CN110707421A - Dual-polarization tightly-coupled phased array antenna based on end overlapping - Google Patents

Abstract

The invention discloses a dual-polarization tightly coupled phased array antenna based on overlapping ends, comprising a plurality of periodically arranged array units, the array units comprising a square dielectric substrate (1), a dipole antenna (2), a dielectric A wide-angle matching layer (3), a feeding structure (4), and a metal floor (5); the dielectric wide-angle matching layer (3) is stacked on the upper surface of the dielectric substrate (1), and the dipole antenna (2) is tightly Affixed to the lower surface of the dielectric substrate (1), the metal floor (5) is placed under the dielectric substrate (1) in parallel, and the feeding structure (4) is placed between the dielectric substrate (1) and the metal floor (5). In between, the upper end is connected to the dipole antenna (2), and the lower end is connected to the metal floor (5); the dipole antenna (2) is a dual-polarized tightly coupled antenna with overlapping ends. The dual-polarization tightly coupled phased array antenna of the invention has good impedance matching, wide bandwidth angle, and is convenient for processing and production.

Description

Dual-polarized tightly coupled phased array antenna based on overlapping ends

technical field

The invention belongs to the technical field of broadband phased array antennas, in particular to a dual-polarization tightly coupled phased array antenna based on overlapping ends.

Background technique

Phased array antenna is a modern antenna form developed on the basis of array antenna. Using broadband antenna units, according to certain rules, they are arranged in one-dimensional, two-dimensional or other array forms to avoid possible pattern distortion and scanning blind spots, which constitute the basic structure of broadband phased array. The phased array is based on the principle that the beam shifts when the phase of the aperture field is linearly changed, and the phase of the radiation field of each element in the array antenna is changed by electronic control, and the main lobe beam is used for scanning. When the broadband characteristics and the wide-angle scanning characteristics are combined, a broadband phased array antenna is formed.

With the rapid development of electronic countermeasures and radar fields, especially the development of broadband interference and anti-jamming, high-resolution and multi-dimensional imaging, target recognition, etc., there are higher requirements for the working frequency band of array antennas. On the other hand, for electronic countermeasures and radar system platforms, the reduction of the number of antennas used can reduce the complexity of electronic equipment and the mutual coupling between each antenna, so this type of system platform has an urgent need for ultra-wideband array antennas.

Traditional ultra-wideband array antennas mostly use Vivaldi antennas as array elements. Due to the limitations of this design method, there is little room for bandwidth expansion. For example, the antenna element bandwidth will limit the array bandwidth, and the spatial scan angle will be affected by the mutual coupling between elements. In order to maintain the radiation performance of the array, traditional ultra-wideband antenna arrays often use some methods to suppress the coupling between units, such as adding metal partitions between units, or adding absorbing materials and so on. In addition to physical isolation, there is also a way to select compensation to suppress coupling, that is, multiply the signal by an inverse coupling factor before feeding to eliminate the influence of mutual coupling. However, these methods often bring certain negative effects, such as gain reduction, pattern distortion, increased design difficulty, and so on. At the same time, the traditional broadband phased array needs to be realized by dividing sub-arrays, applying optical modulation and demodulation technology, and optical fiber delay lines, which requires a large amount of equipment, complex technology, high cost, and inconvenient debugging and maintenance. In the design of phased array antenna, in addition to solving the broadband matching problem of general array antennas, it is also necessary to solve the matching problem of wide-angle scanning.

In addition to the coupling problem, the ultra-wideband antenna array has the disadvantage of being large in size. The traditional Vivaldi antenna array and the ridge-shaped gradient slotted antenna array often need a long length in order to realize the gradient of the impedance; while the traditional flat helical antenna, in order to achieve Ultra-broadband characteristics require larger radii. It can be seen that the traditional ultra-wideband antenna array is difficult to achieve the requirements of miniaturization and easy conformality due to the volume problem.

For example, in a patent (application number CN201810126029.2) published by Zhang Hui, Wang Jun and others in their patent titled "A Reconfigurable Tightly Coupled Broadband Array Antenna" (application number CN201810126029.2), they proposed a An antenna that can switch between the coupling mode and the conventional mode and can achieve full coverage of the S/C/X/Ku frequency bands. The antenna includes a dipole antenna plate, a dielectric wide-angle matching plate and a metal floor. Although it obtains three times the antenna bandwidth and achieves full coverage in the S/C/X/Ku frequency band, it does not use the feed balun structure, which is not easy to realize the conversion from unbalanced to balanced feed, and the antenna The structure is relatively complex, especially the four switch structures for realizing reconfigurable characteristic settings, which are not easy to process.

For example, in 2017, Zhang Shuai, Liu Shuang and others published a patent called "Ultra Wideband Array Antenna" (application number: CN201710483872.1), which includes a dipole antenna array plate, a resistive frequency selective surface plate, The grounding plate and the feeding balun, the antenna array plate is composed of multiple dipole radiation periodic elements, and the tight coupling between the elements is used to satisfy the reflection coefficient of less than or equal to 6dB in the frequency band of 0.63GHz to 4.6GHz. However, the bandwidth of the array antenna is not very wide, and the structure is relatively complex.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a dual-polarized tightly coupled phased array antenna based on overlapping ends, which has good impedance matching, wide bandwidth angle, and is easy to process and produce.

The technical solution that realizes the purpose of the present invention is:

A dual-polarized tightly coupled phased array antenna based on overlapping ends, comprising a plurality of periodically arranged array elements,

The array unit includes a square dielectric substrate 1, a dipole antenna 2, a dielectric wide-angle matching layer 3, a feeding structure 4, and a metal floor 5;

The dielectric wide-angle matching layer 3 is stacked on the upper surface of the dielectric substrate 1, the dipole antenna 2 is closely attached to the lower surface of the dielectric substrate 1, the metal floor 5 is placed parallel to the dielectric substrate 1, and the feeding structure 4 is placed between the dielectric substrate 1 and the metal floor 5, the upper end is connected to the dipole antenna 2, and the lower end is connected to the metal floor 5;

The dipole antenna 2 is a dual-polarized tightly coupled antenna with overlapping ends.

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

1. Good impedance matching: the present invention widens the antenna bandwidth by strengthening the coupling between the array elements, can ensure impedance matching in a wide frequency band, realize a low voltage standing wave ratio in a wide frequency band, and is easy to conform;

2. Wide bandwidth angle: The present invention adopts the Marchand balun of the microstrip structure to realize impedance conversion and field matching, realizes the wide bandwidth angle performance of the phased array antenna, and facilitates the integration of the antenna.

3. It is easy to process and produce: the present invention uses a metasurface to replace the traditional dielectric matching plate, which reduces the antenna profile; the microstrip power divider adopts a microstrip structure, which further simplifies the difficulty of processing and facilitates the overall processing of the antenna on a PCB board.

4. Small size: By reducing the mutual coupling between the antenna units, the distance between the antenna units is reduced, making the antenna units more compact and reducing the overall volume of the antenna.

In addition, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Description of drawings

FIG. 1 is a schematic diagram of a unit structure according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a dipole unit according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of a metasurface structure according to an embodiment of the present invention.

FIG. 4 is a schematic structural diagram of a feeding balun according to an embodiment of the present invention.

FIG. 5 is a schematic structural diagram of a metal floor according to an embodiment of the present invention.

FIG. 6 is a schematic structural diagram of a 2×2 array according to an embodiment of the present invention.

FIG. 7 is a diagram of a working bandwidth of an antenna unit according to an embodiment of the present invention.

FIG. 8 is a return loss diagram of an antenna unit according to an embodiment of the present invention.

FIG. 9 is a directional diagram of an antenna unit according to an embodiment of the present invention.

In the figure, the dielectric substrate 1, the dipole antenna 2, the dielectric wide-angle matching layer 3, the feeding structure 4, the metal floor 5, the metasurface 6,

first dipole unit 21, second dipole unit 22, first dipole arm 211, second dipole arm 212, third dipole arm 221, fourth dipole arm 222,

The first dielectric board 41 , the second dielectric board 42 , and the printing boards 411 and 412 .

Detailed ways

The present invention is based on a dual-polarized tightly coupled phased array antenna with overlapping ends, which includes a plurality of periodically arranged array elements.

As shown in FIG. 1 , the array unit includes a square dielectric substrate 1 , a dipole antenna 2 , a dielectric wide-angle matching layer 3 , a feeding structure 4 , and a metal floor 5 ;

The dielectric wide-angle matching layer 3 is stacked on the upper surface of the dielectric substrate 1, the dipole antenna 2 is closely attached to the lower surface of the dielectric substrate 1, the metal floor 5 is placed parallel to the dielectric substrate 1, and the feeding structure 4 is placed between the dielectric substrate 1 and the metal floor 5, the upper end is connected to the dipole antenna 2, and the lower end is connected to the metal floor 5;

The dipole antenna 2 is a dual-polarized tightly coupled antenna with overlapping ends.

as shown in picture 2,

The dipole antenna 2 includes a first dipole unit 21 and a second dipole unit 22 having the same shape,

The first dipole unit 21 is in the shape of a bow tie, and includes a first dipole arm 211 and a second dipole arm 212 that are symmetrically arranged. The first dipole arm 211 and the second dipole arm 212 Both are formed by connecting surfaces of a rectangle and a trapezoid bottom side, the trapezoid top side of the first dipole arm 211 is opposite to the trapezoid side of the second dipole arm 212, and a gap is provided between the two trapezoid top sides;

The second dipole unit 22 is in the shape of a bow tie, and includes a third dipole arm 221 and a fourth dipole arm 222 that are symmetrically arranged. The third dipole arm 221 and the fourth dipole arm 222 Both are formed by connecting surfaces of a rectangle and a trapezoidal bottom edge, the trapezoidal top edge of the third dipole arm 221 is opposite to the trapezoidal edge of the fourth dipole arm 222, and a gap is provided between the two trapezoidal top edges;

The axis of the first dipole unit 21 is parallel to one side of the square dielectric substrate 1, and the first dipole unit 21 is close to this side, and the axis of the second dipole unit 22 is parallel to the first dipole unit. The axis of 21 is vertical and is close to the other side of the square dielectric substrate 1. The rectangle of the fourth dipole arm 222 of the second dipole unit 22 is the same as that of the second dipole arm 212 of the first dipole unit 21. The rectangles are stacked vertically.

As shown in Figure 3,

The feeding structure 4 includes a first dielectric plate 41 and a second dielectric plate 42 placed vertically and intersecting with each other vertically,

The upper end of the first dielectric plate 41 is connected to the central axis of the first dipole unit 21 , and the upper end of the second dielectric plate 42 is connected to the central axis of the second dipole unit 22 .

The second dielectric plate 42 has the same shape and structure as the first dielectric plate 41;

The first dielectric board 41 is rectangular in appearance, and includes two layers of printed boards 411 and 412 and a microstrip structure feeding balun interposed between the two layers of printed boards 411 and 412 .

As shown in Figure 5,

A first rectangular slot 51 is opened at the connection between the metal floor 5 and the lower end of the first dielectric plate 41 , and the first rectangular slot 51 is located directly below the central axis of the first dipole arm 211 ;

A second rectangular slot 52 is formed at the connection between the metal floor 5 and the lower end of the second dielectric plate 42 , and the second rectangular slot 52 is located directly below the central axis of the third dipole arm 221 .

As shown in Figure 4,

The upper surface of the dielectric wide-angle matching layer 3 is coated with a metasurface 6 of a split resonator ring structure.

Preferably, the dielectric constant of the equivalent dielectric wide-angle matching layer of the metasurface 6 is 3.66 when the antenna operating frequency is 0 to 15 GHz.

The thickness of the dielectric wide-angle matching layer 3 is 6 mm, and the relative dielectric constant is 1.7.

In the embodiment, the dielectric substrate 1 is a square plate-like structure with a side length of 17.25 mm and a thickness of 0.508 mm.

The dipole antenna 2 includes dipole units 21 and 22, and the dipole unit 21 is in the shape of a bow tie, including dipole arms 211 and 212, the arm length d1=6.65mm, the arm width d2=2.75mm, A rectangular slot is set between the two antenna arms, the slot length w1=0.5mm, the width w0=0.45mm, the part where the antenna arm and the slot meet is trapezoidal, the trapezoid height L=2.75mm, the dipole unit 21 is placed horizontally on the dielectric substrate 1 The lower surface of , the line of which is parallel to the side length of the dielectric substrate 1, and is 4.2226mm away from one side of the dielectric substrate.

The dipole unit 22 is perpendicular to the dipole unit 21 , and the center line is 4.2226 mm away from one side of the dielectric substrate 1 . When forming an array antenna, the end of one arm 212 of the dipole 21 overlaps with the end of the dipole arm of the adjacent antenna unit, and the overlapping part is 2.6 mm long. The end of one arm 222 of the dipole 22 is also the same as the other The ends of the dipole arms of adjacent antenna elements overlap, and the overlapping portion of each end of the "cross" is 2mm long.

The overlapping part realizes the tight coupling of the array antenna, so the bandwidth of the antenna can be widened, the impedance matching can be ensured in a wide frequency band, and the low voltage standing wave ratio in the wide frequency band can be achieved, which is easy to conform. In addition, since the mutual coupling between the antenna units is reduced, the distance between the antenna units is reduced, so that the antenna units are more compact and the overall volume of the antenna is reduced.

The dielectric wide-angle matching layer 3 is a rectangular block structure and is placed close to the dielectric substrate 1. The dielectric wide-angle matching layer 3 has a length and width of 17.25 mm and a thickness of 6 mm. The upper layer of the dielectric wide-angle matching layer can be coated The metasurface of a layer of split resonator ring structure, the gap part of the resonator ring is 0.435mm long and the radius is 1.35mm,

Loading the metasurface can reduce the thickness of the dielectric wide-angle matching layer and realize the design of low-profile and miniaturized antennas.

The feeding structure 4 includes two dielectric plates 41 and 42, each with a thickness of 0.3048mm, a height of 16.992mm and a length of 17.25mm, and is vertically placed between the dielectric substrate 1 and the metal floor, the metal floor is parallel to the dielectric substrate, and the dielectric plate 41 and 42 are perpendicular to each other, their upper ends are respectively connected to the center lines of the dipole units 21 and 22, and their lower ends are connected to the rectangular slits 51 and 52 opened on the metal floor 5 respectively. The dielectric board 41 (or 42 ) includes two-layer printed boards 412 (or 421 ) and 412 (or 422 ), and a feeding balun is printed in the middle layer of the two-layer printed board.

The feeding balun can adopt a microstrip structure to realize impedance conversion and field matching, thereby realizing the wide bandwidth angle performance of the phased array antenna, and at the same time facilitating the integration of the antenna.

The feeding balun is composed of microstrip lines and short wires, with a width of 6mm, a height of 16.992mm, and a thickness of 0.3084mm. There are two gaps between the balun and the lower surface of the dielectric substrate, with a width of 2.25mm and a height of 0.5mm. There is a slot, width w1=0.05mm, height 1.65mm, the slot is connected to a rectangular hollow slot. The centerline of the rectangular hollow groove coincides with the centerline of the balun, with a width of 3.7mm and a height of 12.5mm. The width of the microstrip line is Wfeed=0.015mm, the bottom is connected to the metal floor, it extends upwards by 1.0825mm perpendicular to the metal floor, and then extends 2.16mm parallel to the dielectric substrate, and then connects to the tip of the short wire. The short wire gradually changes from the tip to a rectangle with a width of the rectangle. doc=0.5mm, the upper edge of the horizontal part of the rectangular short wire is 0.825mm away from the dielectric substrate 1, and the lower edge is 1.325mm from the dielectric substrate 1; The centerline of the metal floor part is 2.425mm away from the centerline of the balun.

Due to the impedance conversion of the short wire, the energy obtained by the feeding can be radiated to the space through the short wire.

There are two rectangular slits 51 and 52 on the metal floor 5, and they are located directly below the center lines of the dipole arms 211 and 221 respectively. The depth s2 of the rectangular slot 52 is 3.18065mm, the excitation units 511 and 521 are arranged in the rectangular slot, the length of the excitation unit 511 is 1.15mm, the length of the excitation unit 521 is 0.6096mm, and the outer ends of the excitation units 511 and 521 are close to the metal The length of the edge of the floor 5 is all ss=1.5702mm.

A microstrip power divider can be connected under the metal floor 5, and after forming an antenna array, the phase can be linearly graded through phase compensation to realize beam direction shift. The microstrip power divider adopts a microstrip structure, which further simplifies the difficulty of processing and facilitates the overall processing of the antenna on a PCB board.

After the excitation is set at the excitation units 511 and 521 of the metal floor 5, the current propagates along the microstrip line to the tip of the short wire, where the energy is collected, that is, the middle of the two antenna arms of the dipole units 21 and 22. At the rectangular gap, it propagates along the short wire and finally radiates out.

FIG. 6 is a schematic structural diagram of a 2×2 array according to an embodiment of the present invention.

According to the above embodiment, the electromagnetic simulation software HFSS can be used to obtain the port VSWR curves as shown in FIG. 7 and FIG. 8 . It can be seen from the curves that, on the premise that the port VSWR is less than 2.5, as shown in this embodiment The ultra-wide bandwidth angle tightly coupled antenna array can achieve wide-angle scanning performance of E-plane and H-plane up to 45° in the ultra-wideband of 2GHz to 7GHz.

Claims (8)

1. A dual-polarized close-coupled phased array antenna based on end overlapping comprises a plurality of array units which are periodically arranged, and is characterized in that:

the array unit comprises a square dielectric substrate (1), dipole antennas (2), a dielectric wide-angle matching layer (3), a feed structure (4) and a metal floor (5);

the dielectric wide-angle matching layer (3) is superposed on the upper surface of the dielectric substrate (1), the dipole antenna (2) is tightly attached to the lower surface of the dielectric substrate (1), the metal floor (5) is arranged below the dielectric substrate (1) in parallel, the feed structure (4) is arranged between the dielectric substrate (1) and the metal floor (5), the upper end of the feed structure is connected with the dipole antenna (2), and the lower end of the feed structure is connected with the metal floor (5);

the dipole antenna (2) is a dual-polarized tightly-coupled antenna with overlapped tail ends.

2. The phased array antenna of claim 1, wherein:

the dipole antenna (2) comprises a first dipole unit (21) and a second dipole unit (22) which are identical in shape,

the first dipole unit (21) is in a bow-tie shape and comprises a first dipole arm (211) and a second dipole arm (212) which are symmetrically arranged, the first dipole arm (211) and the second dipole arm (212) are formed by connecting a rectangle with the bottom edge of a trapezoid, the trapezoid top edge of the first dipole arm (211) is opposite to the trapezoid edge of the second dipole arm (212), and a gap is arranged between the two trapezoid top edges;

the second dipole unit (22) is in a bow-tie shape and comprises a third dipole arm (221) and a fourth dipole arm (222) which are symmetrically arranged, the third dipole arm (221) and the fourth dipole arm (222) are formed by connecting a rectangle with the bottom side of a trapezoid, the trapezoid top side of the third dipole arm (221) is opposite to the trapezoid side of the fourth dipole arm (222), and a gap is formed between the two trapezoid top sides;

the axis of the first dipole unit (21) is parallel to one side of the square dielectric substrate (1), the first dipole unit (21) is close to the side, the axis of the second dipole unit (22) is perpendicular to the axis of the first dipole unit (21) and close to the other side of the square dielectric substrate (1), and the rectangle of the fourth dipole arm (222) of the second dipole unit (22) is vertically superposed with the rectangle of the second dipole arm (212) of the first dipole unit (21).

3. The phased array antenna of claim 2, wherein:

the feed structure (4) comprises a first dielectric plate (41) and a second dielectric plate (42) which are vertically arranged and are mutually and vertically crossed,

the upper end of the first dielectric plate (41) is connected with the central axis of the first dipole unit (21), and the upper end of the second dielectric plate (42) is connected with the central axis of the second dipole unit (22).

4. The phased array antenna of claim 3, wherein:

the second dielectric plate (42) and the first dielectric plate (41) have the same shape and structure;

the first dielectric plate (41) is rectangular in appearance and comprises two layers of printed boards (411 and 412) and a microstrip structure feed balun arranged between the two layers of printed boards (411 and 412).

5. The phased array antenna of claim 4, wherein:

a first rectangular gap (51) is formed at the connection position of the metal floor (5) and the lower end of the first dielectric plate (41), and the first rectangular gap (51) is positioned right below the central axis of the first dipole arm (211);

and a second rectangular gap (52) is formed at the connection part of the metal floor (5) and the lower end of the second dielectric plate (42), and the second rectangular gap (52) is positioned right below the central axis of the third dipole arm (221).

6. Phased array antenna according to one of the claims 1 to 5, characterized in that:

and the upper surface of the medium wide-angle matching layer (3) is coated with a super surface (6) of an open resonator ring structure.

7. The phased array antenna of claim 6, wherein:

when the working frequency of the antenna is 0 to 15GHz, the dielectric constant of the equivalent dielectric wide-angle matching layer of the super surface (6) is 3.66.

8. The phased array antenna of claim 6, wherein:

the thickness of the medium wide-angle matching layer (3) is 6mm, and the relative dielectric constant is 1.7.

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