Utilization of a Novel High-Permittivity Flexible Substrate for the Design of a Wearable Antenna for In-Body Communications

This paper involves the design and analysis of a coplanar waveguide-fed loop antenna produced on a novel high-permittivity flexible substrate (HPFS). The fabricated HPFS with the dielectric constant of 10 provides the authors with not only desired durable flexibility but also facilitates outstanding antenna miniaturization. The proposed antenna has an overall size of 53 mm x 68.5 mm x 2 mm and operates at 403 MHz centred MICS band. It is designed to be directly placed on the human body without any separation. The input parameters of the antenna are analyzed for different bending scenarios. The in-body transmission performance is analyzed in a back-to-back scenario where two antennas are located on the anterior and posterior torso. It has been shown that the antenna is operational at the intended frequency band with more than 30 dB return loss and approximately -46 dB simulated transmission coefficient for 21 cm in-body propagation length.