An approach towards understanding an open-structure frequency-doubler

Open-structure frequency-multipliers have increasingly become a subject for research in the past decade. A great deal of effort has been dedicated to understanding its operation characteristics. Based on the key elements, a new monolithic approach has been studied now, consisting of a planar Schottky varactor, a planar antenna, and a bias circuit. A step-by-step approach has been developed to contribute to the understanding of the frequency-doubler device. The Schottky diode structure has been characterised at DC, 1 MHz and up to 26.5 GHz using a dedicated test structure. The antenna has been optimised with respect to its input impedance. A scaled model has been implemented to verify this. Finally, a monolithically integrated Schottky frequency-doubler was fabricated and measured at 290 GHz.