In-mouth antenna for tongue controlled wireless devices: characteristics and link-loss.

We have investigated the possibility of using a curved dipole antenna inside the mouth for the tongue controlled wireless devices in 2.45 GHz ISM band. These devices can be interfaced with the wheelchair or the computer used by the paraplegic patients. Two antenna placement positions have been investigated: in front of the teeth and behind the teeth. The investigations were done through the FDTD simulations on a realistic heterogeneous phantom with the mouth closed and open. The link loss between the in-mouth dipole antenna and an external dipole antenna at 400 mm from the center of the head was calculated. It was found that the radiation pattern changed according to the placement of the antennas inside the mouth and whether the mouth was open or closed. The link loss for the in front of the teeth placement was found to be 9 dB-11 dB lower than the behind the teeth placement depending on the open or the closed mouth. The variation in the link loss was 1 dB-4 dB for the open mouth when compared with the closed mouth depending on the antenna placement position. By using these results, a reliable wireless link for the in-mouth device can be designed.