FDTD modeling for ultra-wideband unipolar and bipolar electrical pulse generated by photoconductive switches transmission line

D´Alembert´s method is used to analyze transient pulse propagation in the transmission line. A total reflection border and the implementation of a new field source excitation are devised to satisfy the initial conditions and boundary conditions of the transmission line. Finite time difference method coupled with the D´Alembert´s formula algorithm solves the pulse generation and propagation by photoconductive switches (PCSS) in the transmission line under bias voltage. The computed propagation results are discussed. The effect of Blumlein line geometrics on pulse amplitude is studied. Experiments results that compare well with the simulated values are presented. An ultra short bipolar pulse generator based on the PCSS is developed.