Radiation-Pattern Reconfigurable Antenna for Medical Implants in MedRadio Band

The objective of this letter is to design a radiation-pattern reconfigurable antenna that operates at the Medical Device Radio communications Service band (MedRadio band: 401–406 MHz) for medical implants. By spiraling a monopole, an antenna miniaturization is accomplished. Two artificial switches are employed to perform a radiation-pattern reconfigurable property. The proposed antenna has dimensions of28~mm× 11.5~mm× 0.6~mm~ (193.2~mm³)and utilizes substrate (FR4 ~ε ᵣ=4.4). A one-layer skin model (ε ᵣ =46.74,σ =0.69~S/m) is adopted for the antenna simulation and in vitro test.