In this study, the design and fabrication of a 110–140-GHz varistor mode frequency tripler made with four Schottky diodes pair are presented. Nonlinear simulations were performed to calculate the optimum diode embedding impedance and the required input power. A compact microstrip resonant cell (CMRC) filter was introduced for the first time in submillimeter multiplier, instead of the traditional low-and-high impedance microstrip filter. The shorter size and the wider stop band of the CMRC filter improved the performance of the tripler. The tripler exhibited the best conversion efficiency of 5.2% at 129 GHz and peak output power of 5.3 mW at 125 GHz. Furthermore, within the output bandwidth from 110 to 140 GHz, the conversion efficiency was greater than 1.5%.