Rigorous Analysis of the Active Antennas using FDTD

A rigorous finite-difference time-domain (FDTD) modeling method has been presented to analyze the Gunn diodes covering three grid cells in the axial direction. The numerical results of an active antenna are near to the measured results and better than the computed ones in previous studies. This approach is convenient to study millimeter and sub-millimeter wave circuits with nonlinear lumped elements. According to the practical grid structures, the iterated field equations group of the diodes occupying two, four or more grid cells can be achieved easily