CN110635232A - A dual-polarized microstrip antenna unit with wide-angle wide-band scanning capability - Google Patents

Abstract

The invention discloses a dual-polarized microstrip antenna unit suitable for wide-angle and wide-band scanning, and belongs to the technical field of antenna engineering. The antenna consists of a laminated patch layer, a dual-polarized feed layer, and a metal base plate; the laminated patch layer contains two layers of PCB boards, and uses a metal wall as a support; the feed layer contains a horizontally polarized microstrip feeder , the cross-shaped coupling slot on the ground, and the vertically polarized asymmetrical stripline feed are respectively arranged on the three-layer PCB. Through the metal wall and the metal bottom plate, the mechanical strength and stability of the antenna are increased; the air cavity supported by the metal wall increases the bandwidth of the antenna, avoids the use of low dielectric constant PCB boards, and reduces the number of PCB board layers, thereby The alignment error in the assembly process is reduced and the cost is reduced; the feeding layer avoids blind holes, which reduces processing difficulty and processing cost. The simulation and experimental results show that this antenna unit can achieve a relative bandwidth of 15% when used in a phased array, and no grating lobes and high side lobes will appear when scanning ±45 degrees within the bandwidth, the active standing wave is lower than 2.5, and the cross-polarization Below ‑20dB, the isolation is above 23dB.

Description

A dual-polarized microstrip antenna unit with wide-angle wide-band scanning capability

technical field

The invention belongs to the technical field of antenna engineering, and relates to a dual-polarized microstrip antenna unit capable of realizing wide-angle and wide-band scanning.

Background technique

Dual-polarized antennas can double the spectrum utilization rate and are widely used in communication systems. In the field of radar detection and imaging, different polarizations can also obtain different imaging information of targets; microstrip antennas have the advantages of low profile, simple structure, and low processing cost. , However, the common microstrip antenna bandwidth is only 2% to 5%, which limits its application. In the document "Wide-Bandmicrostrip antenna with an H-shaped coupling aperture", the use of stacked patches increases the bandwidth of the microstrip antenna; in the document "Dual polarized wide-band aperture stacked patch antennas", the use of cross-shaped coupling slots And the Y-shaped feeder excites the laminated patch to realize the broadband dual-polarized microstrip antenna. However, the antenna in the literature is a single antenna, the size is too large, and the scanning characteristics in the array environment are not considered, so it is not suitable as a phased array antenna unit.

On this basis, the document "A cross-stacked radiating antenna with enhancedscanning performance for digital beamforming multifunction phased-arrayradars" further designed a phased array stacked microstrip antenna unit suitable for wide-angle and broadband scanning. However, this antenna unit uses 8 layers of dielectric, and a large number of blind holes are used. Firstly, the processing and assembly errors are increased; secondly, a large number of blind holes and dielectric laminated structures increase the difficulty and cost of processing, and the antenna layer adopts RT/duroid 5880LZ material with low dielectric constant, which also increases the cost; again , the antenna lacks a metal skeleton, and the mechanical strength of the dielectric material is not enough. Finally, the paper does not give the active standing wave versus frequency curve of the antenna unit under different scan angles.

Contents of the invention

On the basis of the background technology, the present invention proposes a dual-polarized microstrip antenna unit with high mechanical strength, difficult processing and low cost, which has wide-angle and wide-band scanning capabilities.

The technical solution adopted by the present invention is: a dual-polarized microstrip antenna unit with wide-angle wide-band scanning capability, the antenna unit includes: a stacked patch layer, a dual-polarized feeding layer, metal floor;

The laminated patch layer includes: a first laminated patch, a first PCB layer, a second laminated patch, a second PCB layer, and a metal frame; the first laminated patch is arranged on the first The upper surface of the PCB layer, and the area is smaller than the upper surface of the first PCB layer; the second laminate patch is arranged on the upper surface of the second PCB layer, and the area is smaller than the upper surface of the second PCB layer; The second PCB layer is embedded in the metal frame, and the first PCB layer is supported by the metal frame, so that an air cavity layer is formed between the first PCB layer and the second PCB layer;

The dual-polarization feed layer includes: the third, fourth, and fifth PCB layers stacked sequentially from top to bottom, the upper surface of the third PCB layer is provided with a horizontally polarized feeder line, and the fourth PCB layer A cross-shaped coupling groove is arranged in the layer, and a vertically polarized feeder is arranged on the upper surface of the fifth PCB board layer;

A vertically polarized feeding probe and a horizontally polarized feeding probe are arranged on the metal base plate, and the vertically polarized feeding probe starts from the metal base plate and passes through the fifth PCB layer and the fourth PCB layer in sequence. Reaching the lower surface of the third PCB board layer, the vertically polarized feeding probe is connected to the vertically polarized feeder input end arranged on the upper surface of the fifth PCB board layer when passing through the fifth PCB board layer; the horizontally polarized feeding The probe starts from the metal base plate and passes through the fifth PCB layer, the fourth PCB layer, and the third PCB layer to reach the lower surface of the second PCB layer. When the horizontally polarized feed probe passes through the third PCB layer connected to the input end of the horizontally polarized feeder arranged on the upper surface of the third PCB layer;

A ring of metallized via holes is provided in the dual-polarized feeding layer, which is used to surround the horizontally polarized feeding line, the vertically polarized feeding line, the vertically polarized feeding probe, and the horizontally polarized feeding probe.

Further, the horizontally polarized feeder is a Y-shaped microstrip line along the y direction, and the vertically polarized feeder is a Y-shaped stripline along the x-direction.

Further, each branch end of the cross-shaped coupling groove is provided with a rectangular groove whose width is larger than that of the cross-shaped coupling groove and communicates with it; the depth of the cross-shaped coupling groove is the same as that of the rectangular groove and is equal to that of the fourth PCB layer thickness of.

Further, two through holes are provided in the metal bottom plate, which are respectively connected to the horizontally polarized feeding probe and the vertically polarized feeding probe.

Further, the shape of the second stacked patch is the same size as the shape surrounded by a circle of metallized vias set in the dual-polarization feeding layer, and the first stacked patch is located on the second stacked patch Directly above, and the area is larger than that of the second laminated patch.

Further, the horizontally polarized feeder line includes two parts: a "U" type microstrip line part and a "1" type microstrip line part, and the apex of the "1" type microstrip line part is connected to the "U" type microstrip line part. The middle point of the bottom edge of the stripline part, and the bottom point of the "1" type microstrip line part is the input point.

The invention adopts the metal wall and the metal bottom plate as the antenna skeleton, which increases the mechanical strength and stability of the antenna; the metal wall supports the air cavity, increases the bandwidth of the antenna, avoids the use of low dielectric constant PCB boards, and reduces PCB The number of board layers reduces the alignment error in the assembly process and reduces the cost; the feed layer avoids blind holes, reduces processing difficulty and reduces processing costs.

Description of drawings

Fig. 1 is a schematic diagram of the 3D structure of the present invention.

Figure 2 is the active standing wave (Active VSWR) versus frequency curve of the periodic unit simulation in the infinite array environment, where (a) and (b) are the performance of vertical and horizontal polarization respectively.

Figure 3 is a schematic diagram of a 5×5 array, and the cylinders around the unit in the figure are the screw positions during the assembly process.

Figure 4 is the curve of the horizontally polarized active standing wave of the central unit of the 5×5 array as a function of frequency, where (a), (b), and (c) are the simulation and test results of the H plane, D plane, and E plane, respectively.

Fig. 5 is a transmission coefficient curve between dual-polarized ports of the central unit of a 5×5 array.

Figure 6 is the simulated and measured gain pattern of the 5×5 array at 4.2GHz, where (a), (b), and (c) are the central unit pattern, the E-plane scanning pattern, and the H-plane scanning pattern in sequence.

Fig. 7 is a front view of Fig. 1 .

FIG. 8 is a plan view of each layer structure in FIG. 1 .

Detailed ways

The structure of the antenna unit in this embodiment is shown in Figure 1. The antenna is divided into six layers as a whole, which are five layers of PCB board layers 10, 20, 30, 40, 50 and a layer of metal base plate 62. The thicknesses are 0.5mm, 1.5mm, 0.5 mm, 0.5mm, 3mm, 3mm, the dielectric constant of the PCB board is 2.2; the 10, 20 layers and the metal frame 22 constitute the laminated patch layer, the thickness of the metal frame is 5mm, and the 30, 40, 50 layers constitute the feed layer ; The unit size is 40×40mm ² .

The laminated patches 11 and 21 are square patches with side lengths of 25.5 mm and 19 mm respectively, and the inner wall width of the metal frame is 38 mm.

Horizontally polarized Y-shaped feeder 31 main line and branch line width are 1.59mm and 0.45mm respectively, branch line spacing is 6mm, branch line terminal is 6mm from unit center; cross-shaped bone-shaped coupling groove 41 internal fine groove length and width are 8.5mm mm, 0.5mm, the length and width of the terminal rectangular slots of the y-direction slots are 5mm and 2.5mm respectively, the length and width of the terminal rectangular slots of the x-direction slots are 5mm and 2mm respectively; They are 1.59mm and 0.45mm respectively, the distance between the branch lines is 7mm, and the distance between the terminal of the branch lines and the center of the unit is 6.5mm.

The metallized via hole 43 has a diameter of 0.8 mm, a part of which surrounds the stripline feeder to form a rectangular area of 21×18 mm ² , and the adjacent spacing is 1.5 mm, and the other part surrounds the vertically polarized feeder probe 64 and the horizontally polarized feeder probe 64 . Electrical probe 65, 2mm away from the probe.

The two through-holes 66 in the metal base plate are respectively on the center line in the x and y directions, 5 mm away from the edge of the unit, and have a diameter of 2.9 mm; standard SMA connectors are used for power feeding, and the diameters of the inner cores 64 and 65 are both 1.27 mm.

It can be seen from Figure 2 that the antenna unit scans from 0 to 45 degrees in the two polarizations of E, H, and D planes, and the standing waves in 3.6-4.2 GHz are all lower than 2.5, and the bandwidth is 15%. This conclusion is verified, see Figure 4.

It can be seen from Fig. 5 that the measured dual-polarization port isolation is above 23dB.

It can be seen from Figure 6(a) that the maximum gain of the antenna unit is above 5dB, from which it can be calculated that the aperture efficiency is above 80%, the cross polarization is below -20dB, and the front-to-back ratio is above 12dB; from Figure 6(b), (c) It can be seen that the array scans from 0 to 45 degrees, the sidelobe level is below -10dB, and no grating lobe appears.

Claims (6)

1. A dual-polarized microstrip antenna unit with wide-angle wide-band scanning capability, the antenna unit comprises: a stacked patch layer, a dual-polarized feed layer, and a metal base plate that are sequentially stacked from top to bottom; The laminated patch layer includes: a first laminated patch, a first PCB layer, a second laminated patch, a second PCB layer, and a metal frame; the first laminated patch is arranged on the first The upper surface of the PCB layer, and the area is smaller than the upper surface of the first PCB layer; the second laminate patch is arranged on the upper surface of the second PCB layer, and the area is smaller than the upper surface of the second PCB layer; The second PCB layer is embedded in the metal frame, and the first PCB layer is supported by the metal frame, so that an air cavity layer is formed between the first PCB layer and the second PCB layer; The dual-polarization feed layer includes: the third, fourth, and fifth PCB layers stacked sequentially from top to bottom, the upper surface of the third PCB layer is provided with a horizontally polarized feeder line, and the fourth PCB layer A cross-shaped coupling groove is arranged in the layer, and a vertically polarized feeder is arranged on the upper surface of the fifth PCB board layer; A vertically polarized feeding probe and a horizontally polarized feeding probe are arranged on the metal base plate, and the vertically polarized feeding probe starts from the metal base plate and passes through the fifth PCB layer and the fourth PCB layer in sequence. Reaching the lower surface of the third PCB board layer, the vertically polarized feeding probe is connected to the vertically polarized feeder input end arranged on the upper surface of the fifth PCB board layer when passing through the fifth PCB board layer; the horizontally polarized feeding The probe starts from the metal base plate and passes through the fifth PCB layer, the fourth PCB layer, and the third PCB layer to reach the lower surface of the second PCB layer. When the horizontally polarized feed probe passes through the third PCB layer connected to the input end of the horizontally polarized feeder arranged on the upper surface of the third PCB layer; A ring of metallized via holes is provided in the dual-polarized feeding layer, which is used to surround the horizontally polarized feeding line, the vertically polarized feeding line, the vertically polarized feeding probe, and the horizontally polarized feeding probe. 2. A kind of dual-polarized microstrip antenna unit with wide-angle broadband scanning capability as claimed in claim 1, wherein said horizontally polarized feeder is a Y-shaped microstrip along the y direction, and the vertically polarized feeder is It is a Y-shaped strip line along the x direction. 3. A kind of dual-polarized microstrip antenna unit with wide-angle wide-band scanning capability as claimed in claim 1, characterized in that each branch end of the cross-shaped coupling groove is provided with a width greater than that of the cross-shaped coupling groove And the rectangular groove communicating with it; the depth of the cross-shaped coupling groove is the same as that of the rectangular groove, and is equal to the thickness of the fourth PCB board layer. 4. A kind of dual-polarized microstrip antenna unit with wide-angle wide-band scanning capability as claimed in claim 1, characterized in that two through holes are arranged in the metal base plate to connect horizontally polarized feeding probes respectively , Vertically polarized feed probe. 5. A kind of dual-polarized microstrip antenna unit with wide-angle wide-band scanning capability as claimed in claim 1, characterized in that the shape of the second stacked patch is the same as that of a circle set in the dual-polarized feeding layer The shapes and sizes enclosed by the metallized via holes are the same, and the first stacked patch is located directly above the second stacked patch, and has a larger area than the second stacked patch. 6. A dual-polarized microstrip antenna unit with wide-angle wide-band scanning capability as claimed in claim 2, wherein said horizontally polarized feeder line comprises two parts: a "U" type microstrip line part and a " 1" type microstrip line part, the apex of the "1" type microstrip line part is connected to the middle point of the lower bottom edge of the "U" type microstrip line part, and the bottom point of the "1" type microstrip line part is the input point .

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