The dynamic characteristics of a quartz crystal resonator（QCR） in thicknessshear modes（TSM） with the upper surface covered by an array of micro-beams immersed in liquid are studied. The liquid is assumed to be inv...The dynamic characteristics of a quartz crystal resonator（QCR） in thicknessshear modes（TSM） with the upper surface covered by an array of micro-beams immersed in liquid are studied. The liquid is assumed to be inviscid and incompressible for simplicity. Dynamic equations of the coupled system are established. The added mass effect of liquid on micro-beams is discussed in detail. Characteristics of frequency shift are clarified for different liquid depths. Modal analysis shows that a drag effect of liquid has resulted in the change of phase of interaction（surface shear force）, thus changing the system resonant frequency. The obtained results are useful in resonator design and applications.展开更多
This paper reports that the central position of the reflected and transmitted beams of a nonlinear polarized light beam at the interface between two media undergoes transverse shifts. It presents a solution to the pro...This paper reports that the central position of the reflected and transmitted beams of a nonlinear polarized light beam at the interface between two media undergoes transverse shifts. It presents a solution to the problem of transverse shift of a non-uniformly polarized paraxial light beam transmitting through interfaces between two homogeneous media by using a two-form amplitude and an extension matrix to represent the vector angular spectrum of a three-dimensional （3D） light beam. It derives general formula for the transverse shift of the transmitted beam, and discusses the shift of a well-collimated beam transmitting through an interface between two homogeneous media and a thin dielectric slab.展开更多
Focal shift of radially polarized Bessel-modu- lated Gaussian (QBG) beam by phase shifting is investigated theoretically by vector diffraction theory. The phase shifting distribution is the function of the radial coor...Focal shift of radially polarized Bessel-modu- lated Gaussian (QBG) beam by phase shifting is investigated theoretically by vector diffraction theory. The phase shifting distribution is the function of the radial coordinate. Calculation results show that intensity distribution in focal region can be altered considerably by the topo- logical charge of QBG beam and the phase pa-rameter that indicates the vary degree of the phase shifting along radial coordinate. Topolo- gical charge induces the focal shift in trans-verse direction, while phase parameter leads to the focal shift along optical axis of the focusing system. More interesting, the focal shift may be incontinuous in certain case.展开更多
This paper proposes a new reconfigurable intelligent surface based three-dimensional beam tracking method to solve the beam tracking problems for the unmanned aerial vehicle with obstacles in communication channels.Th...This paper proposes a new reconfigurable intelligent surface based three-dimensional beam tracking method to solve the beam tracking problems for the unmanned aerial vehicle with obstacles in communication channels.The proposed beam tracking method can not only regulate the reconfigurable intelligent surfaces to achieve the beam tracking of the obstructed communications,but also optimize the transmission efficiency of the communication.Firstly,a reconfigurable intelligent surface is proposed,which can correlate the transmission signals by adjusting the phaseshift matrix.Meanwhile,a new communication channel is constructed according to the reconfigurable intelligent surface,which consists of two parts.The first one is the channel between the unmanned aerial vehicle and the reconfigurable intelligent surface,the other is the channel between the reconfigurable intelligent surface and the ground base station.Note that the transmission performance of the communications can be optimized by adjusting the phase shift of each uniform linear array on the reconfigurable intelligent surface.Then,a new beam tracking method for the unmanned aerial vehicle with obstructed communications is proposed on the basis of the reconfigurable intelligent surface.By proposing the mixed genetic algorithm,the estimation accuracy of the azimuth and elevation angles is improved to enhance the performance of the beam tracking.Finally,the simulations are provided to verify the effectiveness of the proposed three-dimensional beam tracking method with reconfigurable intelligent surface.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.11272127 and51425006)the Research Fund for the Doctoral Program of Higher Education of China(No.20130142110022)the Grant from the Impact and Safety of Coastal Engineering Initiative Program of Zhejiang Provincial Government at Ningbo University(No.zj1213)
文摘The dynamic characteristics of a quartz crystal resonator（QCR） in thicknessshear modes（TSM） with the upper surface covered by an array of micro-beams immersed in liquid are studied. The liquid is assumed to be inviscid and incompressible for simplicity. Dynamic equations of the coupled system are established. The added mass effect of liquid on micro-beams is discussed in detail. Characteristics of frequency shift are clarified for different liquid depths. Modal analysis shows that a drag effect of liquid has resulted in the change of phase of interaction（surface shear force）, thus changing the system resonant frequency. The obtained results are useful in resonator design and applications.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60377025 and 60777017)Science andTechnology Commission of Shanghai Municipal (Grant No 04JC14036)the Shanghai Leading Academic Discipline Program(Grant No T0104)
文摘This paper reports that the central position of the reflected and transmitted beams of a nonlinear polarized light beam at the interface between two media undergoes transverse shifts. It presents a solution to the problem of transverse shift of a non-uniformly polarized paraxial light beam transmitting through interfaces between two homogeneous media by using a two-form amplitude and an extension matrix to represent the vector angular spectrum of a three-dimensional （3D） light beam. It derives general formula for the transverse shift of the transmitted beam, and discusses the shift of a well-collimated beam transmitting through an interface between two homogeneous media and a thin dielectric slab.
文摘Focal shift of radially polarized Bessel-modu- lated Gaussian (QBG) beam by phase shifting is investigated theoretically by vector diffraction theory. The phase shifting distribution is the function of the radial coordinate. Calculation results show that intensity distribution in focal region can be altered considerably by the topo- logical charge of QBG beam and the phase pa-rameter that indicates the vary degree of the phase shifting along radial coordinate. Topolo- gical charge induces the focal shift in trans-verse direction, while phase parameter leads to the focal shift along optical axis of the focusing system. More interesting, the focal shift may be incontinuous in certain case.
基金co-supported by the National Natural Science Foundation of China(Nos.61867005,61703411)。
文摘This paper proposes a new reconfigurable intelligent surface based three-dimensional beam tracking method to solve the beam tracking problems for the unmanned aerial vehicle with obstacles in communication channels.The proposed beam tracking method can not only regulate the reconfigurable intelligent surfaces to achieve the beam tracking of the obstructed communications,but also optimize the transmission efficiency of the communication.Firstly,a reconfigurable intelligent surface is proposed,which can correlate the transmission signals by adjusting the phaseshift matrix.Meanwhile,a new communication channel is constructed according to the reconfigurable intelligent surface,which consists of two parts.The first one is the channel between the unmanned aerial vehicle and the reconfigurable intelligent surface,the other is the channel between the reconfigurable intelligent surface and the ground base station.Note that the transmission performance of the communications can be optimized by adjusting the phase shift of each uniform linear array on the reconfigurable intelligent surface.Then,a new beam tracking method for the unmanned aerial vehicle with obstructed communications is proposed on the basis of the reconfigurable intelligent surface.By proposing the mixed genetic algorithm,the estimation accuracy of the azimuth and elevation angles is improved to enhance the performance of the beam tracking.Finally,the simulations are provided to verify the effectiveness of the proposed three-dimensional beam tracking method with reconfigurable intelligent surface.
