Design Of Small Flexible Wearable Antenna Systems For ISM Band

In recent years,the rapid development and progress of wearable devices are obvious to all.Wearable technology has been widely used in the fields of health assistance and military equipment.With the increasing demand of the market,a variety of wearable devices have appeared in the market and people's daily life.Common wearable smart glasses,watches,bracelets,etc.As an important part of wearable devices,the research on wearable antennas has attracted widespread attention from industry,academia and research communities.Common wearable antenna structures include microstrip antennas,inverted F antennas,and button antennas.Unlike wearable devices such as bracelets,when a flexible material is used in a wearable antenna designed on clothing,not only the performance of the antenna in a limited size,but also the antenna's performance in stretching,Impact on antenna performance under bending and other conditions.At the same time,since the wearable device is close to the human body,the SAR value of the antenna must be strictly controlled under international standards.The research work of this paper is mainly composed of the following parts:First,the first chapter introduces the research background and significance of wearable antennas,compares the research status at home and abroad,and determines the research direction and content.The related theoretical basis of microstrip antennas and wearable antennas will be introduced in Chapter 2.The third chapter designs a flexible wearable antenna for the 5.8GHz ISM band.The design is simple,compact and small.Since MKKTN260 conductive cloth is used instead of traditional conductive materials,and felt is used as a substrate instead of hard materials,the antenna can maintain a good conformity with the human body.Adopting the floating floor structure and coplanar waveguide feeding can effectively reduce the SAR value while ensuring good radiation characteristics,and these excellent characteristics can be maintained even when the antenna is bent.In Chapter 4,a small,flexible dual-band wearable MIMO antenna designed for the 2.4GHz and 5.8GHz ISM bands is proposed.The antenna uses coplanar waveguide feeding and coupled branches to generate 2.4GHz and 5.8GHz frequency bands.Combined with the suspended floor structure,the intensity of back radiation can be effectively suppressed.The two antenna elements are placed symmetrically,and at 2.4GHz frequency,current paths with different rotation directions are formed to generate higher isolation.Due to the shielding effect of the two inner loop units,it can also play a good decoupling effect at the frequency of 5.8GHz.In the two ISM frequency bands,the isolation of the antenna unit is always maintained above 30 dB.The fifth chapter summarizes the research contents of this article and prospects for the future development of the wearable antenna field.