A Novel Architecture for Frequency Doubler Featuring Compact 3-D Stacked Packaging and Four Multiplying Structures

This letter reports on a compact 110-GHz Schottky diode-based frequency doubler based on 3-D stacked packaging which allows combining four discrete multiplying circuits. The proposed architecture could increase the power handling capabilities by a factor of 4 compared with the traditional balanced doubler with drastically reduced electrical path length. Meanwhile, the whole circuit is composed of two critical submodules which can be evaluated separately to minimize the manually assembly and fabrication imbalances. The doubler is designed to operate in the 100–115-GHz band, which can deliver a peak power of 407 mW at 112 GHz when pumped with powers over 1.3 W. Besides, the measured conversion efficiency is roughly 82.6% of that of the single doubler, which directly proves the low combination losses of this architecture.