A Polarization Rotation EBG-based Circularly Polarized Fabric Wearable Antenna for Medical Monitoring

Lei Li, Jingxu Cao, Ruifeng Xu

Abstract: Based on the polarization rotation Electromagnetic Band Gap(EBG) structure, an all-fabric circularly polarized wearable antenna is designed to improve the comfort of patients and avoid polarization mismatch generated by body movement in smart medical applications. A polarization rotation EBG based on two intersecting crosses is introduced, where two congruent triangles are cut in the diagonal direction so that the circular polarization is achieved in the low-frequency band of the ISM while processing a lower profile. The experimental results show that the proposed antenna has a -10 dB impedance bandwidth and a 3 dB axial ratio bandwidth of 2.40-2.48 GHz and 2.40-2.49 GHz, respectively, and the maximum realized gain is improved by about 3.5 dBi. The proposed antenna is shown to operate in the ISM band with conformal and mechanical stability despite bending along the y-axis. Meanwhile, the SAR on the human tissue model is only 0.2 W/kg, which proves that the wearable antenna meets the demand of the medical and health monitoring field.