A 330 GHz frequency doubler using European MMIC Schottky process based on e-beam lithography

The Submillimetre-Wave Instrument (SWI) is a passive microwave spectrometer included in the large-class mission in ESA's Cosmic Vision JUpiter ICy moons Explorer (JUICE). It will spend at least three years making detailed observations of the molecular spectral signature of the atmospheres of the giant gaseous planet Jupiter and three of its largest moons, Ganymede, Callisto and Europa. The Submillimeter Wave instrument consists in a 600 GHz radiometer that involves compact, non-cryogenic Schottky diodes based solid-state devices for the mixer and last stage local oscillator frequency multipliers. LERMA-LPN is in charge of the SWI local oscillator 280 GHz last stage frequency doubler. In this article we report on recent progress of LERMA-LPN Schottky diode process for the 310–360 GHz prototype circuit that is proposed during the first phase of the program. It is fully based on e-beam lithography for the highest precision of small features, like the anodes and the air-bridges. This multiplier features 4 anodes in a balanced configuration monolithically integrated on a 5μm-thick GaAs membrane circuit connected to a split waveguide-block by metallic beam-leads. The circuit has been mounted in a split block with techniques that will facilitate space qualification. A conversion efficiency of about 15–22% has been measured in the 310–360 GHz band, in very good agreement with simulations. A lifetime test over more than 1600 hours of continuous RF operations with 45 mW of input power has been successfully recorded at LERMA. The design, fabrication process and measurement of the LERMA-LPN 310–360 GHz frequency doubler will be presented at the conference.