Helmet-Mounted Inverted-F Antenna at VHF Band

Abstract

. A helmet for disaster prevention must be worn to prevent secondary disasters in rescue and evacuation activities when a disaster occurs. Helmet antennas have been widely developed as wearable antennas. In this paper, we investigated the effect of ohmic loss due to the material of the hemispherical conductor. In addition, the validity of the simulation results was verified through experiment. The loading position of the antenna element was examined to further improve the gain. As a result, the maximum gain of −2.6 dBi and the local specific absorption rate value of 0.07 W/kg was achieved at 150 MHz.