Design of broadband implantable loop antenna for human brain applications

In this paper, a flexible loop implantable patch antenna is proposed for brain applications. The proposed antenna covers a high bandwidth. It covers the Med Radio band (402-406MHz) which is the standard band for Bio Implantable applications, ISM bands 433-434.8MHz and 902-928MHz. The hollow cylindrical antenna is made of biocompatible lossy ceramic alumina substrate with a relative permittivity of 9.9. This design have outer and inner radii 6.37mm, 6.3446mm respectively and height of 15mm. The patch is wrapped over the cylindrical alumina substrate. The brain simulated antenna is having a -10dB Bandwidth of 1.486GHz (334MHz-1820MHz) resonates at 444MHz having VSWR between 1 and 2 throughout the bandwidth. The Radiation pattern of this antenna is unidirectional having a gain of -25.4dB at 402MHz. This antenna is also verified in stomach and three layered human body models for gain, SAR at different ISM band frequencies also mentioned.