Herein, a 190-GHz frequency doubler with a high output power is designed and realized using a balanced double-frequency construction based on the anti-series gallium arsenide planar Schottky varactors. A method that combines a three-dimensional electromagnetic field and nonlinear harmonic balance is employed to conduct a simulation. The simulation results demonstrate that the proposed frequency doubler has been effectively fabricated, assembled, and tested. The frequency-doubling efficiency of the proposed doubler can reach more than 8% in the output frequency range of 182-196 GHz. Moreover, at an output frequency of 187 GHz, the frequency-doubling efficiency and the output power can reach 15.4% and 85 mW, respectively.