CN116632536A - A kind of circularly polarized antenna array and its preparation method - Google Patents

Abstract

The invention discloses a circularly polarized antenna array and a preparation method thereof. A super-surface covering structure is arranged above the circularly polarized antenna array, and an air layer with the height of 6.5mm is designed between the super-surface covering structure and the circularly polarized antenna array. The super-surface covering structure comprises an insulating medium layer I, an upper metal array and a lower metal array which are respectively fixed on two opposite sides of the insulating medium layer I. The plurality of lower metals of the upper metal array are in one-to-one correspondence with the plurality of upper metals of the lower metal array at the upper and lower positions on the first insulating medium layer. Each upper metal layer is provided with two transverse slits, two longitudinal slits and a middle slit; each lower metal layer is in an inclined cross shape. The circularly polarized antenna array designed by the invention can introduce an indirect coupling field between adjacent antennas, and perform field combination and cancellation with the original coupling field to achieve decoupling effect, thus being applicable to microstrip circularly polarized antenna arrays with very close array element spacing. The decoupled circularly polarized antenna array can reduce the coupling between antennas and improve the radiation performance of the unit.

Description

A kind of circularly polarized antenna array and its preparation method

technical field

The invention relates to the field of antenna decoupling, in particular to a circularly polarized antenna array and a preparation method thereof.

Background technique

Currently, wireless communication technology is developing towards 6G communication. Demands such as large channel capacity and high-speed transmission promote the development of Multiple-Input-Multiple-Output (MIMO) technology. In the MIMO platform, due to the miniaturization of the carrier and the large-scale integration of the number of antennas, the electromagnetic coupling between the antennas cannot be ignored and the performance of the antennas will be reduced. Reducing the mutual coupling between antennas is the key to the development of wireless communication.

On the one hand, the circularly polarized antenna can receive electromagnetic waves in any linear polarization direction. On the other hand, when the circularly polarized wave is incident on a symmetrical target (such as a spherical water droplet in the air), the reflected electromagnetic wave has the opposite direction of rotation. In actual communication, circular polarization can not only suppress rain and fog interference, but also reduce multipath interference, and is widely used in vehicle and satellite communications.

The current decoupling technology is mostly used in linearly polarized antenna arrays, and the decoupling method is not suitable for circularly polarized antenna arrays. The decoupling of circularly polarized antenna arrays is more challenging than that of linearly polarized antenna arrays. In the working frequency band, impedance matching, coupling level and circular polarization axial ratio characteristics need to be considered at the same time.

Contents of the invention

In order to improve the isolation between existing antennas and improve the radiation performance of units, the invention provides a circularly polarized antenna array and a preparation method thereof. The circularly polarized antenna array utilizes the metasurface coating to regulate the electromagnetic field to realize field cancellation, so as to improve the isolation between antennas and improve the unit radiation performance.

The present invention is achieved through the following technical solutions: a circularly polarized antenna array, a metasurface covering structure is installed above the circularly polarized antenna array, and a design is made between the metasurface covering structure and the circularly polarized antenna array It is an air layer, and the height of the air layer is 6.5mm; the supersurface covering structure includes an insulating dielectric layer one and an upper metal array and a lower metal array respectively fixed on the opposite sides of the insulating dielectric layer one, and the lower layer a metal array facing the circularly polarized antenna array;

Wherein, the upper-layer metal array includes a plurality of upper-layer metals distributed in a layer array, and each upper-layer metal is provided with two transverse slits that run through the opposite ends of the corresponding upper-layer metal in the transverse direction, and both penetrate the corresponding upper-layer metal in the longitudinal direction. Two longitudinal slits at both ends, a central slit between and parallel to the two longitudinal slits; both ends of the central slit pass through the two transverse slits but the length of the central slit is less than the length of the two longitudinal slits;

The lower layer metal array includes a plurality of lower layer metals distributed in a layer array, and the plurality of lower layer metals correspond to the positions of the plurality of upper layer metals on the first insulating medium layer one by one; each lower layer metal is in the shape of an inclined cross.

As a further improvement of the above solution, the metasurface covering structure is fixed above the circularly polarized antenna array through a plurality of nylon pillars.

As a further improvement of the above solution, the interval between two adjacent upper metal layers is 10 mm.

As a further improvement of the above scheme, each upper layer of metal is in a square shape, the width of the two transverse slits is the same, and the width of the two longitudinal slits is also the same;

The width of two transverse slits, the center distance between two transverse slits and the corresponding upper metal layer, the width of two longitudinal slits, the center distance between two longitudinal slits and the corresponding upper metal layer, the length of the middle slit, the width of the middle slit, the corresponding upper layer The side length ratio of the metal is 0.4mm: 1.6mm: 0.2mm: 2.3mm: 6.4mm: 0.4mm: 8.4mm.

Furthermore, the long axis of each underlying metal is formed by etching away two equilateral right-angled triangles whose sides are Bmm at the opposite corners of the patch in the positive direction with a side length of A mm; the short axis of each underlying metal is It is formed by etching away two equilateral right-angled triangles with a side length of Dmm from a positive direction patch with a side length of Cmm; A:B:C:D is 5.6:4.4:3.6:2.8.

As a further improvement of the above scheme, the circularly polarized antenna array includes:

The second insulating medium layer is located below the first insulating medium layer;

Two metal patches are fixed on the side of the insulating medium layer 2 facing the insulating medium layer 1;

The metal ground layer is tiled and fixed on the opposite side of the insulating medium layer 2 facing away from the insulating medium layer 1.

Further, the dielectric constants of the insulating dielectric layer 1 and the insulating dielectric layer 2 are both 4.4, both are made of FR4, and the thickness is 1.5mm. The length and width of the two insulating dielectric layers are the same as that of the circularly polarized antenna array. same length and width.

Further, the two metal patches are symmetrical about the two centers of the insulating medium layer, and coaxial feed structures are respectively provided; each metal patch is an equilateral right angle of F mm in the positive direction with a side length of E mm. Triangle, the distance between the sides of the metal patch is G mm; E:F:G is 14:4:3.

The present invention also provides a method for preparing the above-mentioned arbitrary circularly polarized antenna array, which includes the following steps:

First design the circularly polarized antenna array, design the coaxial feed structure at the antenna array layer of the circularly polarized antenna array, and punch four M3 through holes symmetrically at the four corners of the antenna array layer, and the distance between the through holes is long 55mm, width 35mm;

A plurality of upper-layer metals and a plurality of lower-layer metals are respectively engraved on opposite sides of the insulating dielectric layer 1; through holes are symmetrically drilled around the insulating dielectric layer 1, and the positions thereof are consistent with the positions of the through holes on the insulating dielectric layer 2;

Install an insulating support structure for each pair of through-hole positions, leaving an air layer with a thickness of 6.5mm.

As a further improvement of the above solution, when designing a circularly polarized antenna array, a metal patch layer and a metal ground layer are respectively printed on opposite sides of the insulating medium layer 2 to form the antenna array layer.

The present invention utilizes the metasurface covering structure to improve the isolation between circularly polarized antenna arrays, the metasurface covering structure is mainly composed of upper and lower metal layers and dielectric layers; the design between the metasurface covering structure and the antenna layer of the circularly polarized antenna array is The air layer can utilize nylon struts to fix the structure. The metasurface covering structure designed by the present invention can be applied in a microstrip circularly polarized antenna array with very close spacing between array elements, and the decoupled circularly polarized antenna array can reduce the coupling between antennas and improve the radiation performance of the units at the same time.

Therefore, the metasurface designed in the present invention can decouple the microstrip circularly polarized antenna array with small margins, and has the following advantages:

1. The introduction of a new resonance point broadens the impedance matching bandwidth, and the range of S11 below 10dB has been increased by more than 300%.

2. The coupling level is greatly reduced, and the isolation at the center frequency band is increased by more than 30dB.

3. The bandwidth of the circular polarization axis ratio is widened, and the mismatch between the axis ratio of the initial circular polarization array and the offset of the impedance matching frequency band is corrected.

4. The envelope correlation coefficient of the circularly polarized antenna array drops sharply, tends to 0 as a whole, and the radiation pattern is irrelevant.

5. The radiation efficiency of the antenna is improved after loading the metasurface.

Description of drawings

Fig. 1 is a schematic structural diagram of a microstrip circularly polarized antenna array with a metasurface covering structure provided by an example of the present invention.

FIG. 2 is a schematic diagram of the upper metal structure of the metasurface covering structure in FIG. 1 .

FIG. 3 is a schematic diagram of the underlying metal structure of the metasurface covering structure in FIG. 1 .

FIG. 4 is a schematic diagram of the metal patch layer structure of the circularly polarized antenna array in FIG. 1 .

Fig. 5 is a parameter comparison diagram of the circularly polarized antenna array in Fig. 1, wherein Fig. 5a and Fig. 5b are schematic diagrams of simulated S parameters of the unloaded and loaded metasurfaces of the microstrip circularly polarized antenna array provided by the example of the present invention, respectively.

Fig. 6 is a schematic diagram of the simulated axial ratio before and after the microstrip circularly polarized antenna array is loaded with the metasurface covering structure provided by the example of the present invention.

Fig. 7 is a schematic diagram of the envelope correlation coefficient before and after the microstrip circularly polarized antenna array is loaded with the metasurface covering structure provided by the example of the present invention.

Fig. 8 is a schematic diagram of the radiation efficiency of the microstrip circularly polarized antenna array before and after loading the metasurface covering structure provided by the example of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

It should be noted that when a component is said to be "mounted on" another component, it can be directly on the other component or there can also be an intervening component. When a component is said to be "set on" another component, it may be set directly on the other component or there may be an intervening component at the same time. When a component is said to be "fixed" to another component, it may be directly fixed to the other component or there may be an intervening component at the same time.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

The microstrip circularly polarized antenna array of the present invention has a metasurface covering structure as shown in Figure 1, and a metasurface covering structure is installed above the circularly polarized antenna array, that is to say, the metasurface coating is placed on the microstrip Above the circularly polarized antenna array. An air layer is designed between the metasurface covering structure and the circularly polarized antenna array, and the height of the air layer is 6.5mm. The basic principle of the invention is to introduce an indirect coupling field between adjacent antennas, and perform field merge and cancellation with the original coupling field to achieve decoupling. The metasurface covering structure can be fixed above the circularly polarized antenna array through a plurality of supporting structures 7 such as nylon pillars.

The metasurface covering structure includes an insulating dielectric layer 2 and an upper metal array and a lower metal array respectively fixed on opposite sides of the insulating dielectric layer 2, and the lower metal array faces the circularly polarized antenna array. The elements of the upper metal array and the lower metal array are not only corresponding in number, but also corresponding in position on the upper and lower opposite sides of the insulating medium layer-2.

Please refer to FIG. 2 , the upper metal array includes a plurality of upper metals 1 distributed in a layered array, and the interval between two adjacent upper metals 1 is 10mm. In this embodiment, the plurality of upper metal layers 1 are 15 basic units arranged periodically in 3 rows and 5 columns, and the unit period interval is 10 mm.

Each upper layer of metal 1 is provided with two transverse slits 11 , two longitudinal slits 12 and one middle slit 13 . Two transverse slits 11 run through the opposite ends of the corresponding upper layer metal 1 in the transverse direction, two longitudinal slits 12 run through the opposite ends of the corresponding upper layer metal 1 in the longitudinal direction, and the middle slit 13 is between the two longitudinal slits 12 and connected to the two longitudinal slits 12. The longitudinal slits 12 are parallel, the two ends of the middle slit 13 pass through the two transverse slits 11 but the length of the middle slit 13 is shorter than the length of the two longitudinal slits 12 . Each upper layer of metal 1 is in the shape of a square, the width of the two transverse slits 11 is the same, and the width of the two longitudinal slits 12 is also the same. The width of the two transverse slits 11, the center distance between the two transverse slits 11 and the corresponding upper metal 1, the width of the two longitudinal slits 12, the center distance between the two longitudinal slits 12 and the corresponding upper metal 1, the length of the middle slit 13, The ratio of the width of the middle gap 13 to the side length of the corresponding upper layer metal 1 is 0.4mm: 1.6mm: 0.2mm: 2.3mm: 6.4mm: 0.4mm: 8.4mm.

In this embodiment, the upper metal layer 1 is a square patch with a side length of 8.4mm and etched horizontal and vertical slits. The two transverse slits 11 are the same, with a width of 0.4 mm and a distance of 1.6 mm from the center. The left and right longitudinal slits 12 are the same, with a width of 0.2 mm and a distance of 2.3 mm from the center. The middle longitudinal slit, namely the middle slit 13, has a length of 6.4 mm and a width of 0.4 mm.

The lower layer metal array includes a plurality of lower layer metals 3 distributed in a layer array, and the plurality of lower layer metals 3 correspond to the positions of the plurality of upper layer metals 1 on the first insulating medium layer 2 one by one. That is to say, in this embodiment, the multiple underlying metals 3 are 15 basic units arranged periodically in 3 rows and 5 columns, and the unit period interval is also 10mm.

Please refer to FIG. 3 , each lower layer metal 3 is in the shape of an inclined cross. The major axis of each underlying metal 3 is formed by etching away two equilateral right-angled triangles whose sides are Bmm in the opposite corner with a positive patch with a side length of A mm; the minor axis of each underlying metal 3 is formed by The patch in the positive direction with a side length of Cmm is formed by etching away two equilateral right-angled triangles with a side length of Dmm at the diagonal; A:B:C:D is 5.6:4.4:3.6:2.8.

In this embodiment, the long axis of each underlying metal 3 is formed by etching away two equilateral right-angled triangles with a side length of 4.4 mm from a positive patch with a side length of 5.6 mm. The minor axis of each underlying metal 3 is formed by etching away two equilateral right-angled triangles with a side length of 2.8 mm from a positive patch with a side length of 3.6 mm.

The dielectric constant of the metasurface dielectric layer, that is, the insulating dielectric layer-2, is 4.4, the thickness is 1.5 mm, the length is 60 mm, and the width is 40 mm, and it is made of FR4.

Please refer to FIG. 4 , the circularly polarized antenna array includes an insulating dielectric layer 2 5 , two metal patches 4 , and a metal ground layer 6 . The insulating medium layer 2 5 is located below the insulating medium layer 1 2; two metal patches 4 are fixed on the side of the insulating medium layer 2 5 facing the insulating medium layer 1 2; the metal ground layer 6 is tiled and fixed on the insulating medium layer 2 5 On the other side opposite to the insulating dielectric layer one 2 . The insulating dielectric layer 2 5 has a dielectric constant of 4.4, a thickness of 1.5 mm, a length of 60 mm, and a width of 40 mm, and is made of FR4.

The two metal patches 4 are symmetrical about the center of the insulating medium layer 25, and coaxial feed structures are respectively provided; each metal patch 4 is an equilateral right angle of F mm in the positive direction with a side length of E mm. Triangle, the distance between the sides of the metal patch is G mm; E:F:G is 14:4:3.

In this embodiment, the metal patch of the microstrip circularly polarized array includes two metal patches, the designed patch positions are symmetrical with respect to the center of the substrate, and coaxial feeding structures are provided respectively. The metal patch is an equilateral right-angled triangle with a side length of 14mm and a 4mm diagonal etching in the positive direction (compared with the metal patch before decoupling, which is 2.8mm in the positive direction with a side length of 13.4mm) equilateral right triangle). The distance between the edges of the metal patch is 3mm.

Through holes of M3 are respectively designed at the four corners of the metasurface cladding layer and the antenna array layer (that is, the four corners of the first insulating dielectric layer 2 and the second insulating dielectric layer 5), corresponding up and down. The support structure is designed as nylon struts. Install nylon struts at the through-hole locations to separate the metasurface cladding and antenna array layers.

When the circularly polarized antenna array of the present invention is prepared, its preparation method includes the following steps.

First design the circularly polarized antenna array, design the coaxial feed structure at the antenna array layer of the circularly polarized antenna array, and punch four M3 through holes symmetrically at the four corners of the antenna array layer, and the distance between the through holes is long 55mm, 35mm wide. Wherein, when designing a circularly polarized antenna array, the metal patch layer 4 and the metal ground layer 6 are respectively printed on opposite sides of the insulating medium layer 2 5 to form the antenna array layer.

Secondly, a plurality of upper-layer metals 1 and a plurality of lower-layer metals 3 are respectively imprinted on opposite sides of the insulating dielectric layer one 2 .

Then, through holes are symmetrically drilled around the first insulating medium layer 2 , and the positions thereof are consistent with the positions of the through holes on the second insulating medium layer 5 .

Finally, install an insulating support structure 7 for each pair of through-hole positions, leaving an air layer 8 with a thickness of 6.5 mm.

In this embodiment, the specific preparation method of the circularly polarized antenna array may be specifically introduced as follows. First, the antenna array layer is designed, and the metal patch layer 4 and the metal ground layer 6 are engraved on the top and bottom of the antenna dielectric layer 5 with a thickness of 1.5mm, a length of 60mm, and a width of 40mm to form the antenna array layer. The antenna dielectric layer 5 adopts FR4 with a dielectric constant of 4.4. Design a coaxial feed structure on the antenna array layer, and drill four M3 through holes symmetrically at the four corners. The distance between the through holes is 55mm long and 35mm wide. The super-surface coating is to engrave the upper metal layer 1 and the lower metal layer 2 on the upper and lower sides of the meta-surface dielectric layer 2 with a thickness of 1.5 mm, a length of 60 mm, and a width of 40 mm. The metasurface dielectric layer 2 adopts FR4 with a dielectric constant of 4.4. Holes are symmetrically punched around the metasurface covering layer, and the positions thereof are consistent with the positions of the through holes of the antenna array layer. Finally, the nylon column support structure 7 is installed at the position of the through hole, leaving the air layer 8 . The thickness of the air layer is 6.5mm.

The basic principle of the invention is to introduce an indirect coupling field between adjacent antennas, and perform field merge and cancellation with the original coupling field to achieve decoupling. It can be seen from the comparison of S parameters in Fig. 5a and Fig. 5b that the decoupling method of the present invention can not only broaden the impedance matching frequency, but also reduce the coupling value, and the isolation at the central frequency band is increased by more than 30dB. The comparison of axial ratio parameters in Figure 6 shows that the design method can widen the axial ratio bandwidth of circular polarization. In addition to the improvement of port performance isolation, metasurface cladding can improve antenna radiation performance. As shown in Fig. 7, after loading the metasurface, the envelope correlation coefficient of the circularly polarized antenna array tends to 0, and the radiation pattern is not correlated. As shown in Figure 8, the radiation efficiency of the antenna is improved after loading the metasurface.

The invention can realize a better decoupling effect for the microstrip circularly polarized antenna array with a relatively close side distance. In summary, the present invention places a metasurface coating just above a microstrip circularly polarized antenna array. The metasurface covering layer consists of upper and lower metal layers and dielectric layers; the introduced microstrip circularly polarized antenna includes a diagonally etched triangular metal patch layer, an antenna dielectric layer and a metal formation layer. An air layer is designed between the metasurface covering layer and the antenna layer, and nylon pillars are used to fix the structure.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. a circularly polarized antenna array is characterized in that a metasurface covering structure is installed above the circularly polarized antenna array, and an air layer is designed between the supersurface covering structure and the circularly polarized antenna array , the height of the air layer is 6.5mm; the metasurface covering structure includes an insulating dielectric layer one (2) and an upper metal array and a lower metal array respectively fixed on opposite sides of the insulating dielectric layer one (2), and The lower metal array faces the circularly polarized antenna array; Wherein, the upper-layer metal array includes a plurality of upper-layer metals (1) distributed in a layer array, and each upper-layer metal (1) is provided with two transverse slits ( 11), two longitudinal slits (12) that run through the opposite ends of the corresponding upper layer metal (1) in the longitudinal direction, a middle slit (13) between the two longitudinal slits (12) and parallel to the two longitudinal slits (12) ); the two ends of the middle slit (13) all pass through two transverse slits (11) but the length of the middle slit (13) is less than the length of the two longitudinal slits (12); The lower-layer metal array includes a plurality of lower-layer metals (3) distributed in a layer array, and the plurality of lower-layer metals (3) and the plurality of upper-layer metals (1) are located on the insulating medium layer (2) and next to each other. Corresponding; each lower layer metal (3) is in the shape of an inclined cross. 2. The circularly polarized antenna array according to claim 1, wherein the metasurface covering structure is fixed above the circularly polarized antenna array by a plurality of nylon pillars. 3. The circularly polarized antenna array according to claim 1, characterized in that the interval between two adjacent upper layer metals (1) is 10 mm. 4. circularly polarized antenna array as claimed in claim 1, is characterized in that, each upper layer metal (1) is square, and the width of two transverse slits (11) is identical, and the width of two longitudinal slits (12) is also same; The width of the two transverse slits (11), the center distance between the two transverse slits (11) and the corresponding upper metal (1), the width of the two longitudinal slits (12), the distance between the two longitudinal slits (12) and the corresponding upper metal ( 1) The distance between centers, the length of the middle gap (13), the width of the middle gap (13), and the side length ratio of the corresponding upper layer metal (1) are 0.4mm: 1.6mm: 0.2mm: 2.3mm: 6.4mm: 0.4mm : 8.4mm. 5. circularly polarized antenna array as claimed in claim 4, is characterized in that, the long axis of each lower layer metal (3) is by the positive direction patch that side length is A mm, etches away two side lengths of diagonal The remaining equilateral right-angled triangles of Bmm are formed; the short axis of each lower layer metal (3) is a patch in the positive direction with side lengths of Cmm, and the remaining equilateral right-angled triangles with side lengths of Dmm at the opposite corners are etched away. into; A:B:C:D is 5.6:4.4:3.6:2.8. 6. circularly polarized antenna array as claimed in claim 1, is characterized in that, described circularly polarized antenna array comprises: Insulation medium layer two (5), which is located below the insulation medium layer one (2); Two metal patches (4) are fixed on the side of the insulating medium layer two (5) facing the insulating medium layer one (2); The metal ground layer (6) is tiled and fixed on the opposite side of the insulating medium layer two (5) facing away from the insulating medium layer one (2). 7. circularly polarized antenna array as claimed in claim 6, is characterized in that, the dielectric constant of insulating dielectric layer one (2), insulating dielectric layer two (5) is 4.4, all adopts FR4 to make, and thickness is uniform. The length and width of the two insulating medium layers are the same as those of the circularly polarized antenna array. 8. circularly polarized antenna array as claimed in claim 6, is characterized in that, two metal stickers (4) are symmetrical about insulating medium layer two (5) centers, coaxial feed structure is set respectively; Each metal sticker Sheet (4) is an equilateral right-angled triangle with F mm diagonally etched in the positive direction with a side length of E mm, and the distance between the sides of the metal patch is G mm; E: F: G is 14:4 : 3. 9. A preparation method of the circularly polarized antenna array according to any one of claims 1 to 8, characterized in that it comprises the following steps: First design the circularly polarized antenna array, design the coaxial feed structure at the antenna array layer of the circularly polarized antenna array, and punch four M3 through holes symmetrically at the four corners of the antenna array layer, and the distance between the through holes is long 55mm, width 35mm; Respectively imprint a plurality of upper layer metals (1) and a plurality of lower layer metals (3) on opposite sides of the insulating medium layer one (2); Symmetrical through-holes are drilled around the insulating medium layer one (2), and its position is consistent with the through-hole position on the insulating medium layer two (5); Install an insulating support structure (7) for each pair of through-hole positions, leaving an air layer (8) with a thickness of 6.5 mm. 10. the preparation method of circularly polarized antenna array as claimed in claim 9 is characterized in that, when designing circularly polarized antenna array, engrave metal patch layer respectively on the opposite two sides of insulating medium layer two (5) (4) and the metal formation (6), constituting the antenna array layer.