A dual-band transmissive metasurface unit with a small frequency interval

Abstract

The present invention is a dual-band transmissive metasurface unit with a small frequency interval. The metasurface unit includes four identical metal structure layers (4) with dielectric substrates (3) arranged in sequence. The metal structure layers are separated by air. Each metal structure layer surface contains two square open-loop metal slots, namely a first square open-loop metal slot (1) symmetrically arranged up and down in the middle and second square open-loop metal slots (2) symmetrically arranged up and down on both sides of the first square open-loop metal slot. The longitudinal slot lengths Ly1 and Ly2 remain unchanged, and the transverse slot lengths Ls1 and Ls2 can be independently set, so as to realize the regulation of the transmission phase in two adjacent frequency bands with a small interval. The invention integrates the transmission phase regulation functions of two frequency bands of 7.52 GHz and 8.9 GHz, while realizing a large range of phase regulation, ensuring that its transmittance is not lower than -3 dB, and is applied in fields such as dual-frequency transmission array antennas and dual-frequency metasurface communications.

Description

Technical Field

[0001] The present invention belongs to the cross - field of novel artificial electromagnetic materials and antenna technologies, and relates to a dual - band transmissive metasurface unit with a small frequency interval. More specifically, it is a transmissive metasurface unit operating at two frequency bands of 7.45 GHz and 8.8 GHz, which can independently achieve a large - range continuous phase modulation within the two frequency bands, and the interval between the two frequency bands is small, only 16%, and it can be applied in the fields of antennas and imaging. Background Art

[0002] The metasurface technology is one of the novel technologies that have been focused on in the field of transmissive array antennas. By modulating parameters such as the amplitude and phase of the transmitted wave using metasurface units, functions such as electromagnetic beam shaping, beam scanning, and near - field electric field distribution reconstruction can be achieved. Compared with reflective units, transmissive metasurface units are not affected by feed - source occlusion and are very suitable for application in array antennas and radar front - ends. Based on the classical single - band phase - modulation transmissive metasurface units, in recent years, several dual - band transmissive metasurface designs have emerged. By introducing two less - interfering control structures, independent phase modulation in two frequency bands can be achieved. However, since a high transmission amplitude needs to be ensured while achieving dual - band transmission phase modulation, the interval between the two operating frequency bands of most designs is large, generally more than 30%, so as to ensure that there is no mutual interference between the two frequency bands. However, too large a frequency - band interval will make the receiving - end equipment complex. Therefore, it is urgent to initiate the research and development of dual - band transmissive metasurface units with a small frequency interval to achieve dual - frequency independent phase modulation within a small frequency - band range. Summary of the Invention

[0003] Technical Problem: The purpose of the present invention is to provide a dual - band transmissive metasurface unit with a small frequency interval. By designing two specifications of symmetric square - open - loop metal slot gaps and independently changing their lateral slot lengths Ls 1 and Ls 2 , the transmission phase modulation of two adjacent frequency bands is achieved, and then the purpose of regulating the far - field pattern is achieved.

[0004] Technical Solution: A dual - band transmissive metasurface unit with a small frequency interval of the present invention includes four identical metal - structure layers with dielectric substrates arranged in sequence. The metal - structure layers are separated by air. Each metal - structure layer surface contains two square - open - loop metal slot gaps, namely a first square - open - loop metal slot gap symmetrically arranged up and down in the middle and second square - open - loop metal slot gaps symmetrically arranged up and down on both sides of the first square - open - loop metal slot gap.

[0005] There are 2 first square - open - loop metal slot gaps symmetrically arranged up and down in the middle on each metal - structure layer.

[0006] There are 4 second - party split - ring metal slots on each metal structure layer, which are located on both sides of the first - party split - ring metal slot and are symmetrically arranged vertically.

[0007] The longitudinal slot length Ly 1 and the transverse slot length Ls 1 of the first - party split - ring metal slot can be independently designed. By changing the transverse slot length Ls 1 the transmission phase at frequency band 1 is regulated.

[0008] The longitudinal slot length Ly 2 and the transverse slot length Ls 2 of the second - party split - ring metal slot can be independently designed. By changing the transverse slot length Ls 2 the transmission phase at frequency band 2 is regulated.

[0009] The longitudinal slot length Ly 1 of the first - party split - ring metal slot is not equal to the longitudinal slot length Ly 2 of the second - party split - ring metal slot.

[0010] The electrical - size thickness of the metal structure layer ranges from 0.0001 wavelength to 0.1 wavelength.

[0011] The first - party split - ring metal slot and the second - party split - ring metal slot are processed on a dielectric substrate, and the electrical - size thickness H of the dielectric substrate ranges from 0.0001 wavelength to 0.5 wavelength.

[0012] The electrical - size thickness of the air separation H 0 ranges from 0.0001 wavelength to 0.5 wavelength.

[0013] The width P of the metal structure layer ranges from 0.0001 wavelength to 1 wavelength.

[0014] Advantages: Compared with the prior art, the present invention has the following advantages

[0015] 1. Compared with the single - band transmission - type metasurface unit, the present invention can independently operate in two adjacent frequency bands, and the integration degree of the unit is higher.

[0016] 2. Compared with the existing dual - band transmission - type metasurface, the two operating frequency bands of the present invention have a smaller interval and lower mutual coupling.

[0017] 3. The present invention has a large phase coverage range and can be continuously regulated, enabling more precise electromagnetic wave regulation.

[0018] 4. The four - layer metal units of the present invention are exactly the same, and the processing cost is lower. Description of the Drawings

[0019] Figure 1 It is the front view of the unit structure of the present invention.

[0020] Figure 2 It is the side view of the unit structure of the present invention.

[0021] Figure 3 It is the schematic diagram of the induced electric field of the unit of the present invention.

[0022] Figure 4 It is the relationship diagram between the transmission phase regulation and the size of the unit of the present invention at 7.45 GHz.

[0023] Figure 5 It is the relationship diagram between the transmission amplitude and the size of the unit of the present invention at 7.45 GHz.

[0024] Figure 6 It is the relationship diagram between the transmission phase regulation and the size of the unit of the present invention at 8.8 GHz.

[0025] Figure 7 It is the relationship diagram between the transmission amplitude and the size of the unit of the present invention at 8.8 GHz.

[0026] In the figure: the first square split-ring metal slot 1, the second square split-ring metal slot 2, the dielectric substrate 3, the metal structure layer 4. Detailed implementation manners

[0027] The dual-band transmissive metasurface unit with a small frequency interval of the present invention includes four identical metal structure layers with a dielectric substrate 3 separated by air. Each layer contains 2 first square split-ring metal slots 1 and 4 second square split-ring metal slots 2, which are located in the middle and on both sides respectively, and their transverse slot lengths Ls 1 and Ls 2 can be independently varied, so as to realize the transmission phase regulation in two frequency bands with a small interval.

[0028] Among them,

[0029] The size of the split-ring metal slot ranges from 0.0001 wavelength to 0.1 wavelength.

[0030] The metal layer is processed on a dielectric substrate with any dielectric constant, and the electrical size thickness of the dielectric substrate ranges from 0.0001 wavelength to 0.5 wavelength.

[0031] The material of the metal layer has excellent conductivity, and the electrical size thickness ranges from 0.0001 wavelength to 0.1 wavelength.

[0032] The air separation H 0 has an electrical size thickness ranging from 0.0001 wavelength to 0.5 wavelength.

[0033] The width P of the metal structure layer ranges from 0.0001 wavelength to 1 wavelength.

[0034] A dual-band transmissive metasurface unit with a small frequency interval according to the present invention can operate simultaneously in two adjacent frequency bands with a small frequency interval, realize independent regulation of the dual-band transmission phase, and ensure a high transmittance. It is designed with two different specifications of low-coupling symmetric square split-ring metal slots, located in the middle and on both sides respectively. Each slot includes two longitudinal slots and one transverse slot, where the length of the longitudinal slot Ly 1 and Ly 2 remain unchanged, and the length of the transverse slot Ls 1 and Ls 2 can be independently set. By adjusting the size, the resonant frequency of the unit is changed, so as to realize independent regulation of the transmission phase at 7.45 GHz and 8.8 GHz.

[0035] Figure 1 and Figure 2 show the front view and side view of the unit structure of the present invention, including four identical metal layers with dielectric substrates separated by air. Each layer contains two independent square split-ring metal slots, namely the first square split-ring metal slot 1 symmetrically arranged up and down in the middle and the second square split-ring metal slot 2 symmetrically arranged up and down on both sides of the first square split-ring metal slot 1. Where the length of the longitudinal slot Ly 1 and Ly 2 remain unchanged, and the length of the transverse slot Ls 1 and Ls 2 can be independently set, so as to realize the regulation of the transmission phase within two frequency bands with a small interval. Among them, the slot size ranges from 0.0001 wavelength to 0.1 wavelength; the metal layer material has excellent conductivity, and the electrical size thickness ranges from 0.0001 wavelength to 0.1 wavelength; the metal layer is processed on a dielectric substrate with any dielectric constant, and the electrical size thickness H ranges from 0.0001 wavelength to 0.5 wavelength; the electrical size thickness of the air separation H 0 ranges from 0.0001 wavelength to 0.5 wavelength; the broadband P of the metal structure layer ranges from 0.0001 wavelength to 1 wavelength.

[0036] Figure 2 shows the schematic diagram of the induced electric field of the unit of the present invention. It can be seen that when the operating frequency is 7.52 GHz, the resonance mainly occurs in the first square split-ring metal slot (1) located in the middle, and the resonance in the second square split-ring metal slot 2 on both sides is relatively small, indicating that the transmission phase at 7.45 GHz is mainly determined by the size of the first square split-ring metal slot 1; when the operating frequency is 8.8 GHz, the resonance mainly occurs in the second square split-ring metal slot 2 located on both sides, and there is almost no resonance in the first square split-ring metal slot 1 in the middle, indicating that the transmission phase at 8.9 GHz is mainly determined by the size of the control structures on both sides, and the isolation degree is relatively high.

[0037] Figure 4 and Figure 5 give the relationship diagrams of the transmission phase regulation and the transmission amplitude versus size of the unit of the present invention at 7.45 GHz. It can be seen that the transmission phase mainly changes with the transverse slot size Ls of the first split-ring metal slot 1 1 but is affected by the transverse slot size Ls of the second split-ring metal slot 2 2 . However, since the regulation freedom degree of the control structure is greater than the phase regulation freedom degree, appropriate size combinations can be selected to achieve a large range of phase regulation. Combining the phase response in Figure 4 and Figure 5 the amplitude response in, it is obtained that under the condition that the transmittance is higher than -3 dB, about 320° of phase control can be achieved at 7.45 GHz.

[0038] Figure 6 and Figure 7 give the relationship diagrams of the transmission phase regulation and the transmission amplitude versus size of the unit of the present invention at 8.8 GHz. It can be seen that the transmission phase mainly changes with the transverse slot size Ls of the second split-ring metal slot 2 2 and is basically not affected by the transverse slot size Ls of the first split-ring metal slot 1 1 . Therefore, appropriate size combinations can be selected to achieve a large range of phase regulation. Combining the phase response in Figure 6 and Figure 7 the amplitude response in, it is obtained that under the condition that the transmittance is higher than -3 dB, about 360° of phase control can be achieved at 8.8 GHz.

Claims

1. A dual-band transmissive metasurface unit with a small frequency interval, characterized in that the metasurface unit includes four identical metal structure layers (4) with dielectric substrates (3) arranged in sequence. The metal structure layers (4) are separated by air. Each metal structure layer (4) surface contains two square open-loop metal slots, namely the first square open-loop metal slot (1) symmetrically arranged up and down in the middle and the second square open-loop metal slots (2) symmetrically arranged up and down on both sides of the first square open-loop metal slot (1); The longitudinal slot length Ly of the first-party open-loop metal slot (1) 1 and the transverse slot length Ls 1 can both be independently designed. By changing the transverse slot length Ls 1 the transmission phase at frequency band 1 can be regulated; The longitudinal slot length Ly of the second open-loop metal slot (2) 2 and the transverse slot length Ls 2 can both be designed independently. By changing the transverse slot length Ls 2 the transmission phase at frequency band 2 can be regulated; the first square open-loop metal slot (1) has 2 symmetrically arranged up and down in the middle on each metal structure layer (4); the second square open-loop metal slots (2) have a total of 4 on each metal structure layer (4), and are symmetrically arranged up and down on both sides of the first square open-loop metal slot (1); The longitudinal slot length Ly of the first split-ring metal slot (1) 1 is not equal to the longitudinal slot length Ly of the second split-ring metal slot (2) 2 .

2. The dual-band transmissive metasurface unit with a small frequency interval according to claim 1, characterized in that: the electrical size thickness of the metal structure layer (4) ranges from 0.0001 wavelength to 0.1 wavelength.

3. The dual-band transmissive metasurface unit with a small frequency interval according to claim 1, characterized in that: the first square open-loop metal slot (1) and the second square open-loop metal slots (2) are processed on the dielectric substrate (3), and the electrical size thickness H of the dielectric substrate (3) ranges from 0.0001 wavelength to 0.5 wavelength.

4. The dual-band transmissive metasurface unit with a small frequency interval according to claim 3, characterized in that: The air-spaced H 0 has an electrical size thickness ranging from 0.0001 wavelength to 0.5 wavelength.

5. The dual-band transmissive metasurface unit with a small frequency interval according to claim 2, characterized in that: the width P of the metal structure layer (4) ranges from 0.0001 wavelength to 1 wavelength.

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