Electromagnetic wave front generator

Abstract

The application provides an electromagnetic wave front generator, and belongs to the technical field of microwave frequency electromagnetic wave regulation and control, comprising a plurality of linear polarization transmission / reflection selective units, the plurality of linear polarization transmission / reflection selective units are arranged into a rectangle, each linear polarization transmission / reflection selective unit comprises a sandwiched metal grating, two layers of dielectric substrates and two layers of metal cross patches, one side of each layer of dielectric substrate is connected with two sides of the sandwiched metal grating respectively; and one side of each layer of metal cross patch is connected with the other side of each layer of dielectric substrate respectively. The application can respectively make transverse electric waves and transverse magnetic waves generate independent functions in transmission half space and reflection half space respectively, since the two linear polarized waves are orthogonal in space, the directional electromagnetic wave front generator has good polarization multiplexing and function integration effect; and the application can effectively expand the angle domain and directivity of electromagnetic wave front regulation and control.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microwave frequency electromagnetic wave regulation, and particularly relates to an electromagnetic wave front generator. BACKGROUND

[0002] As the basis of almost all electromagnetic devices, flexible electromagnetic wave front regulation has become a research hotspot in academic and engineering technology. Traditional regulation devices are difficult to meet the multi-regulation and functional reuse of electromagnetic waves due to their large size, high cost and difficult operation. The integrated development of modern electronic information systems and optical microwave fields urgently needs a single flat device to realize two or more specified electromagnetic wave fronts and achieve directional regulation of electromagnetic waves.

[0003] As a two-dimensional equivalent form of metamaterials, metasurface is a planar structure composed of artificially arranged subwavelength periodic unit structures, and has unique electromagnetic physical properties. After years of development, a large number of anisotropic and cascaded multilayer metasurfaces based on resonant phase and geometric phase have been realized, and have been widely used in various electromagnetic wave front regulations such as beam abnormal deflection, vortex beam generation, achromatic focusing lens and full-color hologram, providing great convenience for frequency and polarization reuse of electromagnetic waves. However, existing electromagnetic wave front generators can only function on incident electromagnetic waves with limited polarization states in half space, and generally consider the case of normal incidence of electromagnetic waves, which leads to the inability to generate different functions in the whole space and the serious limitation of the incident angle domain, greatly hindering the applicability and expandability of the electromagnetic wave front generator and limiting its actual application range. SUMMARY

[0004] In order to overcome the deficiencies of the prior art, the application provides an electromagnetic wave front generator.

[0005] In order to achieve the above purpose, the application provides the following technical scheme:

[0006] An electromagnetic wave front generator comprises a plurality of linear polarization transmission / reflection selective units, the plurality of linear polarization transmission / reflection selective units are arranged in a rectangle, and each linear polarization transmission / reflection selective unit comprises:

[0007] A sandwich metal grating;

[0008] Two layers of dielectric substrates, one side of each dielectric substrate is connected with one side of the sandwich metal grating;

[0009] Two layers of metal cross patches, one side of each metal cross patch is connected with the other side of the dielectric substrate;

[0010] The electromagnetic wave in the air is incident on the two-layer metal cross patch and the surface of the sandwiched metal grating in the electromagnetic wave front generator, so that a plurality of the linear polarization trans / reflective selective units simultaneously resonate, the impedance of the medium and the air at two frequency points corresponding to the horizontal electric wave is matched, and the projected electromagnetic wave is transmitted forward along the incoming wave direction through the medium when the projected electromagnetic wave is greater than a set value; the electromagnetic wave front is deflected to specific three incoming wave directions according to the phase distribution of the corresponding coded atoms, and the corresponding backscattering enhancement is realized.

[0011] Preferably, the length of the sandwiched metal grating is 6.1 mm, the width is 5 mm, the length and width of the medium substrate are equal to the length and width of the sandwiched metal grating, and the thickness of the medium substrate is 1.5 mm.

[0012] Preferably, the sandwiched metal grating is arranged in two horizontal rectangular strips along the X axis and three vertical rectangular strips along the Y axis, the edges of the two vertical rectangular strips at both ends are respectively aligned with the two ends of the sandwiched metal grating, and the vertical rectangular strip in the middle is aligned with the geometric center line of the sandwiched metal grating.

[0013] Preferably, the length of the horizontal rectangular strip is equal to the length of the sandwiched metal grating, the width is 1.2 mm, the length of the vertical rectangular strip is equal to the width of the sandwiched metal grating, the width of the two vertical rectangular strips at both ends is 0.1 mm, and the width of the vertical rectangular strip in the middle is twice the width of the vertical rectangular strip at both ends.

[0014] Preferably, the medium substrate is a ceramic matrix composite substrate, the relative dielectric constant is 3.6, and the loss tangent is 0.002.

[0015] Preferably, the metal cross patch comprises a first metal strip and a second metal strip, the first metal strip and the second metal strip are both in the shape of "I", the first metal strip is arranged horizontally along the X axis, and the second metal strip is arranged along the Y axis.

[0016] Preferably, the sizes of the first metal strips of two adjacent linear polarization trans / reflective selective units along the X axis are different and periodically arranged, the lengths are 4.2 mm and 2.6 mm respectively, the middle widths are 0.3 mm and 0.3 mm respectively, the lengths at both ends are 1.4 mm and 0.8 mm respectively, and the widths at both ends are 0.3 mm and 0.2 mm respectively.

[0017] Preferably, the height of the second metal strip is 1.9 mm, the middle width is 0.25 mm, the length at both ends is 2.1 mm, and the height at both ends is 0.25 mm.

[0018] Preferably, the material of the sandwich metal grating, the first metal strip and the second metal strip is copper.

[0019] The electromagnetic wave front generator provided by the application has the following beneficial effects:

[0020] (1) The directional electromagnetic wave front generator provided by the application can respectively make the transverse electric wave and the transverse magnetic wave generate independent functions in the transmission half-space and the reflection half-space respectively, since the two linearly polarized waves are orthogonal in space, the directional electromagnetic wave front generator has good polarization multiplexing and function integration effects.

[0021] (2) The two-layer metal cross patch provided by the application can simultaneously introduce the corresponding polarized direction class Fabry-Perot cavity structure and 0 / 180 degree resonance phase distribution to expand the transmission angle domain and bandwidth of the transverse electric wave and realize three-channel transverse magnetic wave co-polarized backscattering enhancement, effectively expanding the angle domain and directivity of the electromagnetic wave front regulation.

[0022] (3) The structure of the application is variable, the parameters of the sandwich grating and the upper and lower metal cross patches can be flexibly adjusted according to the polarization state and incoming wave direction of the electromagnetic wave to generate different directional electromagnetic wave fronts, and the design structure is simple, the processing cost is low, and it has strong practicability and integration degree. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the application and the design scheme, the following will briefly introduce the drawings needed by the embodiments. The drawings in the following description are only part of the embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0024] Figure 1 The basic structure schematic diagram of the directional electromagnetic wave front generator provided by the embodiment of the application is shown in the figure.

[0025] Figure 2 The structure schematic diagram of the linear polarization transmission / reflection selection unit provided by the embodiment of the application is shown in the figure, wherein (a) is a perspective view of a five-layer unit structure, and (b) is a front view of the five-layer unit structure.

[0026] Figure 3 The class Fabry-Perot cavity structure schematic diagram provided by the embodiment of the application is shown in the figure.

[0027] Figure 4 The simulation results of the transmission / reflection coefficients of the ceramic matrix composite substrate before and after loading the sandwich metal grating provided by the embodiment of the application are shown in the figure, wherein (a) is a comparison of the transmission coefficients of the ceramic matrix composite substrate under transverse electric wave vertical incidence, and (b) is a comparison of the reflection coefficients of the ceramic matrix composite substrate under transverse magnetic wave vertical incidence.

[0028] Figure 5 The simulation results of the transmittance of the ceramic matrix composite substrate and the directional electromagnetic wave front generator of the same size under the irradiation of transverse electric waves at different incident angles, wherein (a) is the transmittance of the ceramic matrix composite substrate, and (b) is the transmittance of the directional electromagnetic wave front generator;

[0029] Figure 6 The three-dimensional / two-dimensional far field simulation results of the directional electromagnetic wave front generator under the irradiation of transverse magnetic waves, wherein (a) is under the condition of f1 = 14.3 GHz, θ i = 60° incidence, (b) is under the condition of f2 = 16.4 GHz, θ i = 60° incidence, (c) is under the condition of f1 = 14.3 GHz, θ i = -60° incidence, (d) is under the condition of f2 = 16.4 GHz, θ i = -60° incidence;

[0030] Figure 7 The simulation results of the ceramic matrix composite substrate and the directional electromagnetic wave front generator of the same size under the irradiation of transverse magnetic waves at different incident angles, wherein (a) is the reflectance of the ceramic matrix composite substrate of the same size, (b) is the reflectance of the directional electromagnetic wave front generator, and (c) is the phase response of two different superatoms when θ i = ± 55°;

[0031] Figure 8 The three-dimensional / two-dimensional far field simulation results of the directional electromagnetic wave front generator and the metal plate of the same size at 15 GHz under the irradiation of transverse magnetic waves, wherein (a) is under the condition of θ i = -55° incidence, (b) is under the condition of θ i = 55° incidence, and (c) is under the condition of θ i = 0° incidence;

[0032] Figure 9 The directional electromagnetic wave front generator provided by the embodiment of the present application is shown in the figure;

[0033] Figure 10 The transmittance test platform and the transmittance test results of the ceramic matrix composite substrate and the directional electromagnetic wave front generator of the same size under the irradiation of transverse electric waves, wherein (a) is the transmittance test platform, (b) is the transmittance of the ceramic matrix composite substrate, and (c) is the transmittance of the directional electromagnetic wave front generator;

[0034] Figure 11The reflection coefficient and far-field test platform provided by the embodiment of the present application, and the test results of the same size metal plate and the directional electromagnetic wave front generator under transverse magnetic wave irradiation, wherein (a) is the reflection coefficient test platform, (b) is the far-field test platform, (c) is the reflection coefficient test results of the qualitative electromagnetic wave front generator under different incident angles, (d)-(f) are respectively the bistatic reflection coefficient test results of the same size metal plate and the directional electromagnetic wave front generator under the incident angles of θ i = -55°, 55°, 0°.

[0035] Legend of reference signs:

[0036] 1 - sandwich metal grating, 2 - dielectric substrate, 3 - metal cross patch, 4 - horizontal rectangular strip, 5 - vertical rectangular strip, 6 - first metal strip, 7 - second metal strip. DETAILED DESCRIPTION

[0037] In order for those skilled in the art to better understand the technical solutions of the present application and to implement them, the present application will be described in detail below in conjunction with the drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0038] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the technical solutions of the present application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0039] In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of the present application, it should be noted that unless otherwise explicitly specified or limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. In the description of the present application, unless otherwise stated, the meaning of "multiple" is two or more, which will not be described in detail here.

[0040] Example 1

[0041] The application provides an electromagnetic wave front generator, comprising a plurality of linear polarization transmission / reflection selective units, the plurality of linear polarization transmission / reflection selective units are arranged into a rectangle, the size of the rectangle is 732mm*300mm, each linear polarization transmission / reflection selective unit comprises a sandwiched metal grating 1, two layers of dielectric substrates 2 and two layers of metal cross patches 3, as shown in Figure 1 Fig. 2a and Fig. 2b. One side of the two layers of dielectric substrates 2 is connected with two sides of the sandwiched metal grating 1 respectively; one side of the two layers of metal cross patches 3 is connected with the other side of the two layers of dielectric substrates 2 respectively, as shown in Figure 2 Fig. 3a and Fig. 3b. The specific working principle is as follows: electromagnetic waves in the air are incident on the upper surfaces of the two layers of metal cross patches 3 and the sandwiched metal grating 1 in the electromagnetic wave front generator, so that the plurality of linear polarization transmission / reflection selective units simultaneously generate resonance, the impedance of the medium and the air at two frequency points corresponding to the transverse electric wave is matched, and the transverse electric wave almost has no reflection and is transmitted forward along the wave direction through the medium; according to the phase distribution of the corresponding coded atoms, the electromagnetic wave front is deflected to specific three wave directions, and the corresponding backscattering enhancement is realized.

[0042] In the embodiment, the length of the sandwiched metal grating 1 is p1=6.1mm, the width is p2=5mm, the sandwiched metal grating 1 is arranged into two horizontal rectangular strips 4 along the X axis and three vertical rectangular strips 5 along the Y axis, the edges of the two vertical rectangular strips 5 at both ends are aligned with the two ends of the sandwiched metal grating 1 respectively, the vertical rectangular strip 5 in the middle is aligned with the geometric center line of the sandwiched metal grating 1, the length of the horizontal rectangular strip 4 is equal to the length of the sandwiched metal grating 1, that is, p1=6.1mm, the width is w 22 =1.2mm, the length of the vertical rectangular strip 5 is equal to the width of the sandwiched metal grating 1, that is, p2=5mm, the width of the two vertical rectangular strips 5 at both ends is w 21 / 2 =0.1mm, the width of the vertical rectangular strip 5 in the middle is twice the width of the vertical rectangular strip 5 at both ends, that is, w 21 =0.2mm, as shown in Fig. 1b. Figure 2

[0043] The length and width of the dielectric substrate 2 are equal to the length and width of the sandwiched metal grating 1, and the thickness of the dielectric substrate 2 is d=1.5mm; the dielectric substrate 2 is a ceramic matrix composite substrate, the relative dielectric constant of which is 3.6, and the loss tangent is 0.002.

[0044] The metal cross patch 3 comprises a first metal strip 6 and a second metal strip 7, the first metal strip 6 and the second metal strip 7 are both in the shape of “I”, the first metal strip 6 is arranged horizontally along the X axis, and the second metal strip 7 is arranged along the Y axis. The sizes of the first metal strips 6 of two linear polarization transmission / reflection selective units adjacent along the X axis are different and periodically arranged, the lengths of the first metal strips 6 are l​32 = 4.2 mm and 2.6 mm, middle width w 32 = 0.3 mm and 0.3 mm, length of both ends l 31 = 1.4 mm and 0.8 mm, width w 31 = 0.3 mm and 0.2 mm; height of the second metal strip 7 l 12 = 1.9 mm, middle width w 12 = 0.5 mm, length of both ends l 11 = 2.1 mm, height w 11 = 0.25 mm.

[0045] In the embodiment, the sandwich metal grating 1, the first metal strip 6 and the second metal strip 7 are all made of copper.

[0046] Embodiment 2

[0047] Figure 3 After loading the upper and lower layers of metal cross patches 3, the transmission / reflection amplitude and phase of the ceramic matrix composite substrate at the air-dielectric interface are explained. Because the refractive index of the dielectric at the air-dielectric interface on both sides is different, the incident angles a s and a i are different. The metal cross patch 3 resonates under the action of external electromagnetic waves, and the electromagnetic waves are transmitted / reflected multiple times. The transmission / reflection coefficients of each time are t 12 exp(jθ 12 ), t 23 exp(jθ 23 ), t 21 exp(jθ 21 )……, and r 21 exp(jθ 21 ), r 23 exp(jθ 23 ). In the formula, the multiple times of transmission / reflection electromagnetic waves finally interfere with each other, and the transmission is enhanced and the reflection is reduced at the resonance frequency point of the upper and lower layers of metal cross patches 3.

[0048] Figure 4 The simulation results of the transmission / reflection coefficients of the ceramic matrix composite substrate before and after loading the sandwich metal grating 1. Through the Trowe model In the formula, ω pmrepresents the resonant frequency of the sandwiched metal grating 1, c0 and π represent the speed of light and the circle constant respectively, and a and r represent the width and radius of the sandwiched metal grating 1 respectively, the resonant frequencies of the sandwiched metal grating 1 under the transverse electric wave and the transverse magnetic wave irradiation are 21.2 GHz and 40.1 GHz respectively, and the transmission / reflection selection function of the two linear polarized waves is realized by adjusting the equivalent dielectric constant of the medium in the specific resonant region. Referring to Figure 4 (a) It can be seen that by loading the optimized metal grating, the transmission coefficient of the ceramic matrix composite substrate in the Ku band for the transverse electric wave vertical incidence is gradually increased from 0.5 to 0.95, which is obviously improved compared with the transmission coefficient 0.8 without loading. From Figure 4 (b) It can be seen that the reflection coefficient of the ceramic matrix composite substrate in the Ku band for the transverse magnetic wave vertical incidence is 0.96, which is improved by about 50% compared with the reflection coefficient 0.5 without loading.

[0049] Figure 5 The simulation results of the transmission coefficient of the directional electromagnetic wave front generator under the transverse electric wave irradiation at different incident angles, and in addition, the same size ceramic matrix composite substrate is selected for comparison. From Figure 5 (a) and (b) can be seen that, compared with the ceramic matrix composite substrate, the directional electromagnetic wave front generator has obvious transmission enhancement effect in the transmission channels I and II caused by the cavity structure of the upper and lower metal cross patch 3(1), (5) and the resonant band of the sandwiched metal grating 1(3) under different angle incidence, and the transmission amplitude is improved by about 40% on average.

[0050] Figure 6 The three-dimensional simulation results of the directional electromagnetic wave front generator under the transverse electric wave irradiation, and the corresponding two-dimensional simulation results in the xoz section. Referring to Figure 6 (a)-(d), it can be seen that when the electromagnetic wave is incident at f1=14.3 GHz, θ i =60°, f2=16.4 GHz, θ i =60°, f1=14.3 GHz, θ i =-60°, and f2=16.4 GHz, θ i =-60°, the electromagnetic wave is transmitted from the upper half z space to the rear half z space along the incident direction, and has obvious forward scattering enhancement effect.

[0051] Figure 7 The simulation results and phase distribution of the directional electromagnetic wave front generator under the transverse magnetic wave irradiation at different incident angles, and in addition, the same size ceramic matrix composite substrate is selected for comparison. Referring to Figure 7(a) and (b) can be compared, relative to the ceramic matrix composite substrate, under different angle of incidence, by loading three-layer metal structure (1), (3), (5), the reflection amplitude of the directional electromagnetic wave front generator is increased by about 80% on average at 13-18GHz. From Figure 7 (c) can be found that when the transverse magnetic wave is incident at θ i = ± 55°, the reflection phase difference value at 15GHz is about 180 degrees, combined with the generalized Snell law θ r = arcsin (sin (θ i ) +▽φ x / k i ), the phase distribution of the electromagnetic directional wave front generator is calculated as shown in Figure 7 (d).

[0052] Figure 8 is the three-dimensional simulation result of the directional electromagnetic wave front generator under transverse magnetic wave irradiation, and the corresponding two-dimensional simulation result in the xoz section, and the same size metal plate is selected for comparison. From Figure 8 (a)-(c) can be seen that for the transverse magnetic wave at 15GHz, when θ i = -55°, 55°, 0°, the directional electromagnetic wave front generator has obvious backscattering enhancement in the direction of the incoming wave, while the same size metal plate is specular reflection; relative to the metal plate, the backscattering amplitude of the directional electromagnetic wave front generator is 35dBsm.

[0053] Figure 9 is the same sample as the simulation model made by using PCB process and hot pressing process, and its transmission / reflection coefficient test and far field test are carried out.

[0054] Figure 10 is the transmission coefficient test platform built and the transmission coefficient test result of the directional electromagnetic wave front generator under transverse electric wave irradiation, here, the same size ceramic matrix composite substrate is selected and processed for comparison. Referring to Figure 10 (b) and (c), it can be seen that under the irradiation of transverse magnetic wave, the directional electromagnetic wave front generator has two obvious transmission peaks I and II, and relative to the ceramic matrix composite substrate, its transmission amplitude is obviously improved at 13-17.5GHz, the overall amplitude is improved by about 45%, and it has good wave transmission effect.

[0055] Figure 11 is the reflection coefficient and far field test platform built and the transmission coefficient test result of the directional electromagnetic wave front generator under transverse magnetic wave irradiation, here, the same size metal plate is selected and processed for comparison. Referring to Figure 11(c), it can be seen that the reflection coefficient of the directional electromagnetic wave front generator under the irradiation of transverse magnetic wave at different incident angles is about 0.88 in the Ku band, and has good reflection effect. Figure 11 (d)-(f) can be compared, the directional electromagnetic wave front generator under the irradiation of transverse magnetic wave at 15GHz, θ i =-55°, 55°, 0°, the electromagnetic wave is returned to the wave direction efficiently, and the bistatic reflection coefficient has obvious peak value, in addition, the equal-sized metal plate efficiently reflects the electromagnetic wave along the mirror symmetry direction, which fully verifies the high-efficiency backscattering enhancement effect of the application.

[0056] From the above description, the electromagnetic wave front generator provided by the application has the following advantages:

[0057] (1) The directional electromagnetic wave front generator provided by the application can generate independent functions in the transmission half-space and the reflection half-space for transverse electric wave and transverse magnetic wave respectively, because the two linearly polarized waves are orthogonal in space, the directional electromagnetic wave front generator has good polarization multiplexing and function integration effect.

[0058] (2) The application introduces bandpass and bandstop effects by resonant effect through reasonable design of the structure size of the sandwich metal grating 1, so that two different functions are realized in different half-spaces, and the crosstalk between the two different functions is greatly reduced.

[0059] (3) The two-layer metal cross patch 3 provided by the application can introduce corresponding polarized direction class Fabry-Perot cavity structure and 0 / 180 degree resonant phase distribution at the same time, so as to expand the transmission angle domain and bandwidth of transverse electric wave and realize three-channel transverse magnetic wave co-polarized backscattering enhancement, which effectively expands the angle domain and directivity of electromagnetic wave front regulation.

[0060] (4) The application has variable structure, and can flexibly adjust the parameters of the sandwich grating and the upper and lower metal cross patch 3 according to the polarization state and wave direction of the electromagnetic wave to generate different directional electromagnetic wave fronts, and the design structure is simple, the processing cost is low, and the application has strong practicability and integration degree.

[0061] The above-described embodiments are only the preferred specific embodiments of the application, and the protection scope of the application is not limited thereto, and any simple change or equivalent replacement of the technical solutions within the technical range disclosed by the application can be obtained by those skilled in the art, which belongs to the protection scope of the application.

Claims

1. An electromagnetic wave front generator, characterized by, The application relates to a linear polarization trans / reflective selective unit. The application relates to a sandwich metal grating (1). Two layers of medium substrates (2) are connected with two surfaces of the sandwich metal grating (1) respectively. Two layers of metal cross patches (3) are connected with the other surfaces of the two medium substrates (2) respectively. When electromagnetic waves in the air are incident on the upper surfaces of the two layers of metal cross patches (3) and the sandwich metal grating (1) in the electromagnetic wave front generator, multiple linear polarization trans / reflective selective units simultaneously generate resonance, impedance matching of the medium and the air under two frequency points corresponding to the transverse electric wave is realized, and the transmission electromagnetic wave greater than a set value is transmitted to the front along the wave direction through the medium; according to the phase distribution of the corresponding coded atoms, the electromagnetic wave front is deflected to specific three wave directions, and corresponding backscattering enhancement is realized. The length of the sandwich metal grating (1) is 6.1 mm, the width is 5 mm, the length and the width of the medium substrate (2) are equal to those of the sandwich metal grating (1), and the thickness of the medium substrate (2) is 1.5 mm. The sandwich metal grating (1) is arranged in two horizontal rectangular strips (4) along the X axis and three vertical rectangular strips (5) along the Y axis, the edges of the two vertical rectangular strips (5) at two ends are aligned with the two ends of the sandwich metal grating (1) respectively, and the vertical rectangular strip (5) in the middle is aligned with the geometric center line of the sandwich metal grating (1). The length of the horizontal rectangular strip (4) is equal to that of the sandwich metal grating (1), the width is 1.2 mm, the length of the vertical rectangular strip (5) is equal to the width of the sandwich metal grating (1), the width of the two vertical rectangular strips (5) at two ends is 0.1 mm, and the width of the vertical rectangular strip (5) in the middle is twice that of the vertical rectangular strip (5) at two ends. The metal cross patch (3) comprises a first metal strip (6) and a second metal strip (7), the first metal strip (6) and the second metal strip (7) are both in the shape of "I", the first metal strip (6) is arranged horizontally along the X axis, and the second metal strip (7) is arranged along the Y axis. The sizes of the first metal strips (6) of two adjacent linear polarization trans / reflective selective units along the X axis are different and arranged periodically, the lengths are 4.2 mm and 2.6 mm respectively, the middle widths are 0.3 mm and 0.3 mm respectively, the lengths at two ends are 1.4 mm and 0.8 mm respectively, and the widths at two ends are 0.3 mm and 0.2 mm respectively. The height of the second metal strip (7) is 1.9 mm, the middle width is 0.25 mm, the length at two ends is 2.1 mm, and the height at two ends is 0.25 mm.

2. The electromagnetic wave front generator of claim 1, wherein, The medium substrate (2) is a ceramic matrix composite substrate, the relative dielectric constant is 3.6, and the loss tangent is 0.

002.

3. The electromagnetic wave front generator of claim 1, wherein, The material of the interlayer metal grating (1), the first metal strip (6) and the second metal strip (7) is copper.

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