Exponential log-periodic antenna design using improved particle swarm optimization with velocity mutation

A new log-periodic antenna (LPA) geometry is presented in this study. The LPA is considered to be composed of 14 wire dipoles with lengths and distances that follow an exponential rule. This geometry can be optimized by properly adjusting two specific parameters called length factor and spacing factor. To perform the optimization, we introduce an improved particle swarm optimization variant, which induces mutation on the velocities of the swarm, in combination with the CST Microwave Studio. The optimized exponential LPA is required to operate in 790-2500MHz frequency range, in order to cover the most usual services (2G, 3G, 4G, and Wi-Fi), and also to provide in this range the highest possible forward gain, gain flatness below 2dB, secondary lobe level less than -20dB with respect to the main lobe peak, and standing wave ratio below 1.9. The optimized geometry exhibits the effectiveness of the proposed optimization technique.