A compact implantable antenna for bio-telemetry

A compact implantable planar inverted-F antenna with the full ground plane is presented for bio-telemetry applications in the medical device radiocommunications service (MedRadio) band (401-406 MHz). A basic three layer phantom model of skin, fat and muscle is initially considered and the antenna is placed in the muscle layer. Later, Gustav voxel model is used to verify the design. The overall size of the antenna is 11.635 × 11.635 × 1.975 mm³, equivalent to 0.0156λ_o × 0.0156λ_o × 0.00266λ_o (here, λ_o is the free space wavelength at 403.5 MHz). The antenna has an impedance bandwidth of 2.73% (397.4-408.4 MHz) with a voltage standing wave ratio of 2:1 and peak realized gain of -29.6 dBi at 403 MHz. The estimated maximum SAR value of this antenna satisfies the IEEE and FCC standard safety guidelines for 1-g and 10-g average SAR at 403 MHz, allowing 3.37 mW and 27.05 mW maximum input power, respectively.