An ultrathin cross-polarization converter for transmission and reflection modes of operation

Abstract

The present invention provides an ultra-thin cross-polarization converter for transmission and reflection working modes, comprising a square dielectric substrate and two metal layers located above and below the dielectric substrate; the upper and lower metal layers are connected by metallized through holes, each having an "I"-shaped groove, eight tooth-shaped grooves and forty circular holes; the upper and lower metal layers are orthogonally symmetrical. The present invention adopts an ultra-thin single-layer structure, which can realize cross-polarization conversion of transmission waves and reflection waves at the working frequencies of the two modes while maintaining high amplitude; the present invention has the characteristic of polarization insensitivity, and no matter how the polarization angle of the incident electromagnetic wave changes between 0° and 90°, the polarization converter maintains excellent stability in the transmission and reflection working modes. And by adjusting the curvature of the arc grooves at both ends of the "I"-shaped groove or the width of the teeth in the tooth-shaped groove, the working frequency of the reflection or transmission mode can be independently regulated without affecting the working frequency of the other mode.

Description

Technical Field

[0001] The present invention belongs to the field of artificial electromagnetic metamaterials, and in particular relates to an ultra-thin cross-polarization converter for transmission and reflection working modes. Background Art

[0002] Polarization is one of the basic properties of electromagnetic waves. It refers to the phenomenon that the electric field vector or magnetic field vector oscillates along a specific direction during the propagation of electromagnetic waves. The polarization of electromagnetic waves can be divided into linear polarization, circular polarization, and elliptical polarization. Among them, the direction of the electric field vector remains unchanged during the propagation process, and only the electromagnetic wave whose size changes with time is called a linearly polarized wave. However, linearly polarized waves will be disturbed by environmental factors (such as the ionosphere and atmosphere) during the propagation of free space, causing the polarization direction to change, which will cause a certain amount of energy loss when the receiving antenna receives it. When the polarization direction changes by 90°, the receiving antenna can hardly receive the electromagnetic wave signal. Therefore, a polarization converter is needed to change the polarization direction of the incident wave to make it consistent with the receiving antenna, reduce energy loss, and improve signal transmission efficiency.

[0003] Polarization converters play an important role in optimizing signal transmission, improving system performance, enhancing anti-interference capabilities, improving spectrum efficiency and enhancing system flexibility. They are one of the indispensable key devices in modern communication systems and radar systems. However, due to their large geometric structures and the low efficiency of natural materials used, traditional polarization converters are difficult to meet the current miniaturization requirements of microwave and optical system integration. As a branch of metamaterials, metasurfaces not only have unique electromagnetic (EM) properties that do not exist in natural materials, but also have advantages in design, manufacturing and integration compared with traditional devices.

[0004] Generally speaking, polarization converters can be divided into reflective and transmissive types. Reflective polarization converters have relatively high performance due to their non-transmissive characteristics. As for transmissive polarization converters, since their structure inevitably causes reflection, there will be a certain interference between transmission and reflection. Most of the metasurfaces proposed so far can only manipulate the transmission or reflection of electromagnetic waves alone. Therefore, it is still a difficult problem in practical applications to simultaneously manipulate the reflected and transmitted waves under the incidence of electromagnetic waves with different polarizations.

[0005] Most traditional polarization conversion devices can only achieve polarization conversion of incident electromagnetic waves of specific frequencies. When the frequency of the incident electromagnetic wave is non-operating frequency, the polarization conversion efficiency will be greatly reduced, which greatly limits the scope of use of the device. Summary of the invention

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide an ultra-thin cross-polarization converter for transmission and reflection working modes in view of the shortcomings of the prior art, which is used to solve the problems of difficult combination of transmission and reflection, thick thickness, polarization sensitivity and few working frequency bands existing in traditional polarization conversion devices.

[0007] The ultra-thin cross-polarization converter comprises a square dielectric substrate and two metal layers;

[0008] The two metal layers are respectively located above and below the square dielectric substrate and are connected via metallized through holes;

[0009] The two metal layers each have one I-shaped groove, eight tooth-shaped grooves and forty metallized through holes (if there are too few through holes, the energy of the incident electromagnetic wave cannot be effectively transmitted, resulting in a reduction in the amplitude of the transmitted wave. A large number of experiments have shown that 40 through holes can achieve a better effect);

[0010] The two metal layers are orthogonally symmetrical.

[0011] The material of the square dielectric substrate is F4B plate; the material of the two metal layers is copper.

[0012] The material of the metallized through hole is copper, and the metallized through hole is located at the edges of the polarization converter.

[0013] The I-shaped groove is formed by connecting two arc grooves and a rectangular groove; the I-shaped groove is located at the center of the metal layer.

[0014] The I-shaped grooves on the two metal layers are orthogonal to each other, and the curvature of the arc groove can be freely adjusted.

[0015] The eight tooth-like grooves are divided into an inner part and an outer part, each of which has 4 tooth-like grooves, and the 4 tooth-like grooves in the inner part and the 4 tooth-like grooves in the outer part are rotationally symmetrical at 90°; two adjacent tooth-like grooves in the inner part and the outer part are engaged with each other, and the width of the teeth in the tooth-like grooves can be freely adjusted.

[0016] The polarization converter adopts an ultra-thin single-layer design, specifically: the thickness of the polarization converter is less than one eighteenth of the wavelength of the transmission mode working frequency, and less than one tenth of the wavelength of the reflection mode working frequency.

[0017] The polarization converter can perform cross-polarization conversion on the transmitted wave of the linearly polarized incident electromagnetic wave and the reflected wave of the linearly polarized incident electromagnetic wave.

[0018] The polarization converter has the characteristic of being polarization insensitive. No matter how the polarization angle of the incident electromagnetic wave changes between 0° and 90°, the polarization converter maintains excellent stability in both transmission and reflection working modes.

[0019] By adjusting the curvature of the arc grooves at both ends of the I-shaped groove or the width of the teeth in the toothed groove, the operating frequencies of the reflection mode and the transmission mode can be independently regulated without affecting the operating frequency of the other mode;

[0020] The transmission operating frequency of the polarization converter is in a relatively low frequency band, while the reflection operating frequency is in a relatively high frequency band, and the reflection mode and the transmission mode do not interfere with each other.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention adopts an ultra-thin single-layer structure, avoiding multi-layer stacking, which can significantly reduce the size and thickness of the structure, and helps to achieve miniaturization and integration of polarization conversion devices.

[0023] (2) The present invention can achieve cross-polarization conversion of transmitted waves and reflected waves at the operating frequencies of the two modes while maintaining high transmission amplitude and high reflection amplitude.

[0024] (3) The present invention has the characteristic of being polarization insensitive. No matter how the polarization angle of the incident electromagnetic wave changes between 0° and 90°, the polarization converter maintains excellent stability in both transmission and reflection working modes.

[0025] (4) The present invention has high structural flexibility and can independently control the operating frequency of the reflection mode or the transmission mode by adjusting the curvature of the arc grooves at both ends of the "I"-shaped groove or the width of the teeth in the toothed groove without affecting the operating frequency of the other mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The schematic diagram of the structure of the upper and lower metal layers of an ultra-thin cross-polarization converter for transmission and reflection working modes of the present invention is shown.

[0027] Figure 2 The present invention is a schematic diagram of a dielectric substrate structure of an ultra-thin cross-polarization converter for transmission and reflection working modes.

[0028] Figure 3 The schematic diagram of the working principle of an ultra-thin cross-polarization converter for transmission and reflection working modes of the present invention is shown.

[0029] Figure 4 The figure is a simulation result diagram of the transmission and reflection amplitudes corresponding to an ultra-thin cross-polarization converter for transmission and reflection working modes of the present invention when irradiated by mutually orthogonal x-polarization or y-polarization incident waves.

[0030] Figure 5The present invention is a graph showing the relationship between the width of teeth in a tooth-shaped slot of an ultra-thin cross-polarization converter for transmission and reflection working modes, the amplitude of transmission and reflection cross-polarization conversion, and the working frequency.

[0031] Figure 6 The present invention is a diagram showing the relationship between the curvature of the arc grooves at both ends of the "I"-shaped groove in an ultra-thin cross-polarization converter for transmission and reflection working modes, the amplitude of the transmission and reflection cross-polarization conversion, and the working frequency.

[0032] Figure 1 In the figure, 1 is an I-shaped groove; 2 is a tooth structure in the toothed groove; 3 is a metallized through hole; 4 is an outer toothed groove; 5 is an inner toothed groove; and 6 is a dielectric substrate. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0034] like Figure 1 , Figure 2 As shown, in Embodiment 1 of the present invention, an ultra-thin cross-polarization converter for transmission and reflection working modes is provided, wherein the unit structure of the converter comprises a square dielectric substrate and two metal layers located above and below the dielectric substrate; the upper and lower metal layers are connected by metallized through holes, each having an I-shaped groove, eight tooth-shaped grooves and forty circular holes; the upper and lower metal layers are orthogonally symmetrical. Figure 1 It is a metal layer located on the upper and lower layers of the dielectric substrate, connected by metallized through holes; each of the metal layers has an "I"-shaped groove, eight tooth-shaped grooves and forty round holes. Figure 2 It is a dielectric substrate, the material is F4B plate, and the thickness is 4mm. Figure 1 In the figure, 1 is an I-shaped groove, and the arc of the arc grooves at both ends is ; 2 is the tooth structure in the toothed groove, with a width of .

[0035] The "I"-shaped groove 1 is formed by connecting two arc grooves and a rectangular groove, and is located at the center of the metal layer. The two "I"-shaped grooves on the upper and lower metal layers are orthogonal to each other, and the arcs of the arc grooves at both ends are , radian value It can be freely adjusted within a certain range. In this embodiment, the arc value is designed =83°.

[0036] The width of the tooth structure 2 in the tooth-shaped groove is , can also be freely adjusted within a certain range. In this embodiment, the width of the tooth structure is designed =1.2mm.

[0037] The material of the metallized through hole 3 is copper, and it is located at the edge of the unit structure, 0.9 mm away from the edge of the converter unit structure. There are 40 through holes in total.

[0038] As for the outer tooth-shaped grooves 4 and the inner tooth-shaped grooves 5, there are four tooth-shaped grooves in each part, and the four tooth-shaped grooves in each part are rotationally symmetrical by 90 degrees, and two adjacent tooth-shaped grooves in different parts are meshed with each other.

[0039] The dielectric substrate 6 is made of F4B plate with a thickness of 4 mm.

[0040] Figure 3 The figure shows the working principle of an ultra-thin cross-polarization converter designed in this embodiment for transmission and reflection working modes: no matter whether the electromagnetic wave irradiated on the polarization converter is x-polarized or y-polarized, and no matter whether the incident direction of the linearly polarized electromagnetic wave is +z direction or -z direction, the polarization converter can convert the transmitted wave and the reflected wave into cross-polarized electromagnetic waves in the corresponding working frequency region.

[0041] Figure 4 This is a diagram showing simulation results of transmission and reflection amplitudes corresponding to an ultra-thin cross-polarization converter for transmission and reflection working modes in this embodiment when irradiated by mutually orthogonal x-polarization or y-polarization incident waves.

[0042] Principle of transmission cross-polarization conversion: When the incident wave irradiates the surface of the polarization converter, its electric field will be decomposed into components along the x direction and components along the y direction by the metal layer slotted along the x direction and the metal layer slotted along the y direction. At this time, a strong induced current will be formed on the metal layer with slots along the x direction and the y direction. The induced current passes through the metallized through-hole and the dielectric substrate and reaches the other end of the polarization converter. Since the rectangular grooves of the metal layer at the other end are orthogonal to the rectangular grooves of the metal layer at the incident end, the components of the electric field of the incident wave will be converted into corresponding orthogonal components, and the converted electric field components will be synthesized into a transmitted wave again. The polarization direction of the transmitted wave is converted by 90° relative to the incident wave, that is, the cross-polarization conversion of the transmitted wave is completed.

[0043] Reflection cross-polarization conversion principle: The x-axis and y-axis are rotated 45° counterclockwise to obtain the u-axis and v-axis, so the electric field of the incident wave is decomposed into components along the u-axis and the component along the v axis , and the components of the reflected wave electric field along the u-axis and along the v-axis are respectively recorded as , . At the same time, define the co-polarization reflection coefficient:

[0044] ,

[0045] ,

[0046] in is the ratio of the electric field amplitude of the incident wave with u polarization to the electric field amplitude of the reflected wave with u polarization; It is the ratio of the electric field amplitude of the incident wave with v polarization to the electric field amplitude of the reflected wave with v polarization.

[0047] Define the cross-polarization reflection coefficient:

[0048] ,

[0049] .

[0050] in is the ratio of the electric field amplitude of the incident wave with u polarization to the electric field amplitude of the reflected wave with v polarization; It is the ratio of the electric field amplitude of the incident wave with v polarization to the electric field amplitude of the reflected wave with u polarization.

[0051] When the phase difference = hour, ,in represents an integer, and z is a set of integers. The direction of the synthetic electric field of the reflected wave rotates 90° relative to the electric field of the incident wave, that is, the polarization direction changes by 90°, completing the cross-polarization conversion of the reflected wave. is the reflection phase from u polarization to u polarization, is the reflection phase from v polarization to v polarization.

[0052] like Figure 5 As shown, in Embodiment 2 of the present invention, an ultra-thin cross-polarization converter for transmission and reflection working modes is provided. Figure 5 The horizontal axis is the frequency of the incident electromagnetic wave, and the vertical axis is the transmission and reflection amplitude. The polarization converter can adjust the width of the teeth in the tooth-shaped slot. The operating frequency of the transmission mode is independently regulated without affecting the operating frequency of the reflection mode.

[0053] like Figure 6 As shown in the figure, the horizontal axis is the frequency of the incident electromagnetic wave, and the vertical axis is the transmission and reflection amplitudes. The polarization converter of the present invention can adjust the curvature of the arc grooves at both ends of the "I"-shaped groove. The operating frequency of the reflection mode is independently regulated without affecting the operating frequency of the transmission mode.

[0054] The present invention provides an ultra-thin cross-polarization converter for transmission and reflection working modes. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. An ultra-thin cross-polarization converter for transmission and reflection modes of operation, characterized in that: It includes a square dielectric substrate and two metal layers; The two metal layers are respectively located above and below the square dielectric substrate and are connected via metallized through holes; The two metal layers each have an I-shaped groove, eight tooth-shaped grooves and forty metallized through holes; The two metal layers are orthogonally symmetrical; The I-shaped groove is formed by connecting two arc grooves and a rectangular groove; the I-shaped groove is located at the center of the metal layer; The I-shaped grooves on the two metal layers are orthogonal to each other, and the curvature of the arc grooves can be freely adjusted; The eight tooth-like grooves are divided into an inner part and an outer part, each of which has 4 tooth-like grooves, and the 4 tooth-like grooves in the inner part and the 4 tooth-like grooves in the outer part are rotationally symmetrical at 90°; two adjacent tooth-like grooves in the inner part and the outer part are engaged with each other, and the width of the teeth in the tooth-like grooves can be freely adjusted.

2. An ultra-thin cross-polarization converter for transmission and reflection working modes according to claim 1, characterized in that: The material of the square dielectric substrate is F4B plate; the material of the two metal layers is copper.

3. An ultra-thin cross-polarization converter for transmission and reflection working modes according to claim 2, characterized in that: The material of the metallized through hole is copper, and the metallized through hole is located at the edges of the polarization converter.

4. The ultra-thin cross-polarization converter for transmission and reflection working modes according to claim 3, characterized in that: The polarization converter adopts an ultra-thin single-layer design, specifically: the thickness of the polarization converter is less than one eighteenth of the wavelength of the transmission mode working frequency, and less than one tenth of the wavelength of the reflection mode working frequency.

5. The ultra-thin cross-polarization converter for transmission and reflection working modes according to claim 4, characterized in that: The polarization converter can perform cross-polarization conversion on a transmitted wave of a linearly polarized incident electromagnetic wave and a reflected wave of the linearly polarized incident electromagnetic wave.

6. The ultra-thin cross-polarization converter for transmission and reflection working modes according to claim 5, characterized in that: The operating frequencies of the reflection mode and the transmission mode can be independently regulated by adjusting the curvature of the arc grooves at both ends of the I-shaped groove or the width of the teeth in the toothed groove, without affecting the operating frequency of the other mode.

7. An ultra-thin cross-polarization converter for transmission and reflection working modes according to claim 6, characterized in that: The transmission operating frequency of the polarization converter is in a relatively low frequency band, while the reflection operating frequency is in a relatively high frequency band, and the reflection mode and the transmission mode do not interfere with each other.

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