Design of a proposed folded dipole antenna for use with an implantable RFID tag at 915 MHz

An antenna has been designed for use with a UHF band (902-928 MHz) RFID tag for implantation in live human brain tissue as the front end for a smart RFID. The COMSOL computational electromagnetic package was used for the design process. The COMSOL model was validated against the measurement of several test antennas when radiating into a bulk homogenous medium simulating human tissue. The proposed antenna is a 22 mm by 3.5 mm planar folded dipole consisting of a thin gold conductor (1 μm thick) placed on a dielectric substrate and coated with acrylic, giving a bio-compatible structure. The folded dipole dimensions are chosen to give an inductive input impedance that provides a good match to the capacitive load of the RFID tag when operating within brain tissue to maintain near optimal harvest efficiency.