Time domain radiation characteristics of simple wire antenna arrays

The transient input currents and radiation fields of Yagi-Uda antenna arrays and a dipole near an infinite conducting plate are calculated, and the effects of the distances between two elements of an array on the maximum transient field intensities are analyzed with the time-stepping method. Numerical results are presented and discussed. It is noted that in the time domain a reflector with a suitable distance from an active dipole of a Yagi-Uda antenna can enhance the maximum instantaneous values of the radiation field intensities but that further enhancement could not be achieved with a reflector and a director on opposite sides of an active dipole, which is different from the case of the frequency domain. An effective method to enhance the maximum instantaneous values of radiation field intensities of a dipole in a certain direction is to install a conducting plate on the side of the active dipole, with an appropriate separation distance.<>