Research On Wearable Antenna Based On EBG Structure

In recent years,with the rapid development of the Internet of Things,wearable devices have gradually become a research hotspot.As the terminal carrier of communication,wearable devices have a wide application prospect in medical treatment,military,communication and other aspects,and have attracted more attention from researchers and gained more development.The development trend of wearable antenna is more and more inclined to miniaturization and integration,which not only requires the performance of bendable,wearable,high gain,broadband,etc.,but also requires the realization of wearable antenna on the basis of reducing the radiation value generated to the human body to greatly reduce the SAR value.In this paper,based on the traditional wearable,the electromagnetic tape gap structure and microstrip patch antenna are combined to improve the degree of isolation between the antenna and the human body,so as to reduce the excessive heating effect of electromagnetic waves on the human body,and achieve the purpose of reducing the SAR value.The main work of this paper is as follows:1.Design a single-band wearable antenna based on EBG structure.The antenna can be used in the operating frequency range of 2.34GHz--2.76 GHz fully covers the ISM band(2.42GHz--2.4835 GHz free band).Two different kinds of wearable materials are used as the dielectric substrate for the antenna,among which felt fabric is used for the EBG substrate,while denim fabric is used for the lower substrate of the antenna.The antenna has good performance and wide bandwidth,return loss in center frequency 2.6GHz S11(return loss)is 33.5 d B,which in-around 10 d B bandwidth can reach 0.42 GHz,as a result of EBG structure and patch antenna,the antenna in the SAR values around human body also slash was far below the standards set by the international level can be wearable devices use demand.2.Designed a model based on EBG structure(electromagnetic band gap)of double frequency wearable antenna,the antenna can work at 2.45 GHz and 5.8 GHz dual band wireless communication domain,the antenna in the range of bandwidth in the center frequency 2.45 GHz to 2.07 GHz--3.45 GHz,when the center frequency 5.8 GHz bandwidth in the range of 5.70 GHz--5.90 GHz,the bandwidth of the two frequencies can cover for scientific and medical research in the ISM band spectrum(free space).The antenna uses denim fabric as the substrate of EBG structure and the dielectric substrate of the antenna.The return loss performance of the antenna is good,the S11(return loss)can reach-24.5d B near the center frequency of 2.45 GHz,and the S11(return loss)can reach-22.1d B at the center frequency of 5.8 GHz.In this paper,by combining the EBG structure(electric tape gap structure)and the FSMA antenna,the radiation of the antenna to the human body can be greatly reduced,and the SAR value(specific absorption rate)can be reduced.At the same time,the antenna is bent on the X axis and Y axis respectively to a certain extent to simulate it,which fully meets the needs of wearable.3.An inverted F-type three-band wearable antenna based on EBG(electric tape gap)structure is designed.The antenna can work in the central frequency of 2.3 GHz,3.7 GHz and 5.9 GHz,in which the central frequency of 2.3 GHz and 5.9 GHz can cover the ISM frequency band(free frequency band),and in the central frequency of 3.7GHz,it can be used in the N77 frequency band of 5G communication.In addition,the antenna designed in this chapter is also improved on the EBG structure.The equivalent capacitance and equivalent resistance in the circuit model of EBG structure are increased by increasing the number of voitures inside the EBG unit and increasing the path of voitures,so as to further improve the leading reflection ability of EBG structure and then reduce the specific absorption ratio of the antenna.In this chapter,the bending performance and specific absorption rate of the antenna are also simulated and measured.In the process of bending,the performance of the antenna will be reduced,but it can still meet the requirements of use.There are 94 figures,11 tables and 74 references.