Conductive segments (transmission line conductors) are positioned within a transmission line structure in order to generate multi-cycle microwave pulses. The conductor segments are switchably coupled to one or the other conductor of the transmission lines, inside the transmission line structure. Microwave pulses may be induced in the transmission line by closing the switches in a controlled manner to discharge successive segments, or successive groups of segments, into the transmission lines. The induced pulses travel uninterrupted along the transmission lines in a desired direction to the load. Efficiency of systems and energy delivered to the load in multi-section transmission lines is increased and/or maximized by adjusting the ratio of characteristic impedances associated with the transmission line conductor segments according to an optimum ratio.