Design Of Flexible Transparent Coding Absorber Based On ITO Film

In recent years,communication technology in China has developed rapidly.Many communication base stations and electronic devices are applied,which give people intelligent convenience.At the same time,they also bring electromagnetic pollution.As a result,the electromagnetic protection of communication equipment is a current research priority.In addition,with the improvement of radar detection technology,military equipment has put forward new requirements for high-performance electromagnetic shielding equipment.Due to their electromagnetic parameters,the traditional absorbing materials generally have the disadvantages of not being wide band,not thin,and not high absorption rate.The new absorbers proposed by some scholars to overcome this difficulty still have difficulties such as visual opacity and non-conformability.This dissertation develops a theoretical analysis of microwave absorbers.Based on ITO(Indium Tin Oxide)thin films,the structural design of high-performance microwave absorbers is proposed around the properties of optical transparency,bending conformality,and RCS(radar scattering cross section)reduction.The research work in this dissertation is as follows:(1)To address the difficulty of the visual opacity of the absorber.In this dissertation,a cross-ring island-shaped high-performance ultra-broadband transparent absorber based on ITO surface is designed and prepared.It uses flexible and transparent absorptive materials such as ITO and PET(Polyethylene Terephthalate),and it achieves an optical transmittance of85%.It also covers an ultra-broadband of 17.6 GHz.In this dissertation,the absorption mechanism is analyzed by equivalent impedance and electric field distribution,and the samples are tested to verify the absorption performance.(2)For the application of absorber bending conformal.In this dissertation a transparent bendable broadband microwave absorber operating in the frequency band around 5 GHz is designed and produced by adding a flexible and transparent PMMA substrate(Polymethyl Methacrylate)to the ITO-PET structure.It operates in the low-frequency band from 4.16-7.48 GHz.In addition,the PMMA substrate is replaced with a PDMS(Polydimethylsiloxane)substrate of the same specifications in this dissertation to obtain better flexibility performance in simulation experiments.(3)For the application of absorber to circumvent radar detection.In this dissertation,a chessboard encoded microwave absorber based on RCS reduction is designed by combining the above flexible and transparent ITO-PET absorbing structure,which can achieve >90%absorption in the low-frequency band 4.6-8.4 GHz,with RCS reduction of more than 10 d B based on PEC(Perfect Electrical Conductor)sheet.In this dissertation,the absorption mechanism of a flexible transparent absorber is obtained by the designed patterned ITO ultra-broadband transparent absorber.On this basis,the transparent bendable absorber with low-frequency absorption is designed to investigate whether it can maintain its excellent absorption performance under bending.Finally,the flexible and transparent absorber is combined with a chessboard-encoded sequence to ensure absorption performance while improving the RCS reduction.These absorbers were proposed to achieve excellent properties such as visual transparency,flexible commonality,broadband absorption,and RCS reduction.