  Analyze of experimental results shows that the energy discharge efficiency of
the modern modulators is 0.92-0.93. The energy transfer efficiency can be
reached up to 0.7 for 1.5 usec pulse width and up to 0.8 for 3.0 usec
accordingly. The geometry and core material of the transformer is one element
of modulator, which limits the efficiency due to limitation if transmission
band of the pulse power. Ways of the rise of energy transfer efficiency had
been discussed. The use of features of coupled transmission lines lies in the
base of an idea how the energy transfer efficiency can be improved up to 0.85
in the frame of the conventional approach. In the second part of the paper the
transformerless modulator approaches are presented upon a modified Marx method
of voltage multiplication using on/off IGBT instead of on switches.
