Wide-angle incidence energy selective surface

Abstract

The present application belongs to the field of microwave high-power protection, and specifically provides a wide-angle incident energy selection structure to meet the requirements of various electronic devices such as radars in the military and other fields against strong electromagnetic pulse weapon attacks; the energy selection structure unit is composed of, from top to bottom, a first energy control layer, a first dielectric substrate, a frequency selection grid, a second dielectric substrate, a second energy control layer, and PIN diodes loaded on the first energy control layer and the second energy control layer; the first energy control layer is located on the upper surface of the first dielectric substrate; the frequency selection grid is printed in the middle of the first dielectric substrate and the second dielectric substrate; and the second energy control layer is located on the lower surface of the second dielectric substrate. The present application combines and stacks the energy selection unit and the frequency selection unit to form an electromagnetic protection surface that can adapt to wide incident angles.

Description

Technical Field

[0001] This invention belongs to the field of microwave high-power protection, specifically providing an energy selective surface with a wide angle of incidence and good bandpass characteristics. Background Technology

[0002] With the continuous development of electronic information technology and wireless communication systems, various electronic devices have been widely used in military equipment and civilian systems. However, these devices and their internal sensitive electronic components are highly sensitive to the external electromagnetic environment, especially susceptible to the effects of high-power microwaves. High-power microwaves can originate from natural electromagnetic phenomena such as lightning, or they can be caused by man-made strong electromagnetic pulses or directed energy weapons. When electromagnetic pulses with specific frequencies and high energy couple into electronic devices through communication channels such as antennas and feeders, they often interfere with the normal operation of the system, and in severe cases, may even lead to device failure or permanent damage.

[0003] In response to the electromagnetic threats posed by high-power microwaves, scholars both domestically and internationally have proposed the concept of an Electromagnetic Shielding Structure (ESS) in recent years. An ESS typically incorporates nonlinear devices such as diodes into a traditional Fiber Optic Shielding Structure (FSS), making the structure's response to electromagnetic waves dependent on the incident power. When the incident power is low, the structure is essentially transparent to electromagnetic waves. However, under high-power microwave irradiation, the ESS undergoes a state change, reflecting or suppressing electromagnetic waves, thereby providing a degree of protection for downstream electronic equipment.

[0004] Despite significant research progress on energy selective surfaces (ESS), their engineering applications still face several limitations. One prominent issue is that existing ESSs typically only provide protection against high-power microwaves within their designed frequency band, while still allowing strong transmission of high-power electromagnetic waves out of the band, making comprehensive electromagnetic shielding difficult. To address this problem, some researchers have proposed cascading ESSs with free-side surface shielding (FSS) to broaden the overall protection bandwidth. However, this cascading structure often significantly increases the system thickness, hindering low-profile and miniaturized designs, thus limiting its practical application.

[0005] With the increasing demands for electronic devices operating in complex electromagnetic environments, especially in military and aerospace fields, higher requirements are being placed on electromagnetic protection structures that combine broadband protection capabilities with low profile characteristics. Therefore, research into novel energy-selective surfaces to improve electromagnetic protection performance while maintaining structural compactness is of significant research importance and engineering value. Summary of the Invention

[0006] This invention addresses the technical problem that electronic devices, including radar systems, are susceptible to high-power microwave interference in complex electromagnetic environments by providing an energy selective surface structure capable of operating over a wide incident angle range.

[0007] To achieve the above invention object, the technical solution of the present invention is as follows:

[0008] A wide-angle incident energy selection surface, from top to bottom, successively comprises: a first energy control layer, a first dielectric substrate, a frequency selection grid, a second dielectric substrate, a second energy control layer, and PIN diodes loaded on the first energy control layer and the second energy control layer; the first energy control layer is located on the upper surface of the first dielectric substrate; the frequency selection grid is printed between the first dielectric substrate and the second dielectric substrate; the second energy control layer is located on the lower surface of the second dielectric substrate.

[0009] As a preferred solution, the first energy control layer is composed of four rectangular conductive metal sheets and narrow strip-shaped metal bands extending from the outer edges of the patches.

[0010] As a preferred solution, the four rectangular conductive metal sheets of the first energy control layer are respectively located at the four corners of the unit structure, showing a centrosymmetric distribution. The four rectangular conductive metal sheets are separated by a cross-shaped gap in the central region, and the width of the rectangular conductive metal sheet is w1 = 3.5 mm.

[0011] As a preferred solution, the narrow strip-shaped metal bands of the first energy control layer are located on the four sides of the unit structure, respectively connecting the four rectangular conductive metal sheets. The width of the narrow strip-shaped metal band is w2 = 0.8 mm, the length at both ends of the narrow strip-shaped metal band is l1 = 1.7 mm, and the distance between the narrow strip-shaped metal band and the unit edge is l2 = 0.4 mm.

[0012] As a preferred solution, the PIN diodes are located in the middle of the narrow strip-shaped metal bands of the first energy control layer and the second energy control layer. The length of the PIN diode is l3 = 1 mm, and the width is w3 = 0.8 mm.

[0013] As a preferred solution, the thickness of the first dielectric substrate and the second dielectric substrate is h = 2 mm, and the size is p*p, where p = 12 mm. The dielectric substrate is selected as Rogers RO4350C, and the relative dielectric constant is 3.66.

[0014] As a preferred solution, the frequency selection grid is composed of a "field" - shaped metal grid structure, and the metal grid includes a peripheral square metal closed loop and a cross-shaped metal strip located inside.

[0015] As a preferred solution, the widths of the metal rings on the periphery of the "field" - shaped grid loaded on the frequency selection grid are respectively a1 = 0.3 mm, a2 = 1.2 mm, a3 = 1.5 mm, and the widths of the cross-shaped metal strips inside are respectively b1 = 0.4 mm, b2 = 2.2 mm, b3 = 2.2 mm.

[0016] In terms of working principle:

[0017] This invention employs a multilayer dielectric substrate stacked structure, with different functional metasurface units set on the surface of each dielectric substrate, forming a sandwich-type energy selective surface structure. By introducing PIN diodes into the energy selective units, the transmission and reflection states of electromagnetic waves can be controllably adjusted. Under high-power electromagnetic wave incident conditions, the PIN diodes are in the conducting state, at which point the diodes can be equivalent to low-impedance elements with a resistance of approximately 5 Ω, making the overall energy selective structure present a low-impedance state, thereby reflecting the incident high-power electromagnetic waves and reducing their transmission to the downstream structure. Under low-power electromagnetic wave incident conditions, the PIN diodes are in the cut-off state, at which point the diodes can be equivalent to capacitor elements with a capacitance of approximately 0.15 pF, making the overall energy selective structure present a high-impedance state, thereby allowing low-power electromagnetic waves to transmit into the downstream structure. This achieves adaptive selective transmission and suppression of incident electromagnetic waves of different power levels; the design of the frequency selective structure enables the bandpass characteristics of the energy selective structure. Compared with existing similar energy selective surfaces, this invention can achieve effective protection against high-power microwaves over a wider incident angle range. When high-power electromagnetic waves irradiate the structure at different incident angles, the nonlinear devices in the energy-selective surface 1 enter a conducting state due to the high incident power. This causes the energy-selective structure to exhibit reflective characteristics, thereby preventing high-power microwaves from transmitting to the back-end electronic equipment and avoiding electromagnetic interference or damage. For low-power electromagnetic waves emitted by back-end electronic equipment such as radar under normal operating conditions, even at a large emission angle, the nonlinear devices remain in a cutoff state, and the energy-selective structure maintains its transmission characteristics. Low-power electromagnetic waves can pass smoothly through the energy-selective surface and radiate outward without affecting the normal communication and detection functions of the equipment. Therefore, this invention achieves adaptive suppression of wide-angle incident high-power microwaves while ensuring effective transmission of low-power operating signals, possessing both excellent electromagnetic protection performance and engineering practicality.

[0018] The innovation of this invention lies in:

[0019] I. This invention optimizes the design of the energy selection unit and its nonlinear device loading method, enabling the energy selection surface to maintain stable power selection characteristics over a wide incident angle range, thereby achieving wide-angle incident protection against high-power microwaves and effectively improving protection capabilities in complex electromagnetic environments.

[0020] Second, the present invention adopts a compact stacked structure integrating a multilayer metasurface and a multilayer dielectric substrate, which significantly reduces the overall structural thickness while ensuring high-power microwave suppression effect. Compared with existing similar energy selective surface designs, it has significant advantages in low profile and miniaturization. Attached Figure Description

[0021] Figure 1 This is a schematic diagram and dimension annotations of the unfolded multi-layer structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the overall configuration of the present invention;

[0023] Figure 3 This is the frequency response curve of the energy selective structure of the present invention under low power conditions when the y-direction polarized electromagnetic wave is incident at 0°.

[0024] Figure 4 This is the frequency response curve of the energy selective structure of the present invention under low power conditions when the y-direction polarized electromagnetic wave is incident at 60°.

[0025] Figure 5 This is the frequency response curve of the energy selective structure of the present invention under low power conditions when the x-direction polarized electromagnetic wave is incident at 0°.

[0026] Figure 6 This is the frequency response curve of the energy selective structure of the present invention under low power conditions when an x-direction polarized electromagnetic wave is incident at 75°.

[0027] Figure 7 The frequency response curves of the energy selective structure of the present invention under high power conditions when y-direction polarized electromagnetic waves are incident at 0° and 60°.

[0028] Figure 8 This is the frequency response curve of the energy selective structure of the present invention under high power conditions when x-direction polarized electromagnetic waves are incident at 0° and 75°. Detailed Implementation

[0029] The technical solution of the present invention will be described below with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention. It should be noted that, without departing from the technical concept and protection scope of the present invention, the present invention can also adopt other forms of implementation, and the relevant structures, parameters and details in this specification can be adjusted or modified accordingly according to actual application needs.

[0030] This design provides a wide-angle incident energy selective surface, characterized in that, from top to bottom, it comprises: a first energy control layer 1, a first dielectric substrate 2, a frequency selective grid 3, a second dielectric substrate 4, a second energy control layer 5, and a PIN diode 6 loaded on the first energy control layer 1 and the second energy control layer 5; the first energy control layer 1 is located on the upper surface of the first dielectric substrate 2; the frequency selective grid 3 is printed between the first dielectric substrate 2 and the second dielectric substrate 4; and the second energy control layer 5 is located on the lower surface of the second dielectric substrate 4.

[0031] In this embodiment, the width of the four rectangular conductive metal sheets of the first energy control layer is w1 = 3.5 mm.

[0032] In this embodiment, the width of the narrow strip-shaped metal band of the first energy control layer is w2 = 0.8 mm, and the lengths at both ends of the narrow strip-shaped metal band are l1 = 1.7 mm.

[0033] In this embodiment, the distance between the narrow strip-shaped metal band of the first energy control layer and the cell edge is l2 = 0.4 mm.

[0034] In this embodiment, the length of the PIN diode is l3 = 1 mm, and the width is w3 = 0.8 mm.

[0035] In this embodiment, the thickness of the first dielectric substrate and the second dielectric substrate is h = 2 mm, and the size is p*p, where p = 12 mm.

[0036] In this embodiment, the widths of the metal rings around the "tian" - shaped grid loaded on the frequency - selective grid are a1 = 0.3 mm, a2 = 1.2 mm, and a3 = 1.5 mm respectively.

[0037] In this embodiment, the widths of the cross - shaped metal strips inside the "tian" - shaped grid loaded on the frequency - selective grid are b1 = 0.4 mm, b2 = 2.2 mm, and b3 = 2.2 mm respectively.

[0038] Figure 1 is a schematic three - dimensional split structure diagram of the wide - angle incident energy - selective surface of the present invention;

[0039] Figure 2 is a schematic overall structure diagram of the wide - angle incident energy - selective surface of the present invention.

[0040] Figure 3 is the frequency - characteristic curve of the energy - selective structure when the y - polarized electromagnetic wave is incident at 0° under low - power conditions for the wide - angle incident energy - selective surface of the present invention. The wave - transmitting performance is good within a relatively wide frequency band, and the insertion loss is less than 5 dB.

[0041] Figure 4 is the frequency - characteristic curve of the energy - selective structure when the y - polarized electromagnetic wave is incident at 60° under low - power conditions for the wide - angle incident energy - selective surface of the present invention. The wave - transmitting performance is good within a relatively wide frequency band, and the insertion loss is less than 5 dB.

[0042] Figure 5 is the frequency - characteristic curve of the energy - selective structure when the x - polarized electromagnetic wave is incident at 0° under low - power conditions for the wide - angle incident energy - selective surface of the present invention. The wave - transmitting performance is good within a relatively wide frequency band, and the insertion loss is less than 5 dB.

[0043] Figure 6 The frequency response curve of the wide-angle incident energy selective surface of the present invention, under low power conditions, shows that when the x-direction polarized electromagnetic wave is incident at 75°, the energy selective structure exhibits good wave transmission performance over a wide frequency range and an insertion loss of less than 5dB.

[0044] Figure 7 The frequency response curves of the energy selection structure of the wide-angle incident energy selective surface of the present invention under high power conditions, when the y-direction polarized electromagnetic wave is incident at 0° and 60°, show that the protection effectiveness is greater than 30dB across the entire frequency band.

[0045] Figure 8 The frequency response curves of the energy selection structure of the wide-angle incident energy selective surface of the present invention are shown under high power conditions when x-direction polarized electromagnetic waves are incident at 0° and 75°. The protection effectiveness is greater than 10dB across the entire frequency band.

[0046] The above embodiments are only used to illustrate the technical concept and implementation effects of the present invention, and do not constitute a limitation of the present invention. Those skilled in the art can make various adjustments or modifications without departing from the core idea of ​​the present invention. All equivalent substitutions or improvements made based on the technical solution of the present invention should fall within the protection scope of the claims of the present invention.

Claims

1. A wide-angle incident energy selection surface, which consists of, from top to bottom, a first energy control layer (1), a first dielectric substrate (2), a frequency selection grid (3), a second dielectric substrate (4), a second energy control layer (5), and PIN diodes (6) loaded on the first energy control layer (1) and the second energy control layer (5).

2. The wide-angle incident energy selective surface according to claim 1, characterized in that: The first energy control layer (1) is composed of four rectangular conductive metal sheets and narrow strip-shaped metal bands extending from the outer edges of the patches.

3. A wide-angle incident energy selective surface according to claim 2, characterized in that: The four rectangular conductive metal sheets are respectively located at the four corners of the unit structure, showing a centrosymmetric distribution. The four rectangular conductive metal sheets are separated by a cross-shaped slit in the central area, and the width of the rectangular conductive metal sheet is w1.

4. A wide-angle incident energy selective surface according to claim 2, characterized in that: The narrow strip-shaped metal bands are located on the four sides of the unit structure and are respectively connected to the four rectangular conductive metal sheets. The width of the narrow strip-shaped metal band is w2, the lengths at both ends of the narrow strip-shaped metal band are l1, and the distance between the narrow strip-shaped metal band and the unit edge is l2.

5. A wide-angle incident energy selective surface according to claim 1, characterized in that: The PIN diodes (6) are located in the middle of the narrow strip-shaped metal bands of the first energy control layer (1) and the second energy control layer (5). The length of the PIN diode (6) is l3, and the width is w3.

6. A wide-angle incident energy selective surface according to claim 1, characterized in that: The first dielectric substrate (2) is located on the lower surface of the first energy control layer (1) and on the upper surface of the frequency selection grid (3). The second dielectric substrate (4) is located on the lower surface of the frequency selection grid (3) and on the upper surface of the second energy control layer (5).

7. A wide-angle incident energy selective surface according to claim 7, characterized in that: The thicknesses of the first dielectric substrate (2) and the second dielectric substrate (4) are h, and the size is p*p. The dielectric substrate is selected as Rogers RO4350C, and the relative dielectric constant is 3.

66.

8. A wide-angle incident energy selective surface according to claim 1, characterized in that: The frequency selection grid (3) is composed of a "field" - shaped metal grid structure, and the metal grid includes a peripheral square metal closed loop and a cross-shaped metal strip located inside.

9. A wide-angle incident energy selective surface according to claim 8, characterized in that: The widths of the metal rings on the periphery of the "field" - shaped grid loaded on the frequency selection grid (3) are a1, a2, a3 respectively; the widths of the cross-shaped metal strips inside are b1, b2, b3 respectively.

10. A wide-angle incident energy selective surface according to claim 1, characterized in that: The structure of the second energy control layer (5) is the same as that of the first energy control layer (1) and is located on the lower surface of the second dielectric substrate (4).

Images