CN111106858A - Wireless power transmission equipment and method based on antenna array design - Google Patents
Wireless power transmission equipment and method based on antenna array design Download PDFInfo
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Abstract
Embodiments of the present disclosure relate to a method, apparatus, and system for wireless power transmission based on antenna array design. By adopting the embodiment of the disclosure, a plurality of discrete users in the space can be charged simultaneously according to different energy distribution requirements, and when the positions of the users are switched, the transmitting array can quickly respond and adjust the radiation direction of the wave beam. Compared with a traditional phased array, the array is more accurate in beam pointing under a multi-beam pointing scene; cosine and pulse signals are adopted to complete time modulation, compared with a conventional rectangular pulse modulation array, the number of radiation beams generated by the array is easy to control, and the direction of each beam is independently controllable, so that waste caused by useless sideband radiation is avoided, and the point-to-multipoint space transmission efficiency is improved. The time modulation of the antenna channel is realized in a digital control mode, the multi-beam independent directional control and ultra-low side lobe radiation of the array can be realized without a phase shifter, and the efficiency of a wireless power transmission system is effectively improved.
Description
Technical Field
Embodiments of the present disclosure relate generally to the field of wireless power transmission via antenna arrays, and more particularly, to multi-beam time-modulated inverting arrays applied to wireless power transmission.
Background
Wireless power transfer is a technique that enables the transfer of electrical energy from a transmitting source to a receiving load without a wire connection. There are two general approaches according to the mechanism of energy transmission: near-field transmission based on a non-radiation mode and far-field transmission based on a radio-frequency radiation mode. The far-field wireless power transmission has a wide application prospect because the transmission distance is longer, and the information interaction function of users at the receiving end and the transmitting end can be considered. The far-field wireless power transmission follows the electromagnetic wave propagation model in free space, and according to the Friis formula, the energy obtained at the receiving end suffers from path loss. In order to ensure that sufficient energy is obtained in a receiving area, an array antenna is usually adopted as a transmitting device, and technologies such as array beam forming are adopted to synthesize a high-directivity narrow beam to accurately point to a receiving target, so that the energy transmission efficiency of a link is improved.
In order to realize accurate beam pointing, a high-precision phase shifter can be introduced into a transmitting antenna array channel, but the method is expensive and needs to predict the angular position of a receiving target, so that the array feed network is complex and the signal processing process is complicated. The working principle of the reverse array is that when the transmitting and receiving phases of the antenna units in the array meet the generalized conjugate condition, the transmitted signals return along the incoming wave direction, i.e. the 'reverse' of the electromagnetic wave transmission is realized. The main implementation forms of the inverse matrix are as follows: a Van Atta (Van Atta) form, a phase conjugate array (Pon-Type structure) based on a superheterodyne technology, a phase conjugate array based on a phase detection phase-locked loop, a digital inverse array, and the like. The fanatata array has strict requirements on array symmetry and antenna unit consistency, and is only suitable for planar arrays with plane wave incidence. Compared with the former, the superheterodyne-based inverse array adopts a phase conjugate mixing circuit based on a mixer to realize wavefront reconstruction at each antenna unit, and the array form is not strictly limited any more, so that the superheterodyne-based inverse array is widely applied to systems such as communication, radar, wireless energy transmission and the like.
However, the conventional inverse array is based on a phased array system, and radiation performance is seriously degraded when the number of pointing targets is increased.
Disclosure of Invention
The present disclosure overcomes the shortcomings of the prior art and presents an improved method and apparatus for wireless power transfer.
According to a first aspect of the present disclosure, a method of wireless power transmission based on an antenna array design is provided. The method comprises the following steps: receiving a pilot signal from at least one user equipment with a plurality of antenna elements; for each antenna element of the plurality of antenna elements: mixing the received pilot signal with a local oscillator signal, filtering the mixed signal through a low pass filter to generate a lower sideband signal phase-conjugated with the pilot signal, determining a value of a pulse control parameter as a function of an attribute of the pilot signal and a power requirement of at least one user device, generating at least one non-rectangular pulse control signal-the number of which is determined by the number of the at least one user device-the non-rectangular pulse control signal being a function of the pulse control parameter, modulating the lower sideband signal as a function of the at least one non-rectangular pulse control signal; and radiating the modulated lower sideband signal with the plurality of antenna elements. The phase conjugation mixing circuit is added with a single side band modulator which completes the time modulation function besides a mixer and a filter, and has stronger beam pointing capability than the conventional time modulation inverse array.
In one embodiment, the method may further comprise: the modulation frequency of the at least one non-rectangular pulse control signal is determined based on an operating frequency of each of the plurality of antenna elements, which is substantially greater than the modulation frequency, e.g., at least 1000 times, or 10000 times, or more. Preferably, the pulse control parameters may include: aiming at the periodic conduction duration of the at least one non-rectangular pulse control signal, the antenna unit is subjected to time modulation; and a weight for each of the at least one non-rectangular pulse control signal for weighting the temporal modulation of each non-rectangular pulse control signal. Alternatively, the pulse control parameter may consist of or only include: aiming at the periodic conduction duration of the at least one non-rectangular pulse control signal, the antenna unit is subjected to time modulation; and a weight for each of the at least one non-rectangular pulse control signal for weighting the temporal modulation of each non-rectangular pulse control signal. The phase conjugation relation of the backtracking signal and the incoming wave signal can be ensured without adding extra phase control.
In one embodiment, the property of the pilot signal may include a phase of a lower sideband signal.
In one embodiment, the power requirements may include the power required by each user device and the range over which the user devices are distributed.
In one embodiment, the value of the pulse control parameter may also be determined by means of random optimization.
In one embodiment, the method may further comprise: the modulated lower sideband signal is amplified prior to the radiation.
In one embodiment, the method may further comprise: the local oscillator signal is distributed by a multi-path equipower splitter to a loop associated with each of the plurality of antenna elements.
In one embodiment, the number of non-square pulse control signals may be equal to the number of user equipments for each of the plurality of antenna elements.
In one embodiment, the method may further comprise: modulating the lower sideband signal according to the at least one non-rectangular pulse control signal on one channel, namely an in-phase channel, in the quadrature dual-channel circuit to obtain a first modulation signal; modulating the lower sideband signal according to the quadrature signal of the at least one non-rectangular pulse control signal on the other channel, namely the quadrature channel, in the quadrature dual-channel circuit, and phase-shifting by pi/2 to obtain a second modulation signal; and combining the first modulated signal with the second modulated signal. By introducing the single-sideband modulation module with orthogonal double channels, the generation of mirror harmonic wave beams is inhibited, and the waste caused by useless radiation is avoided. The variable gain amplifier realizes non-rectangular pulse modulation, is different from square wave pulse modulation controlled by a conventional radio frequency switch, and the number of generated sideband beams is controllable, so that useless radiation generated by a large number of harmonic beams in the square wave modulation is avoided. In addition, the direction of each harmonic wave beam is independently controllable, and the flexibility of the square wave pulse modulation scheme is stronger.
According to another aspect of the present disclosure, there is provided an apparatus for wireless power transmission based on an antenna array. The apparatus includes a plurality of antenna loops, each antenna loop of the plurality of antenna loops comprising: an antenna unit for receiving a pilot signal from at least one user equipment; a mixer for mixing the received pilot signal with a local oscillator signal; a low pass filter for filtering the mixed signal to generate a lower sideband signal phase-conjugated with the pilot signal; a single sideband modulator modulating the lower sideband signal in accordance with at least one non-rectangular pulse control signal, the modulated lower sideband signal being adapted to be radiated by the antenna element; a pulse generator configured to: determining a value of a burst control parameter based on the attributes of the pilot signal and the power requirements of the at least one user equipment; and generating the at least one non-rectangular pulse control signal for each of the plurality of antenna loops, the number of non-rectangular pulse control signals being determined by the number of the at least one user equipment, the non-rectangular pulse control signal being a function of the pulse control parameter. The phase conjugation mixing circuit is added with a single side band modulator which completes the time modulation function besides a mixer and a filter, and has stronger beam pointing capability than the conventional time modulation inverse array.
In one embodiment, the pulse generator may be configured to determine the modulation frequency of the at least one non-rectangular pulse control signal according to an operating frequency of the antenna elements in the plurality of antenna loops, the operating frequency being much greater than the modulation frequency, for example at least 1000 times, or 10000 times, or higher. Preferably, the pulse control parameters may include: aiming at the periodic conduction duration of the at least one non-rectangular pulse control signal, the antenna unit is subjected to time modulation; and a weight for each of the at least one non-rectangular pulse control signal for weighting the temporal modulation of each non-rectangular pulse control signal. Alternatively, the pulse control parameter may consist of or only include: aiming at the periodic conduction duration of the at least one non-rectangular pulse control signal, the antenna unit is subjected to time modulation; and a weight for each of the at least one non-rectangular pulse control signal for weighting the temporal modulation of each non-rectangular pulse control signal. The phase conjugation relation of the backtracking signal and the incoming wave signal can be ensured without adding extra phase control.
In one embodiment, the property of the pilot signal may include a phase of a lower sideband signal.
In one embodiment, the power requirements may include the power required by each user device and the range over which the user devices are distributed.
In one embodiment, the value of the pulse control parameter may also be determined by means of random optimization.
In one embodiment, each antenna loop of the plurality of antenna loops may further include: an amplifier for amplifying the modulated lower sideband signal.
In one embodiment, the apparatus may further include: a multi-path equipower divider for distributing the local oscillation signal to the frequency mixer of each antenna loop in the plurality of antenna loops.
In one embodiment, the number of non-square pulse control signals may be equal to the number of user equipments for each of the plurality of antenna elements.
In one embodiment, the single sideband modulator may be comprised of a quadrature dual channel circuit comprising: a first variable gain amplifier on one of the quadrature two-channel circuits, i.e., the in-phase channel, for receiving the at least one non-rectangular pulse control signal and thereby modulating the lower sideband signal to obtain a first modulated signal; a second variable gain amplifier in series with the phase shifter on the other of the quadrature two-channel circuits, the second variable gain amplifier for receiving the quadrature signal of the at least one non-rectangular pulse control signal and thereby modulating the lower sideband signal, and the phase shifter for phase shifting the modulated lower sideband signal by pi/2 to obtain a second modulated signal; and a combiner for combining the first modulation signal and the second modulation signal. By introducing the single-sideband modulation module with orthogonal double channels, the generation of mirror harmonic wave beams is inhibited, and the waste caused by useless radiation is avoided. The variable gain amplifier realizes non-rectangular pulse modulation, is different from square wave pulse modulation controlled by a conventional radio frequency switch, and the number of generated sideband beams is controllable, so that useless radiation generated by a large number of harmonic beams in the square wave modulation is avoided. In addition, the direction of each harmonic wave beam is independently controllable, and the flexibility of the square wave pulse modulation scheme is stronger.
According to yet another aspect of the present disclosure, a wireless power transmission system based on an antenna array design is provided. The system comprises a device for wireless power transmission according to the antenna array based design as described above, and at least one user equipment that sends a pilot signal to the device for wireless power transmission and receives a radiated signal from the device for wireless power transmission.
The advantages that are brought about by embodiments of the present disclosure are generally: the reverse technology and the time modulation technology are combined, and the automatic tracking advantage of the reverse technology and the low sidelobe and multi-beam characteristics of the time modulation technology are utilized to realize the spatial low sidelobe, multi-beam and automatic direction backtracking transmitting array. Meanwhile, a variable gain amplifier is adopted in the time modulation part to generate an appropriate non-rectangular pulse modulation signal, so that the problem of useless sideband radiation generated by the conventional rectangular square wave modulation is solved, the energy utilization efficiency of the transmitting array is improved, and great advantages are brought to the wireless power transmission application. In addition, a plurality of harmonic wave beams generated by the time modulation array have small frequency difference, and the frequency difference is consistent with the frequency of the modulation signal, so that the beam pointing error caused by signal mutual interference of the multi-beam direction backtracking array is reduced.
Drawings
The above and other objects, features and advantages of the embodiments of the present disclosure will become more readily understood through the following detailed description with reference to the accompanying drawings. Various embodiments of the present disclosure will be described by way of example and not limitation in the accompanying drawings, in which:
fig. 1 shows a flow diagram of a power transfer method according to an embodiment of the present disclosure;
fig. 2 shows a schematic diagram of a power transfer system according to an embodiment of the present disclosure;
fig. 3 illustrates a system block diagram of a wireless power transfer device in accordance with an embodiment of the present disclosure;
FIG. 4 shows a schematic diagram of an example of equal power transmission according to one embodiment of the present disclosure;
FIG. 5 shows an optimized cosine pulse component weight distribution and channel on-time distribution for the equal power transmission example of FIG. 4;
FIG. 6 shows an array radar cross-sectional scattering area single-station test chart and a double-station test chart of the equal-power transmission example of FIG. 4;
FIG. 7 shows the optimized array normalized single and dual site patterns for the equal power transmit example of FIG. 4;
FIG. 8 shows a schematic diagram of an example of unequal power transmission according to another embodiment of the present disclosure;
FIG. 9 shows an optimized cosine pulse component weight distribution and channel on-time distribution for the non-uniform power transmission example of FIG. 8; and
figure 10 shows the optimized array normalized single and dual site patterns for the non-equal power transmit example of figure 8.
Detailed Description
The principles of the present disclosure will now be described with reference to various exemplary embodiments shown in the drawings. It should be understood that these examples are described merely to enable those skilled in the art to better understand and further implement the present disclosure, and are not intended to limit the scope of the present disclosure in any way. It should be noted that where feasible, similar or identical reference numerals may be used in the figures and that similar or identical reference numerals may indicate similar or identical functions. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the embodiments of the disclosure described herein.
The terms "include" and variations thereof are to be read as open-ended terms that mean "including, but not limited to. The term "or" should be understood as "and/or" unless the context clearly dictates otherwise. In addition, the term "based on" or "based on" should be understood as "based at least in part on" or "based at least in part on". The terms "one embodiment" and "an embodiment" should be understood as "at least one embodiment". The term "another embodiment" should be read as "at least one other embodiment". Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings.
Fig. 1 shows a flow diagram of a power transfer method 100 according to an embodiment of the disclosure. First, in step 101, a pilot signal from at least one user equipment is received with a plurality of antenna elements. The pilot signal is typically a position pilot signal in the uplink phase of the signal, in which multiple antenna units are in a receiving state.
Thereafter, steps 102 to 106 are performed for each of the plurality of antenna elements. At step 102, the received pilot signal is mixed with a local oscillator signal. The local oscillator signal frequency is related to the frequency of the pilot signal, specifically 2 times thereof. The mixed signal is filtered by a low-pass filter in step 103, resulting in a lower sideband signal phase-conjugated with the pilot signal, i.e. the phase-conjugated component of the received pilot signal. In step 104, a value of the burst control parameter is determined based on the properties of the pilot signal and the power requirements of the at least one user equipment. Such an attribute may be the pilot signal or all or part of an attribute associated with the pilot signal, such as the phase of the filtered lower sideband signal; the power requirement includes an absolute value of the power requirement and a relative value of the power requirement between the multiple user equipments (in other words, the power required by each user equipment) and a user area (in other words, a range in which the user equipments are distributed), a radiation pattern peak level corresponding to the antenna array (corresponding to the absolute value of the power requirement), a side lobe level (corresponding to the relative value of the power requirement between the multiple user equipments) and a beam width parameter (corresponding to the user area). At step 105, at least one non-rectangular pulse control signal is generated, the number of which is determined by the number of the at least one user equipment, the non-rectangular pulse control signal being a function of the pulse control parameter. In other words, the number of non-rectangular pulsed control signals is related to, e.g. the same as, the number of user equipments. Thus, one component of the non-rectangular pulse control signal corresponds to one user equipment for modulating the signal to be radiated to the user equipment. The non-rectangular pulse control signal may be a cosine pulse control signal or other pulse control signal that is not rectangular in one example. In step 106, the lower sideband signal is modulated according to at least one non-rectangular pulse control signal. Therefore, if there are a plurality of non-rectangular pulse control signals, the lower sideband signal is also divided into a plurality to be modulated by the corresponding non-rectangular pulse control signals, respectively.
After the lower sideband signal is modulated, it is radiated with a plurality of antenna elements in step 107. The steps of method 100 described above are not limited in order, and some steps may be ordered, such as placing step 104 before step 103.
Fig. 2 shows a schematic diagram of a power transfer system 20 according to an embodiment of the present disclosure. The power transfer system 20 includes a wireless power transfer apparatus 200 and at least one user equipment. The wireless power transfer apparatus 200 generally serves as a receiving and transmitting terminal of signals and includes a plurality of antenna loops, i.e., a plurality of antenna elements. The user equipment is typically plural, e.g. P-user equipment 300 as shown in FIG. 21、3002……300P. In the left diagram of fig. 2, by each user equipment 3001、3002……300PA pilot signal is transmitted to the wireless power transfer device 200, a process commonly referred to as uplink. After the phase conjugation and time modulation are performed on the received signal, in the right diagram of fig. 2, the modulated lower sideband signal is forwarded to the free space through the antenna, and the signal automatically traces back to each user equipment, which is generally called downlink.
Fig. 3 illustrates a system block diagram of a wireless power transfer device 200 according to an embodiment of the present disclosure. The wireless power transfer apparatus 200 includes a pulse generator 220 and a plurality of antenna loops 210. Each antenna loop 210 comprises an antenna element 211 for receiving a pilot signal from the user equipment and radiating a modulated lower sideband signal, a mixer 212 for mixing the received pilot signal with a local oscillator signal, a low pass filter 213 for filtering the mixed signal to generate a lower sideband signal phase-conjugated with the pilot signal, and a single sideband modulator 214 for modulating the lower sideband signal in accordance with at least one non-rectangular pulse control signal. The pulse generator 220 is used to generate a non-rectangular pulse control signal to modulate the lower sideband signal.
Additionally or in a particular embodiment, each antenna loop 210 may include only one antenna element 211. In the particular example shown in fig. 3, each antenna loop 210 may further include a circulator coupled to the antenna element 211 for isolating the transceived signals. In the particular example shown in fig. 3, each antenna loop 210 may also include an amplifier 215 to amplify the modulated lower sideband signal to a desired power prior to radiation. In the specific example shown in fig. 3, the wireless power transfer device 200 may further include a multi-way equipower divider 230 for distributing the local oscillator signal to the mixers 212 in each of the plurality of antenna loops 210. In addition, a pulse generator 220 is also connected to the single sideband modulator 214 in each antenna loop 210. The number of the antenna loops 210 is plural, for example, N.
In a particular embodiment, the pulse generator 220 may be controlled, for example, by a Field Programmable Gate Array (FPGA) to generate a plurality of non-rectangular pulse control signals for each antenna loop 210. The number of non-rectangular impulse control signals is determined by the number of user equipments, e.g. ten non-rectangular impulse control signals may be allocated for each antenna loop 210 if there are ten user equipments. The single sideband modulator 214 in each antenna loop 210 may be, for example, the quadrature two-channel circuit configuration shown in fig. 3. In this example, one channel, the in-phase channel, has a first variable gain amplifier 216 thereon for receiving the non-rectangular pulse control signal and thereby modulating the lower sideband signal to obtain a first modulated signal. The other, quadrature, path has a second variable gain amplifier 217 and a phase shifter 218 in series with it. The second variable gain amplifier 217 is arranged to receive the quadrature non-rectangular pulse control signal and modulate the lower sideband signal accordingly, and the phase shifter 218 is arranged to phase shift the modulated lower sideband signal by pi/2 to obtain a second modulated signal. The quadrature dual channel circuit structure also includes a combiner 219 for combining the first modulated signal with the second modulated signal for output to optional amplifier 215. By introducing the single-sideband modulation structure with orthogonal double channels, the generation of mirror harmonic wave beams is inhibited, and the waste caused by useless radiation is avoided. In this example, the pulse generator 220 is connected to and feeds the non-rectangular pulse control signal to the first and second variable gain amplifiers 216, 217 in the single sideband modulator 214 in each antenna loop 210.
The inventive concept and the working principle of the present disclosure are explained below by describing two embodiments in conjunction with fig. 4 to 10. The corresponding devices of the two embodiments can be referred to fig. 2 and fig. 3. It should be understood, however, that the embodiments described in this specification are only for better understanding of the principles of the disclosure, and do not impose any limitation on the scope of the disclosure.
In the first embodiment, the number of antenna elements N is 16, and the antenna unit 211 is operated at f0An omni-directional antenna element of 2.45GHz means that the frequency of the uplink pilot signal transmitted by the user equipment is 2.45 GHz. Half-wavelength of array element spacing: d ═ λ0/2, where λ0＝c/f0And c is the speed of light. System modulation frequency fpShould be chosen to be much smaller than the operating frequency of the antenna element, for example a thousandth or less thereof, for example 25 kHz. Local oscillator signal frequency fLODependent on the operating frequency of the antenna element, in particular fLO＝2f0。
The scenario of this embodiment is set as follows: user equipment 300 to be charged with P-3 equidistant r-6 m from the transmitting terminal array (i.e., the array formed by antenna elements 211 in wireless power transfer device 200) in space1、3002、3003. The axial direction of the transmitting array is taken as a reference direction, and the three user equipment are respectively distributed at theta (40 degrees, 60 degrees and 110 degrees)]As shown in fig. 4. The center frequencies of the uplink signals sent from the user equipment are all f0Taking a single-frequency signal as an example, the signals arriving at the transmitting terminal array are:
Vin,l、θin,ldenotes the intensity and angle of incidence of the l-th signal at the antenna front, n denotes the nth user equipment, t denotes time, and k denotes the electromagnetic wave free space wavenumber, k 2 pi/λ0Wherein λ is0＝c/f0. By VLOIndicating the local oscillator signal strength, the received pilot signal and local oscillator signal mixed at mixer 212 are:
the lower sideband signal filtered by the low pass filter 213 is:
the phase of the signal is conjugate to the phase of the pilot signal. The single sideband modulator 214 time modulates the signal with amplitude weighting using Un(t) represents the periodic modulation signal, i.e., the non-moment, generated by the pulse generator 220Shape pulse control signal, AnRepresenting the amplitude weights of the nth transmit channel (i.e., for the nth antenna loop or antenna element), let A ben1. The modulated signals are:
the present embodiment employs a time modulation scheme based on weighted cosine and pulse signals, and the non-rectangular pulse control signal U will be described belown(t) the production process.
Firstly, the system modulation frequency f is determinedpWhen there are 3 targets that need to be charged, 25kHz, 3 non-rectangular pulse control signals (cosine pulse control signals in this example) are required, with a frequency: f. ofp、2fp、3fp。τnRepresents the conduction time (normalization) of the nth antenna unit in one period for time modulation of the non-rectangular pulse control signal; a isnpWeights representing the temporal modulation of the p-th non-rectangular pulse control signal for the nth antenna element are used to weight the temporal modulation of each non-rectangular pulse control signal in the form:
wherein
rect represents a rectangular pulse function. U shapeni(t),Unq(t) modulation signals representing the in-phase and quadrature channels, respectively, are generated by the FPGA control circuit at the pulse generator 220. In which the pulse control parameter taun、anpAnd obtaining the target by adopting a random optimization method according to the optimization target. Such as genetic algorithms, differential evolution, artificial bee colony algorithms, and the like. Superior foodThe quantization target may be a specified number of attribute-related performance index (sidelobe level, peak level, beamwidth) references. The optimization objective function is constructed according to a certain functional form, which will be explained below.
Next, an objective function is constructed, and pulse modulation parameters are determined from the side lobe level SLL, the peak level PL, and the beam width BW in the antenna radiation pattern parameters. SLL, PL and BW are antenna radiation performance indicators corresponding to the power requirements of the user equipment, from which pulse control parameters may be determined by random optimization such as an Artificial Bee Colony (ABC) algorithm. With optimization target SLLdesRepresenting a desired maximum sidelobe level value or indicator, thereby reducing energy leakage in non-target areas; with optimization of target PLdesRepresenting a desired peak level value or index, thereby allocating beam energy or power directed to each user; with optimized target BWdesRepresenting a desired beam width value or index to avoid energy dispersion into non-target areas. Thus, the objective function is constructed as follows:
w1、w2、w3respectively represent the weight values of the respective optimization targets, and H represents the Heaviside step function. According to the target scenario of this embodiment, 3 independent ues in the space are in equal power transmission, and the normalized peak level values of the optimization target are all PLdesThe 3dB beam width values of the optimization target are all BW (bandwidth of 0 dB)des5 DEG, and the maximum sidelobe level value of the optimization target is SLLdes-40 dB. Make SLLp、PLp、BWpApproaching to their respective optimized target values as much as possible, corresponding pulse control parameters taun、anpThe value of (c) is its optimized value. For example, in the present example, the resulting pulse control parameter τ is optimizedn、anp(normalized) distribution as shown in fig. 5-left diagram shows normalized weights a at 16 antenna elements for 3 user equipmentsnpThe right diagram shows the normalized on-time τ for 16 antenna elementsn. As defined above, for example, in the left diagram of fig. 5, it can be seen that for the nth antenna element, the respective time-modulated weights a of the 3 non-rectangular pulse control signalsn1、an2And an3The sum is equal to 1.
The direction backtracking performance of the inverse array is measured by Beam Pointing Error (BPE), and needs to be determined by measuring the scattering sectional area of the array radar, which is a physical quantity representing the scattering strength of the antenna array. The single-site pattern characterizes the beam-backtracking angular range of the antenna array, which is tested as shown in the left diagram of fig. 6, i.e., the transmit and receive antennas are moved synchronously at different angular positions relative to the antenna array so that the receive antenna detects the normalized power. The two-station pattern characterizes the beam pointing error as tested by the right diagram in fig. 6, i.e., the transmit antenna is fixed in position and the receive antenna is individually moved at different angles relative to the antenna array to allow the receive antenna to detect the normalized power. In the above embodiment, the single-station and double-station patterns of the optimized antenna array are shown in fig. 7. Under the action of the modulation time sequence obtained through optimization, the array backtracking field radiates along the incoming wave direction of each user, and the energy distribution is uniform.
In the following second embodiment, it is assumed that there are 3 users to be charged in a space that are not equidistant from the transmitting terminal array (i.e., the array formed by the antenna units 211 in the wireless power transmission device 200), and the users are distributed in the directions of θ ═ 40 °,60 °,110 ° ] with the transmitting array axial direction as the reference direction, and the distances from the transmitting terminals are in this order: r ═ 9.5m,3m,4.5m ], as shown in fig. 8. The up-link phase of the user pilot signal is identical to the first embodiment described above, and the signal is received and processed by the mixer 212 and the low-pass filter 213, and fed to the single-sideband modulator 214. The form of the objective function in this scenario is the same as in the first embodiment, but the optimization objectives are different:
normalized peak level values of the optimization targets are respectively PL1,des＝0dB、PL2,des＝-10dB、PL3,desThe beam width values of the optimization target are all BW (bandwidth ratio) — 6dBdesThe maximum sidelobe level value of the optimization target is SLL (5 degrees)des-40 dB. Optimizing the resulting weight anpAnd on duration taunThe distributions are shown in the left and right diagrams of fig. 9, respectively. The single-station, dual-station pattern of the second embodiment optimized array is shown in fig. 10. Under the action of pulse control parameters obtained through optimization, an array backtracking field radiates along the incoming wave direction of each user, the energy is reconfigured, the beam gain of a long-distance user is high, the beam gain of a short-distance user is low, and the near-far effect commonly encountered in multi-user transmission is solved to a certain extent.
It is worth noting that according to one embodiment of the present disclosure, the pulse control parameter may include only the weight anpAnd on duration taun. In other words, no additional phase control is added in the time modulation process, and the phase conjugation relation between the backtracking signal and the incoming wave signal is ensured.
Advantages of embodiments according to the present disclosure are: 1) the control of the switch-on time and the switch-on duration is equivalent to the amplitude-phase weighting of the antenna unit, so that the switch replaces the action of a radio frequency phase shifter in the traditional array, the beam pointing and scanning functions are realized, the pointing error problem caused by the quantization precision of the phase shifter is avoided on one hand, and the hardware cost of an antenna system is greatly reduced on the other hand; 2) the equivalent amplitude weighting of the time control switch enlarges the dynamic range of channel gain control in the traditional amplitude weighting method, and the ultralow sidelobe weighting is easy to realize; 3) due to the time domain periodic switching action, the energy radiated by the antenna unit is distributed in a discrete interval in a frequency domain, and after the energy is relatively superposed, radiation components of a plurality of frequencies (frequency intervals are related to the period of time modulation) are generated in space, namely simultaneous multi-beam is generated.
In addition, compared with a phased array antenna and an intelligent antenna, the antenna array disclosed by the invention can automatically forward energy to the direction of a target user without predicting the direction information of incoming waves of the user and without complex digital signal processing; the method has application advantages to multi-user scenarios, generates independent response beams for a plurality of uplink signals with low hardware cost and low processing complexity, and can realize flexible point-to-multipoint energy transmission. According to the antenna array, the non-rectangular pulse modulation signals are adopted for time modulation, the number of radiation beams generated by the array is easy to control, and the direction of each beam is independently controllable, so that waste caused by useless harmonic radiation brought by traditional rectangular square wave modulation is avoided, and the transmission efficiency of a wireless power transmission system is improved. Moreover, a plurality of harmonic wave beams generated by the time modulation array have small frequency difference, and the frequency difference is consistent with the frequency of the modulation signal, so that the beam pointing error caused by signal mutual interference of the multi-beam direction backtracking array is reduced.
Although claims have been formulated in this application to particular combinations of features, it should be understood that the scope of the disclosure also includes any novel feature or any novel combination of features disclosed herein either explicitly or implicitly or any generalisation thereof, whether or not it relates to the same aspect as presently claimed in any claim. The applicants hereby give notice that new claims may be formulated to such features and/or combinations of such features during the prosecution of the present application or of any further application derived therefrom.
Claims (23)
1. A method of wireless power transmission based on an antenna array, comprising:
receiving (101) pilot signals from at least one user equipment with a plurality of antenna elements;
for each antenna element of the plurality of antenna elements:
mixing (102) the received pilot signal with a local oscillator signal;
filtering (103) the mixed signal by a low-pass filter to generate a lower sideband signal phase-conjugated with the pilot signal;
determining (104) a value of a burst control parameter based on the properties of the pilot signal and the power requirements of the at least one user equipment;
generating (105) at least one non-rectangular pulse control signal, the number of non-rectangular pulse control signals being determined by the number of the at least one user equipment, the non-rectangular pulse control signal being a function of the pulse control parameter;
modulating (106) the lower sideband signal in accordance with the at least one non-rectangular pulse control signal; and
radiating (107) the modulated lower sideband signal with the plurality of antenna elements.
2. The method of claim 1, further comprising:
determining a modulation frequency of the at least one non-rectangular pulse control signal based on an operating frequency of each of the plurality of antenna elements, the operating frequency being at least 1000 times the modulation frequency.
3. The method of claim 2, wherein the pulse control parameters comprise:
for the period conducting duration of the at least one non-rectangular pulse control signal, time modulating the antenna unit; and
a weight for each of the at least one non-rectangular pulse control signal for weighting the temporal modulation of each non-rectangular pulse control signal.
4. The method of claim 2, wherein the pulse control parameter consists of:
for the period conducting duration of the at least one non-rectangular pulse control signal, time modulating the antenna unit; and
a weight for each of the at least one non-rectangular pulse control signal for weighting the temporal modulation of each non-rectangular pulse control signal.
5. The method of claim 1, wherein the property of the pilot signal comprises a phase of the lower sideband signal.
6. The method of claim 1, wherein the power requirements include power required by each user equipment and a range over which the user equipment is distributed.
7. The method according to any one of claims 1 to 6, wherein the values of the pulse control parameters are also determined by means of random optimization.
8. The method of any of claims 1 to 6, further comprising:
amplifying the modulated lower sideband signal prior to said radiating (107).
9. The method of any of claims 1 to 6, further comprising:
the local oscillator signal is distributed by a multi-path equipower splitter to a loop associated with each of the plurality of antenna units.
10. The method of any of claims 1-6, wherein the number of non-square pulse control signals is equal to the number of user equipments for each of the plurality of antenna elements.
11. The method according to any one of claims 1 to 6, wherein the modulating (106) comprises:
modulating the lower sideband signal according to the at least one non-rectangular pulse control signal on an in-phase channel in a quadrature two-channel circuit to obtain a first modulated signal;
modulating the lower sideband signal according to the orthogonal signal of the at least one non-rectangular pulse control signal on an orthogonal channel in the orthogonal dual-channel circuit, and phase-shifting pi/2 to obtain a second modulation signal; and
combining the first modulated signal with the second modulated signal.
12. An apparatus for wireless power transmission based on an antenna array, comprising:
a plurality of antenna loops (210), each antenna loop of the plurality of antenna loops comprising:
an antenna unit (211) for receiving pilot signals from at least one user equipment;
a mixer (212) for mixing the received pilot signal with a local oscillator signal;
a low pass filter (213) for filtering the mixed signal to generate a lower sideband signal phase-conjugated with the pilot signal;
a single sideband modulator (214) for modulating the lower sideband signal in accordance with at least one non-rectangular pulsed control signal, the modulated lower sideband signal being adapted to be radiated by the antenna element;
a pulse generator (220) configured to:
determining a value of a burst control parameter based on an attribute of the pilot signal and a power requirement of the at least one user equipment; and
generating the at least one non-rectangular pulse control signal for each of the plurality of antenna loops, the number of non-rectangular pulse control signals determined by the number of the at least one user equipment, the non-rectangular pulse control signal being a function of the pulse control parameter.
13. The apparatus of claim 12, wherein the pulse generator is configured to determine a modulation frequency of the at least one non-rectangular pulse control signal based on an operating frequency of the antenna elements in the plurality of antenna loops, the operating frequency being at least 1000 times the modulation frequency.
14. The apparatus of claim 13, wherein the pulse control parameters comprise:
for the period conducting duration of the at least one non-rectangular pulse control signal, time modulating the antenna unit; and
a weight for each of the at least one non-rectangular pulse control signal for weighting the temporal modulation of each non-rectangular pulse control signal.
15. The apparatus of claim 13, wherein the pulse control parameter consists of:
for the period conducting duration of the at least one non-rectangular pulse control signal, time modulating the antenna unit; and
a weight for each of the at least one non-rectangular pulse control signal for weighting the temporal modulation of each non-rectangular pulse control signal.
16. The apparatus of claim 12, wherein the property of the pilot signal comprises a phase of the lower sideband signal.
17. The apparatus of claim 12, wherein the power requirements comprise power required by each user equipment and a range over which the user equipment is distributed.
18. The apparatus of any of claims 12 to 17, wherein the values of the pulse control parameters are further determined by means of random optimization.
19. The apparatus of any of claims 12-17, wherein each antenna loop of the plurality of antenna loops further comprises:
an amplifier (215) for amplifying the modulated lower sideband signal.
20. The apparatus of any of claims 12 to 17, further comprising:
a multi-path equipower divider (230) for distributing the local oscillator signal to the mixers of each of the plurality of antenna loops.
21. The apparatus according to any of claims 12-17, wherein a number of the non-rectangular pulse control signals is equal to a number of the user equipments for each of the plurality of antenna loops.
22. The apparatus of any of claims 12-17, wherein the single sideband modulator is comprised of a quadrature dual channel circuit comprising:
a first variable gain amplifier (216) on an in-phase channel of the quadrature two-channel circuit for receiving the at least one non-rectangular pulse control signal and modulating the lower sideband signal thereby to obtain a first modulated signal;
a second variable gain amplifier (217) on a quadrature channel in the quadrature two-channel circuit and a phase shifter (218) in series therewith, the second variable gain amplifier (217) for receiving a quadrature signal of the at least one non-rectangular pulse control signal and modulating the lower sideband signal thereby, the phase shifter (218) for phase shifting the modulated lower sideband signal by pi/2 to obtain a second modulated signal; and
a combiner (219) for combining the first modulated signal with the second modulated signal.
23. An antenna array based wireless power transmission system comprising:
apparatus for wireless power transmission based on an antenna array according to any of claims 12 to 22; and
at least one user equipment that sends a pilot signal to the apparatus for wireless power transmission and receives a radiated signal from the apparatus for wireless power transmission.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113567914A (en) * | 2021-07-23 | 2021-10-29 | 上海交通大学 | Omnidirectional broadband direction finding system and method based on time modulation array |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2498526A1 (en) * | 1999-09-23 | 2001-03-29 | Ut-Battelle, Llc | Pulse transmission transceiver architecture for low power communications |
| CN201352797Y (en) * | 2008-12-25 | 2009-11-25 | 中国电子科技集团公司第五十研究所 | CPM modulator based on corrective Gaussian pulse shaping |
| CN103402213A (en) * | 2013-07-24 | 2013-11-20 | 西安交通大学 | Method of forming time asynchronous robust distributed beam |
| CN104079517A (en) * | 2014-06-19 | 2014-10-01 | 哈尔滨工程大学 | Continuous phase modulation achieving method based on pulse function weighing |
| WO2017194167A1 (en) * | 2016-05-13 | 2017-11-16 | Huawei Technologies Co., Ltd. | Radio transceiving device and method using waveform adaptation |
-
2018
- 2018-10-26 CN CN201811272914.8A patent/CN111106858A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2498526A1 (en) * | 1999-09-23 | 2001-03-29 | Ut-Battelle, Llc | Pulse transmission transceiver architecture for low power communications |
| CN201352797Y (en) * | 2008-12-25 | 2009-11-25 | 中国电子科技集团公司第五十研究所 | CPM modulator based on corrective Gaussian pulse shaping |
| CN103402213A (en) * | 2013-07-24 | 2013-11-20 | 西安交通大学 | Method of forming time asynchronous robust distributed beam |
| CN104079517A (en) * | 2014-06-19 | 2014-10-01 | 哈尔滨工程大学 | Continuous phase modulation achieving method based on pulse function weighing |
| WO2017194167A1 (en) * | 2016-05-13 | 2017-11-16 | Huawei Technologies Co., Ltd. | Radio transceiving device and method using waveform adaptation |
Non-Patent Citations (4)
| Title |
|---|
| 张克潜, 王盾, 王震宇: "单脉冲微波功率与能量的量测", 真空电子技术, no. 01 * |
| 李雪松;张天骐;杨柳飞;代少升;: "DS-UWB信号伪码周期的谱估计", 系统仿真学报, no. 10 * |
| 范玉芳, 梁甸农: "非正弦波SAR的方位向分辨力", 国防科技大学学报, no. 03 * |
| 蒋廷勇;宁辉;邵浩;刘小龙;: "微波短脉冲时域合成效率研究", 微波学报, no. 01 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113567914A (en) * | 2021-07-23 | 2021-10-29 | 上海交通大学 | Omnidirectional broadband direction finding system and method based on time modulation array |
| CN113567914B (en) * | 2021-07-23 | 2023-11-07 | 上海交通大学 | Omnidirectional broadband direction-finding system based on time modulation array |
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