Performance evaluation of multiplication chains up to THz frequencies

Frequency multipliers are the current choice for the generation of local oscillator signal for submillimetre-wave receivers up to terahertz frequencies. We have investigated multiplier chains based on Schottky diodes using a numerical physical model and validated these results with measurements for Herschel instruments from Jet Propulsion Laboratory (JPL). Experimental results approach the theoretical limit of operation at frequencies below 1 THz. However, at increasing frequencies the output power drops with frequency faster than 1/f² predicted by theory. Therefore, devices at high frequencies are operating inefficiently mainly because anode areas are not optimized at all. Proper selection of this parameter allows a big improvement in output power above 1 THz.