Antenna Design For RF Energy Harvesting

At present,electronic information equipment is applied more and more widely in social life,and problems such as large battery size,short service life,high maintenance cost and the like occur in electronic information equipment.The RF energy harvesting system can solve such problems well,and can also provide technical support for the subsequent development of the Internet of Things.The system is mainly composed of a receiving antenna and a rectifier circuit.This dissertation is based on previous studies of RF energy harvesting systems.For the narrow bandwidth of RF energy harvesting systems,the nonlinear characteristics of diodes in rectifier circuits will generate higher harmonics,and the RF energy harvesting environment is complex and changeable.Broadband antennas,band-notch antennas,circularly polarized antennas,and matching rectifier circuits are designed for RF energy collection.The broadband antenna has a working bandwidth of 9GHz and a bandwidth ranging from 1.5GHz to 10.5GHz.It can collect radio frequency energy emitted by electronic information equipment in daily life.Aiming at the problem that the nonlinear characteristics of the diodes in the back-end rectifier circuit of the RF energy harvesting system generate high-order harmonics,the antenna branches are optimized based on a broadband antenna to suppress the high-order harmonics generated at 4.9GHz,7.35 GHz,and 9.8GHz frequencies,forming notch antenna.The broadband antenna and the notch antenna are respectively combined with the same2.45 GHz rectifier circuit to form two rectifier antennas with different functions.The actual comparison of energy collection efficiency shows that the notch antenna forms a rectifying antenna,which not only improves the energy collection efficiency but also simplifies the overall system structure.Aiming at the problem that the working environment of the RF energy collection system is complex and changeable,a circularly polarized antenna is designed as a receiving antenna for RF energy collection,which further improves the working performance of the entire system.This dissertation designs three antennas for radio frequency energy collection,which has certain practical reference value for the development of wireless sensors,smart homes and the Internet of Things.