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A Helmet Antenna Using Disk-Loaded Monopole Antenna for Disaster Prevention

In this study, a novel helmet antenna is proposed using a disk-loaded monopole antenna. The proposed antenna operates at the very high frequency (VHF) band with omnidirectional and vertically polarized radiation pattern in the horizontal plane. In addition, an annular slit is created on the outer shell of the proposed antenna in order to reduce radio waves radiated toward the human head. The effect of slit is studied by simulating the proposed antenna with the human head. Simulation results show that the VSWR characteristic of the proposed antenna is largely maintained even when close to the human head and the radio waves radiated toward the human head are extremely weak.