17) is cut at four corners on the basis of the whole edge unit, so that it is a cross structure when viewed from above; the thickness of each arm of the cross structure is between 0.14λ0 and 0.18λ0, and the cross intersection part is rounded; The bottom is cut to leave four arc-shaped columns, the specifications of which are consistent with those of the edge units, and the arc-shaped columns and the metal partition (20) form a resonant cavity, the height of which is between 0.16λ0 and 0.20λ0; and an orthogonal metal partition embedded groove having a width consistent with the specifications of the orthogonal metal partition is cut between the four arc-shaped columns after the bottom is cut.

6. The ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units according to claim 5, characterized in that: The depth of the embedded groove of the orthogonal metal partition is 1.5mm.

7. The ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units according to claim 5, characterized in that: The metal partition (20) is composed of two metal plates combined in an "X" shape perpendicular to the XOY plane, and a through hole is left after the center of the "X" is cut to fix the conical main structure, the metal partition and the bottom plate.

8. The ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units according to claim 7, characterized in that: The thickness of the metal plate is 1 to 1.5 mm and the height is 6 mm.

9. The ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units according to claim 5, characterized in that: For the edge unit and the middle unit, two adjacent arc columns are selected from the four arc columns of each antenna unit, and part of the height is cut off to form a horizontal gap between the edge unit and the metal bottom plate, and the height of the horizontal gap is between 0.016λ0 and 0.024λ0.

10. The ultra-wideband dual-polarization all-metal array antenna based on heterogeneous conical units according to claim 1, characterized in that: The radio frequency connector (4) adopts a coaxial radio frequency connector, the coaxial line dielectric part and the probe are embedded in the metal bottom plate, and the feeding probe passes through the bottom plate and contacts the bottom surface of the arc column with a horizontal gap cut out.

Images