CN114284746B - Double-layer multi-frequency point focusing lens super-surface array - Google Patents

Abstract

The invention relates to a super-surface array of a double-layer multi-frequency point focusing lens, and belongs to the field of artificial electromagnetism. The focusing lens super-surface array comprises an I-shaped discrete unit and a double T-shaped discrete unit; each discrete unit comprises a two-layer single-layer unit structure and an air medium layer; each discrete unit comprises a first metal sheet, a first dielectric plate, a second metal sheet, an air dielectric layer, a third metal sheet, a second dielectric plate and a fourth metal sheet from top to bottom; the focusing lens super-surface array is a planar structure and is horizontally placed along the xoy coordinate. The double-layer multi-frequency point focusing lens super-surface array unit structure adopts the capacitive coupling arm structure as the metal layer, the unit coverage bandwidth is wider, and the stacking of one layer of medium can be reduced compared with the traditional super-surface lens. The transmission phase is adjusted by utilizing two different discrete medium unit structures, so that the design is more flexible and the control precision of electromagnetic waves is higher compared with the traditional phase shift unit.

Description

Double-layer multi-frequency point focusing lens super-surface array

Technical Field

The invention belongs to the field of artificial electromagnetism, and relates to a double-layer multi-frequency point focusing lens super-surface array.

Background

In the optical wave band, the lens is one of important components in the optical system, can realize the control of convergence, divergence, beam expansion, collimation and the like of light waves, and is widely applied to the fields of imaging, illumination, laser, medical treatment and the like. The application of the traditional optical lens technology in the microwave band can generate various problems of overlarge lens volume, high manufacturing cost, unfavorable system integration and the like. The super surface can change the information of the phase, amplitude, polarization and the like of electromagnetic waves, can effectively control the propagation path of reflected or transmitted electromagnetic waves, and provides a new idea for replacing the traditional lens in the microwave range. In recent years, in order to meet the demands of channel bandwidth, transmission rate, and the like, satellite communication system frequency bands have gradually shifted to Ku bands with higher frequencies. The super-surface lens can reduce the path loss influence of rain attenuation, snow attenuation and the like of the Ku wave band under the condition of not improving the transmitting power, and improves the utilization rate of signals. The subsurface unit structure may be equivalent to a resonant circuit to some extent, so that it may be possible to introduce discontinuous phases at the interface by changing the shape and size of its structure. And the reflection and transmission of electromagnetic waves can be controlled by artificially designing the phase distribution of the unit structure.

Higher transmission phase coverage is achieved by the multi-layer dielectric stack relative to conventional supersurfaces. The super-surface unit designed in the design is composed of two layers of media, so that the media layers between two layers of unit structures are reduced, the loss is reduced, and the design freedom degree is increased. Through separating the units stacked by the traditional super-surface lenses, the air spacing layer introduced by increasing the distance between the units can enable the electromagnetic waves to continuously accumulate the phase in the space transmission process, and ensure that the phase difference of the electromagnetic waves after being transmitted by the super-surface units can still meet the requirements. The phase of the transmitted electromagnetic wave is controlled by varying the size of the cell structure so that it has a different phase response. Because the transmission range of electromagnetic waves generated by a single super-surface unit cannot cover a 360-degree range, the design adopts two different discrete medium super-surface unit structures, each unit covers a different phase range, and the design requirements are met by combining the phases covered by the two units. The design designs a super-surface energy lens with good electromagnetic focusing characteristics in a Ku wave band by utilizing the phase characteristics of the unit structure, and can effectively improve the problems of the thickness and the layer number of the traditional super-surface lens.

Disclosure of Invention

Accordingly, the present invention is directed to a dual-layer multi-frequency point focusing lens super-surface array.

In order to achieve the above purpose, the present invention provides the following technical solutions:

A double-layer multi-frequency point focusing lens super-surface array comprises an I-shaped discrete unit and a double T-shaped discrete unit;

Each discrete unit comprises a two-layer single-layer unit structure and an air medium layer;

Each discrete unit comprises a first metal sheet, a first dielectric plate, a second metal sheet, an air dielectric layer, a third metal sheet, a second dielectric plate and a fourth metal sheet from top to bottom;

The focusing lens super-surface array is a planar structure and is horizontally placed along the xoy coordinate.

Optionally, the first metal sheet and the third metal sheet are respectively located on the top layer of the single-layer unit structure;

the second metal sheet and the fourth metal sheet are respectively positioned at the bottom layer of the single-layer unit structure;

the first metal sheet, the second metal sheet, the third metal sheet and the fourth metal sheet have the same shape and size and are all placed along the axial direction;

the air medium layer is arranged between the second metal sheet and the third metal sheet;

the first dielectric plate and the second dielectric plate are the same size.

Optionally, the first dielectric plate and the second dielectric plate adopt F4B, the dielectric constant is 2.65, and the tangent value of the loss angle is 0.001;

The thickness of the first dielectric plate and the second dielectric plate is 1.5mm.

Optionally, the first metal sheet, the second metal sheet, the third metal sheet and the fourth metal sheet are all made of copper metal.

Optionally, in the i-shaped discrete unit, the transmission amplitude and the phase are changed by adjusting the width w2 of the connecting line and the size h2 of the openings on two sides, the transmission amplitude is above 0.7, and the transmission phase is about-330 degrees to-150 degrees;

in the double T-shaped discrete units, the transmission amplitude and the phase are changed by changing the widths w1 and h1 of the T-shaped metal structure, the transmission amplitude is above 0.7, the transmission phase is complementary with the transmission phase of the first medium discrete unit structure, and the 360-degree phase coverage is satisfied;

The working frequency band of the double-layer multi-frequency point focusing lens super-surface array is 14 GHz-17 GHz, so that 0-360 DEG phase continuous change is realized; the focusing capability of the array on the transmitted electromagnetic waves is realized through independent change of the transmission phase.

The invention has the beneficial effects that:

(1) The double-layer multi-frequency point focusing lens super-surface array unit structure adopts the capacitive coupling arm structure as the metal layer, the unit coverage bandwidth is wider, and the stacking of one layer of medium can be reduced compared with the traditional super-surface lens. The transmission phase is adjusted by utilizing two different discrete medium unit structures, so that the design is more flexible and the control precision of electromagnetic waves is higher compared with the traditional phase shift unit.

(2) The double-layer multi-frequency point focusing lens super-surface array has the characteristic of wider-band coverage, the relative bandwidth is 19.4%, and a good focusing effect can be realized at a position 40mm away from the super-surface lens within the range of 14-17GHz of the working frequency band, and the focal diameter ratio is 0.27;

(3) The double-layer multi-frequency point focusing lens super-surface array can realize a focusing function in a Ku frequency band, and has potential application value in a Ku frequency band high-gain antenna.

(4) The double-layer multi-frequency point focusing lens super-surface array adopts the F4B material with the thickness of 1.5mm as the first dielectric plate and the second dielectric plate, has lower cost in the high-frequency plate, and has the characteristics of miniaturization and integration while keeping low loss and high performance.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and other advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the specification.

Drawings

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in the following preferred detail with reference to the accompanying drawings, in which:

FIG. 1 is a diagram of a first discrete dielectric element deformation I-shaped element structure of a double-layer multi-frequency point focusing lens super-surface array according to the invention;

FIG. 2 is an equivalent circuit diagram of a first discrete dielectric element deformation I-shaped element of a double-layer multi-frequency point focusing lens super-surface array of the invention;

FIG. 3 is a diagram of a second discrete dielectric element "T" shaped element configuration of a double layer multi-frequency point focusing lens super surface array according to the present invention;

FIG. 4 is an equivalent circuit diagram of a second discrete dielectric element "T" shaped element of the double layer multi-frequency point focusing lens super surface array of the present invention;

FIG. 5 illustrates the effect of air spacing of a dual-layer multi-frequency point focusing lens super-surface array of the present invention on the transmission performance of a first discrete dielectric element; FIG. 5 (a) is a transmission phase; FIG. 5 (b) is the transmission amplitude;

FIG. 6 is a graph showing the effect of the width w2 of the middle line and the size h2 of the openings on the two sides of the first discrete dielectric element of the super-surface array of the dual-layer multi-frequency point focusing lens on the transmission performance; FIG. 6 (a) is a transmission phase; FIG. 6 (b) is the transmission amplitude;

FIG. 7 illustrates the effect of air spacing of a dual-layer multi-frequency point focusing lens super-surface array of the present invention on the transmission performance of a second discrete dielectric element; FIG. 7 (a) is a transmission phase; FIG. 7 (b) is the transmission amplitude;

FIG. 8 is a graph showing the effect of widths w1 and h1 of a second discrete dielectric element of a double-layer multi-frequency point focusing lens supersurface array of the present invention on transmission performance; FIG. 8 (a) is a transmission phase; fig. 8 (b) is the transmission amplitude;

FIG. 9 is a graph showing the transmission phase distribution and array structure distribution of the super-surface array of the dual-layer multi-frequency point focusing lens of the present invention; FIG. 9 (a) is a transmission phase profile; FIG. 9 (b) is an array structure distribution diagram;

FIG. 10 is an electric field diagram and focal plane electric field diagram of each frequency point of a double-layer multi-frequency point focusing lens super-surface array of the present invention; FIG. 10 (a) is a view of a 14GHzyoz plane electric field; FIG. 10 (b) is a 14GHz focal plane electric field diagram; FIG. 10 (c) is a 15GHz yoz plane electric field diagram; FIG. 10 (d) is a 15GHz focal plane electric field diagram; FIG. 10 (e) is a 16GHzyoz plane electric field diagram; FIG. 10 (f) is a 16GHz focal plane electric field diagram; FIG. 10 (g) is a 17GHzyoz plane electric field diagram; FIG. 10 (h) is a 17GHz focal plane electric field diagram;

FIG. 11 is a graph showing the electric field distribution of focal plane of each frequency point obtained by actual measurement after processing the super-surface array of the double-layer multi-frequency point focusing lens according to the present invention; FIG. 11 (a) is a 14GHz electric field distribution; FIG. 11 (b) is a 15GHz electric field distribution; FIG. 11 (c) is a 16GHz electric field distribution; fig. 11 (d) shows the 17GHz electric field distribution.

Reference numerals: 1-first metal sheet, 2-first dielectric plate, 3-second metal sheet, 4-air dielectric layer, 5-third metal sheet, 6-second dielectric plate, 7-fourth metal sheet.

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be noted that the illustrations provided in the following embodiments merely illustrate the basic idea of the present invention by way of illustration, and the following embodiments and features in the embodiments may be combined with each other without conflict.

Wherein the drawings are for illustrative purposes only and are shown in schematic, non-physical, and not intended to limit the invention; for the purpose of better illustrating embodiments of the invention, certain elements of the drawings may be omitted, enlarged or reduced and do not represent the size of the actual product; it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numbers in the drawings of embodiments of the invention correspond to the same or similar components; in the description of the present invention, it should be understood that, if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc., that indicate an azimuth or a positional relationship based on the azimuth or the positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, but not for indicating or suggesting that the referred device or element must have a specific azimuth, be constructed and operated in a specific azimuth, so that the terms describing the positional relationship in the drawings are merely for exemplary illustration and should not be construed as limiting the present invention, and that the specific meaning of the above terms may be understood by those of ordinary skill in the art according to the specific circumstances.

Referring to fig. 1 and 3, the first discrete medium unit structure and the second discrete medium unit structure of the super-surface array of the double-layer multi-frequency point focusing lens respectively comprise two types of I-shaped and double-T-shaped discrete unit structures; each discrete unit comprises two single-layer unit structures and an air medium layer; each discrete unit comprises a first metal sheet 1, a first dielectric plate 2, a second metal sheet 3, an air dielectric layer 4, a third metal sheet 5, a second dielectric plate 6 and a fourth metal sheet 7 from top to bottom; the proposed lens array is a planar structure and is placed horizontally along xoy. The first metal sheet 1 and the third metal sheet 5 are respectively positioned on the top layer of the single-layer unit structure; the second metal sheet 3 and the fourth metal sheet 7 are respectively positioned at the bottom layer of the single-layer unit structure; the first metal sheet 1, the second metal sheet 3, the third metal sheet 5 and the fourth metal sheet 7 have the same shape and size and are all placed along the axial direction; the air medium layer is arranged between the second metal sheet 3 and the third metal sheet; the first dielectric plate 2 and the second dielectric plate 6 are of the same size. The first dielectric plate 2 and the second dielectric plate 6 are both made of F4B (dielectric constant is 2.65, and tangent value of loss angle is 0.001); the thickness of the first dielectric plate 2 and the second dielectric plate 4 is 1.5mm. The first metal sheet 1, the second metal sheet 3, the third metal sheet 5 and the fourth metal sheet 7 are all made of copper. Referring to fig. 1, an i-shaped structure is adopted in the first discrete medium unit, the width w2 of the middle connecting line and the size h2 of openings at two sides are changed by adjusting the parameters w2 and h2, the transmission amplitude is above 0.7, and the transmission phase is about-330 degrees to-150 degrees. Referring to fig. 2, a T-shaped structure is adopted in the second discrete medium unit, the widths w1 and h1 of the T-shaped metal structure are changed to change the transmission amplitude and the phase, the transmission amplitude is above 0.7, the transmission phase is complementary with the transmission phase of the first discrete medium unit structure, and 360-degree phase coverage is satisfied. The working frequency band of the lens array formed by the unit combination is 14 GHz-17 GHz, so that higher transmission amplitude and 360-degree phase continuous change are realized; the focusing capability of the array on the transmitted electromagnetic waves is realized through independent change of the transmission phase.

In the invention, the working frequency band of the super-surface array of the double-layer multi-frequency point focusing lens is 14 GHz-17 GHz, the central frequency point of the super-surface array is 15GHz, and the period P of the optimizing unit is 10mm of sub-wavelength; the first metal sheet 1, the second metal sheet 3, the third metal sheet 5 and the fourth metal sheet 7 have the same size, the branch width in the first discrete medium unit is 1mm, the branch width in the second discrete medium unit is 1mm, and the w3 is 1.9mm; the first dielectric plate 2 and the second dielectric plate 6 have the same height h=1.5 mm; the height of the air medium layer 4 is 2mm; in order to meet the independent and full-coverage regulation and control of the transmission phase, the parameters of the two discrete medium unit structures w2, h2, w1 and h1 are simultaneously optimized in a parameter combination mode, so that the transmission phase of the two unit structures meets 360 degrees.

FIG. 2 is an equivalent circuit diagram of the structure of the H-shaped discrete dielectric units of the super-surface array of the double-layer multi-frequency point focusing lens. For the case when the applied uniform electric field is vertically incident on the metal sheet, the structure will generate stronger coupling effect with the electric field, so the equivalent circuit will generate equivalent gap capacitance C and inductance L. Under the action of an electric field, the structure can be equivalent to an LC resonant circuit, and the working frequency can be adjusted by changing the capacitance and inductance. Namely, the transmission phase of the electromagnetic wave after passing through the super-surface unit is controlled by changing the width w2 of the middle connecting line and the size h2 of the openings at the two sides.

FIG. 4 is an equivalent circuit diagram of the structure of a T-shaped discrete dielectric unit of a super-surface array of a double-layer multi-frequency point focusing lens. The structure can be equivalent to an LC resonant circuit under the action of an electric field, and the working frequency can be adjusted by changing the capacitance and inductance. Namely, the length h1 and the width w1 of the T-shaped line are changed to control the transmission phase of the electromagnetic wave after passing through the super-surface unit.

Fig. 5 and 6 show the effect of air dielectric layer hw and structural parameters w2 and h2 on transmission performance in an i-shaped discrete dielectric unit of a super-surface array of a double-layer multi-frequency point focusing lens. FIG. 5 (a) is a transmission phase; FIG. 5 (b) is the transmission amplitude; FIG. 6 (a) is a transmission phase; fig. 6 (b) is the transmission amplitude. The "i" shaped unit is not particularly sensitive to the air gap hw. At 15GHz, when hw varies between 1-5mm, the transmission phase distribution difference is at most about 50 °, and the transmission phase distribution is not uniform. In the 14-17GHz frequency band, as the structural parameters w2 and h2 change: the transmission phase rises to about-150 degrees from-330 degrees in sequence, and the phase distribution is more uniform; the transmission amplitude is above 0.7, and the highest transmission amplitude is near 0.95.

Fig. 7 and 8 show the effect of the air dielectric layer hw and the structural parameters w1 and h1 on the transmission performance in the T-shaped discrete dielectric unit of the super-surface array of the double-layer multi-frequency point focusing lens. FIG. 7 (a) is a transmission phase; FIG. 7 (b) is the transmission amplitude; FIG. 8 (a) is a transmission phase; fig. 8 (b) is the transmission amplitude. It can be seen that the transmission phase of the T-shaped structure gradually increases along with hw, and the transmission amplitude in the frequency band also gradually decreases, especially in the 16-17GHz frequency band. When the air interval hw=2mm, the transmission amplitude of the unit is highest, and the transmission amplitude performance can be kept above 0.9 in the designed frequency band of 15-17 GHz. Along with the change of the structural parameters w1 and h1, the transmission phase of the unit is uniformly changed and approaches to linearization distribution in the frequency band of 13-15 GHz. The phase change starts to be unevenly distributed in the high-frequency part, the transmission amplitude of the corresponding frequency band is obviously deteriorated, but most of the transmission amplitude still remains above 0.7, and the design requirement is met.

FIG. 9 is a diagram of array phase distribution and structural dimensions of a dual-layer multi-frequency point focusing lens super-surface array formed by discrete dielectric elements expanding in the vertical and horizontal directions. FIG. 9 (a) is a transmission phase profile; fig. 9 (b) is an array structure distribution diagram. A17X 17 two-dimensional square lens array structure is formed by 289 units, and extends along the directions of an x axis and a y axis, and as part of transmission phases and amplitudes in discrete medium units cannot meet the requirements, metal small rod units capable of meeting the design requirements are used for replacement.

Fig. 10 is an electric field diagram and a focal plane electric field diagram of each frequency point obtained by simulating the double-layer multi-frequency point focusing lens super-surface array by simulation software, wherein the working frequency is 14-17GHz, and four frequency points are sampled. FIG. 10 (a) is a view of a 14GHz yoz plane electric field; FIG. 10 (b) is a 14GHz focal plane electric field diagram; FIG. 10 (c) is a 15GHzyoz plane electric field diagram; FIG. 10 (d) is a 15GHz focal plane electric field diagram; FIG. 10 (e) is a 16GHzyoz plane electric field diagram; FIG. 10 (f) is a 16GHz focal plane electric field diagram; FIG. 10 (g) is a 17GHzyoz plane electric field diagram; FIG. 10 (h) is a 17GHz focal plane electric field diagram; the phenomenon that the electromagnetic wave passes through the super-surface lens and then has focus aggregation at the position of 40mm of design index can be obviously seen from the electric field of yoz faces, and the designed unit can have the function of phase compensation on the incident wave. Seen from the focal plane of each frequency point, the electromagnetic wave gradually gathers towards a preset focal point after passing through the super-surface lens, and obvious focal spots can be observed at the focal point, and the energy density of the focal spots is far higher than that of other areas.

FIG. 11 is a graph showing the electric field distribution of focal plane of each frequency point obtained by actually measuring the super-surface array of the double-layer multi-frequency point focusing lens after processing. FIG. 11 (a) is a 14GHz electric field distribution; FIG. 11 (b) is a 15GHz electric field distribution; FIG. 11 (c) is a 16GHz electric field distribution; fig. 11 (d) shows the 17GHz electric field distribution. At 15GHz the focal spot appears at about 40mm from the lens at the center of the focal plane and no higher energy spots appear elsewhere on the focal plane. At other frequency points, the focal spot energy intensity is weaker than the focal spot at 15GHz in fig. 11 (b), although the focal spot is present at the focal plane center. And an abnormal rise in energy occurs at the edge of the focal plane at 17GHz, even at the edge, with a higher energy intensity than at the central focal spot. And the focal distance meets the expected design criteria of about 40mm.

Finally, it is noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present invention, which is intended to be covered by the claims of the present invention.

Claims (4)

1. The double-layer multi-frequency point focusing lens super-surface array is characterized in that: comprises an I-shaped discrete unit and a double T-shaped discrete unit;

Each discrete unit comprises a two-layer single-layer unit structure and an air medium layer;

Each discrete unit comprises a first metal sheet, a first dielectric plate, a second metal sheet, an air dielectric layer, a third metal sheet, a second dielectric plate and a fourth metal sheet from top to bottom;

the focusing lens super-surface array is of a planar structure and is horizontally placed along an xoy coordinate;

The first metal sheet and the third metal sheet are respectively positioned on the top layer of the single-layer unit structure;

the second metal sheet and the fourth metal sheet are respectively positioned at the bottom layer of the single-layer unit structure;

the first metal sheet, the second metal sheet, the third metal sheet and the fourth metal sheet have the same shape and size and are all placed along the axial direction;

the air medium layer is arranged between the second metal sheet and the third metal sheet;

the first dielectric plate and the second dielectric plate are the same size.

2. The dual-layer multi-frequency point focusing lens super-surface array of claim 1, wherein: the first dielectric plate and the second dielectric plate adopt F4B, the dielectric constant is 2.65, and the tangent value of the loss angle is 0.001;

The thickness of the first dielectric plate and the second dielectric plate is 1.5mm.

3. The dual-layer multi-frequency point focusing lens super-surface array of claim 1, wherein: the first metal sheet, the second metal sheet, the third metal sheet and the fourth metal sheet are all made of metal copper.

4. The dual-layer multi-frequency point focusing lens super-surface array of claim 1, wherein: in the I-shaped discrete unit, the transmission amplitude and the phase are changed by adjusting the width w2 of the connecting line and the size h2 of the openings on two sides, the transmission amplitude is above 0.7, and the transmission phase is about-330 degrees to-150 degrees;

in the double T-shaped discrete units, the transmission amplitude and the phase are changed by changing the widths w1 and h1 of the T-shaped metal structure, the transmission amplitude is above 0.7, the transmission phase is complementary with the transmission phase of the first medium discrete unit structure, and the 360-degree phase coverage is satisfied;

The working frequency band of the double-layer multi-frequency point focusing lens super-surface array is 14 GHz-17 GHz, so that 0-360 DEG phase continuous change is realized; the focusing capability of the array on the transmitted electromagnetic waves is realized through independent change of the transmission phase.