UWB Bow-Tie Antenna with Tapered Inductive Loading

Abstract

A UWB bow-tie antenna, designed to work in the VHF -UHF band, is realized by a novel implementation of tapered inductive loading. The antenna with the proposed loading profile has been manufactured as a printed antenna on an FR4 material. It exhibits a fractional bandwidth of over 90% with dimensions of only 20×20 cm for a center frequency of 450 MHz. Despite its relatively small size, the proposed antenna works with very high efficiency, as the proposed loading scheme introduces no ohmic loss. In principle, it can be applied to other frequency bands as well, by scaling the antenna dimensions up or down according to the desired center frequency. Additionally, resistive loading such as microwave absorbers can be added when a larger bandwidth is needed.