Design and modeling of a multiband electrically coupled loop antenna for biomedical applications

Abstract

A triple-band Electrically Coupled Loop Antenna (ECLA) is designed to operate in the three standard bands for biomedical implantation purposes: Medical Implant Communications Services (MICS) (402–405 MHz), Wireless Medical Telecommunication Services (WMTS) (1395–1405 MHz) and Industrial, Scientific, and Medical (ISM) (2400–2480 MHz). An equivalent circuit is derived for the multiband ECLA based on simple equations relate the dimensions with the circuit parameters to get a good understanding of antenna operation as well as saving time in simulations. The proposed antenna size is 15 × 13.8 × 13 mm3 and simulated in a muscle phantom with size 100 × 100 × 100 mm3. The calculated peak realized gain values are − 18, − 30 and − 33.3 dBi and the peak 10 g averaged Specific Absorption Rate (SAR) values are 11.59, 43.07 and 49.75 W/Kg for the three bands, respectively. A detuning study is carried out to ensure that the proposed antenna is robust against electrical properties variation thus it can be implanted in different tissues of different people in various health circumstances. Two antenna prototypes have been fabricated and tested in a solution that mimics human tissue.