Effects of Tapered Coaxial Feedlines on the Performance of a 3D Monopole UWB Antenna

Triangular Distribution tapering techniques are applied to the feedline of a three-dimensional monopole antenna. The impedance transformation provided by the taper is demonstrated to control the power carried by propagating modes across the operating bandwidth of the antenna. Thus, tapering solutions can be used to equalize the resonances within the bandwidth of interest and optimize the time-domain response of the antenna for pulse-based UWB communications, where phase distortion must be significantly reduced. The effects of tapered feedlines are numerically analyzed both in terms of impedance and radiation characteristics.