Efficient evaluation of radiation patterns for periodic structures using a periodic FDTD method

An efficient time-domain technique for evaluating the radiation pattern of infinite periodic antenna arrays with finite source excitations is presented. The method is based on the reciprocity theorem together with a periodic finite-difference time-domain (FDTD) method. Using this proposed approach, only a single unit cell element needs to be modeled. This technique allows for arbitrary excitations on the array. The efficiency and accuracy of this technique are demonstrated through numerical examples.