CN219371392U - Reflective phase gradient super surface capable of improving antenna gain - Google Patents

Abstract

The utility model discloses a reflective phase gradient super surface capable of improving antenna gain, which is formed by gradually arranging super surface units with different phases from the center to the periphery according to different phases, wherein the super surface units comprise a super surface layer and a dielectric substrate, the super surface layer is printed on the dielectric substrate and comprises a first spiral line, a second spiral line, a first stub line, a second stub line, a third stub line and a fourth stub line, the central area of the first spiral line and the second spiral line is rectangular, the initial positions of the first spiral line and the second spiral line are respectively positioned at the left upper part and the right lower part of the rectangle, the spiral lines are respectively wound for 2.5 turns along the clockwise direction and are alternately nested with each other, the first spiral line and the second spiral line are connected through the first stub line and the second stub line at the upper horizontal gap and the lower horizontal gap around the second layer of the two spiral lines, and a closed loop is formed by connecting the third stub line and the fourth stub line at the tail end of the spiral lines. The utility model can be used for the phase gradient super surface with compact structure, simple process and low cost in lower frequency band.

Description

Reflective phase gradient super surface capable of improving antenna gain

Technical Field

The utility model relates to the technical field of electromagnetic metamaterials, in particular to a reflective phase gradient subsurface capable of improving antenna gain.

Background

With the development and progress of scientific technology, the communication system is developed, the performance of the antenna has a great influence on the whole communication system, and in the application fields of the antenna such as satellite communication, microwave remote transmission, deep space exploration and the like, the antenna is often required to have higher gain for realizing remote wireless communication. The traditional gain improvement method comprises an array antenna, a large-caliber reflecting surface antenna and the like. The array antenna can realize higher gain, but the feed network is complex, and the decoupling problem between units is complex; the reflector antenna is large in size and has certain limitations in application in miniaturized and portable devices. Therefore, how to achieve high gain while keeping small and easy to process is a problem to be solved.

The super surface is a periodic structure formed by a quasi-two-dimensional plane sub-wavelength artificial material structure, and can flexibly regulate and control the amplitude, the phase, the polarization mode and the like of electromagnetic waves, so that the super surface has wide application fields. According to the generalized Snell's law of reflection, the phase gradient subsurface may reflect a normally incident spherical wave as a plane wave to achieve focusing. The change of the cell phase can be realized by loading active devices, selecting cells or changing the size of a cell part, and further, the cells with different phases are arranged according to the phase difference to obtain the phase gradient super surface.

Most of currently reported phase gradient super-surfaces work in the X-band and the Ku-band with higher frequency, often adopt a multilayer structure, and the process complexity is further increased due to the fact that active devices are loaded. In view of this, it is necessary to design a phase gradient super surface which can be used for a low frequency band with a compact structure, a simple process and a low cost, so as to meet the requirement of a high gain antenna in the low frequency band.

Disclosure of Invention

In order to solve the defects and shortcomings of the prior art, the reflection type phase gradient super-surface capable of improving the antenna gain is provided, and the reflection type phase gradient super-surface can be used for a phase gradient super-surface with a compact structure, a simple process and a low cost in a lower frequency band.

The utility model provides a reflective phase gradient super surface capable of improving antenna gain, which is a super surface array, and is formed by arranging super surface units with different phases from the center to the periphery in a gradual change way according to different phases, wherein the super surface units comprise a super surface layer and a dielectric substrate, the super surface layer is printed on the dielectric substrate and comprises a first spiral line, a second spiral line, a first stub, a second stub, a third stub and a fourth stub, the central areas of the first spiral line and the second spiral line are rectangular, the initial positions of the first spiral line and the second spiral line are respectively positioned at the upper left part and the lower right part of the rectangle, the spiral lines are respectively wound by 2.5 turns along the clockwise direction and are alternately nested, the first spiral line and the second spiral line are connected through the first stub and the second stub at the upper horizontal gap and the lower horizontal gap surrounded by the second layer of the two spiral lines, and a closed loop is formed by connecting the third stub and the fourth stub at the tail part of the spiral lines.

As a further improvement of the scheme, the first spiral line and the second spiral line are rectangular in wound shape, and the length and the width of the spiral lines are equal; the first stub and the second stub are equal in size; the third stub and the fourth stub are equal in size.

As a further improvement of the scheme, the width L1 of the first spiral line and the second spiral line is a key parameter influencing the reflecting phase of the super surface, and the phase of the super surface unit can be regulated and controlled by regulating the width L1 of the first spiral line and the second spiral line; the values of L1 are set to be 0.5mm, 0.7mm, 1mm and 1.2mm, so that four reflection-type phase gradient super-surfaces with different phases can be obtained, and the areas of the spiral lines surrounding the formed middle rectangular areas are different.

As a further improvement of the scheme, the super-surface units sequentially take values of 0.5mm, 0.7mm, 1mm and 1.2mm from the center to the outside according to the phase difference, and 5 layers are arranged in a parabolic shape to form the 9 multiplied by 9 super-surface array.

As a further improvement of the scheme, the dielectric substrate material is an FR4 dielectric substrate, the dielectric constant is 4.4, the loss tangent is 0.02, and the dimensions are 150mm multiplied by 1mm; the distance L2 between the first spiral line and the second spiral line is 0.4mm; the length L3 of the first stub and the second stub is 1mm; the length L4 of the third stub and the fourth stub is 0.4mm; the side length p of the reflective phase gradient super-surface is 14mm.

The beneficial effects of the utility model are as follows:

compared with the prior art, the reflection type phase gradient super-surface capable of improving the antenna gain can regulate and control the change of reflection phases by changing the widths of the first spiral line and the second spiral line, and super-surface units with different phases are arranged according to paraboloids to obtain the reflection type phase gradient super-surface, namely a super-surface array, and the array can reflect a spherical wave which is vertically incident into an approximate plane wave. The antenna is placed at the focal point of the super-surface array, spherical waves radiated by the antenna become near-plane waves after being reflected by the super-surface units, and the gain of the antenna is greatly improved.

The metal super surface layer on the reflective phase gradient super surface is only distributed on the upper surface of the dielectric substrate, the process is simple, the cost is low, the focusing of incident electromagnetic waves can be realized in the frequency band of 4.6GHz-5.8GHz, the microstrip patch antenna working at 5.4GHz is placed at the focus of the super surface array, and the gain can be averagely improved by more than 6dB.

Drawings

The utility model is described in further detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a top view of a subsurface unit provided by the present utility model;

FIG. 2 is a top view of a 9X 9 subsurface array provided by the present utility model;

FIG. 3 is a graph showing the variation of reflection phase with frequency for a reflective phase gradient subsurface of different widths L1;

FIG. 4 is a graph showing the electric field distribution in the x-Z and y-Z planes of a planar electromagnetic wave according to the present utility model after incidence along the Z-axis direction: wherein, (a) is an x-z plane electric field profile and (b) is an electric field profile in the y-z plane;

FIG. 5 is a top view of a reflector antenna formed by placing a microstrip patch antenna at the focal point of a super-surface array provided by the present utility model;

fig. 6 is a schematic diagram of a spherical wave radiated by a feed source and converted into a plane wave after being reflected by a super-surface array: the left side is spherical wave radiated by the feed source, and the right side is plane wave reflected by the super-surface array;

FIG. 7 is a schematic diagram of return loss of a microstrip patch antenna provided by the present utility model disposed at the focal point of a super-surface array;

fig. 8 is a graph showing gain versus frequency variation of the microstrip patch antenna provided by the utility model before and after being placed at the focal point of the super-surface array.

Detailed Description

Referring to fig. 1, the reflective phase gradient super-surface provided by the utility model is a super-surface array 9, and is formed by gradually arranging super-surface units with different phases from the center to the periphery according to different phases, and a microstrip patch antenna is placed at the focus of the super-surface array 9 to form a reflective surface antenna, so that the gain can be improved in a wide frequency band. The super-surface unit comprises a dielectric substrate 2 and a super-surface layer 1; the super-surface layer 1 comprises a first spiral 3, a second spiral 4, a first stub 5, a second stub 6, a third stub 7 and a fourth stub 8; two spiral lines in the super-surface layer 1 are mutually nested and encircle 2.5 turns clockwise, a rectangle is formed by encircling the central area of the super-surface layer, and the two spiral lines respectively encircle from the upper left part and the lower right part of the rectangle; at the second turn of the horizontal line, connected by stubs 5 and 6, and at the ending, connected by stubs 7 and 8; the shape, the length and the width of the first spiral line 3 and the second spiral line 4 of the two spiral lines are equal; the first stub 5 and the second stub 6 are identical in shape, and the length L3 is 1mm; the distance L2 between the two spiral lines is 0.4mm; the third stub 7 and the fourth stub 8 are identical in shape, and the length L4 is 0.4mm; the side length p of the unit is 14mm.

Referring to fig. 2, by changing the reflection phases of the width L1 adjusting and controlling units of the two spiral lines, the values of L1 are respectively 0.5mm, 0.7mm, 1mm and 1.2mm, four kinds of super-surface units with different phases are obtained, 5 layers are arranged in a parabolic shape from the center to the outside according to the phase difference to form a 9 x 9 super-surface array 9, and the values of the units in the array are gradually changed from the center to the edge according to the following values: 0.5mm, 0.7mm, 1mm, 1.2mm; the formed super-surface array is centrosymmetric.

Referring to FIG. 3, when the reflective phase gradient super surface takes 0.5mm, 0.7mm, 1mm and 1.2mm respectively from the spiral line width L1, the reflective phase forms a phase gradient along with the increase of L1 within the frequency of 4.6-5.8 GHz.

FIG. 4 shows that a planar electromagnetic wave perpendicularly enters a super-surface array along the z-axis direction to obtain simulated electric field distribution diagrams on the x-z and y-z surfaces, and it can be seen that the super-surface array can realize a focusing function on perpendicularly incident electromagnetic waves, and the focal point is about 10 mm.

Fig. 5 is a schematic diagram of placing a microstrip patch antenna 10 with a center frequency of 5.4GHz and a working frequency band of 4.5-6GHz as a feed source at a focal point of a super-surface array, wherein the distance between the feed source and the super-surface array is 10mm, and air is filled between the feed source and the super-surface array to form a reflecting surface antenna.

Fig. 6 is a graph of radiated electric field contrast for a microstrip patch antenna placed before and after the focal point of the super surface. When the antenna is not placed at the focal point of the super-surface, the antenna radiates as spherical waves, and after the antenna is placed at the focal point of the super-surface, the antenna radiates to form approximate plane waves after being reflected by the super-surface.

FIG. 7 is a diagram of the |S of the reflector antenna of FIG. 5 ₁₁ The I parameter simulation curve shows that the impedance band of-10 dB of the antenna is 4.6-5.8GHz, the center frequency is 5.48GHz, the relative bandwidth is 21.9%, and the antenna can still normally work in the WLAN frequency band after loading the super-surface array and still maintain the broadband performance.

Fig. 8 is a graph of gain contrast between the above microstrip antenna and the front and back of the focal point of the super-surface array, and it can be seen that, after loading the super-surface array, the antenna gain reaches the maximum of 9dB at 5.52GHz, which is improved by 7dB compared with the case of not loading the super-surface array, the gain is always greater than 6dB between 4.6GHz and 5.8GHz, and the gain of the reflector antenna is improved by about 6dB in average in the above frequency range compared with the case of not loading the super-surface structure.

The above embodiments are not limited to the technical solution of the embodiments, and the embodiments may be combined with each other to form a new embodiment. The above embodiments are only for illustrating the technical solution of the present utility model and not for limiting the same, and any modifications or equivalent substitutions without departing from the spirit and scope of the present utility model should be covered in the scope of the technical solution of the present utility model.

Claims (5)

1. A reflection type phase gradient super surface capable of improving antenna gain is characterized in that: the reflective phase gradient super surface is a super surface array (9), the super surface units with different phases are formed by gradually arranging the super surface units from the center to the periphery according to the different phases, the super surface units comprise a super surface layer (1) and a medium substrate (2), the super surface layer (1) is printed on the medium substrate (2), the super surface layer (1) comprises a first spiral line (3), a second spiral line (4), a first stub (5), a second stub (6), a third stub (7) and a fourth stub (8), the central areas of the first spiral line (3) and the second spiral line (4) are rectangular, the initial positions of the first spiral line (3) and the second spiral line (4) are respectively located at the upper left part and the lower right part of the rectangle, the spiral lines are respectively wound by 2.5 turns in a clockwise direction and are alternately nested with each other, the first spiral line (3) and the second spiral line (4) are connected with the second stub (7) at the upper horizontal gap and the lower horizontal gap around the second spiral line, and the second stub (6) are connected with the third stub (7) by the first stub (5) and the second stub (6), and the fourth stub (8) are formed to be connected in a closed mode.

2. A reflective phase gradient subsurface for increasing antenna gain as recited in claim 1, wherein: the first spiral line (3) and the second spiral line (4) are rectangular in shape, and the length and the width of the spiral lines are equal; the first stub (5) and the second stub (6) are equal in size; the third stub (7) and the fourth stub (8) are of equal size.

3. A reflective phase gradient subsurface for increasing antenna gain as claimed in claim 2, wherein: the values of the width L1 of the first spiral line (3) and the second spiral line (4) are set to be 0.5mm, 0.7mm, 1mm and 1.2mm.

4. A reflective phase gradient subsurface for increasing antenna gain as recited in claim 1, wherein: the super-surface units are sequentially 0.5mm, 0.7mm, 1mm and 1.2mm in value from the center to the outside according to the phase difference, and 5 layers are arranged in a parabolic shape to form the 9 multiplied by 9 super-surface array (9).

5. A reflective phase gradient subsurface for increasing antenna gain as claimed in claim 2, wherein: the dielectric substrate (2) is made of FR4 dielectric substrate, has a dielectric constant of 4.4, a loss tangent of 0.02 and a size of 150mm multiplied by 1mm; the distance L2 between the first spiral line (3) and the second spiral line (4) is 0.4mm; the length L3 of the first stub (5) and the second stub (6) is 1mm; the length L4 of the third stub (7) and the fourth stub (8) is 0.4mm; the side length p of the reflective phase gradient super-surface is 14mm.