Numerical Analysis of Helical and Log-periodic Antennas for Short Pulse Applications

Abstract

The planar log-periodic (LP) and helical antennas are numerically studied as two antennas with a wide range of applications. The advantages of the LP antenna are the large adjustable bandwidth as a frequency independence radiator, its low profile, and that it can be made to be elliptically polarized. The main advantages of a helical antenna are its excellent power handling capability and tunable gain. The helical antenna is widely used in many UWB applications such as Radar, satellite communication, GPS, and other short-pulse applications. High far-field gain is essential to many applications, but a tradeoff between gain, and time-domain dispersion exists if the input of the helical antenna is to consist of short-pulses. To quantify the level of dispersion, the antennas considered in this work are modeled as linear systems, and their time-domain impulse response is calculated using CST Microwave time-domain and FEKO frequency-domain simulations of the structure. A comprehensive parametric study of the helical antenna is conducted in FEKO followed by a multigoal optimized design of an L band helical antenna to minimize pulse dispersion, size, and input impedance while maximizing far-field gain and pulse shape preservation.