Terahertz beam deflector for 6G based on liquid crystal metasurface

Abstract

Methods and apparatus for a terahertz beam deflector are disclosed. In one embodiment, a reconfigurable smart surface device comprises: a metasurface that reflects terahertz transmissions at a reflection angle, where the reconfigurable smart surface device comprises: a transceiver; and a processor coupled to the transceiver, where the processor is configured to: transmit, via the transceiver, a parameter for controlling a reflection angle of the metasurface; and receiving, via the transceiver, an indication of the coded sequence for controlling the reflection angle.

Description

TECHNICAL FIELD

[0001] The subject matter disclosed herein relates to wireless communications, and more particularly, to an apparatus and method for liquid crystal metasurface based terahertz (THz) beam deflector for 6G. BACKGROUND

[0002] The sixth generation (6G) mobile communication will use THz bands to provide very high-speed information transmission and ubiquitous wireless connectivity. However, THz links have the disadvantage of loss of channel path and line of sight transmission, which greatly limits the communication transmission.

[0003] Future wireless communication systems will require new antenna technologies to meet the requirements of 6G networks. Recently, the development of electromagnetic (EM) metasurfaces has shown promise to improve the performance of wireless networks by manipulating and radiating RF signals with reduced size, weight, power, cost, and relative complexity compared to traditional phased arrays. Reconfigurable intelligent surface (RIS) based THz communication systems provide a platform for implementing THz technology.

[0004] The present invention is directed to improvements in RIS. SUMMARY

[0005] A method and apparatus for a terahertz beam deflector are disclosed.

[0006] In one embodiment, a RIS device comprises: a metasurface that reflects a terahertz transmission at a reflection angle, wherein the RIS device comprises: a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the RIS device to: transmit a parameter for controlling the reflection angle of the metasurface; and receive an indication of a coded sequence for controlling the reflection angle.

[0007] In some embodiments, the parameter for controlling the reflection angle of the metasurface is a mapping relationship between an index and the reflection angle, and the indication of the coded sequence is the index.

[0008] In some embodiments, the metasurface is composed of metasatoms, wherein ≥ 1 and ≥ 1, each unit cell is composed of metasatoms, wherein ≥ 1 and ≥ 1, the parameter for controlling the reflection angle of the metasurface is , , and the value of The coded sequence can include a number of bits. Each bit in the coded sequence can control the state of all the hyperatoms in one unit cell. Each bit in the coded sequence can be set to a '0' or a '1' corresponding to a different state of the hyperatoms in one unit cell. Each bit in the coded sequence can be converted to a bias voltage by an operational amplifier.

[0009] In some embodiments, the metasurface is composed of a plurality of hyperatoms, each hyperatom including a liquid crystal layer sandwiched between an upper metal layer and a lower metal layer. In particular, a symmetric split ring is removed from the upper metal layer, where the inner side of the ring is connected to the outer side of the ring with two symmetric portions of the ring not removed. Further in particular, the outer radius of the ring is 300 , the inner radius of the ring is 190 , and the orientation angle of each symmetric portion is 30°.

[0010] In another embodiment, a method performed at a RIS device including a metasurface that reflects a terahertz transmission at a reflection angle includes: sending a parameter for controlling the reflection angle of the metasurface; and receiving an indication of a coded sequence for controlling the reflection angle.

[0011] In yet another embodiment, a base unit includes: a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the base unit to: receive a parameter for controlling a reflection angle of a metasurface of a RIS device, wherein the metasurface reflects a terahertz transmission at the reflection angle; and send an indication of a coded sequence for controlling the reflection angle.

[0012] In some embodiments, the parameter for controlling the reflection angle of the metasurface is a mapping relationship between an index and the reflection angle, and the indication of the coded sequence is the index.

[0013] In some embodiments, the metasurface is composed of hyperatoms, where ≥ 1 and ≥ 1, each unit cell is composed of hyperatoms, where ≥ 1 and ≥ 1, the parameter for controlling the reflection angle of the metasurface is , , and , and the indication of the reflection angle is a coded sequence having bits. Each bit in the coded sequence can control the state of all the hyperatoms in one unit cell. Each bit in the coded sequence can be set to a '0' or a '1' corresponding to a different state of the hyperatoms in one unit cell.

[0014] In yet another embodiment, a method performed at a base unit includes receiving parameters for controlling a reflection angle of a hypersurface of a RIS device, wherein the hypersurface reflects terahertz transmissions at the reflection angle; and sending an indication of a coded sequence for controlling the reflection angle.804 BRIEF DESCRIPTION OF DRAWINGS

[0015] More specific descriptions of the embodiments briefly described above will be rendered by reference to specific embodiments illustrated in the drawings. It is to be understood that the drawings are only depictions of some embodiments and accordingly do not purport to be to scale of the embodiments, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

[0016] Figure 1 illustrates a RIS device;

[0017] Figures 2(a), 2(b), 2(c) and 2(d) show examples of structures of each LC superatom of a hypersurface according to the present disclosure;

[0018] Figures 3(a) and 3(b) show the distribution of liquid crystal molecules under applied voltage;

[0019] Figure 4(a) shows the reflection amplitude of a superatom;

[0020] Figure 4(b) shows the phase difference between a superatom in "state a" and a superatom in "state b";

[0021] Figures 5(a) to 5(d) illustrates different implementations of a unit cell;

[0022] Figure 6 illustrates the structure of a terahertz communication system;

[0023] Figure 7 is a schematic flow chart illustrating an embodiment of a method according to the present application;

[0024] Figure 8 is a schematic flow chart illustrating an embodiment of a method according to the present application; and

[0025] Figure 9 is a schematic block diagram illustrating an apparatus according to an embodiment.

[0026] The description of elements in each of the figures can refer to elements of the preceding figures. The same reference numbers in all the figures indicate the same elements including alternative embodiments of the same elements. DETAILED DESCRIPTION

[0027] Figure 1The diagram illustrates a RIS device (100). The RIS device (100) consists of an array (110) (referred to as a metasurface) and an array control module (e.g., a controller) (120). The array control module may include an FPGA (120-2) and an operational amplifier (120-1). The metasurface comprises a number of repeating cells distributed on one or more panels, where each cell can be referred to as a superatom.

[0028] The RIS device can be configured to control the radiation direction of a light beam (e.g., a THz beam). The beam steering function is explained using the Snell formula. The RIS device can control the radiation direction of the light beam based on the Snell formula given by equation (1):

[0029] (1)

[0030] in and The incident angle and reflection angle of the THz beam were defined respectively; The operating wavelength of the THz beam is defined; Defined by The refractive index of the medium (e.g., air) above the designed metasurface, and This corresponds to the phase gradient imparted by the metasurface.

[0031] Various aspects of this disclosure can determine the refractive index of air (i.e., the medium above the metasurface is air) under a normally incident THz beam. ) equals 1, where the normal incident THz beam means the incident angle ( ) equals 0° (i.e., =0). The above equation (1) can be simplified to equation (2):

[0032] (2).

[0033] As a result, the reflection angle of the reflected THz beam (which indicates the radiation direction or deflection direction) can be determined according to equation (3). ):

[0034] (3).

[0035] Therefore, it is possible to change the phase gradient ( This is used to tune the radiation direction of the THz beam reflected by RIS devices (especially metasurfaces).

[0036] Under specular reflection conditions, the reflection angle equals the incident angle. Due to the properties of the metasurface, when a THz beam is reflected by the metasurface, a deflection angle is added to the reflection angle. This means that the reflection direction is deflected or redirected by the deflection angle caused by the metasurface. In other words, the actual reflection angle reflected by the metasurface is equal to the sum of the reflection angle and the deflection angle. In this disclosure, the incident angle is equal to 0°. Therefore, the deflection angle and the actual reflection angle have the same value. In the following description, the actual reflection angle is referred to as the reflection angle. In other words, in the following description, the reflection angle and the deflection angle have the same value.

[0037] This disclosure proposes a RIS device used at a frequency of THz (e.g., 0.213 THz), wherein the metasurface of the RIS device is based on liquid crystal (LC). This means that Figure 1 Each superatom shown can be an LC superatom. LC superatoms can be controlled by a controller to control the radiation direction of the reflected THz beam. For example, a field-programmable gate array (FPGA) can output a sequence that is converted into a bias voltage by an operational amplifier. The bias voltage is used to control the superatoms to change the phase gradient of the metasurface at a THz frequency. ), where THz frequency indicates the operating bandwidth of the RIS device.

[0038] Figures 2(a), 2(b), 2(c), and 2(d) illustrate examples of the structure of each LC superatom of the metasurface according to the present disclosure. Figure 2(a) shows a three-dimensional view; Figure 2(b) shows a front view; Figure 2(c) shows a top view of the lower metal layer; and Figure 2(d) shows a top view of the upper metal layer.

[0039] As shown in Figures 2(a) and 2(b), the LC layer is sandwiched between two metal (e.g., copper) layers (e.g., an upper metal layer and a lower metal layer), wherein the LC layer has, for example, a 25 thickness ( ), and each metal layer has, for example, 2 thickness ( A metal layer sandwiching an LC layer is sandwiched between two quartz layers (e.g., an upper quartz layer and a lower quartz layer), wherein each quartz layer has, for example, 500... thickness ( Note that the upper quartz layer is not shown in Figure 2(a).

[0040] Figure 2(c) shows a top view of the lower metal layer on the lower quartz layer. The lower metal layer has... Length in direction Its greater than Length in direction . For example, the length is 630 ; For example, the length is 590 Two additional portions in the lower metal layer (with a total length of [missing information] in the x-direction) () can be filled with LC.

[0041] Figure 2(d) shows a top view of the upper metal layer. The upper metal layer occupies a side length of... A square. As shown in Figures 2(a) and 2(d), the symmetrical split ring is removed from the upper metal layer. The outer radius of the ring ( For example, 300 And the inner radius of the ring ( For example, 190 The inner side of the ring is connected to the outer side of the ring using two symmetrical portions of the ring (i.e., the portions not removed from the ring). This means that, in addition to the two symmetrical portions that connect the inner side of the ring to the outer side, two other symmetrical portions of the ring are removed. The orientation angle of each symmetrical portion (which connects the inner side of the ring to the outer side of the ring) is... The orientation angle ( ) refers to the angle of the symmetrical part within the ring. For example, it is 30°. As can be seen from Figure 2(d), the orientation angle of each symmetrical part ( The angle bisector along The symmetrical split rings of the upper metal layer form a resonant ring structure.

[0042] Figures 3(a) and 3(b) show the distribution of LC molecules under an applied voltage (e.g., a bias voltage, or simply "bias"). When there is no voltage difference between the two metal layers (i.e., bias off), all LC molecules are aligned horizontally, which is referred to as "state a" (see Figure 3(a)). When there is a voltage difference between the two metal layers (i.e., bias on), due to the resonant ring structure of the upper metal layer, only a portion of the LC molecules are aligned along the electric field direction, which is referred to as "state b" (see Figure 3(b)). In "state a", the refractive index of LC is referred to as the unusual refractive index (…). In "state b", the refractive index of LC is called the ordinary refractive index (LC). Therefore, the refractive index of LC is different in "state a" or "state b"—that is, when different bias voltages are applied.

[0043] For reference Figures 2(a) to 2(d) Simulations were performed on the superatoms of the described structure. In the simulation, an LC model LC NC-M-LC-LDn03 was used. Measurements at a frequency of THz (e.g., 0.213 THz) indicated that the refractive index of the LC was: =1.513 and =1.656.

[0044] Figure 4(a) shows the reflection amplitude of the superatoms. This shows that the reflection coefficients at a frequency of 213 GHz (i.e., 0.213 THz) are almost the same for superatoms in "state a" (i.e., there is no voltage difference between the two metal layers (i.e., bias off)) and for superatoms in "state b" (i.e., there is a voltage difference between the two metal layers (i.e., bias on)).

[0045] Figure 4(b) shows the phase difference between the superatoms in "state a" and "state b" at a frequency of 213 GHz (i.e., 0.213 THz). The phase is approximately 180° (i.e., close to). ).

[0046] When some superatoms of a metasurface are controlled to be in "state a" and other superatoms are controlled to be in "state b", a phase gradient is imparted by the metasurface. Different combinations of some superatoms in "state a" and other superatoms in "state b" result in different phase gradients, which in turn result in different radiation directions (or deflection directions) of the THz beam reflected by the metasurface. This means that it is possible to change the radiation direction of the THz beam reflected by the metasurface by configuring the state of each superatom of the metasurface (or by configuring the phase gradient of the metasurface). In other words, the radiation direction of the THz beam can be changed without altering the structure of the metasurface.

[0047] The following description focuses on dynamically controlling the phase gradient of a metasurface (i.e., dynamically controlling the state of each superatom of the metasurface) so that the radiation direction of a THz beam reflected by the metasurface can be controlled accordingly (which may be referred to as beam steering).

[0048] Each of Figures 5(a), 5(b), 5(c), and 5(d) illustrates a schematic diagram of a metasurface comprising an LC superatomic array, wherein the array contains ( The surface has 1 (>=1) rows and N (N>=1) columns. To control the beam direction, the state of each superatom on the metasurface is controlled. As mentioned above, each superatom can be in either "state a" or "state b".

[0049] The superatom in "state a" or "state b" depends on the bias voltage applied to the upper and lower metal layers. When there is no bias voltage between the upper and lower metal layers of the superatom, the superatom is in "state a"; when there is a bias voltage between the upper and lower metal layers of the superatom, the superatom is in "state b".

[0050] This disclosure proposes using a 1-bit indicator to indicate whether a bias voltage is applied to the superatom (specifically, to the upper and lower metal layers of the superatom). For example, '0' indicates that a bias voltage is not applied to the superatom (or 0V is applied), i.e., the superatom is in "state a". On the other hand, '1' indicates that a bias voltage (e.g., 20V) is applied to the superatom, i.e., the superatom is in "state b".

[0051] In the first embodiment, independent control Each superatom in a superatom. This means that each superatom is a unit cell (see Figure 5(a)). The first implementation makes the phase distribution very complex while achieving beam deflection with maximum degrees of freedom.

[0052] In the second embodiment, all Each superatom is divided into several unit cells, where each unit cell is composed of... It is composed of superatoms. This means that... The superatoms are divided into A unit cell (assuming) , >=1 and >=1; and , >=1 and >=1, therefore, = ), where each unit cell is composed of Composed of superatoms (see Figure 5(b)). A unit cell contains... The superatoms are controlled together, which means that all the superatoms in a unit cell are controlled together. Each superatom is in "state a" or all of them in a unit cell. The superatom is in "state b". Compared to the first embodiment, the second embodiment has fewer degrees of freedom for beam deflection.

[0053] In the third embodiment, In the column Each column of superatoms is a unit cell (see Figure 5(c)). The third embodiment can be considered as such. = and =1, a specific second implementation. In a unit cell (i.e., a column). Each superatom is controlled together, which means that all of them in a unit cell (i.e., a column) are controlled together. One superatom is in "state a" or all of a column One superatom is in "state b".

[0054] In the fourth implementation, each row of superatoms can be a unit cell (see Fig. 5(d)). The fourth implementation is also a specific second implementation, where = 1 and = 1. The superatoms in one unit cell (i.e., in one row) are controlled together, which means that all the superatoms in one unit cell (i.e., in one row) are in “state a” or all the superatoms in one row are in “state b”.

[0055] Compared to the first implementation, the third or fourth implementation has less freedom for beam deflection. On the other hand, the superatoms can be controlled in one dimension (per column or per row), which is simple for control.

[0056] Figure 6 Fig. illustrates the structure of a THz communication system 600. As Figure 6 shown, a RIS device (620) (in particular, a metasurface) reflects a light beam received from a base unit (610) (e.g., a gNB) to a UE (630). The RIS device (620) includes a RIS controller (625) that functions as a processor and a FPGA. THz light beam control is achieved by controlling the phase gradient of the superatoms of the metasurface (i.e., controlling the state of each superatom of the metasurface). For example, a code sequence (e.g., a code sequence ID indicating the code sequence) is indicated from the gNB (610) to the RIS controller (625). The code sequence corresponding to the indicated code sequence ID is generated by the FPGA to be applied to the metasurface. That is, each bit in the code sequence, which is either ‘0’ or ‘1’, is applied to one unit cell. In particular, ‘0’ is converted to “bias off’ (i.e., no voltage bias, e.g., 0V) to be applied to all the superatoms in the unit cell; and ‘1’ is converted to “bias on’ (i.e., voltage bias, e.g., 20V) to be applied to all the superatoms in the unit cell.

[0057] To help the gNB (610) to generate or indicate the appropriate code sequence, the RIS device (620) should report its array structure and corresponding parameters to the gNB (610). In particular, considering that the metasurface is composed of superatoms and each unit cell is composed of superatoms, the , , and The value of . Assuming a unit cell has Superatoms are controlled together, meaning they are controlled in the same state ("state a" or "state b").

[0058] based on , , and Given the value, gNB can generate a coded sequence and send it to the RIS device.

[0059] For example, if a report is sent from a RIS device to a gNB =18, =16, =18, =1, then gNB knows that the metasurface is composed of 18 It consists of 16 superatoms, and each column of 18 superatoms is controlled together. gNB can generate structures with 16 (= A coded sequence of bits is applied to the metasurface. When the coded sequence is received from the gNB by the RIS device (e.g., by the RIS controller), the RIS controller (e.g., the FPGA) inputs the coded sequence to an operational amplifier (see...). Figure 1 The operational amplifier outputs a bias voltage (e.g., 0V corresponding to '0' or 20V corresponding to '1') to the unit cells (i.e., columns) of the superatoms on the metasurface. For example, if the coded sequence '0101010101010101' is received, the bias voltages to be applied to each column (from column #1 to column #16) of the superatoms on the metasurface are shown in Table 1.

[0060]

[0061] Table 1

[0062] Incidentally, when the report , , and When the value is , if =1 and =1, then assume the first implementation method; if = and =1, then assume the third implementation method; and if =1 and = Therefore, we assume the diversity of the third implementation method.

[0063] Alternative Report , , and The RIS device can report the mapping relationship between the code sequence (or code sequence index) and the beam direction.

[0064] Conventionally, the beam direction (e.g., reflection angle) can be controlled by a set of downtilt angle ( ) and azimuth angle ( ), i.e., ( , ). This means that the beam direction includes two-dimensional downtilt angle ( ) and azimuth angle ( ). When the reflected beam of the metasurface can only be steered in a single dimension, only one of the downtilt angle ( ) and azimuth angle ( ) can be steered by the metasurface. To help the gNB send the correct code sequence to generate the desired reflection angle, each code sequence can be associated with the beam direction ( , ) or at least one of the downtilt angle ( ) and azimuth angle ( ). For example, the mapping between the code sequence (and / or code sequence index) and the beam direction can be established as in Table 2.

[0065]

[0066] Table 2

[0067] The code sequence corresponds to the reflection angle (or steering angle), which means the radiation direction (or deflection direction) of the metasurface. The RIS device can report the mapping relationship between the index (e.g., code sequence index) and the deflection direction to the gNB, as shown in Table 3.

[0068]

[0069] Table 3

[0070] Based on the mapping relationship between the code sequence index and the deflection direction as shown in Table 3, the gNB can determine the desired code sequence (through its code sequence index) based on the desired deflection direction. The FPGA can store all code sequences corresponding to all supported deflection directions. When receiving the code sequence index, the FPGA can generate the code sequence corresponding to the code sequence index, and input the code sequence to the operational amplifier, which generates a bias voltage to each unit cell of the metasurface.

[0071] From the perspective of the gNB, the gNB does not need to know that the index indicating the deflection direction is the index of the code sequence. This means that the gNB only has to know that the index indicates the deflection direction. In other words, the gNB can regard Table 3 as Table 4.

[0072]

[0073] Table 4

[0074] When a desired deflection direction is needed (e.g., (a) or (b) above), the gNB determines an index (e.g., 1) from Table 4, and indicates the index (e.g., 1) corresponding to the desired deflection direction to the RIS device.

[0075] As a whole, the deflection direction of the metasurface can be controlled by the code sequence. That is, when the deflection direction of the metasurface is changed according to the code sequence, the structure of the metasurface (or the structure of each meta-atom of the metasurface) does not need to be changed. In other words, the deflection direction of the metasurface (or RIS), in particular, the metasurface (or RIS device) is reconfigurable.

[0076] Figure 7 is a schematic flow chart illustrating an embodiment of a method 700 according to the present application. In some embodiments, the method 700 is performed by an apparatus, such as a RIS device, wherein the RIS device comprises a metasurface that reflects THz transmissions at a reflection angle. In certain embodiments, the method 700 can be performed by a processor, e.g., a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like, executing program code.

[0077] The method 700 can comprise: 702 transmitting a parameter for controlling a reflection angle of a metasurface; and 704 receiving an indication of a code sequence for controlling the reflection angle.

[0078] In some embodiments, the parameter for controlling the reflection angle of the metasurface is a mapping relationship between an index and the reflection angle, and the indication of the code sequence is the index.

[0079] In some embodiments, the metasurface is composed of meta-atoms, wherein ≥ 1 and ≥ 1, each unit cell is composed of meta-atoms, wherein ≥ 1 and ≥ 1, the parameter for controlling the reflection angle of the metasurface is , , and the value of the indication of the reflection angle is a code sequence having ​The coded sequence can be a sequence of bits. Each bit in the coded sequence can control the state of all the hyperatoms in one unit cell. Each bit in the coded sequence can be set to either a '0' or a '1' corresponding to a different state of the hyperatoms in one unit cell. Each bit in the coded sequence can be converted to a bias voltage by an operational amplifier.

[0080] In some embodiments, the metasurface is composed of a plurality of hyperatoms, each hyperatom including a liquid crystal layer sandwiched between an upper metal layer and a lower metal layer. In particular, a symmetric split ring is removed from the upper metal layer, where the inner side of the ring is connected to the outer side of the ring with two symmetric portions of the ring not removed. Further in particular, the outer radius of the ring is 300 , the inner radius of the ring is 190 , and the orientation angle of each symmetric portion is 30°.

[0081] Figure 8 is a schematic flowchart illustrating an embodiment of a method 800 according to the present application. In some embodiments, the method 800 is performed by an apparatus, such as a base unit. In certain embodiments, the method 800 can be performed by a processor executing program code - e.g., a microcontroller, microprocessor, CPU, GPU, auxiliary processing unit, FPGA, etc.

[0082] The method 800 can include 802 receiving a parameter for controlling a reflection angle of a metasurface of a RIS device, wherein the metasurface reflects a terahertz transmission at the reflection angle; and 804 sending an indication of a coded sequence for controlling the reflection angle.

[0083] In some embodiments, the parameter for controlling the reflection angle of the metasurface is a mapping relationship between an index and the reflection angle, and the indication of the coded sequence is the index.

[0084] In some embodiments, the metasurface is composed of a plurality of hyperatoms, each hyperatom including a liquid crystal layer sandwiched between an upper metal layer and a lower metal layer. In particular, a symmetric split ring is removed from the upper metal layer, where the inner side of the ring is connected to the outer side of the ring with two symmetric portions of the ring not removed. Further in particular, the outer radius of the ring is 300 , the inner radius of the ring is 190 , and the orientation angle of each symmetric portion is 30°. , the inner radius of the ring is 190 , and the orientation angle of each symmetric portion is 30°. , the inner radius of the ring is 190 , and the orientation angle of each symmetric portion is 30°. , , and , and the indication of the reflection angle is a coded sequence having bits. Each bit in the coded sequence can control the state of all the hyperatoms in one unit cell. Each bit in the coded sequence can be set to either a '0' or a '1' corresponding to a different state of the hyperatoms in one unit cell.

[0085] Figure 9 is a schematic block diagram illustrating an apparatus according to one embodiment.

[0086] Referring to Figure 9 , the RIS device includes a processor, a memory, and a transceiver, which is a transmitter and / or a receiver. The processor implements the functions, processes, and / or methods presented in Figure 7 .

[0087] An RIS device includes a metasurface that reflects a terahertz transmission at a reflection angle, wherein the RIS device includes: a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the RIS device to: transmit a parameter for controlling the reflection angle of the metasurface; and receive an indication of a coded sequence for controlling the reflection angle.

[0088] In some embodiments, the parameter for controlling the reflection angle of the metasurface is a mapping relationship between an index and the reflection angle, and the indication of the coded sequence is the index.

[0089] In some embodiments, the metasurface is composed of metasatoms, wherein ≥ 1 and ≥ 1, each unit cell is composed of metasatoms, wherein ≥ 1 and ≥ 1, the parameter for controlling the reflection angle of the metasurface is , , and the value of , and the indication of the reflection angle is a coded sequence with bits. Each bit in the coded sequence can control the state of all metasatoms in one unit cell. Each bit in the coded sequence can be set to ‘0’ or ‘1’ corresponding to different states of the metasatoms in one unit cell. Each bit in the coded sequence can be converted to a bias voltage by an operational amplifier.

[0090] In some embodiments, the metasurface is composed of a plurality of metasatoms, each metasatom including a liquid crystal layer sandwiched between an upper metal layer and a lower metal layer. In particular, a symmetric split ring is removed from the upper metal layer, wherein the inner side of the ring is connected to the outer side of the ring with two symmetric parts of the ring not removed. Further in particular, the outer radius of the ring is 300 , the inner radius of the ring is 190 , and the orientation angle of each symmetric part is 30°.

[0091] The gNB (i.e., a base unit) includes a processor, a memory, and a transceiver, which is a transmitter and / or a receiver. The processor implements the functions, processes, and / or methods presented in Figure 8The functions, procedures, and / or methods presented in the specification.

[0092] The base unit includes a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the base unit to: receive a parameter for controlling a reflection angle of a metasurface of the RIS device, wherein the metasurface reflects the terahertz transmission at the reflection angle; and transmit an indication of a coded sequence for controlling the reflection angle.

[0093] In some embodiments, the parameter for controlling the reflection angle of the metasurface is a mapping relationship between an index and the reflection angle, and the indication of the coded sequence is the index.

[0094] In some embodiments, the metasurface is composed of metasatoms, wherein ≥ 1 and ≥ 1, each unit cell is composed of metasatoms, wherein ≥ 1 and ≥ 1, the parameter for controlling the reflection angle of the metasurface is , , and the value of the indication of the reflection angle is a coded sequence with bits. Each bit in the coded sequence can control the state of all metasatoms in one unit cell. Each bit in the coded sequence can be set to ‘0’ or ‘1’ corresponding to different states of the metasatoms in one unit cell.

[0095] As those skilled in the art will appreciate, some aspects of the embodiments can be embodied as a system, a device, a method or a program product. Accordingly, the embodiments can take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.) or an embodiment combining software and hardware aspects that can all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, the embodiments can take the form of a program product embodied in one or more computer readable storage devices storing machine-readable code, computer readable code, and / or program code, hereinafter referred to as code. The storage devices can be tangible, non-transitory, and / or non-transmission. The storage devices can not embody signals. In a certain embodiment, the storage devices only employ signals for accessing the code.

[0096] Certain of the functional units described in this specification can be labeled as "modules," in order to more particularly emphasize their implementation independence. For example, a module can be implemented as a hardware circuit comprising custom very-large-scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module can also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

[0097] Modules can also be implemented in code and / or software for execution by various types of processors. An identified module of code may, for instance, include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but the module can include disparate instructions stored in different locations which, like a file, a section of a file, or a department store, logically group the instructions together when executed.

[0098] Indeed, a module of code can include a single instruction, or many instructions, and can even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data can be identified within the modules and illustrated as being stored in memory, but such data can be stored in any

[0099] Any combination of one or more computer readable medium can be utilized. The computer readable medium can be a computer readable storage medium. The computer readable storage medium can be a storage device storing the code. The storage device can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0100] A non-exhaustive list of more specific examples of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium can be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0101] Code for carrying out operations for embodiments can include any number of lines and any combination of lines, including any number of lines of code in any combination of programming languages, including an object-oriented programming language such as the Python, Ruby, Java, Smalltalk, C++, or the like and conventional procedural programming languages, such as the "C" programming language, or the like, and / or machine languages such as assembly languages. The code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0102] Reference throughout this specification to "one embodiment", "an embodiment", or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment", "in an embodiment", and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean "one or more but not all embodiments". The terms "including", "comprising", "having" and variations thereof mean "including but not limited to", unless expressly specified otherwise. The enumeration of items does not, unless expressly specified otherwise, imply that any or all of those items are mutually exclusive. The terms "a", "an" and "the" also mean "one or more", unless expressly specified otherwise.

[0103] Furthermore, the described features, structures, or characteristics of the various embodiments can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail in order to avoid obscuring aspects of embodiments.

[0104] The code can also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function specified in the flowchart diagrams and / or block diagrams block or blocks.

[0105] The code can also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function specified in the flowchart diagrams and / or block diagrams block or blocks.

[0106] The code can also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions specified in the flowchart diagrams and / or block diagrams block or blocks.

[0107] The flow diagrams and / or block diagrams in the drawings are illustrative of the architectures, functional operations, and / or acts of possible implementations of apparatuses, systems, methods and program products according to various embodiments. In this regard, each block in the flow diagrams and / or block diagrams can represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical functions.

[0108] It should also be noted that in some alternative implementations, the functions noted in the blocks can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks can sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods can be conceived that are equivalent in function, logic, or effect to those illustrated, with the possession of equivalents structures, functions, results, and / or objects.

[0109] Although various arrow types and line types can be employed in the flowcharts and / or block diagrams, these are understood to be taken in a descriptive sense in which there can be any quantity of devices arranged to perform the functions, and each line that can be drawn may

[0110] The layers of the radio interface protocol can be implemented by the processor. The memory is connected with the processor to store a variety of pieces of information for driving the processor. The transceiver is connected with the processor to transmit and / or receive a radio signal. Of course, the transceiver can be implemented as a transmitter for transmitting a radio signal and a receiver for receiving a radio signal.

[0111] The memory can be located inside or outside the processor, and connected with the processor through a variety of well-known means.

[0112] In the above-described embodiments, components and features of the embodiments are combined in a predetermined form. Each component or feature should be considered selective unless explicitly specified otherwise. Each component or feature can be implemented as not associated with other components or features. Also, a new embodiment can be configured by combining some components and / or features. The order that operations described in the embodiments can be changed. Some components or features of any embodiment can be included in another embodiment or replaced with components and features corresponding to another embodiment. It is obvious that claims not explicitly cited in the claims are combined to form embodiments or included in new claims.

[0113] The embodiments can be implemented by hardware, firmware, software, or a combination thereof. In the case of implementation by hardware, the exemplary embodiments described herein can be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, etc., according to hardware implementation.

[0114] The embodiments can be practiced in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. Therefore, the scope of the application is indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. A reconfigurable smart surface device, the reconfigurable smart surface device comprising a metasurface that reflects terahertz transmission at a reflection angle, the reconfigurable smart surface device comprising: transceiver; as well as A processor coupled to the transceiver, wherein the processor is configured to cause the reconfigurable smart surface device to: Send parameters for controlling the reflection angle of the metasurface; and Receive an instruction for a coded sequence to control the reflection angle.

2. The reconfigurable smart surface device according to claim 1, wherein, The parameter used to control the reflection angle of the metasurface is a mapping relationship between the index and the reflection angle, and The index is the indicator of the coded sequence.

3. The reconfigurable smart surface device according to claim 1, wherein, The metasurface is made of It is composed of superatoms, among which... >=1 and >=1, Each unit cell is composed of It is composed of superatoms, among which... >=1 and >=1, The parameter used to control the reflection angle of the metasurface is , , and The value, and The indication of the reflection angle is having The coded sequence of bits.

4. The reconfigurable smart surface device according to claim 3, wherein, Each bit in the coded sequence controls the state of all superatoms in a unit cell.

5. The reconfigurable smart surface device according to claim 4, wherein, Each bit in the coded sequence is set to either '0' or '1', corresponding to a different state of a superatom in a unit cell.

6. The reconfigurable smart surface device according to claim 4, wherein, Each bit in the coded sequence is converted into a bias voltage by an operational amplifier.

7. The reconfigurable smart surface device according to claim 1, wherein, The metasurface is composed of multiple superatoms. Each superatom includes a liquid crystal layer sandwiched between an upper metal layer and a lower metal layer.

8. The reconfigurable smart surface device according to claim 7, wherein, The symmetrical split ring is removed from the upper metal layer, wherein the inner side of the ring is connected to the outer side of the ring by means of the two symmetrical portions of the ring that have not been removed.

9. The reconfigurable smart surface device according to claim 8, wherein, The outer radius of the ring is 300. , The inner radius of the ring is 190. ,and The orientation angle of each symmetrical part is 30°.

10. A basic unit comprising: transceiver; as well as A processor coupled to the transceiver, wherein the processor is configured to cause the basic unit to: Receive parameters for controlling the reflection angle of a metasurface in a reconfigurable smart surface device, wherein the metasurface reflects terahertz transmission at the reflection angle; and Send an instruction for a coded sequence to control the reflection angle.

11. The basic unit according to claim 10, wherein, The parameter used to control the reflection angle of the metasurface is a mapping relationship between the index and the reflection angle, and The index is the indicator of the coded sequence.

12. The basic unit according to claim 10, wherein, The metasurface is made of It is composed of superatoms, among which... >=1 and >=1, Each unit cell is composed of It is composed of superatoms, among which... >=1 and >=1, The parameter used to control the reflection angle of the metasurface is , , and The value, and The indication of the reflection angle is having The coded sequence of bits.

13. The basic unit according to claim 12, wherein, Each bit in the coded sequence controls the state of all superatoms in a unit cell.

14. The basic unit according to claim 13, wherein, Each bit in the coded sequence is set to either '0' or '1', corresponding to a different state of a superatom in a unit cell.

15. A method performed at a reconfigurable smart surface device, the reconfigurable smart surface device comprising a metasurface reflecting terahertz transmission at a reflection angle, the method comprising: Send parameters for controlling the reflection angle of the metasurface; as well as Receive an instruction for a coded sequence to control the reflection angle.

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