Optimization of Log-Periodic Dipole Array Antennas for Wideband Omnidirectional Radiation

This communication shows that, given the correct terminal voltages on each element, a log-periodic dipole array (LPDA) can achieve an omnidirectional radiation pattern over a wide frequency bandwidth. This cannot be achieved by analytical means, but through a global search optimization strategy. An optimization method, which achieves omnidirectional radiation of the array with maximum gain deviations of less than 0.06 dB over more than 30% bandwidth, is discussed and the results are presented.