Analysis of the open-ended image NRD guide using FDTD

Simulation is an indispensable means of designing antennas, especially when the evaluation of the antenna characteristics using theoretical analysis is complex or not very accurate. This work proposes an open-ended image nonradiative dielectric (NRD) guide antenna and presents its characteristics obtained using the finite-difference time-domain (FDTD) method. The key features of the FDTD implementation are discussed, particularly the simple and convenient approximate three dimensional modeling of the coaxial feed cable and the excitation probe that were used. The characteristics of the antenna that were determined are the return loss and absolute gain frequency characteristics and the E- and H-plane radiation patterns. Experimental results are used to verify the characteristics obtained using FDTD and are found to be in good agreement.