A high-pulsed-power varactor doubler has been developed to efficiently transfer the power from a pulsed 95 GHz IMPATT oscillator to the 190 GHz band. The frequency doubler uses waveguide based embedding structures employing high-thermal conductivity circuits and Virginia Diodes, Inc. (VDI) proprietary GaAs Schottky varactor diode technology. The embedding circuitry is based on a balanced doubler topology that delivers state-of-the-art power and fixed-tuned bandwidth at millimeter-wave frequencies. The waveguide structure is modified to provide ample room for the large diode arrays while simultaneously blocking propagation of the unwanted TM modes. Special attention was given to maximizing the heat conduction pathways in the embedding structure to minimize heating of the varactor devices.