Van Atta metasurface

Abstract

The invention provides a Van Atta metasurface which is characterized in that RIS units are symmetrically distributed about the geometric center of a Van Atta array, two RIS units in a symmetrical relation are marked as an antenna pair, the two RIS units are connected, and then direction backtracking is achieved. And the lengths of the transmission lines for connecting the two RIS units in all the antenna pairs are equal. A one-way amplifier is added on the transmission line to form an amplified RIS, and the intensity of a scattered field of the RIS is changed by controlling the gain of the one-way amplifier. The device has the capability of simultaneously realizing signal amplification and direction backtracking, and is simple in structure, low in cost and wide in application prospect; the amplifier is added on the transmission line of the antenna unit pair, and the radiation capability of the RIS can be controlled by controlling the gain of the amplifier.

Description

Technical Field

[0001] The invention belongs to the field of electromagnetic microwave technology, and particularly relates to a Van Atta supersurface. Background Art

[0002] In recent years, as the fifth generation of mobile communication technology (5G) has been widely adopted by many countries, people are increasingly interested in the research and development of the sixth generation of mobile communication technology (6G). In the related research of 6G, reconfigurable intelligent surface (RIS) technology has attracted great attention in the communication industry. Different from traditional metasurfaces, RIS introduces controllable components such as PIN (positive-intrinsic-negative) diodes and varactor diodes in unit design, and integrates processors such as field programmable gate arrays and microcontrollers to achieve intelligent real-time control of spatial electromagnetic waves and form an electromagnetic field with tunable amplitude, phase, polarization and frequency. With its excellent electromagnetic field regulation capability, RIS has significant advantages such as high cost-effectiveness, low power consumption and easy deployment, so its application prospects are very broad. On the other hand, the direction tracing technology can automatically trace the transmitting antenna beam back to the direction of the incoming wave without knowing the prior knowledge such as the position of the incoming wave. It is an effective means of aligning the transmitting and receiving beams under cooperative conditions such as base station communication and wireless energy transmission.

[0003] However, current passive RIS lacks the ability to amplify signals, which greatly limits its transmission range. To address this limitation, some scholars have proposed a new design that combines amplifiers and RIS units. This design integrates the amplifier function directly into the metasurface, thereby enhancing the reflected electromagnetic waves. Although many articles have explored the combination of amplifiers and RIS, there are only a handful of articles that simultaneously achieve signal amplification and phase adjustment on RIS. At present, the solutions in these articles that simultaneously control signal phase and amplitude all rely on phase shifters that only have fixed angle phase shifting functions. Therefore, this solution cannot achieve the function of flexible phase adjustment in phase control, and the addition of multiple phase shifters will make the structure of RIS more complicated, thereby increasing the cost.

[0004] The Van Atta antenna array is usually composed of multiple pairs of antennas. The antenna units in the array are symmetrically distributed and each pair of antenna units is connected by a transmission line of equal physical length or equal electrical length. After one antenna unit in the antenna pair receives the pilot signal, it is transmitted by another antenna unit after being transmitted through an equal-length transmission line to ensure the same phase delay between different antenna pairs, thereby achieving directional retracement. In view of this, if the RIS unit adopts the Van Atta array theoretical layout and an amplifier is added to the transmission line, the new RIS can be designed with passive beam automatic tracking function and can also control the reflected signal amplification gain. This architecture takes into account both amplification capability and directional retracement function and has good application prospects.

[0005] So far, there is no article that combines the Van Atta array with the amplifier and obtains the far-field simulation results through computer joint simulation.

[0006] Therefore, how to provide a Van Atta metasurface has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0007] The object of the present invention is to provide a Van Atta supersurface.

[0008] According to the present invention, a Van Atta metasurface is provided, including: an array layout of RIS units arranged according to the Van Atta array theory to achieve directional backtracking.

[0009] Optionally, the array layout of the RIS units is arranged according to the Van Atta array theory to achieve directional backtracking, which includes:

[0010] The RIS units are symmetrically distributed about the geometric center of the Van Atta array. Two RIS units that are symmetrical to each other are recorded as an antenna pair. The two RIS units are connected to achieve direction tracing.

[0011] Optionally, the length of the transmission lines connecting the two RIS units in all antenna pairs is equal.

[0012] Optionally, the method of making the lengths of transmission lines for connecting two RIS units in all antenna pairs equal comprises:

[0013] A unit is designed through CST, and the operating frequency is the first preset value, that is, the dielectric constant of the dielectric layer is the second preset value; a RIS unit with a third preset value arranged according to the Van Atta array principle is established on CST; the RIS units are symmetrically distributed about the geometric center of the VanAtta array; the CST field-circuit co-simulation method is used to first set the port belonging to each RIS unit in the CST MWS module, and then set the transmission line of each antenna pair in the CST DS module, and use the set transmission line to connect the two RIS units in each antenna pair.

[0014] Optionally, the first preset value is 5.8 GHz.

[0015] Optionally, the second preset value is 4.8.

[0016] Optionally, the third preset value is 2x4 elements.

[0017] Optionally, the metasurface further comprises:

[0018] A unidirectional amplifier is added to the transmission line to form an amplified RIS, and the strength of the scattering field of the RIS is changed by controlling the gain of the unidirectional amplifier.

[0019] Optionally, adding a unidirectional amplifier on the transmission line to form an amplified RIS comprises:

[0020] A unit is designed through CST, and the operating frequency is the first preset value, that is, the dielectric constant of the dielectric layer is the second preset value; a RIS unit of the third preset value arranged according to the Van Atta array principle is established on CST; the RIS units are symmetrically distributed about the geometric center of the VanAtta array; the CST field-circuit co-simulation method is used to first set the port belonging to each RIS unit in the CST MWS module, and then set the transmission line and amplifier of each antenna pair in the CST DS module; the set transmission line is used to connect the RIS units and amplifiers in each antenna pair.

[0021] Optionally, the method of changing the strength of the scattered field of the RIS by controlling the gain of the unidirectional amplifier includes:

[0022] After adding unidirectional amplifiers with equal gain A to all transmission lines, only half of the RIS units are used as receiving antennas and the other half are used as transmitting antennas, making the scattering field of the amplified RIS

[0023] Among them, E monorad represents the scattered field of the amplified RIS, E rad represents the scattered field of the passive RIS, and A represents the gain of the unidirectional amplifier.

[0024] The beneficial effects brought by the present invention are as follows:

[0025] It can be seen from the above scheme that the embodiment of the present invention provides a Van Atta metasurface, which has the following beneficial effects: it can realize signal amplification and directional tracing capabilities at the same time, and has a simple structure, low cost, and broad application prospects; by adding an amplifier to the transmission line of the antenna unit pair, the radiation capability of the RIS can be controlled by controlling the gain of the amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1a A top view of a RIS unit structure provided according to an embodiment;

[0027] Figure 1b A side view of a RIS unit structure provided according to an embodiment;

[0028] Figure 2a A top view of a RIS array arrangement according to an embodiment;

[0029] Figure 2b A side view of a RIS array arrangement according to an embodiment;

[0030] Figure 3 A CST collaborative simulation circuit diagram provided according to an embodiment;

[0031] Figure 4 This is a far-field result diagram when the incident angle theta0° provided in the embodiment is changed from 0db to 15db;

[0032] Figure 5 The far-field result diagram is a diagram showing an amplifier gain of 15 db and an incident angle theta changing from 0° to 30° according to an embodiment. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. 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.

[0034] According to the present invention, a Van Atta metasurface is provided, including: an array layout of RIS units arranged according to the Van Atta array theory to achieve directional backtracking.

[0035] In some embodiments, the array layout of the RIS units is arranged according to the Van Atta array theory to achieve directional backtracking, including:

[0036] The RIS units are symmetrically distributed about the geometric center of the Van Atta array. Two RIS units that are symmetrical to each other are recorded as an antenna pair. The two RIS units are connected to achieve direction tracing.

[0037] The transmission line lengths used to connect the two RIS units are equal in all antenna pairs.

[0038] Specifically, if the m×n element Van Atta antenna array is located in the xoy plane, select a unit and assume that the position is (x m ,y n ); According to the symmetry relationship, the other antenna unit in the antenna pair is located at (-x m ,-y n );

[0039] When receiving waves from any direction, the port phase ratio is

[0040]

[0041] When the received signal reaches the transmitting antenna through an equal-length transmission line, the phase of the signal is:

[0042]

[0043] In the formula, is the phase delay of the received signal through the transmission line. Since the transmission lines are of equal length, It can be considered as the same constant in all antenna pairs. The sum of the transmit and receive phases of each unit is:

[0044]

[0045] It can be seen from formula (3) that when the antenna array is symmetrically distributed around the center of the array and the transmission lines of the antenna pairs are of equal length, the generalized phase conjugation condition can be achieved, and the return wave can be automatically pointed in the direction of the incoming wave, thus achieving directional return.

[0046] In some embodiments, the method of making the lengths of the transmission lines for connecting two RIS units in all antenna pairs equal comprises:

[0047] like Figure 1a and Figure 1b As shown, a unit is designed by CST, the parameters are shown in Table 1, the operating frequency is the first preset value, that is, the dielectric constant of the dielectric layer is the second preset value; Figure 2a and Figure 2bAs shown, a RIS unit of a third preset value arranged according to the Van Atta array principle is established on the CST; the RIS units are symmetrically distributed about the geometric center of the Van Atta array; the CST field-circuit co-simulation method is used to first set the port belonging to each RIS unit in the CST MWS module, and then set the transmission line of each antenna pair in the CST DS module, and use the set transmission line to connect the two RIS units in each antenna pair.

[0048] Table 1

[0049] Parameter Value / mm Parameter Value / mm A 20 B 25 h 1.8 L1 13.25 L2 9.25 L3 2.25 L4 2.25 L5 6.125 L6 3 L7 0.75 L8 4 L9 1.75

[0050] The first preset value is 5.8 GHz.

[0051] The second preset value is 4.8.

[0052] The third preset value is 2x4 yuan.

[0053] In some embodiments, the metasurface further comprises:

[0054] A unidirectional amplifier is added to the transmission line to form an amplified RIS, and the strength of the scattering field of the RIS is changed by controlling the gain of the unidirectional amplifier.

[0055] The adding of a unidirectional amplifier on the transmission line to form an amplified RIS comprises:

[0056] A unit is designed by CST, and the operating frequency is the first preset value, that is, the dielectric constant of the dielectric layer is the second preset value; a RIS unit of the third preset value arranged according to the Van Atta array principle is established on CST; the RIS units are symmetrically distributed about the geometric center of the VanAtta array; the CST field-circuit co-simulation method is used to first set the port belonging to each RIS unit in the CST MWS module, and then set the transmission line and amplifier of each antenna pair in the CST DS module; the set transmission line is used to connect the RIS unit and the amplifier in each antenna pair. The circuit diagram in CST DS is as follows: Figure 3 shown.

[0057] The method of changing the strength of the scattered field of the RIS by controlling the gain of the unidirectional amplifier comprises:

[0058] After adding unidirectional amplifiers with equal gain A to all transmission lines, only half of the RIS units are used as receiving antennas and the other half are used as transmitting antennas, making the scattering field of the amplified RIS

[0059] Among them, E monorad represents the scattered field of the amplified RIS, E radrepresents the scattered field of the passive RIS, and A represents the gain of the unidirectional amplifier.

[0060] After setting up in CST MWS and CST DS, use plane wave excitation to perform full-wave simulation and set up transient simulation tasks to obtain simulation results in the far field area. Figure 4 As shown in the figure, the incident wave theta angle is 0°, and the amplifier gain is increased from 0db to 15db, and the scattering intensity of the far field is enhanced by about 15db. When the amplifier gain is kept at 15db and the incident wave theta angle is changed to 30°, as shown in the figure below: Figure 5 As shown in Figure 2, the far field intensity obviously moves to the position of theta = 30°. The above results prove the feasibility of amplifying the reconfigurable smart surface functions based on VanAtta array theory.

[0061] The results show that:

[0062] 1) In the attached Figure 4 In the simulation, the theta angle of the incident plane wave is set to 0° and the phi angle is set to 0°, and the amplifier gain is increased from 0dB to 15dB. The simulation results show that the amplitude of the far-field intensity increases by about 15dB, which is consistent with the expected results. It is proved that by adding an amplifier to the transmission line of the antenna unit pair, the radiation capability of the RIS can be controlled by controlling the gain of the amplifier.

[0063] 2) In the attached Figure 5 In the simulation, the amplifier gain is kept at a stable level of 15dB, while the phi angle of the incident plane wave is fixed at 0° and the theta angle is gradually increased from 0° to 30°. The simulation results show that the far-field intensity moves significantly toward theta = 30°. This proves that the new amplified RIS effectively achieves the purpose of directional backtracking and signal amplification.

[0064] In summary, through the CST transient co-simulation method, the far-field results of the new RIS combined with amplifiers according to the Van Atta array theoretical layout are obtained. From the result diagram, it can be seen that this structure can achieve both signal amplification and directional tracing capabilities, and it has a simple structure, low cost, and broad application prospects.

[0065] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A Van Atta metasurface, characterized in that: include: The array layout of the RIS units is arranged according to the Van Atta array theory to achieve directional backtracking.

2. The Van Atta supersurface according to claim 1, characterized in that The array layout of the RIS unit is arranged according to the Van Atta array theory to achieve directional backtracking, which includes: The RIS units are symmetrically distributed about the geometric center of the Van Atta array. Two RIS units that are symmetrical to each other are recorded as an antenna pair. The two RIS units are connected to achieve direction tracing.

3. The Van Atta supersurface according to claim 2, characterized in that The transmission line lengths used to connect the two RIS units are equal in all antenna pairs.

4. The Van Atta supersurface according to claim 3, characterized in that The method of making the lengths of the transmission lines for connecting two RIS units in all antenna pairs equal comprises: A unit is designed through CST, and the operating frequency is the first preset value, that is, the dielectric constant of the dielectric layer is the second preset value; a RIS unit with a third preset value arranged according to the Van Atta array principle is established on CST; the RIS units are symmetrically distributed about the geometric center of the Van Atta array; the CST field-circuit collaborative simulation method is used to first set the port belonging to each RIS unit in the CST MWS module, and then set the transmission line of each antenna pair in the CST DS module, and use the set transmission line to connect the two RIS units in each antenna pair.

5. The Van Atta supersurface according to claim 4, characterized in that The first preset value is 5.8 GHz.

6. The Van Atta supersurface according to claim 4, characterized in that The second preset value is 4.

8.

7. The Van Atta supersurface according to claim 4, characterized in that The third preset value is 2x4 yuan.

8. The Van Atta supersurface according to claim 4, characterized in that The metasurface further comprises: A unidirectional amplifier is added to the transmission line to form an amplified RIS, and the strength of the scattering field of the RIS is changed by controlling the gain of the unidirectional amplifier.

9. The Van Atta metasurface according to claim 8, characterized in that: The adding of a unidirectional amplifier on the transmission line to form an amplified RIS comprises: A unit is designed through CST, and the operating frequency is the first preset value, that is, the dielectric constant of the dielectric layer is the second preset value; a RIS unit of the third preset value arranged according to the Van Atta array principle is established on CST; the RIS units are symmetrically distributed about the geometric center of the Van Atta array; the CST field-circuit co-simulation method is used to first set the port belonging to each RIS unit in the CST MWS module, and then set the transmission line and amplifier of each antenna pair in the CST DS module; the set transmission line is used to connect the RIS units and amplifiers in each antenna pair.

10. The Van Atta metasurface according to claim 8, characterized in that: The method of changing the strength of the scattered field of the RIS by controlling the gain of the unidirectional amplifier comprises: After adding unidirectional amplifiers with equal gain A to all transmission lines, only half of the RIS units are used as receiving antennas and the other half are used as transmitting antennas, making the scattering field of the amplified RIS Among them, E monorad represents the scattered field of the amplified RIS, E rad represents the scattered field of the passive RIS, and A represents the gain of the unidirectional amplifier.

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