Terahertz Broadband Frequency Tripler Based on Novel Graded Elliptical Anode Schottky Diode

An efficient 140–220 GHz frequency tripler covering the full waveguide bandwidth was monolithically fabricated on a GaAs substrate by integrating geometrically tuned anode diodes into an end-to-end connected circular Schottky barrier diode (SBD) chain. This configuration achieves precisely controlled zero-bias junction capacitance (Cj0) for each anode geometry variant without altering anode areas, effectively resolving anode power balancing under nonuniform electric field distribution. Experimental results demonstrate 3%–7.5% conversion efficiency across 140–220 GHz at room temperature under continuous-wave drive, while handling up to 0.35 W maximum input power.