| Recently,a controllable metamaterial-based backscatter communication system has been proposed,which has been widely used in various wireless network applications due to its ability to manipulate electromagnetic waves.However,traditional backscatter systems require the deployment of an excitation source near the controllable metamaterial surface,which dramatically increases the power consumption of the communication node and renders the current backscatter systems unsuitable for low-power applications such as the Internet of Things(Io T).This thesis proposes a monolithic,low-power backscatter communication system suitable for the Io T and analyzes the key issues arising in this system.Although this system has the advantages of low power consumption,good flexibility,strong access,and suitability for the Io T,the system has issues such as lower modulation signal power intensity,higher demand for close-range isolation,and higher modulation efficiency compared to traditional wireless systems.Additionally,due to the system’s monolithic architecture,the associated channel model differs from traditional point-to-point communication systems.To address these issues,this thesis conducts a comprehensive analysis,proposes solutions,and verifies them through experimental testing.First,the radio wave propagation process is theoretically derived,and based on the results,simulations are carried out for specific scenarios,leading to the conclusion that the path loss of this system far exceeds that of point-to-point communication systems.Second,a solution to the close-range isolation problem is proposed,and genetic algorithms are used to implement close-range isolation by combining with a frequencyselective surface.Third,an efficient modulation surface is designed,analyzed,optimized,fabricated,and tested,achieving a low-power,high-efficiency surface that meets the specific requirements of this system.After addressing these key issues,a verification system is designed and implemented,and communication testing is conducted in a real environment.This thesis research achieves an ultra-low power Io T system,with the transmission power consumption of the communication node only at the Microwatt level.Moreover,the key issues of this system are deeply studied,laying a theoretical foundation for its practical application and further research of the system. |
