Bandwidth Enhancement of a Folded Monopole Antenna with an Iron Tower

This paper discusses bandwidth enhancement of a folded monopole antenna using an iron tower (FMAIT). First, the impedance of the FMAIT with one wire is analyzed by electromagnetic (EM) and circuit simulations. It is shown that the bandwidth can be expanded by reducing the step-up ratio in an equivalent circuit of the FMAIT. Then, the FMAIT with three driven-wires is proposed to reduce the step-up ratio. It is verified by EM simulation that the bandwidth enhancement can be achieved by separating wires from each other.