Reasearch On Simultaneous Wireless Information And Power Transfer And Signal Processing Based On Metasurface

Metasurfaces are 2-Dimensional（2D）planar artificial electromagnetic（EM）structures composed of periodically or aperiodically arranged sub-wavelength unit-cells arranged.They have been investigated by researchers for many years due to their powerful abilities to manipulate EM waves and have played an important role in the realm of wireless power transfer,RF energy harvest,new-architecture wireless communications,signal processing and antenna design in the recent decades.With the development of the Internet of Things,more and more low-power wireless devices put forward the demand on both energy and communication,which has promoted the emergence of Simultaneous Wireless Information and Power Transfer（SWIPT）.On the other hand,the demand for ever-increasing data throughput and reliability has spurred considerable interest for microwave analog signal processing.This thesis concentrates on the application of metasurfaces in SWIPT and microwave analog signal processing.The main contents are summarized as follows:1.A frequency division multiplexing architecture for SWIPT based on the space-time coding metasurface is proposed.Simultaneous transmission of separated energy flow and information flow in the frequency domain is realized by using the design of time-domain coding sequences and the spatial multiplexing of metasurfaces.In the time-domain coding method,the+9^th-order and the+1^st-order harmonics reflected by the metasurface are used to transmit information and energy,respectively.In the spatial multiplexing method,the information is transmitted by harmonic modulation,while the fundamental wave is beamformed to transmit energy in the specified direction at the same time.Taking the spatial multiplexing method as an example,a 3-bit phase-encoding metasurface is used and a corresponding RF rectifier circuit is designed to verify the architecture for SWIPT.In the experiment,the real-time transmission of video information is realized through the QPSK modulation of the harmonic signal.Meanwhile,the LED array in different direction is also lit up.2.An antenna capable of independent reception of energy and information for the SWIPT receiving system is proposed.Firstly,by loading Schottky diodes between the unit cells of the energy harvesting metasurface,a polarization-insensitive rectifying metasurface is designed,in which the coplanar integration of energy harvesting,DC conversion and power combining is achieved.Secondly,according to the characteristic mode analysis results of the rectifying metasurface,an antenna that can receive energy and data independently and simultaneously is designed using the high-order modes of the metasurface excited by the slot.The antenna realizes energy collection at 5.85GHz and can be used for information reception in the range of5.25GHz-5.45GHz.In this work,the reception of energy flow and information flow in different frequency bands are separated at the physical space level,which simplifies the receiving antenna system architecture for SWIPT.3.A metasurface-based spatial phaser with switchable group delay response for microwave analog signal processing is proposed.Combined with the design method of the circuit-level reflection-type phaser,by introducing the PIN diode into the structure of the metasurface-based spatial phaser,a switchable phaser is designed that has two complementary dispersion group delay responses of“convex”and“concave”in the frequency band of 8GHz-9GHz according to the“off”or“on”states of the diode.The experimental results verify the accuracy of the design and simulation method.In addition,the analysis shows that it is applicable to the chirping modulation of pulsed electromagnetic waves in the space domain.This work will further promote the development of microwave analog signal processing technology in the space domain.