Influence of characteristic parameters on performance of log-periodic dipole antenna

An optimization method of log periodic antenna is presented. By arranging feed tube spacing, feed point and the length of feed tube, the optimization of voltage standing wave ratio of antenna can be achieved. Four log-periodic dipole antenna models, which operated at different frequency bands, were simulated and tested. The simulation analysis and the experimental result show that when the voltage standing wave ratio is optimal, the length of feed tube spacing is 1.45 times that of the side of feed tube, while the length of feed point to the shortest dipole, is twice the product of the shortest dipole length and the interval constant of antenna, and the length of feed tube end portion to the shortest dipole is 1.15 times that of the feed point. The computed and measured results provide an important basis for the engineering application of the log-periodic antenna, and also provide a more effective method for optimization design.