Efficient transmission type all-dielectric frequency selective surface for improving transmission performance of 5G millimeter wave frequency band mobile phone glass cover plate

Abstract

The invention relates to an efficient transmission type all-dielectric frequency selective surface for improving the transmission performance of a 5G millimeter wave frequency band mobile phone glass cover plate, and aims to solve the problems of large insertion loss and narrow efficient transmission bandwidth of a large dielectric constant medium in the 5G millimeter wave frequency band. The basic unit of the all-dielectric frequency selective surface comprises a first dielectric layer and a second dielectric layer from top to bottom, the first dielectric layer and the second dielectric layer are ceramic dielectric diamond blocks with the dielectric constant of 30. Wherein the first dielectric layer provides magnetic resonance, the second dielectric layer provides electric resonance, and the first dielectric layer and the second dielectric layer act together to improve the transmission performance of the glass cover plate. According to the composite structure of the efficient transmission type all-dielectric frequency selective surface and the mobile phone glass cover plate, the insertion loss in the working frequency band of 23.7-30.7 GHz is smaller than 1 dB, and the composite structure has the performance advantages of ultra wide band, high efficiency, 30-degree oblique incidence stability and the like in the 5G millimeter wave n257 frequency band (26.5-29.5 GHz).

Description

Technical Field

[0001] This invention belongs to the field of artificial electromagnetic metamaterials, specifically relating to a highly efficient transmissive all-dielectric frequency selective surface for improving the transmission performance of 5G millimeter-wave band glass cover plates. Background Technology

[0002] A frequency selective surface (FSS) is an electromagnetic structure with spatial filter characteristics. By designing different electromagnetic parameters, it can meet the needs of electromagnetic wave transmission control. Among them, the frequency selective surface has great application value in energy transmission.

[0003] Most published studies currently employ dielectrics with low dielectric constants and low loss tangents as the substrate for frequency-selective surfaces, rarely considering the impact of dielectrics with high dielectric constants in the millimeter-wave band. Furthermore, most published studies utilize metals as the resonant structure to achieve broadband or high-efficiency transmission electromagnetic performance. However, the introduction of metals in the millimeter-wave band typically introduces additional ohmic losses and Joule heating.

[0004] Recently, with the development of 5G wireless communication, materials with high dielectric constants, such as glass or ceramics, have been used in the design of mobile phone cover plates. However, there is limited research on the performance of such media in the millimeter-wave band and on improving the transmission performance of high dielectric constant media. Scientists have designed dielectric resonator structures to achieve efficient transmission, effectively avoiding ohmic losses. However, designs for the millimeter-wave band are limited, and related research can only operate within a narrow frequency band, which is not suitable for practical applications and is difficult to fabricate.

[0005] Therefore, the design of broadband, high-efficiency, all-dielectric frequency-selective surfaces for millimeter-wave frequencies remains a significant challenge. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to propose a high-efficiency transmissive all-dielectric frequency selective surface for improving the transmission performance of glass cover plates for 5G millimeter-wave mobile phones, so as to improve the problems of high insertion loss and narrow high-efficiency transmission bandwidth of glass dielectric with large dielectric constant in 5G millimeter-wave band, while overcoming the problem of ohmic loss introduced by metal.

[0007] Technical Solution: To achieve the above-mentioned objectives, the present invention proposes the following technical solution:

[0008] A high-efficiency transmissive all-dielectric frequency selective surface for improving the transmission performance of 5G millimeter-wave band glass cover plates, the basic unit structure of which includes a first dielectric layer and a second dielectric layer from top to bottom; the first dielectric layer is composed of a rhombic ceramic dielectric with a dielectric constant of 30; the second dielectric layer is composed of a rhombic ceramic dielectric with a dielectric constant of 30.

[0009] Preferably, the size parameters of the ceramic dielectric in the first dielectric layer mainly determine the operating bandwidth, wherein the smaller the size, the larger the operating bandwidth, and the larger the thickness, the smaller the insertion loss.

[0010] Preferably, the size of the ceramic dielectric in the second dielectric layer mainly determines the operating frequency. The larger the size, the lower the operating frequency of the structure; the larger the thickness, the lower the insertion loss.

[0011] In one possible implementation, the length of the two diagonals of the rhombic ceramic dielectric in the first dielectric layer is r1 = 1 mm, and the dielectric thickness is h1 = 0.52 mm.

[0012] In one possible implementation, the second dielectric layer is placed at a distance of g = 0.2 mm from the first dielectric layer, the two diagonals of the rhomboid dielectric are r2 = 1.8 mm, and the dielectric thickness is h2 = 0.52 mm.

[0013] In one possible implementation, a full-dielectric frequency selective surface consisting of a first dielectric layer and a second dielectric layer is placed under a glass cover plate, the thickness of which is h0 = 0.6 mm and the unit period is p = 3.6 mm.

[0014] Beneficial Effects: This invention utilizes the electromagnetic resonance generated by a double-layer ceramic dielectric with a high dielectric constant to design a broadband, high-efficiency transmission-type all-dielectric frequency-selective surface, improving the transmission performance of the glass cover in the 5G millimeter-wave band. Under x-polarized and y-polarized wave incidence, the overall structure achieves broadband, high-efficiency transmission in the 5G millimeter-wave band. Compared with existing technologies, this invention has the following specific advantages:

[0015] 1) The broadband high-efficiency transmission all-dielectric frequency selective surface proposed in this invention can achieve broadband high-efficiency transmission in the 5G millimeter wave n257 band (26.5GHz~29.5GHz) using a ceramic dielectric with a large dielectric constant. It also has the advantages of simple structure, easy design and low manufacturing cost.

[0016] 2) This invention can be applied to glass cover plates with high dielectric constant to improve the transmission performance of the glass cover plates.

[0017] 3) This invention uses an all-dielectric structure to introduce electromagnetic resonance, which can avoid ohmic losses and thus avoid thermal effects.

[0018] 4) This invention has high symmetry and can maintain the stability of oblique incidence under dual polarization.

[0019] 5) This invention can be moved from the 5G millimeter wave band to other frequency bands by means of proportional scaling, and has good frequency band flexibility.

[0020] 6) This invention is practical and can be applied to the design of mobile phone antennas to improve the beam coverage of mobile phone antennas. Attached Figure Description

[0021] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0022] Figure 1 This is a schematic diagram of the all-dielectric frequency selective surface according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the basic unit three-dimensional structure of an embodiment of the present invention;

[0024] Figure 3 This is a side view schematic diagram of the basic unit structure of an embodiment of the present invention;

[0025] Figure 4 This is a top view schematic diagram of the basic unit structure of an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the all-dielectric frequency selective surface acting on the glass cover plate according to an embodiment of the present invention;

[0027] Figure 6 This is a comparison of simulation results of the transmission amplitude of the all-dielectric frequency selective surface acting on the glass cover plate and the transmission amplitude of the glass medium of the same thickness according to an embodiment of the present invention.

[0028] Figure 7 This is a curve showing the change in y-polarization transmission coefficient when the all-dielectric frequency-selective surface of the present invention is applied to the glass cover plate and incident from 0° to 30°.

[0029] Figure 8 This is a curve showing the change of x-polarization transmission coefficient when the all-dielectric frequency selective surface of the present invention is applied to the glass cover plate and incident from 0° to 30°.

[0030] Figure 9 This is a comparison chart of the test results of the transmission amplitude of the all-dielectric frequency selective surface acting on the glass cover plate and the transmission amplitude of the glass medium of the same thickness according to an embodiment of the present invention. Detailed Implementation

[0031] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. However, it should be understood that the present invention can be implemented in various forms. The exemplary and non-limiting embodiments shown in the accompanying drawings and described below are not intended to limit the invention to the specific embodiments illustrated.

[0032] like Figure 1-3As shown, this invention provides a high-efficiency transmissive all-dielectric frequency selective surface for improving the transmission performance of 5G millimeter-wave band glass covers. It is formed by periodically extending basic units in a two-dimensional xy plane. The basic unit structure includes a first dielectric layer 1 and a second dielectric layer 2 from top to bottom. The first dielectric layer is composed of rhombic ceramic dielectric; the second dielectric layer 2 is also composed of rhombic ceramic dielectric. In this example, the first dielectric layer 1 and the second dielectric layer 2 are made of ceramic material with a dielectric constant of 30 and a loss tangent of 0.0003. The side length of the all-dielectric frequency selective surface unit is p = 3.6 mm.

[0033] like Figure 4 As shown, the first dielectric layer 1 has a rhombic structure, with a diagonal length of r1 = 1 mm and a thickness of h1 = 0.52 mm. The second dielectric layer 2 has a rhombic structure, with a diagonal length of r2 = 1.8 mm and a thickness of h2 = 0.52 mm.

[0034] like Figure 5 As shown, a fully dielectric frequency-selective surface is placed below a glass cover plate with a thickness h0 = 0.6 mm and a length and width p = 3.6 mm. The unit cell is modeled using electromagnetic simulation software. X-polarized and Y-polarized electromagnetic waves are incident on the frequency-selective surface unit cell, with the unit cell serving as the boundary between the X and Y axes.

[0035] Figure 6 The simulation results comparing the transmission amplitude of a 0.6mm thick glass dielectric substrate and the frequency selective surface of this invention applied to the glass dielectric substrate are presented. In the 24–30GHz frequency range, the transmission amplitude of the glass dielectric substrate of the same thickness is below -2dB. When the all-dielectric frequency selective surface of this invention is applied to the glass cover, its transmission amplitude remains above -1dB in the 23.7–30.7GHz frequency band, achieving a relative bandwidth of 25.7% for efficient transmission, with an average insertion loss of 0.55dB. Compared to most passive bandpass all-dielectric frequency selective surfaces, the proposed method in this invention offers the advantage of broadband and efficient transmission, effectively improving the transmission performance of the glass cover in the 5G millimeter-wave band.

[0036] Figure 7 Simulation results are presented for the transmission amplitude of y-polarized electromagnetic waves incident at angles from 0° to 30° after loading a frequency-selective all-dielectric surface onto a glass cover. The overall structure maintains good oblique incidence stability with a transmission amplitude above -1dB in the 5G millimeter-wave band when y-polarized electromagnetic waves are incident obliquely.

[0037] Figure 8Simulation results are presented showing the transmission amplitude of x-polarized electromagnetic waves incident at angles from 0° to 30° with a fully dielectric frequency-selective surface applied to a glass cover. Under x-polarized oblique incidence, the overall structure maintains a transmission amplitude above -1dB in the 5G millimeter-wave band, demonstrating excellent oblique incidence stability. Compared to most passive frequency-selective surface designs, it exhibits the advantage of oblique incidence stability.

[0038] Figure 9 The transmission amplitude test results of a 0.6 mm thick glass cover plate and a glass cover plate loaded with the embodiment of the present invention are compared. In the frequency range of 24–30 GHz, due to the effect of the all-dielectric frequency-selective surface of the embodiment of the present invention, the transmission amplitude of the glass cover plate loaded with the embodiment of the present invention is always greater than that of a glass cover plate of the same thickness.

[0039] It should be noted that the shapes of the first and second dielectric layers are not limited to the above-described configurations, nor are they limited to any specific shape. Rectangular, circular, and annular dielectrics with high dielectric constants can also be used to generate resonant transmission structures in the manner described above.

[0040] The above description is merely a preferred embodiment of the present invention. The same structure can be flexibly designed by scaling the high-transmittance all-dielectric frequency selective surface proportionally, allowing for flexible design of the operating frequency band of the transmissive all-dielectric frequency selective surface. Because the design concept of the present invention is clear and its application prospects are broad, the same structure can be extended to the millimeter-wave band, infrared, terahertz, and visible light bands by scaling the size. This should not be construed as limiting the scope of the present invention; all simple equivalent changes and modifications made in accordance with the claims and description of the present invention should still fall within the scope of the patent coverage of this invention.

Claims

1. A high-efficiency transmissive all-dielectric frequency selective surface for improving the transmission performance of glass cover plates in 5G millimeter-wave band mobile phones, characterized in that, The basic unit structure of the all-dielectric frequency selective surface is periodically extended in the XY two-dimensional plane by basic structural units; the basic unit structure of the all-dielectric frequency selective surface includes a first dielectric layer (1) and a second dielectric layer (2) from top to bottom; the first dielectric layer (1) is composed of a ceramic dielectric with a dielectric constant of 30, which provides magnetic resonance for the structural unit; the second dielectric layer (2) is composed of a ceramic dielectric with a dielectric constant of 30, which provides electrical resonance for the structural unit.

2. The high-efficiency transmissive all-dielectric frequency selective surface for improving the transmission performance of 5G millimeter-wave band mobile phone glass cover glass as described in claim 1, characterized in that, The first dielectric layer (1) is a rhombus-shaped dielectric block with equal diagonals, a length of 1 mm, and a thickness of 0.52 mm. By adjusting the length of the diagonals and the thickness of the rhombus-shaped dielectric, the working frequency and transmission coefficient of the transmission frequency selection surface can be controlled.

3. The high-efficiency transmissive all-dielectric frequency selective surface for improving the transmission performance of 5G millimeter-wave band mobile phone glass cover glass as described in claim 1, characterized in that, The second dielectric layer (2) is a rhombic dielectric block with equal diagonals and a length of 1.8 mm and a thickness of 0.52 mm. By adjusting the length of the diagonal of the rhombic dielectric and the thickness of the rhombic dielectric, the operating frequency and transmission coefficient of the transmission frequency selective surface can be controlled, so that the all-dielectric frequency selective surface unit provides broadband high-efficiency transmission.

4. The high-efficiency transmissive all-dielectric frequency selective surface for improving the transmission performance of 5G millimeter-wave band mobile phone glass cover glass as described in claim 1, characterized in that, The basic unit has a period of 3.6 mm. By reasonably adjusting the unit size, the operating frequency band of the frequency selection surface can be controlled, and the appearance of grid lobes can be avoided within the operating frequency band.

5. The high-efficiency transmissive all-dielectric frequency selective surface for improving the transmission performance of 5G millimeter-wave band mobile phone glass cover glass as described in claim 1, characterized in that, Applying a frequency-selective surface to a glass cover with a dielectric constant of 6.6 can improve its transmission performance. The overall structure has a passband of 23.7–30.7 GHz within 1 dB insertion loss, with a relative bandwidth of 25.7%, which can fully cover the 5G millimeter wave n257 (26.5–29.5 GHz) band.

6. The high-efficiency transmissive all-dielectric frequency selective surface for improving the transmission performance of 5G millimeter-wave band mobile phone glass cover glass as described in claim 1, characterized in that, When the all-dielectric frequency selective surface acts on the glass cover, it has a dual-polarized bandpass filtering effect and can maintain stability at a 30° oblique incidence.

7. The high-efficiency transmissive all-dielectric frequency selective surface for improving the transmission performance of 5G millimeter-wave band mobile phone glass covers according to claims 2 and 3, characterized in that, Not limited to rhomboid media, any shape of media block, such as rectangular, circular, or annular, can have its efficient transmission bandwidth of the frequency selective surface of the entire medium broadened by adjusting its size, and can also be used to improve the transmission performance of the glass cover.

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