Improved Performance of Tri-Band Implanted Antenna Using FSS

This paper presents a method to enhance the performance of a tri-band implanted PIFA antenna operating at 402 MHz, 915 MHz, and 2.4 GHz by incorporating a frequency-selective surface (FSS). Without the FSS, the antenna's directivity is adversely affected due to losses in human tissue. To mitigate this issue, we integrate the antenna with an FSS reflector, resulting in significant improvements in directivity across all three frequency bands. The directivity increases from 4dB to 5dB in the MedRadio band, from 2.5dB to 5dB in the 915 MHz band, and from 5dB to 10dB in the 2.45 GHz band. The overall dimensions of the integrated design are 16 × 11 × 1.27mm³.