Fundamental study on curved folded dipole antenna

As a fundamental study of the helmet antenna for disasters operated at 150 MHz, a circular planar folded dipole antenna has been examined. To begin with the helmet antenna structure is constituted by bending a dipole antenna into the shape of the circle on the plane for simplicity. As a result, it is made clear that adjusting the impedance of the helmet antenna is possible by changing the distance of the antenna tip since the impedance transformation of the dipole antenna can easily be achieved. In addition, it is confirmed that the resonant frequency can be lowered by adjusting the antenna elements on the limited circular plane[1][2].