Ultra-wideband wide-angle electromagnetic absorber based on tight coupling antenna unit structure

Abstract

How to effectively increase the absorption rate of electromagnetic waves is an urgent problem to be solved in the prior art. The invention provides an electromagnetic absorber with ultra-wide-band wide-angle electromagnetic wave absorption capacity based on a tight coupling array antenna unit in order to overcome the defects of an existing electromagnetic absorber. On the basis of a tightly coupled antenna unit, a reciprocity principle is utilized, a resistor is added at an excitation port, and structures such as a wide-angle impedance matching layer and the like are combined, so that ultra-wideband efficient absorption of incident electromagnetic waves under the conditions of large-angle oblique incidence and the like can be realized, and the antenna can be widely applied to reduction of a radar scattering sectional area.

Description

Technical Field

[0001] The invention belongs to the field of wireless communications, and in particular relates to an ultra-wide bandwidth angle electromagnetic absorber based on a tightly coupled antenna unit structure. Background Art

[0002] Objects can present colorful colors, and measuring instruments can distinguish different spectral lines, which are all caused by objects absorbing electromagnetic waves. As we all know, there are electromagnetic waves of different bands in nature, ranging from low to high frequencies, and are widely used in various fields such as television broadcasting, radar communications, cellular mobile networks, medical disinfection and sterilization, anti-counterfeiting labels and banknote detection. If humans want to make full use of the advantages of electromagnetic waves and prevent the harm of electromagnetic waves, one of the most important research directions is to absorb electromagnetic waves. Therefore, electromagnetic wave absorbers have naturally become a basic and important device since humans began to study electromagnetic waves.

[0003] The ability of a substance to absorb electromagnetic waves depends on the intrinsic absorption characteristics of the substance. When electromagnetic waves act on a substance, there will be resistance loss (ohmic lossy materials), dielectric loss (dielectric materials) and hysteresis loss (magnetic dielectric materials), which will cause the electromagnetic energy incident on the object to be converted into other forms and dissipated. In general, the bandwidth of an object absorbing electromagnetic waves is relatively wide, but the absorption rate is very low. If you want to increase the absorption rate, you can increase the thickness of the object to achieve it. In this way, the miniaturization of this type of absorber will be greatly reduced in portability. In addition, in radar communication systems, radar cross-sectional area is one of the most critical indicators. It is a physical quantity that characterizes the intensity of scattered waves generated by a target in a certain direction under the irradiation of radar waves. Using materials that absorb electromagnetic waves to reduce the radar cross-sectional area has been proven to be an extremely effective measure. Therefore, how to effectively increase the absorption rate of electromagnetic waves has received widespread attention in the research of electromagnetic absorbers. Among them, the "perfect absorber" (Perfect Absorber) based on metamaterial electromagnetic waves is an emerging application field. In 2008, Landy et al. first proposed the concept of a perfect absorber, which was the first innovative application that combined metamaterials with the field of electromagnetic wave absorption. By rationally designing the physical dimensions of the absorber device and the dielectric properties and other parameters, the absorber can couple with the electric and magnetic field components of the incident electromagnetic wave, and can absorb all electromagnetic waves incident on the absorber within a certain frequency band. Therefore, electromagnetic absorbers based on metamaterials have potential application value in the fields of bolometers, electromagnetic wave stealth technology, solar cells, etc., and have also received widespread attention in the field of broadband absorbers. However, other types of broadband microwave absorbers are rarely reported. Therefore, based on the ultra-wideband and wide-angle radiation characteristics of the tightly coupled structure and using the reciprocity principle, an ultra-wideband and wide-angle electromagnetic absorber is proposed, which has great significance in practical applications. Summary of the invention

[0004] The present invention aims at solving the problems of the existing absorber and proposes an electromagnetic absorber with ultra-wide bandwidth and electromagnetic wave absorption capability by using a tightly coupled array antenna unit. The electromagnetic wave is effectively absorbed by loading a resistance structure.

[0005] The electromagnetic absorber of the present invention comprises a wide-angle matching layer 1, a wide-angle matching layer 2, a dielectric substrate 1, a dielectric substrate 2, and a metal floor, which are arranged in sequence from top to bottom. Two dipole antenna units are cross-placed on the dielectric substrate 1 to realize a dual-polarization function, and an excitation port is formed at the intersection of the two dipole antenna units. A resistor is loaded on the excitation port to realize ultra-wideband / wide-angle absorption of electromagnetic waves. By loading two layers of wide-angle matching layers, efficient absorption of incident waves at large angles is achieved.

[0006] Preferably, the resistance value of the resistor is 110 ohms.

[0007] Based on the tightly coupled antenna unit, the present invention utilizes the reciprocity principle, adds resistance at the excitation port, and combines structures such as a wide-angle impedance matching layer to achieve ultra-wideband efficient absorption of incident electromagnetic waves under conditions of large-angle oblique incidence, and can be widely used in reducing radar scattering cross-sectional area.

[0008] The beneficial effects of the present invention are

[0009] 1. It can be used for simultaneous absorption of linear polarization or dual polarization, or total reflection of any linear polarization, and efficient absorption of orthogonal polarization.

[0010] 2. It can achieve ultra-wideband / wide-angle efficient absorption of electromagnetic waves.

[0011] 3. It can significantly reduce the radar cross-sectional area. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the electromagnetic absorber unit of the present invention.

[0013] Figure 2 Schematic diagram of the dual-polarized metal patch in the electromagnetic absorber unit of the present invention.

[0014] Figure 3 This is a graph showing how the reflection amplitude at different incident angles varies with frequency in a periodic environment according to the present invention.

[0015] Figure 4 This is a graph showing the absorption efficiency at different incident angles varies with frequency in a periodic environment.

[0016] Figure 5 This is a schematic diagram of the arrangement of an 8×8 small-scale array of the present invention. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Figure 1 It is an ultra-wideband / wide-angle electromagnetic absorber unit based on a tightly coupled antenna unit structure in an embodiment of the present invention. On the basis of the tightly coupled antenna unit, it uses the reciprocity principle to load a resistor on the excitation port to achieve ultra-wideband / wide-angle efficient absorption of electromagnetic waves. In this embodiment, 101-1 and 101-2 are wide-angle matching layers, 101-3 and 101-4 are dielectric substrates, 101-5 is a metal floor, 101-6 is a metal patch, and 101-7 to 101-11 are periodic environment simulation setting boundaries. The thicknesses of t1, t2, t3, t4, and t5 are 2mm, 3.5mm, 0.254mm, 5.5mm, and 2mm, respectively, and the unit size is 8.4mm×8.4mm.

[0019] Figure 2 Schematic diagram of a dual-polarized metal patch of an ultra-wideband / wide-angle electromagnetic absorber unit based on a tightly coupled antenna unit structure in an embodiment of the present invention. 201-2 and 201-3 are loading resistors, and the resistance value of the resistor in this embodiment is 110 ohms.

[0020] Figure 3 The reflection amplitude of the ultra-wideband / wide-angle electromagnetic absorber unit based on the tightly coupled antenna unit structure in the embodiment of the present invention varies with the frequency at different incident angles in a periodic environment;

[0021] Figure 4 The absorption efficiency of the ultra-wideband / wide-angle electromagnetic absorber unit based on the tightly coupled antenna unit structure in the embodiment of the present invention varies with frequency at different incident angles in a periodic environment;

[0022] Figure 5 Schematic diagram of the arrangement of an 8×8 small-scale array of ultra-wideband / wide-angle electromagnetic absorbers based on a tightly coupled antenna unit structure in an embodiment of the present invention.

[0023] Depend on Figure 3 and Figure 4 It can be seen that the ultra-wideband / wide-angle electromagnetic absorber unit based on the tightly coupled antenna unit structure in the embodiment of the present invention can achieve efficient absorption of incident waves at a large angle within an ultra-wide frequency range, proving the feasibility and superiority of the method proposed in the present invention.

[0024] The present invention is not limited to the above specific implementations, and the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made to the above implementations based on the technical essence of the present invention shall be included in the protection scope of the present invention.

Claims

1. An ultra-wideband / wide-angle electromagnetic absorber based on a tightly coupled antenna unit structure, characterized in that: It includes a wide-angle matching layer 1, a wide-angle matching layer 2, a dielectric substrate 1, a dielectric substrate 2, and a metal floor, which are arranged in sequence from top to bottom; wherein two dipole antenna units are cross-placed on the dielectric substrate 1, an excitation port is formed at the intersection, and a resistor is loaded on the excitation port to achieve ultra-wideband / wide-angle absorption of electromagnetic waves.

2. The ultra-wideband / wide-angle electromagnetic absorber based on a tightly coupled antenna unit structure according to claim 1, characterized in that: The resistance value of the resistor is 110 ohms.

Images