Electromagnetic Property Of Typical Building Materials At Millimeter-wave Band

Millimeter wave has been the topic of the 5th Generation(5G)mobile communication system in recent years due to its rich spectrum resources and unique capabilities in high-rate data transmission.However,many important aspects of millimeter wave communication systems have not yet been thoroughly examined.The propagation of millimeter wave in indoor environment is an important issue with significant impacts on the future direction,scope and general extent of the 5G mobile communication system.The indoor propagation behaviour of electromagnetic wave is greatly influenced by building material.Therefore,the information on electromagnetic properties of building materials in the millimeter wave range would provide valuable insights into the appreciation of the capabilities and limitations of 5G technology for indoor applications.This thesis adopts free space method to measure the electromagnetic parameters of common building materials.The tested building materials include marble,granite,latex mattress,linen and other 11 types of materials.The complex permittivities are extracted from these measured data through quantum-behaved particle swarm optimization algorithm.Based on the obtained complex permittivities,two indoor simulation environments are established to study the indoor propagation characteristics of millimeter wave,which is helpful for establishing and optimizing indoor millimeter wave communication in the future.This thesis first introduces the basic theoretical of electromagnetic characteristics.The electromagnetic properties of materials and the significance of measurement are explained.As the main factor element affecting the indoor propagation of electromagnetic wave,the complex permittivity is measured by the free space method.The free space method has the advantages of non-contact,non-destructive and suitable for high frequency measurement.Secondly,the whole measurement system and related measurement methods based on free space method are explained in detail.The tested indoor building materials including plate and cloth materials,the measured data are transmission and reflection coefficient under vertical and parallel polarization,respectively.The phenomena found during the measurement are explained and analyzed.Then,in order to solve the multi-value problem of traditional inversion algorithm,the complex permittivities of building materials are extracted by solving a non-linear data fitting problem.In this paper,the estimation method based on the Quantum-behaved Particle Swarm Optimization algorithm is proposed which is faster and more convenient than traditional methods.In this studies,simulated results indicate that the estimation method based on QPSO algorithm has high accuracy and efficiency.Finally,the complex permittivities of the extracted building materials were used for simulation modeling through the simulation software of Wireless In Site.As the 5G candidate frequency bands,the path loss and RMS delay spread of 28 GHz and 45 GHz are compared in two indoor simulation environments,respectively.