A broadband polarization-insensitive electromagnetic wave absorber based on square dipole antenna structure

Abstract

The application discloses a kind of broadband polarization-insensitive electromagnetic wave absorbers based on square dipole antenna structure, solve electromagnetic wave absorbing bandwidth limited, sensitive to incident wave polarization direction and other problems.The structure of electromagnetic wave absorber includes from top to bottom first metal layer (1), first dielectric layer (2), second metal layer (3), second dielectric layer (4), metal reflecting surface (5), the unit structure of first metal layer includes first metal block (6), second metal block (7), third metal block (8), fourth metal block (9), fifth metal block (10), sixth metal block (11), welding resistance (12) between third metal block (8) and sixth metal block (11), welding resistance (13) between fourth metal block (9) and fifth metal block (10), the unit structure of second metal layer is coupling block (14).The application has relatively wide electromagnetic wave absorption bandwidth, and wave-absorbing characteristics are not sensitive to the polarization direction of incident wave.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic wave absorber technology, and particularly relates to a broadband polarization-insensitive electromagnetic absorber based on a dipole array. Background Technology

[0002] The rapid development of modern communication technology has led to the extensive exploitation of spectrum resources. Interference between electromagnetic signals from different devices can affect the normal operation of communication equipment, becoming a problem hindering the development of wireless communication technology. To shield against mutual interference between electromagnetic signals from different devices, electromagnetic absorbers can be used to absorb electromagnetic radiation generated by the device itself or external interference signals. They convert electromagnetic waves incident on the device's surface into heat or other forms of energy, effectively weakening the reflection and transmission of electromagnetic waves and reducing or eliminating the adverse effects of electromagnetic interference. In addition, electromagnetic absorbers are widely used in areas such as radar cross-section reduction for aircraft and ships, antenna stealth, electromagnetic compatibility measurement, and antenna measurement, playing a positive role in promoting the development of industries such as communications and radar.

[0003] The electromagnetic wave absorber disclosed in patent document 202021135550.1 uses magnetic absorbing materials and a multi-layer structure to achieve the absorption structure. Although it has a certain absorption capacity for electromagnetic waves in a wide range, the absorption rate is not high, and it only has a high absorption rate at dual-frequency points. The absorber disclosed in patent document 202210492215.4 uses an electromagnetic metamaterial resonant structure, which only has a high absorption rate for electromagnetic waves in a narrow range, thus limiting its application scope.

[0004] In summary, the main problems currently facing electromagnetic wave absorbers are how to expand the absorption bandwidth of electromagnetic waves, improve the absorption rate of electromagnetic waves, and how to ensure that electromagnetic wave absorbers can maintain a high absorption rate for incident waves with different polarization angles. Summary of the Invention

[0005] The purpose of this invention is to propose a broadband polarization-insensitive electromagnetic absorber based on a square dipole antenna structure, which overcomes the problems of narrow operating bandwidth and polarization sensitivity of existing electromagnetic absorbers, and can achieve the goal of expanding the electromagnetic wave absorption bandwidth.

[0006] The technical solution of this invention is: a broadband polarization-insensitive electromagnetic absorber based on a square dipole antenna structure. The absorber structure includes, from top to bottom, a first metal layer 1, a first dielectric layer 2, a second metal layer 3, a second dielectric layer 4, and a metal reflective surface 5. The unit structure of the first metal layer includes a first metal block 6, a second metal block 7, a third metal block 8, a fourth metal block 9, a fifth metal block 10, and a sixth metal block 11. A resistor 12 is welded between the third metal block 8 and the sixth metal block 11, and a resistor 13 is welded between the fourth metal block 9 and the fifth metal block 10. The unit structure of the second metal layer is a coupling block 14. The first metal block 6 and the second metal block 7 are isosceles right triangles. The third metal block 8 and the fourth metal block 9 are squares with one end chamfered, and a resistor is welded to one end of the chamfered corner. The fifth metal block 10 and the sixth metal block 11 are isosceles right triangles with one end chamfered, and a resistor is welded to one end of the chamfered corner. The resistors are arranged symmetrically with point O as the origin, consisting of the first metal block 6, the upper half of the second metal block 7 and the third metal block 8, and the left half of the fourth metal block 9. The coupling block 14 is a square with point O as its center. The first metal block 6, the second metal block 7, the third metal block 8 and the fourth metal block 9 are coupled to the coupling block 14 with overlapping portions, and the coupling degree is controlled by their side lengths. The first dielectric layer 2 is the dielectric substrate of the circuit board, and the patterns on the first metal layer 1 and the second metal layer 3 are etched on its upper and lower sides, respectively. The height of the hypotenuse of the first metal block 6, the second metal block 7, the fifth metal block 10 and the sixth metal block 11 is approximately one-eighth of the working wavelength corresponding to the center frequency. The diagonal length of the third metal block 8 and the fourth metal block 9 is approximately one-quarter of the working wavelength corresponding to the center frequency. The thickness of the second dielectric layer 4 is approximately one-quarter of the working wavelength corresponding to the center frequency.

[0007] The principle of this invention is as follows: Electromagnetic waves are incident on the surface of the absorber, captured by the metal blocks on the surface, and then absorbed by the first resistor 12 and the second resistor 13, thereby reducing electromagnetic wave reflection. The dipole antenna structure formed by the first metal block 6, the third metal block 8, and the sixth metal block 11 captures electromagnetic waves in the vertical direction. Similarly, the dipole antenna structure formed by the second metal block 7, the fourth metal block 9, and the fifth metal block 10 captures electromagnetic waves in the horizontal direction. A resistor with an appropriate resistance value is used at the center port of the dipole antenna structure to absorb electromagnetic waves, achieving a high electromagnetic wave absorption rate over a wide bandwidth. The positions of the metal block resistors are designed with chamfered corners to facilitate the soldering of surface-mount resistors. The coupling block 14 is located on the second metal layer 3 and forms mutual coupling with the first metal block 6, the second metal block 7, the third metal block 8, and the fourth metal block 9 on the first metal layer 1, further expanding the bandwidth of the absorber. The diagonal lengths of square metal blocks 8 and 9 are approximately one-quarter of the wavelength corresponding to the center frequency. The hypotenuse lengths of triangular metal blocks 6, 7, 10, and 11 are also approximately one-quarter of the wavelength corresponding to the center frequency. The thickness of the second dielectric layer 4 is approximately one-quarter of the operating wavelength corresponding to the center frequency. By periodically arranging these unit structures to form a complete absorber, electromagnetic wave absorption can be achieved.

[0008] Advantages and beneficial effects of the present invention:

[0009] The broadband polarization-insensitive absorber based on a square dipole antenna structure of this invention is manufactured using common circuit board technology, resulting in simple fabrication and low cost. In terms of electromagnetic wave absorption, the square dipole structure and coupling block design enable it to achieve high absorption efficiency over a wide bandwidth. Furthermore, due to its symmetrical structure, the absorber is insensitive to the polarization direction of the incident electromagnetic wave, maintaining high absorption efficiency for waves arriving in any polarization direction. Attached Figure Description

[0010] Figure 1 This is the pattern of the first metal layer of the unit of the present invention.

[0011] Figure 2 This is the second metal layer pattern of the unit of the present invention.

[0012] Figure 3 This is a side view of the present invention.

[0013] Figure 4 This is an overall structural diagram of the present invention.

[0014] Figure 5 This is a simulated curve of the absorption rate of the present invention under electromagnetic wave irradiation at different polarization angles. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: A broadband polarization-insensitive electromagnetic absorber based on a square dipole antenna structure, the absorber structure comprising, from top to bottom, a first metal layer 1, a first dielectric layer 2, a second metal layer 3, a second dielectric layer 4, and a metal reflective surface 5, as shown below. Figure 3 As shown; the unit structure of the first metal layer includes a first metal block 6, a second metal block 7, a third metal block 8, a fourth metal block 9, a fifth metal block 10, and a sixth metal block 11, as follows. Figure 1 As shown; the welding resistance 12 is between the third metal block 8 and the sixth metal block 11, and the welding resistance 13 is between the fourth metal block 9 and the fifth metal block 10; the unit structure of the second metal layer is a coupling block 14, as shown. Figure 4 As shown; the first metal block 6 and the second metal block 7 are isosceles right triangles; the third metal block 8 and the fourth metal block 9 are squares with one end chamfered, and a resistor is welded to one end of the chamfered corner; the fifth metal block 10 and the sixth metal block 11 are isosceles right triangles with one end chamfered, and a resistor is welded to one end of the chamfered corner; the first metal block 6, the upper half of the second metal block 7, the third metal block 8, and the left half of the fourth metal block 9 are arranged symmetrically with point O as the origin; the coupling block 14 is a square with point O as its center; the first metal block 6, the second metal block 7, the third metal block 8, and the fourth metal block 9 are... The coupling block 14 should not overlap vertically to avoid coupling; the coupling degree is controlled by its side length. The first dielectric layer 2 is the dielectric substrate of the circuit board, with the patterns of the first metal layer 1 and the second metal layer 3 etched above and below it, respectively. The height of the hypotenuse of the first metal block 6, the second metal block 7, the fifth metal block 10, and the sixth metal block 11 is approximately one-eighth of the working wavelength corresponding to the center frequency; the diagonal length of the third metal block 8 and the fourth metal block 9 is approximately one-quarter of the working wavelength corresponding to the center frequency; the thickness of the second dielectric layer 4 is approximately one-quarter of the working wavelength corresponding to the center frequency. The above unit structures are arranged periodically to form a complete electromagnetic absorber structure, such as... Figure 4 As shown.

[0016] To further illustrate the feasibility of the above technical solution, a specific design example is given below: a broadband polarization-insensitive electromagnetic absorber based on a square dipole antenna structure. The first dielectric is a 0.6mm thick FR4 dielectric substrate, and the second dielectric is 7.5mm thick air. Both the first and second metal layers are 0.018mm thick copper foil. Resistors 12 and 13 both have a resistance of 120Ω. The diagonal length of the square metal block in the first layer is 9.5mm, and the side length of the square in the second metal layer is 3.8mm. The gap width between adjacent metal blocks 6, 7, 8, and 9 is 1.64mm. Figure 5The figure shows the simulated absorptivity as a function of frequency. As can be seen from the figure, the absorptivity can be maintained above 90% in the frequency band of 3.08GHz-10.18GHz, and the bandwidth remains basically unchanged under the illumination of different polarized incident waves.

Claims

1. A broadband polarization-insensitive electromagnetic absorber based on a square dipole antenna structure, characterized in that: The absorber structure includes, from top to bottom, a first metal layer (1), a first dielectric layer (2), a second metal layer (3), a second dielectric layer (4), and a metal reflective surface (5); the unit structure of the first metal layer includes a first metal block (6), a second metal block (7), a third metal block (8), a fourth metal block (9), a fifth metal block (10), and a sixth metal block (11); a resistor (12) is welded between the third metal block (8) and the sixth metal block (11), and a resistor (13) is welded between the fourth metal block (9) and the fifth metal block (10); the unit structure of the second metal layer is a coupling block (14); the first metal block (6) and the second metal block (7) are isosceles right triangles; the third metal block (8) and the fourth metal block (9) are squares with one end chamfered, and a resistor is welded to one end of the chamfered corner; the fifth metal block (10) and the sixth metal block (11) are isosceles right triangles with one end chamfered, and a resistor is welded to one end of the chamfered corner; the first metal block (6), the second metal block (7), the third metal block (8), the fourth metal block (9), the fifth metal block (9), the sixth metal block (11), the fifth metal block (10), ... and the The upper half of the metal block (7), the third metal block (8), and the left half of the fourth metal block (9) are arranged symmetrically with point O as the origin; the coupling block (14) is a square with point O as its center; the first metal block (6), the second metal block (7), the third metal block (8), and the fourth metal block (9) are coupled to the coupling block (14) with overlapping parts, and the coupling degree is controlled by its side length; the first dielectric layer (2) is the dielectric substrate of the circuit board, and the patterns on the first metal layer (1) and the second metal layer (3) are etched on its upper and lower sides respectively; the height of the hypotenuse of the first metal block (6), the second metal block (7), the fifth metal block (10), and the sixth metal block (11) is about one-eighth of the working wavelength corresponding to the center frequency, and the diagonal length of the third metal block (8) and the fourth metal block (9) is about one-quarter of the working wavelength corresponding to the center frequency; the thickness of the second dielectric layer (4) is about one-quarter of the working wavelength corresponding to the center frequency.

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