The generation of high-power microwaves can be used in the field of military (protection of convoys and improvised explosive device neutralization) and civil applications (study of biological phenomena such as electroporation, treatment of waste water, and so on). The implementation of such systems requires the use of a high-voltage pulsed source capable of operating in repetitive mode at 100 Hz for a few seconds or at 1 Hz during several hours. A pulse forming line (PFL) is used to convert the monopolar output signal of the generator into a bipolar pulse, which is more suitable to feed an antenna. It induces significant constraints for the pulse generator, which has to supply a mismatched load. Further constraints such as weight, volume, and energy efficiency have to be considered to facilitate the integration of the system on mobile platforms. It also has to be easily remote-controlled to facilitate its use in an operational context. A parametric study was conducted to design a short-pulse Marx generator dedicated to this kind of application. The best compromise was chosen to generate short-rise time high-voltage pulses with a low quantity of energy. For higher energy levels, other stages with a higher capacity can easily be used, using our modular coaxial structure. The tested 11-stage short-pulse Marx generator, connected to a PFL, reached an output voltage of 420 kV, with a rise time , at a 40-kV charging voltage. Inductive charging circuits allow operation in repetitive mode up to 100 Hz during a few seconds. The generator was operated at 1 Hz during several hours using a remote-controlled charging unit. For mobile applications, the generator can be charged by a battery-powered power supply unit.