Beam reconstruction method, antenna, and microwave device

A beam reconstruction method includes: generating or receiving a radio frequency signal, determining a to-be-adjusted beam angle, loading a voltage bias value on each liquid crystal metasurface array unit among a plurality of liquid crystal metasurface array units in a liquid crystal metasurface array based on the beam angle, and either emitting the generated radio frequency signal transmitted through the liquid crystal metasurface array or directing the received radio frequency signal through the liquid crystal metasurface array to a feed of an antenna. A lateral offset of a feed phase center is generated based on the voltage bias value after the radio frequency signal is transmitted through the liquid crystal metasurface array.

TECHNICAL FIELD

This application relates to the communications field, and in particular, to a beam reconstruction method, an antenna, a microwave device, and a network system.

BACKGROUND

Microwave backhaul, featuring fast deployment and flexible installation, is one of solutions for mobile backhaul. With development of mobile and fixed networks, common-band (6 GHz to 42 GHz) microwave backhaul faces the following challenges: With large-scale deployment of 4G networks and evolution to 5G networks, a bandwidth requirement continuously increases. For example, a macro base station requires a gigabit (Gbps)-level bandwidth. More frequency resources are consumed for an increase in bandwidth. This causes a gradual shortage of spectrum resources in common bands (6 GHz to 42 GHz), and it is difficult to obtain the frequencies and meet the bandwidth requirement. To greatly increase the bandwidth and reduce the occupation of spectrum resources in common bands, E-band (71 GHz to 76 GHz/81 GHz to 86 GHz) microwave with 10 GHz spectrum resources will become a solution to the bandwidth and spectrum resources.

The E-band microwave can be applied to long-distance backhaul of macro base stations (for example, a backhaul distance of more than 7 km). However, when the E-band microwave is applied to the long-distance backhaul of macro base stations, the following problems exist: Long-distance E-band requires that an antenna has high gain. A high-gain transmitting antenna has a sharp beam, and the sharp beam makes the antenna sensitive to shaking (for example, if the antenna is installed on a tower, the antenna is sensitive to shaking of the tower). Consequently, gain of a receiving antenna decreases, and a microwave transmission distance is affected.

Therefore, how to design a beam reconfigurable antenna and enhance a capability of resisting shaking of the antenna becomes a technical problem to be resolved.

SUMMARY

In view of this, this application provides a beam reconstruction method, an antenna, a microwave device, and a network system, to resolve a problem that the antenna is sensitive to shaking.

According to a first aspect, this application provides an antenna. The antenna includes a feed, a liquid crystal metasurface array, a liquid crystal bias control circuit, and a beam transformation structure. The liquid crystal metasurface array includes a plurality of liquid crystal metasurface array units, for example, M×N liquid crystal metasurface array units, where M and N are positive integers greater than or equal to 2. The feed may receive a radio frequency signal from an outdoor unit or a radio frequency module of a microwave device, and radiate the received radio frequency signal to the outside. The liquid crystal bias control circuit is configured to: determine a to-be-adjusted beam angle, and load a voltage bias value on each liquid crystal metasurface array unit in the liquid crystal metasurface array based on the beam angle. The liquid crystal metasurface array is configured to: transmit the radio frequency signal, and generate a lateral offset of a feed phase center based on the voltage bias value. The beam transformation structure is configured to emit the radio frequency signal transmitted through the liquid crystal metasurface array. Some embodiments implement a beam reconfigurable antenna with low costs and low complexity, which may be applied to a microwave device at a transmitting end. When a beam direction is not aligned with an antenna at a receive end, the voltage bias value of the liquid crystal metasurface array unit may be adjusted, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment.

In a possible implementation, the liquid crystal bias control circuit changes, based on the loaded voltage bias value, a transmission phase generated when the radio frequency signal is transmitted through each liquid crystal metasurface array unit. The transmission phase of the liquid crystal metasurface array unit is changed, so that the feed phase center is laterally offset, thereby implementing reconfiguration of an antenna beam.

In a possible implementation, the liquid crystal bias control circuit changes a dielectric constant of each liquid crystal metasurface array unit based on the loaded voltage bias value. The liquid crystal dielectric constant is changed based on the voltage bias value, so that the transmission phase of the liquid crystal metasurface array unit is changed.

In a possible implementation, the liquid crystal bias control circuit is further configured to determine the lateral offset of the feed phase center based on the to-be-adjusted beam angle. According to an antenna scanning principle, a relationship between a deflection angle of the antenna beam and the lateral offset of the feed phase center can be obtained. The deflection angle of the antenna beam is the same as the to-be-adjusted beam angle, but the directions are opposite.

In a possible implementation, the liquid crystal bias control circuit is further configured to determine the dielectric constant of each liquid crystal metasurface array unit based on the lateral offset of the feed phase center. A correspondence between the lateral offset of the feed phase center and the dielectric constant of each liquid crystal metasurface array unit may be calculated and stored in advance, thereby improving beam alignment efficiency.

In a possible implementation, the liquid crystal bias control circuit is further configured to determine each voltage bias value based on the dielectric constant of each liquid crystal metasurface array unit. The voltage bias value corresponding to the liquid crystal dielectric constant may be determined by engineering testing or table lookup.

In a possible implementation, the beam transformation structure may include a primary reflector and a secondary reflector, the feed and the liquid crystal metasurface array are located between the primary reflector and the secondary reflector, and the liquid crystal metasurface array is located between the feed and the secondary reflector. A beam reconfigurable Cassegrain antenna is implemented by placing the feed and liquid crystal metasurface array between the primary reflector and the secondary reflector.

In a possible implementation, the beam transformation structure may include a lens, and the liquid crystal metasurface array is located between the feed and the lens. A beam reconfigurable lens antenna is implemented by placing the liquid crystal metasurface array between the feed and the lens.

According to a second aspect, this application provides an antenna. The antenna includes a feed, a liquid crystal metasurface array, a liquid crystal bias control circuit, and a beam transformation structure. The liquid crystal metasurface array includes a plurality of liquid crystal metasurface array units, for example, M×N liquid crystal metasurface array units, where M and N are positive integers greater than or equal to 2. The beam transformation structure receives a radio frequency signal that is sent at a transmitting end and that is propagated through the air. The liquid crystal bias control circuit is configured to: determine a to-be-adjusted beam angle, and load a voltage bias value on each liquid crystal metasurface array unit in the liquid crystal metasurface array based on the to-be-adjusted beam angle. The liquid crystal metasurface array is configured to: transmit the radio frequency signal, and generate a lateral offset of a feed phase center based on the voltage bias value. The feed is configured to receive the radio frequency signal transmitted through the liquid crystal metasurface array. At least one embodiment implements a beam reconfigurable antenna with low costs and low complexity, which may be applied to a microwave device at a receive end. When a beam direction is not aligned with an antenna at a receive end, the voltage bias value of the liquid crystal metasurface array unit may be adjusted, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment.

In a possible implementation, the liquid crystal bias control circuit changes, based on the loaded voltage bias value, a transmission phase generated when the radio frequency signal is transmitted through each liquid crystal metasurface array unit. The transmission phase of the liquid crystal metasurface array unit is changed, so that the feed phase center is laterally offset, thereby implementing reconfiguration of an antenna beam.

In a possible implementation, the liquid crystal bias control circuit changes a dielectric constant of each liquid crystal metasurface array unit based on the loaded voltage bias value. The liquid crystal dielectric constant is changed based on the voltage bias value, so that the transmission phase of the liquid crystal metasurface array unit is changed.

In a possible implementation, the liquid crystal bias control circuit is further configured to determine the lateral offset of the feed phase center based on the to-be-adjusted beam angle. According to an antenna scanning principle, a relationship between a deflection angle of the antenna beam and the lateral offset of the feed phase center can be obtained. The deflection angle of the antenna beam is the same as the to-be-adjusted beam angle, but the directions are opposite.

In a possible implementation, the liquid crystal bias control circuit is further configured to determine the dielectric constant of each liquid crystal metasurface array unit based on the lateral offset of the feed phase center. A correspondence between the lateral offset of the feed phase center and the dielectric constant of each liquid crystal metasurface array unit may be calculated and stored in advance, thereby improving beam alignment efficiency.

In a possible implementation, the liquid crystal bias control circuit is further configured to determine each voltage bias value based on the dielectric constant of each liquid crystal metasurface array unit. The voltage bias value corresponding to the liquid crystal dielectric constant may be determined by engineering testing or table lookup.

In a possible implementation, the beam transformation structure may include a primary reflector and a secondary reflector, the feed and the liquid crystal metasurface array are located between the primary reflector and the secondary reflector, and the liquid crystal metasurface array is located between the feed and the secondary reflector. A beam reconfigurable Cassegrain antenna is implemented by placing the feed and liquid crystal metasurface array between the primary reflector and the secondary reflector.

In a possible implementation, the beam transformation structure may include a lens, and the liquid crystal metasurface array is located between the feed and the lens. A beam reconfigurable lens antenna is implemented by placing the liquid crystal metasurface array between the feed and the lens.

According to a third aspect, this application provides a beam reconstruction method. The method may be performed by an antenna at a transmitting end, and includes: generating a radio frequency signal; determining a to-be-adjusted beam angle; loading a voltage bias value on each liquid crystal metasurface array unit in a liquid crystal metasurface array based on the beam angle, where a lateral offset of a feed phase center is generated based on the voltage bias value after the radio frequency signal is transmitted through the liquid crystal metasurface array, the liquid crystal metasurface array includes M×N liquid crystal metasurface array units, and M and N are positive integers greater than or equal to 2; and emitting the radio frequency signal transmitted through the liquid crystal metasurface array. At least one embodiment implements a beam reconfigurable method with low costs and low complexity, which may be applied to a microwave device at the transmitting end. When a beam direction is not aligned with an antenna at a receive end, the voltage bias value of the liquid crystal metasurface array unit may be adjusted, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment.

In a possible implementation, the method further includes: changing, based on the loaded voltage bias value, a transmission phase generated when the radio frequency signal is transmitted through each liquid crystal metasurface array unit. The transmission phase of the liquid crystal metasurface array unit is changed, so that the feed phase center is laterally offset, thereby implementing reconfiguration of an antenna beam.

In a possible implementation, before changing the transmission phase, the method further includes: changing a dielectric constant of each liquid crystal metasurface array unit based on the loaded voltage bias value. The liquid crystal dielectric constant is changed based on the voltage bias value, so that the transmission phase of the liquid crystal metasurface array unit is changed.

In a possible implementation, the method further includes: determining the lateral offset of the feed phase center based on the to-be-adjusted beam angle. According to an antenna scanning principle, a relationship between a deflection angle of the antenna beam and the lateral offset of the feed phase center can be obtained. The deflection angle of the antenna beam is the same as the to-be-adjusted beam angle, but the directions are opposite.

In a possible implementation, the method further includes: determining the dielectric constant of each liquid crystal metasurface array unit based on the lateral offset of the feed phase center. A correspondence between the lateral offset of the feed phase center and the dielectric constant of each liquid crystal metasurface array unit may be calculated and stored in advance, thereby improving beam alignment efficiency.

In a possible implementation, the method further includes: determining each voltage bias value based on the dielectric constant of each liquid crystal metasurface array unit. The voltage bias value corresponding to the liquid crystal dielectric constant may be determined by engineering testing or table lookup.

According to a fourth aspect, this application provides a beam reconstruction method. The method may be performed by an antenna at a receive end, and includes: receiving a radio frequency signal; determining a to-be-adjusted beam angle; loading a voltage bias value on each liquid crystal metasurface array unit in a liquid crystal metasurface array based on the beam angle, where a lateral offset of a feed phase center is generated based on the voltage bias value after the radio frequency signal is transmitted through the liquid crystal metasurface array, the liquid crystal metasurface array includes M×N liquid crystal metasurface array units, and M and N are positive integers greater than or equal to 2; and receiving the radio frequency signal transmitted through the liquid crystal metasurface array. At least one embodiment implements a beam reconfigurable method with low costs and low complexity, which may be applied to a microwave device at the receive end. When a beam direction is not aligned with an antenna at a receive end, the voltage bias value of the liquid crystal metasurface array unit may be adjusted, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment.

In a possible implementation, the method further includes: changing, based on the loaded voltage bias value, a transmission phase generated when the radio frequency signal is transmitted through each liquid crystal metasurface array unit. The transmission phase of the liquid crystal metasurface array unit is changed, so that the feed phase center is laterally offset, thereby implementing reconfiguration of an antenna beam.

In a possible implementation, before changing the transmission phase, the method further includes: changing a dielectric constant of each liquid crystal metasurface array unit based on the loaded voltage bias value. The liquid crystal dielectric constant is changed based on the voltage bias value, so that the transmission phase of the liquid crystal metasurface array unit is changed.

In a possible implementation, the method further includes: determining the lateral offset of the feed phase center based on the to-be-adjusted beam angle. According to an antenna scanning principle, a relationship between a deflection angle of the antenna beam and the lateral offset of the feed phase center can be obtained. The deflection angle of the antenna beam is the same as the to-be-adjusted beam angle, but the directions are opposite.

In a possible implementation, the method further includes: determining the dielectric constant of each liquid crystal metasurface array unit based on the lateral offset of the feed phase center. A correspondence between the lateral offset of the feed phase center and the dielectric constant of each liquid crystal metasurface array unit may be calculated and stored in advance, thereby improving beam alignment efficiency.

In a possible implementation, the method further includes: determining each voltage bias value based on the dielectric constant of each liquid crystal metasurface array unit. The voltage bias value corresponding to the liquid crystal dielectric constant may be determined by engineering testing or table lookup.

According to a fifth aspect, this application provides a microwave device. The microwave device includes an indoor unit, an outdoor unit, and an antenna. The indoor unit is configured to convert a baseband digital signal into an intermediate frequency analog signal; the outdoor unit is configured to: receive the intermediate frequency analog signal, and convert the intermediate frequency analog signal into a radio frequency signal; and the antenna is configured to: receive the radio frequency signal; determine a to-be-adjusted beam angle; load a voltage bias value on each liquid crystal metasurface array unit in a liquid crystal metasurface array based on the beam angle, where a lateral offset of a feed phase center is generated based on the voltage bias value after the radio frequency signal is transmitted through the liquid crystal metasurface array, the liquid crystal metasurface array includes M×N liquid crystal metasurface array units, and M and N are positive integers greater than or equal to 2; and emit the radio frequency signal transmitted through the liquid crystal metasurface array. At least one embodiment implements a beam reconfigurable antenna with low costs and low complexity, which may be applied to a microwave device at a transmitting end. When a beam direction is not aligned with an antenna at a receive end, the voltage bias value of the liquid crystal metasurface array unit may be adjusted, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment.

In a possible implementation, the antenna changes, based on the loaded voltage bias value, a transmission phase generated when the radio frequency signal is transmitted through each liquid crystal metasurface array unit. The transmission phase of the liquid crystal metasurface array unit is changed, so that the feed phase center is laterally offset, thereby implementing reconfiguration of an antenna beam.

In a possible implementation, the antenna changes a dielectric constant of each liquid crystal metasurface array unit based on the loaded voltage bias value. The liquid crystal dielectric constant is changed based on the voltage bias value, so that the transmission phase of the liquid crystal metasurface array unit is changed.

In a possible implementation, the antenna is further configured to determine the lateral offset of the feed phase center based on the to-be-adjusted beam angle. According to an antenna scanning principle, a relationship between a deflection angle of the antenna beam and the lateral offset of the feed phase center can be obtained. The deflection angle of the antenna beam is the same as the to-be-adjusted beam angle, but the directions are opposite.

According to a sixth aspect, this application provides a microwave device. The microwave device includes an indoor unit, an outdoor unit, and an antenna. The antenna is configured to: receive a radio frequency signal; determine a to-be-adjusted beam angle; load a voltage bias value on each liquid crystal metasurface array unit in a liquid crystal metasurface array based on the beam angle, where a lateral offset of a feed phase center is generated based on the voltage bias value after the radio frequency signal is transmitted through the liquid crystal metasurface array, the liquid crystal metasurface array includes M×N liquid crystal metasurface array units, and M and N are positive integers greater than or equal to 2; and emit the radio frequency signal transmitted through the liquid crystal metasurface array to the outdoor unit. The outdoor unit is configured to: receive the radio frequency signal, and convert the radio frequency signal into an intermediate frequency analog signal. The indoor unit is configured to convert the intermediate frequency analog signal into a baseband signal. At least one embodiment implements a beam reconfigurable antenna with low costs and low complexity, which may be applied to a microwave device at a receive end. When a beam direction is not aligned with an antenna at a receive end, the voltage bias value of the liquid crystal metasurface array unit may be adjusted, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment.

In a possible implementation, the antenna changes, based on the loaded voltage bias value, a transmission phase generated when the radio frequency signal is transmitted through each liquid crystal metasurface array unit. The transmission phase of the liquid crystal metasurface array unit is changed, so that the feed phase center is laterally offset, thereby implementing reconfiguration of an antenna beam.

In a possible implementation, the antenna changes a dielectric constant of each liquid crystal metasurface array unit based on the loaded voltage bias value. The liquid crystal dielectric constant is changed based on the voltage bias value, so that the transmission phase of the liquid crystal metasurface array unit is changed.

In a possible implementation, the antenna is further configured to determine the lateral offset of the feed phase center based on the to-be-adjusted beam angle. According to an antenna scanning principle, a relationship between a deflection angle of the antenna beam and the lateral offset of the feed phase center can be obtained. The deflection angle of the antenna beam is the same as the to-be-adjusted beam angle, but the directions are opposite.

According to a seventh aspect, this application provides a network system. The network system includes a first microwave device and a second microwave device. The first microwave device is configured to: convert a baseband digital signal into an intermediate frequency analog signal; convert the intermediate frequency analog signal into a radio frequency signal; determine a to-be-adjusted beam angle; load a voltage bias value on each liquid crystal metasurface array unit in a liquid crystal metasurface array based on the beam angle, where a lateral offset of a feed phase center is generated based on the voltage bias value after the radio frequency signal is transmitted through the liquid crystal metasurface array, the liquid crystal metasurface array includes M×N liquid crystal metasurface array units, and M and N are positive integers greater than or equal to 2; and emit the radio frequency signal transmitted through the liquid crystal metasurface array to the second microwave device. The second microwave device is configured to: receive the radio frequency signal from the first microwave device, and demodulate the received radio frequency signal. At least one embodiment implements a beam reconfigurable antenna with low costs and low complexity, which may be applied to a microwave device at a transmitting end. When a beam direction is not aligned with an antenna at a receive end, the voltage bias value of the liquid crystal metasurface array unit may be adjusted, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment.

In a possible implementation, the antenna changes, based on the loaded voltage bias value, a transmission phase generated when the radio frequency signal is transmitted through each liquid crystal metasurface array unit. The transmission phase of the liquid crystal metasurface array unit is changed, so that the feed phase center is laterally offset, thereby implementing reconfiguration of an antenna beam.

According to an eighth aspect, this application provides a network system. The network system includes a first microwave device and a second microwave device. The first microwave device is configured to: modulate a baseband digital signal into a radio frequency signal, and transmit the radio frequency signal to the second microwave device. The second microwave device is configured to: receive the radio frequency signal from the first microwave device; determine a to-be-adjusted beam angle; load a voltage bias value on each liquid crystal metasurface array unit in a liquid crystal metasurface array based on the beam angle, where a lateral offset of a feed phase center is generated based on the voltage bias value after the radio frequency signal is transmitted through the liquid crystal metasurface array, the liquid crystal metasurface array includes M×N liquid crystal metasurface array units, and M and N are positive integers greater than or equal to 2; and convert the radio frequency signal transmitted through the liquid crystal metasurface array into an intermediate frequency analog signal, and convert the intermediate frequency analog signal into a baseband signal. At least one embodiment implements a beam reconfigurable antenna with low costs and low complexity, which may be applied to a microwave device at a receive end. When a beam direction is not aligned with an antenna at a receive end, the voltage bias value of the liquid crystal metasurface array unit may be adjusted, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment.

In a possible implementation, the antenna changes, based on the loaded voltage bias value, a transmission phase generated when the radio frequency signal is transmitted through each liquid crystal metasurface array unit. The transmission phase of the liquid crystal metasurface array unit is changed, so that the feed phase center is laterally offset, thereby implementing reconfiguration of an antenna beam.

Still another aspect of this application provides a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium stores an instruction, and when the instruction is run on an antenna or a microwave device, the antenna or the microwave device is enabled to perform the method according to the foregoing aspects.

Yet another aspect of this application provides an executable program product including an instruction. When the executable program product runs on an antenna or a microwave device, the antenna or the microwave device is enabled to perform the method according to the foregoing aspects.

DESCRIPTION OF EMBODIMENTS

The following describes some embodiments in detail with reference to the accompanying drawings.

First, a possible application scenario of some embodiments is described.FIG.1is a schematic diagram of a microwave network architecture according to at least one embodiment. As shown inFIG.1, a beam reconfigurable antenna103or104(which may be referred to as an antenna for short) in accordance with at least one embodiment may be assembled in a microwave device101and a microwave device102, and communication is performed through the antenna103or104. For example, the microwave device101generates and transmits a beam105through the antenna103, and the beam105is received by the antenna104of the microwave device102through spatial transmission over a specific distance. The beam herein may be formed by a radio frequency signal (an electromagnetic wave). The beam reconfigurable antenna is a pattern-reconfigurable antenna, that is, a maximum gain direction or direction of a beam may be flexibly changed. Therefore, when an antenna at a transmitting end and/or an antenna at a receiving end shake/shakes, and a beam cannot be aligned by the antenna at the receiving end for receiving, the beam reconfigurable antenna may adjust a beam direction, to re-implement alignment.

The antenna in at least one embodiment may include a feed, a liquid crystal metasurface array, a beam transformation structure (for example, a reflector or a lens), and the like. The following describes a working principle of the beam reconfigurable antenna in at least one embodiment. A beam emitted by the feed is transmitted through the liquid crystal metasurface array, a resonance characteristic of the liquid crystal metasurface array is used, and a liquid crystal dielectric constant is controlled by using a voltage bias value, to change a transmission phase of a liquid crystal metasurface array unit, and implement a lateral offset of a feed phase center, so that the antenna beam can be reconstructed. The lateral offset of the feed phase center (or the reconfigurable phase center) means that a lateral position of the feed phase center changes, for example, the phase center moves on a plane parallel to the feed aperture plane. The following describes the lateral offset of the feed phase center with reference to the accompanying drawings.

FIG.2Ais a diagram of an initial state of a feed phase center according to at least one embodiment. As shown inFIG.2A, after a beam radiated by a feed201is away from the feed for a specific distance, an equiphase surface202of the feed is approximately a sphere, and a sphere center of the sphere is an equivalent phase center (or a phase center) of the feed. The equivalent phase center is at point A, and total phases generated after a beam is transmitted through liquid crystal metasurface array units (or liquid crystal metasurface array elements) 1, 2, 3, 4, 5, . . . , n are φA1+φ1, φA2+φ2, φA3+φ3, φA4+φ4, φA5+φ5, . . . , φAn+φn(φAnis a spatial phase generated from the point A to the unit n, and φnis a transmission phase generated from the unit n).

FIG.2Bis a diagram of a lateral offset state of a feed phase center according to at least one embodiment. After a liquid crystal bias voltage is changed, transmission phases of the liquid crystal metasurface array units 1, 2, 3, 4, 5, . . . , n are respectively increased by Δφ1, Δφ2, Δφ3, Δφ4, Δφ5, . . . , and Δφn. In this case, the equivalent phase center is at a point B, and total phases generated after the beam is transmitted through the liquid crystal metasurface units 1, 2, 3, 4, 5, . . . , n are respectively φB1+φ1+Δφ1, φB2+φ2+Δφ2, φB3+φ3+Δφ3, φB4+φ4+Δφ4, φB5+φ5+Δφ5, . . . , and φBn+φn+Δφn. After the equivalent phase center moves from the point A to the point B, the equiphase surface moves from202to203, that is, φAn+φn=φBn+φn+Δφn. Therefore, φAn−φBn=Δφn(n=1, 2, 3, 4, 5, . . . ).

FIG.3is a location relationship diagram of a lateral offset state of a feed phase center according to at least one embodiment. As shown inFIG.3, based on a position relationship between a feed301and a liquid crystal metasurface array302, and the lateral offset state of the feed phase center, the following relationship may be deduced.

A distance (d) between a horn aperture surface of the feed and the liquid crystal metasurface array and a side length (L) of the liquid crystal metasurface array meet the following condition:
tan θ=(L/2)/d(1), where

θ is a half illuminating angle of the feed.

It can be learned from φBn−φAn=Δφn(n=1, 2, 3, 4, 5, . . . ) that, a spatial phase change is equal to a transmission phase change φn(n=1, 2, 3, 4, 5, . . . ) of the liquid crystal metasurface array unit:
k√{square root over (sn2+d2)}−k√{square root over ((sn+Δd)2+d2)}=Δφn(2), where

Snis a distance from the feed phase center A to the nthunit; k=2πf/c is a quantity of waves in free space, f is a working frequency of an electromagnetic wave, and c is the speed of light; and Δd is the lateral offset of the feed phase center.

The following parameters are used as an example for quantitative analysis: the working frequency is 73.5 GHz, the half illuminating angle of the feed θ is 35 degrees, and a longitudinal spacing d between the horn aperture surface of the feed and the liquid crystal metasurface array is 6.5 mm. According to the foregoing parameters and with reference to formula (2), a transmission phase change Δφnof each liquid crystal metasurface array unit may be obtained through simulation when phase centers of different feeds are laterally offset by Δd.

The relationship between the liquid crystal dielectric constant and the transmission phase, and the relationship between the liquid crystal dielectric constant and the lateral offset of the phase center can be obtained through simulation after quantitative analysis.FIG.4is a schematic diagram of a liquid crystal metasurface array. The liquid crystal metasurface array may be of a planar structure, or may be of a curved surface structure. The liquid crystal metasurface array may include a liquid crystal layer, a metasurface layer, and a dielectric layer. The following parameters are used as an example for simulation:

(1) A size of a cross section of each liquid crystal metasurface array unit is 1 mm×1 mm;

(2) Liquid crystal layer: The liquid crystal layer is made of liquid crystal with a thickness of 0.1 mm, the relative dielectric constant is between 2.6 and 3.4, and the relative permeability is 1;

(3) Metasurface layer: The metasurface layer is made of oxygen-free copper with a thickness of 0.01 mm, and includes 9×9 liquid crystal metasurface array units (also referred to as metal resonance units). For detailed example parameters of each liquid crystal metasurface array unit, refer toFIG.5; and

(4) Dielectric layer: The dielectric layer is made of Rogers RT5880LZ with a thickness of 0.4 mm, the relative dielectric constant is 1.96, and the relative permeability is 1.

It is assumed that initial states of the liquid crystal metasurface array units are as follows. Dielectric constants of the liquid crystal metasurface array units are equal and each is 3. A simulation is performed based on the foregoing parameters of the liquid crystal metasurface array, to obtain a variation relationship between a transmission phase of a liquid crystal metasurface array unit and a frequency under different liquid crystal dielectric constants.

FIG.6is a curve chart of a relationship between a transmission phase of a liquid crystal metasurface array unit and a frequency under different liquid crystal dielectric constants according to at least one embodiment. InFIG.6, a horizontal coordinate indicates a working frequency, and a vertical coordinate indicates a transmission phase.FIG.6shows two curves whose liquid crystal dielectric constants are 2.6 and 3.4. If the selected working frequency is 73.5 GHz, when the liquid crystal dielectric constant is 2.6, the transmission phase of the liquid crystal metasurface array unit is 118 degrees; and when the liquid crystal dielectric constant is 3.4, the transmission phase of the liquid crystal metasurface array unit is 66.73 degrees. Therefore, it can be learned that the transmission phase decreases by 6.4 degrees for every increase of 0.1 of the liquid crystal dielectric constant.

Under the lateral offsets Δd of different feed phase centers, the liquid crystal dielectric constants of the metasurface array units are obtained according to the simulation analysis.

FIG.7is a diagram of a correspondence between a lateral offset Δd of a feed phase center and a liquid crystal dielectric constant of each liquid crystal metasurface array unit according to at least one embodiment. InFIG.7, a horizontal coordinate indicates a number of the liquid crystal metasurface array units, and a vertical coordinate indicates a liquid crystal dielectric constant.FIG.7shows corresponding liquid crystal dielectric constants of nine liquid crystal metasurface array units when Δd is 0.1, 0.3, or 0.5. When Δd is one of the values of 0.1, 0.3, or 0.5, the liquid crystal dielectric constants of the liquid crystal metasurface array units are different.

There is a fixed relationship between the liquid crystal dielectric constant and the liquid crystal bias voltage. For example, voltage bias values corresponding to different liquid crystal dielectric constants may be obtained through actual engineering testing with reference to the liquid crystal dielectric constant and a liquid crystal model. Alternatively, the liquid crystal voltage bias values corresponding to different liquid crystal dielectric constants may be obtained by looking up a table with reference to a specific liquid crystal model.

The liquid crystal metasurface array in at least one embodiment may be applied to a plurality of types of antennas, for example, a Cassegrain antenna, a reflector antenna, and a lens antenna.

FIG.8is a schematic structural diagram of an antenna according to at least one embodiment. As shown inFIG.8, the antenna800is a Cassegrain antenna, and may include a feed801, a liquid crystal metasurface array802, and a beam transformation structure. The beam transformation structure includes a primary reflector803and a secondary reflector804. The feed801and the liquid crystal metasurface array802are located between the primary reflector803and the secondary reflector804. The liquid crystal metasurface array802includes M×N liquid crystal metasurface array units, and M and N are positive integers greater than or equal to 2. M may be equal or unequal to N. The antenna800may further include a liquid crystal bias control circuit (not shown in the figure), and may include a plurality of voltage control units, for example, M×N voltage control units. In this case, one voltage control unit may be electrically coupled to, and control a voltage bias value of, one liquid crystal metasurface array unit.

When the antenna800is applied to the device at the transmitting end shown inFIG.1, that is, when the antenna800is used as the transmitting antenna103of the microwave device101at the transmitting end inFIG.1, a method900for beam reconstruction shown inFIG.9may be performed.

FIG.9is an example flowchart of a beam reconstruction method according to at least one embodiment. The method may include the following operations.

At operation901, a feed generates a radio frequency signal.

An input port of the feed is configured to receive a radio frequency signal from the outdoor unit or the radio frequency module of the microwave device101, and the radio frequency signal is transmitted to a radiation aperture of the feed through a waveguide tube. The radiation aperture of the feed may be a primary horn antenna that radiates a radio frequency signal towards a secondary reflector of a beam transformation structure. The radio frequency signal may be a microwave signal, that is, an electromagnetic wave of a specific frequency.

At operation902, a liquid crystal bias control circuit determines a to-be-adjusted beam angle, and loads a voltage bias value on each liquid crystal metasurface array unit in the liquid crystal metasurface array based on the beam angle.

According to a calculation formula of an antenna scanning principle, a relationship between a deflection angle of an antenna beam and a lateral offset of a feed phase center may be expressed by using the following formula:

F is an equivalent focal length of the Cassegrain antenna, and D is an aperture of the Cassegrain antenna.

The deflection angle α of the antenna beam may be determined by a microwave device at a receiving end. For example, a primary feed and a secondary feed are disposed in a receiving antenna of the microwave device at the receiving end, and a plurality of (for example, four) secondary feeds are placed around the primary feed. When the beams are aligned, receiving powers of the secondary feeds are the same. When the beam is offset, receiving powers of the secondary feeds are different. The deflection angle α of the antenna beam may be calculated based on changes of the receiving power. After determining the deflection angle α of the antenna beam, the microwave device at the receiving end may notify the microwave device at the transmitting end of the deflection angle α.

A deflection angle α of the antenna beam of a liquid crystal bias circuit at the receiving end and a to-be-adjusted beam angle may be two angles whose angle values are equal but directions are opposite. A voltage bias value of each liquid crystal metasurface array unit may be determined based on the to-be-adjusted beam angle or the deflection angle α of the antenna beam. There are a plurality of implementations for determining the voltage bias value, and three of the implementations are listed below:

First implementation: First, it can be learned from formula (3) that, the lateral offset Δd of the feed phase center may be determined based on the deflection angle α of the antenna beam. Then, it can be learned from formula (2) that changes of a transmission phase Δφnof each liquid crystal metasurface array unit may be determined according to Δd. Then, it can be learned fromFIG.6that a dielectric constant of each liquid crystal metasurface array unit is determined according to Δφn. Finally, based on the dielectric constant of each liquid crystal metasurface array unit, the voltage bias value of each liquid crystal metasurface array unit is determined through engineering testing or table lookup.

Second implementation: First, it can be learned from formula (3) that, the lateral offset Δd of the feed phase center may be determined based on the deflection angle α of the antenna beam. Then, it can be learned fromFIG.7that a correspondence diagram or a correspondence table between Δd and a dielectric constant of each liquid crystal metasurface array unit may be calculated and stored in advance. When the beam angle needs to be adjusted, the dielectric constant of each liquid crystal metasurface array unit may be learned according to Δd. Finally, based on the dielectric constant of each liquid crystal metasurface array unit, the voltage bias value of each liquid crystal metasurface array unit is determined through engineering testing or table lookup.

Third implementation: A correspondence between a deflection angle α of an antenna beam and a voltage bias value of each liquid crystal metasurface array unit may be calculated and stored in advance based on a deduction process in the first implementation. When the beam angle needs to be adjusted, the voltage bias value of each liquid crystal metasurface array unit may be learned according to α. Finally, based on the dielectric constant of the liquid crystal metasurface array unit, the voltage bias value of each liquid crystal metasurface array unit is determined through engineering testing or table lookup.

At operation903, the liquid crystal metasurface array transmits the radio frequency signal, and generates the lateral offset of the feed phase center based on the voltage bias value.

In at least one embodiment, the radio frequency signal emitted by the feed is transmitted through the liquid crystal metasurface array, and the liquid crystal dielectric constant is controlled by using the voltage bias value, to change the transmission phase of the liquid crystal metasurface array unit, and implement the lateral offset of the feed phase center. The voltage bias value loaded on each liquid crystal metasurface array unit can change the transmission phase of radio frequency signals transmitted through each liquid crystal metasurface array unit.

At operation904, the beam transformation structure emits the radio frequency signal transmitted through the liquid crystal metasurface array.

The beam transformation structure inFIG.8includes a primary reflector and a secondary reflector. Radio frequency signals can be reflected on the primary reflector and the secondary reflector, and directional gain can be provided. The reflected radio frequency signals have certain directivity. The radio frequency signals generated by the feed are transmitted through the liquid crystal metasurface array, reflected by the secondary reflector, reflected by the primary reflector, and then transmitted in a certain direction in the air. After the beam angle is adjusted, the beam direction can be aligned with the receiving antenna at the receiving end.

In at least one embodiment, when a direction of the receive beam is not aligned with the antenna at the receiving end, the voltage bias value of the liquid crystal metasurface array unit of the antenna at the transmitting end may be adjusted, and the lateral offset of the feed phase center is generated based on the voltage bias value, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment. According to the foregoing method, at least one embodiment implements a beam reconfigurable antenna with low costs and low complexity, to resolve a problem that the antenna is sensitive to shaking.

When the antenna800is applied to the device at the receiving end shown inFIG.1, that is, when the antenna800is used as the receiving antenna104of the microwave device102at the receiving end inFIG.1, a method1000for beam reconstruction shown inFIG.10may be performed.

FIG.10is an example flowchart of a beam reconstruction method according to at least one embodiment. The method may include the following operations.

At operation1001, a beam transformation structure receives a radio frequency signal.

The beam transformation structure inFIG.8includes a primary reflector and a secondary reflector. The primary reflector and the secondary reflector reflect radio frequency signals received in a relatively large area and focus the signals on the radiation aperture of the feed. The radio frequency signal is first received by the primary reflector, reflected by the primary reflector to the secondary reflector, reflected by the secondary reflector, transmitted through the liquid crystal metasurface array, and received by the feed. In other words, the beam transformation structure directs the received radio frequency signal through the liquid crystal metasurface array to the feed.

At operation1002, a liquid crystal bias control circuit determines a to-be-adjusted beam angle, and loads a voltage bias value on each liquid crystal metasurface array unit in the liquid crystal metasurface array based on the beam angle.

The deflection angle α of the antenna beam may be determined by a microwave device at a receiving end. For example, the deflection angle α is detected by setting a primary feed and a secondary feed. For a specific implementation, refer to operation902. Details are not described herein again. For determining the voltage bias values of the liquid crystal metasurface array units respectively based on the to-be-adjusted beam angle or the deflection angle α of the antenna beam, refer to the implementation of operation902. Details are not described herein again.

At operation1003, the liquid crystal metasurface array transmits the radio frequency signal, and generates a lateral offset of a feed phase center based on the voltage bias value.

In at least one embodiment, the radio frequency signal received by the beam transformation structure is transmitted through the liquid crystal metasurface array, and the liquid crystal dielectric constant is controlled by using the voltage bias value, to change the transmission phase of the liquid crystal metasurface array unit, and implement the lateral offset of the feed phase center. The voltage bias value loaded on each liquid crystal metasurface array unit can change the transmission phase of radio frequency signals transmitted through each liquid crystal metasurface array unit. Optionally, transmission phases generated by the radio frequency signal in the liquid crystal metasurface array units are different.

At operation1004, the feed receives the radio frequency signal transmitted through the liquid crystal metasurface array.

The radio frequency signal received by the feed may be sent to the outdoor unit or the radio frequency module of the microwave device102. After the beam angle is adjusted, the beam direction can be aligned with the receiving antenna at the receiving end.

In at least one embodiment, when a direction of the receive beam is not aligned with the antenna at the receiving end, the voltage bias value of the liquid crystal metasurface array unit of the antenna at the receiving end may be adjusted, and the lateral offset of the feed phase center is generated based on the voltage bias value, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment. According to the foregoing method, at least one embodiment implements a beam reconfigurable antenna with low costs and low complexity, to resolve a problem that the antenna is sensitive to shaking.

FIG.11is a schematic structural diagram of an antenna according to at least one embodiment. As shown inFIG.11, the antenna1100is a single reflector antenna (for example, a paraboloidal antenna), and may include a feed1101, a liquid crystal metasurface array1102, and a reflector1103. The liquid crystal metasurface array1102is located between the feed1101and the reflector1103. The liquid crystal metasurface array includes M×N liquid crystal metasurface array units, and M and N are positive integers greater than or equal to 2. The antenna1100may further include a liquid crystal bias control circuit (not shown in the figure), and may include a plurality of voltage control units, for example, M×N voltage control units. In this case, one voltage control unit may control a voltage bias value of one liquid crystal metasurface array unit. The antenna shown inFIG.11may be used as a beam reconfigurable antenna. A principle of beam reconstruction is similar to that of the antenna shown inFIG.8, i.e., a voltage bias value of a liquid crystal metasurface array unit of the antenna is adjusted, and a lateral offset of a feed phase center is generated based on the voltage bias value, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment. The antenna shown inFIG.11may perform the method shown inFIG.9orFIG.10. Details are not described herein again. According to the foregoing method, at least one embodiment implements a beam reconfigurable antenna with low costs and low complexity, to resolve a problem that the antenna is sensitive to shaking.

FIG.12is a schematic structural diagram of an antenna according to at least one embodiment. As shown inFIG.12, the antenna1200is a lens antenna, and may include a feed1201, a liquid crystal metasurface array1202, and a lens1203. The liquid crystal metasurface array1202is located between the feed1201and the lens1203. The liquid crystal metasurface array includes M×N liquid crystal metasurface array units, and M and N are positive integers greater than or equal to 2. The antenna1200may further include a liquid crystal bias control circuit (not shown in the figure), and may include a plurality of voltage control units, for example, M×N voltage control units. In this case, one voltage control unit may control a voltage bias value of one liquid crystal metasurface array unit. The antenna shown inFIG.12may be used as a beam reconfigurable antenna. A principle of beam reconstruction is similar to that of the antenna shown inFIG.8, i.e., a voltage bias value of a liquid crystal metasurface array unit of the antenna is adjusted, and a lateral offset of a feed phase center is generated based on the voltage bias value, to implement reconfiguration of the feed phase center and reconfiguration of an antenna beam, thereby implementing beam alignment. The antenna shown inFIG.12may perform the method shown inFIG.9orFIG.10. Details are not described herein again. According to the foregoing method, at least one embodiment implements a beam reconfigurable antenna with low costs and low complexity, to resolve a problem that the antenna is sensitive to shaking.

FIG.13is a schematic structural diagram of a microwave device according to at least one embodiment. As shown inFIG.13, the microwave device1300may include an outdoor unit (outdoor unit, ODU, also referred to as outdoor device, or first/second device)1301, an indoor unit (indoor unit, IDU, also referred to as indoor device, or second/first device)1302, an antenna1303, and an intermediate frequency cable1304. The ODU1301and the IDU1302may be connected through the intermediate frequency cable1304, and the ODU may be connected to the antenna through a feeding waveguide.

The ODU1301may include an intermediate frequency module, a sending module, a receiving module, a multiplexer, a duplexer, and the like. The ODU1301performs conversion between an intermediate frequency analog signal and a radio frequency signal. In a transmitting direction, the ODU1301performs up-conversion and amplification on the intermediate frequency analog signal from the IDU1302, converts the intermediate frequency analog signal into a radio frequency signal of a specific frequency, and sends the radio frequency signal to the antenna1303. In a receiving direction, the ODU1301performs down-conversion and amplification on the radio frequency signal received from the antenna1303, converts the radio frequency signal into an intermediate frequency analog signal, and sends the intermediate frequency analog signal to the IDU1302.

The IDU1302may include a board such as a system control, switching, and timing board, an intermediate frequency board, or a service board, and may provide a plurality of service interfaces such as a gigabit Ethernet (Gigabit Ethernet, GE) service, a synchronous transfer mode-1 (synchronous transfer module-1, STM-1) service, and an E1 service. The IDU1302mainly provides services such as processing a baseband signal and performing conversion between a baseband signal and an intermediate frequency analog signal. In a transmitting direction, the IDU1302modulates a baseband digital signal into an intermediate frequency analog signal. In a receiving direction, the IDU1302demodulates and digitizes the received intermediate frequency analog signal and decomposes the intermediate frequency analog signal into baseband digital signals.

The antenna1303may be any one of the antennas shown inFIG.8,FIG.11, andFIG.12in some embodiments. The antenna1303mainly provides a directional sending and receiving function for a radio frequency signal, and implements conversion between a radio frequency signal generated or received by the ODU1301and a radio frequency signal in atmospheric space. In a transmitting direction, the antenna1303converts a radio frequency signal output by the ODU1301into a directional radio frequency signal, and radiates the directional radio frequency signal to space. In a receiving direction, the antenna1303receives the radio frequency signal in the space, focuses the radio frequency signal, and transmits the radio frequency signal to the ODU1301. The beam reconstruction method provided in at least one embodiment may be applied to the antenna in the transmitting direction, or may be applied to the antenna in the receiving direction. For example, in the transmitting direction, the antenna1303receives a radio frequency signal from the ODU1301; determines a to-be-adjusted beam angle; changes a voltage bias value of each liquid crystal metasurface array unit in a liquid crystal metasurface array based on the beam angle, where a lateral offset of a feed phase center is generated based on the voltage bias value after the radio frequency signal is transmitted through the liquid crystal metasurface array; and emits the radio frequency signal transmitted through the liquid crystal metasurface array. In the receiving direction, the antenna1303receives a radio frequency signal radiated in the space; determines a to-be-adjusted beam angle; loads a voltage bias value on each liquid crystal metasurface array unit in a liquid crystal metasurface array based on the to-be-adjusted beam angle, where a lateral offset of a feed phase center is generated based on the voltage bias value after the radio frequency signal is transmitted through the liquid crystal metasurface array; and receives the radio frequency signal transmitted through the liquid crystal metasurface array.

The microwave device1300may be a split-structured microwave device, that is, the IDU1302is placed indoors, and the ODU1301and the antenna1303are assembled and placed outdoors. The microwave device1300may alternatively be a full-outdoor microwave device, that is, the ODU1301, the IDU1302, and the antenna1303are all placed outdoors. The microwave device1300may alternatively be a full-indoor microwave device, that is, the ODU1301and the IDU1302are placed indoors, and the antenna1303is placed outdoors. The ODU1301may also be referred to as a radio frequency module, and the IDU1302may also be referred to as a baseband.

When the beam reconfigurable antenna provided in at least one embodiment is applied to a microwave device, a capability of the device against shaking can be improved, and complexity and costs of the device can be reduced.

In the foregoing embodiments, at least one or some operations may be implemented by using software while at least another or some other operations may be implemented by using hardware. Alternatively, all operations may be implemented by using hardware. In an example, in operation902or operation1002, program code may be loaded on the liquid crystal bias control circuit for calculating the voltage bias value, and a hardware circuit on the liquid crystal bias control circuit loads or adjusts the voltage bias value based on a calculation result. In another example, a correspondence table between a deflection angle α of an antenna beam and a voltage bias value of each liquid crystal metasurface array unit may be stored in a storage element on the liquid crystal bias control circuit, and a hardware circuit on the liquid crystal bias control circuit loads or adjusts the voltage bias value based on a result of the table lookup. In another example, calculation of the voltage bias value or storage of the correspondence table may also be implemented in another module, for example, implemented in an outdoor unit of the microwave device, and the outdoor unit notifies the liquid crystal bias control circuit of the voltage bias value obtained through calculation or table lookup. The program code in at least one embodiment may be implemented by using a hardware description language, for example, a Verilog language. The program code may be loaded in a programmable logic device, such as a field programmable gate array (programmable gate array, FPGA) or a complex programmable logic device (CPLD, complex programmable logic device). When the program code runs in the programmable logic device, all or some of the procedures or functions according to some embodiments are generated.

Examples of a control circuit and/or a hardware circuit include, but are not limited to, a processor (such as a central processing unit or CPU), an application-specific integrated circuit (ASIC), or the like. Examples of a storage element and/or a non-transitory computer-readable storage medium include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, and/or a semiconductor system (or apparatus or device), such as, a semiconductor or solid-state memory, a magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a flash memory, a rigid magnetic disk, an optical disk, a compact disk-read only memory (CD-ROM), a compact disk-read/write (CD-R/W), a digital video disc (DVD), or the like.