Design of Implantable Rectangular Spiral Antenna for Wireless Biotelemetry in MICS Band

© 2015 ETRI Journal, Volume 37, Number 2, April 2015 http://dx.doi.org/10.4218/etrij.15.2314.0005 For this study, we designed an implantable rectangular spiral antenna for medical biotelemetry in the Medical Implant Communications Service band (402 MHz to 405 MHz). The designed antenna has a U-shaped loop for impedance matching. The antenna impedance is easily adjusted by controlling the shape and length of the Ushaped loop. Significant design parameters were studied to understand their effects on the antenna performance. To verify the potential of the antenna for the desired applications, we fabricated a prototype and measured its performance in terms of the resonant characteristics and gain radiation patterns of the antenna. In the testing phase, the prototype antenna was embedded in human skin tissue–emulating gel, which was developed to simulate a real operation environment. The measured resonant characteristics show good agreement with the simulations, and the –10 dB frequency band is within the range of 398 MHz to 420 MHz. The antenna exhibits a maximum gain of –22.26 dBi and an antenna efficiency of 0.215%.