We present a miniaturized dual-band implantable antenna using the planar inverted-F antenna (PIFA) structure for head-implant in biomedical telemetry systems resonating at 902 MHz and 2.4 GHz, the industrial, scientific and medical (ISM) bands. The topology of inserting slots into radiating patch and shorting it to the ground plane result in compact antenna size of 11×19×1.25 mm ³ . The proposed antenna is characterized and optimized based on full wave numerical simulations in the seven- layer human head model considering various parameters effects on the PIFAs design. Overall, we were able to achieve a broadband implantable antenna with the -26.71 dBi gain and radiation efficiency of 0.2% at 902 MHz and obtain -17.5 dBi gain with radiation efficiency of 0.31% at 2.4 GHz.