| With the rapid development of the Internet of Things and microwave wireless power supply technology,the application potential of microwave wireless power supply in Io T-related scenarios has become increasingly prominent.In the wireless power supply system for the Internet of Things,microwaves carry both information and energy.The wireless power supply system that uses microwaves to transmit energy and information at the same time has become a research hotspot in recent years.In order to meet the diverse needs of Io T devices for information transmission and wireless power supply,in different application scenarios,it is necessary to design microwave wireless power supply systems with different functions.In this paper,the corresponding microwave wireless power supply system is designed for three application scenarios.(1)Aiming at the application scenarios that require wireless power supply and two-way information exchange,a frequency diversity information energy simultaneous transmission method based on high isolation common aperture antenna is proposed,and an information energy simultaneous transmission system is built.The system consists of two parts: the transmitter and the receiver.The core of the system is the multi-frequency dual-port co-aperture antenna with high isolation at the receiver.The low-frequency antenna and the high-frequency antenna unit are stacked with a common aperture,and the radiation patch of the low-frequency antenna is used as a The floor of the high-frequency antenna,the realization of structural multiplexing improves the compactness.The antenna has two ports of high and low frequency,working at 5-7GHz and 2.45 GHz,which are used for energy transmission and information transmission respectively.The resonant structure formed by the continuous phase feeding network and the radiating patch generates multiple filter zeros,so that in the 2.45 GHz frequency band used for information transmission,the isolation between the high and low frequency ports reaches 45 d B,which can effectively avoid the energy transmission to the information transmission.interference.Based on the antenna,a wireless information energy simultaneous interpretation system is built,and an application example of wireless electronic price tags based on the system is demonstrated.The system overcomes the problems of separate receiving antennas and low system compactness in the existing frequency diversity information energy simultaneous interpretation system,and at the same time benefits from the high isolation of the antennas and effectively avoids the interference between energy information.Relevant research findings have been published in the IEEE International Wireless Symposium(IWS),and submitted to IEEE TCAS-I,which is accepted.(2)Aiming at the application scenarios where wireless power supply and one-way information transmission are required and the Io T device itself does not have a modulation and demodulation module,an information and energy transmission system based on polarization modulation is built,including two parts: transmitter and receiver.The polar modulation and demodulation circuit has a simple and compact structure,does not require a special demodulation chip,and can directly connect the serial port to transmit the serial port signal from the transmitter to the receiver,especially suitable for Io T devices without modulation and demodulation functions.This paper first designs a high-gain dual linearly polarized transmitter antenna and receiver antenna working at 5.8GHz,which have high gains of 13.2d Bi and10.1d Bi,respectively.Then,the RF switch for polar modulation and the rectifier circuit at the receiving end are designed,and the rectifier circuit achieves a peak efficiency of 68.6% at the operating frequency of 5.8GHz.Finally,a complete transmitter and receiver system was built,and the microwave information energy simultaneous interpretation experiment was carried out to verify the effectiveness of the system.The research group supported by this research won the award in the first National Postdoctoral Innovation and Entrepreneurship Competition,and the relevant technology has been applied for Patent.(3)For the application scenarios where there is a demand for wireless power supply and there are available RF and wind energy in the environment where the equipment is located,a microwave energy-wind energy hybrid collection system that can mix and collect the two types of energy is designed,which is essentially a microwave-wind energy hybrid rectification.antenna.The antenna is innovatively designed in the shape of a windmill.It can not only work like a traditional rectenna,receive the microwave energy provided by the microwave energy source at the transmitting end,but also collect the microwave energy and wind energy in the environment.Driven by the wind,the antenna rotates around the center to drive the integrated micro-motor to generate low-frequency alternating current,which is rectified by the integrated radio frequency-low frequency hybrid rectifier to output direct current.The design of the hybrid rectifier takes advantage of the different characteristics of diodes,capacitors and inductors at low frequency and radio frequency,so that it presents different equivalent circuits for low frequency and radio frequency alternating currents,and a single hybrid rectifier realizes both traditional radio frequency rectifiers and low frequency rectifiers.function,effectively reducing the size.When one of the sources of energy input to the rectenna disappears,the rectenna can also harvest other energy to power the device,improving system reliability.In addition,when receiving both microwave and wind energy at the same time,the two-way electric power superimposed on the rectifier diode can bring it to a higher-efficiency working range to improve the rectifier efficiency.Through the above research on the microwave wireless power supply system,the research and design methods of the microwave wireless power supply system have been enriched,and a foundation has been laid for its future application. |
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