Radiation characterization of an intra-oral wireless device at multiple ISM bands: 433 MHZ, 915 MHZ, and 2.42 GHz

Intra-oral wireless devices are becoming more popular for physiological monitoring of the mouth environment and tongue-operated assistive technologies, such as the internal Tongue Drive System (iTDS). Here we present the experimental measurements and simulations of radiation performance of three commercial wireless transmitters operating at 433 MHz, 915 MHz, and 2.42 GHz, in the industrial-scientific-medical band when they were placed inside human mouth. The measurement and simulation results showed similarities in the attenuation patterns of all tested devices and indicated that the maximum attenuation occurs on the back of the head. There were no significant difference of average attenuation pattern between 433 MHz and 915 MHz, while the attenuation of 2.42 GHz was higher in simulations but not in the measurements.