Multiple-width pulse forming lines with build-in spiral lines

Pulse forming lines (PFLs) with build-in spiral lines are presented in this paper, which can prolong the output pulse width of PFL. Thus PFLs consist of one outer PFL for storing energy and another build-in inner PFL. The inner PFL has an inner conductor made of even spiral lines and an outer shielding cylinder with ladder interior surfaces. The outer PFL is compact, which is based on Tesla transformer. One design example of PFLs with Midel7131 synthetic ester dielectric is given in the end of this paper, whose build-in structure combing spiral lines with double nested coaxial lines, and the result indicates that a pulse with 10 GW peak power and 100 ns width can be generated by the 2 m long PFLs with 1 m interior diameter of outer cylinder.