A Compact Wideband Flexible Implantable Slot Antenna Design With Enhanced Gain

In this communication, a coplanar waveguide-fed, compact, wideband dual-ring slot antenna for biomedical applications in the Industrial, Scientific and Medical frequency band is presented. This implantable antenna is designed using thin and biocompatible substrate-superstrate layers to achieve human body insulation as well as flexibility. Despite showing good antenna performances, only the realized gain value is observed to be reduced (-12 dB). To improve the antenna gain, a metamaterial (MTM) array with epsilon very large behavior has been introduced on the superstrate of the implantable antenna. Using the MTM, about 3 dB gain enhancement has been observed. Even after the introduction of the MTM superstrate, wideband characteristic and flexibility are maintained. Also, the specific absorption rate (SAR) analysis of the antenna configuration with and without MTM has been studied. A low SAR is obtained in both the cases. The fabricated antenna parameters have been measured with the in vitro test by immersing the antenna inside a single-layer tissue emulating gel, as well as, inside a chicken breast slab.