Dual-Band Dual-Mode Textile Antenna on PDMS Substrate for Body-Centric Communications

A dual-band antenna for off- and on-body communications in the 2.45- and 5.8-GHz Industrial, Scientific, and Medical bands is presented. The two radiation characteristics, i.e., patch-like radiation for the off-body link and monopole-like radiation for the on-body link, are achieved by utilizing inherently generated TM11 and TM02 modes of a circular patch antenna. A shorting pin and two arc-shaped slots are employed to tune both modes to the desired operating frequencies. This approach allows a realization of a dual-band dual-mode antenna with a very simple structure, i.e., a single radiator with a simple feed. A further advantage of the proposed antenna is its realization using a silver fabric integrated onto a flexible polydimethylsiloxane substrate that makes it more practical for wearable applications. An experimental investigation of the antenna performance has been carried out in free space and on a semisolid human muscle equivalent phantom, which shows a robust performance against the human body loading effect. When placed on the phantom, the measured bandwidths of 84 and 247 MHz in the 2.45- and 5.8-GHz bands, respectively, are achieved with the corresponding peak gains of 4.16 and 4.34 dBi, indicating a promising candidate for body-centric communications.