Assessment of possibilities to realize a tunable oscillator in the decimillimetre range

Possibilities of realizing tunable backward wave (or similar) oscillators for heterodyne detection of submillimeter infrared radiation were assessed. Improvement of the carcinotron performance in order to reach the minimum power level of 10 mW in the required wavelength range 1 to 0.25 mm, together with an enlarged bandwidth of about 25 % for reducing the total number of tubes necessary to cover the whole frequency range, seems possible, leading to six tubes for a full frequency coverage. For wavelengths below 0.5 mm the cascaded carcinotron is identified as the most suitable concept. Phase-locked loop stabilization experiments on an 8 mm carcinotron have proven the ability of stabilizing a carcinotron signal.