Time dependent output characteristics of horn antennas

In this work, a three-dimensional conformal finite-difference time-domain simulation is employed to study the time dependent output properties of horn antennas for high power microwave (HPM) applications. As a benchmark, fundamental modes in standard rectangular and circular horn antennas are studied and compared with those simulated in frequency domain using HFSS. For steady state operation, the output characteristics shows similar behaviors in both frequency and time domains while in transient regime the time dependent characteristics demonstrates very interesting phenomena which might be better considered for a short pulse HPM operation. The final goal is to study the output characteristics of higher order modes for a specific application. Preliminary results obtained including near field and far field patterns and corresponding antenna parameters will be presented.