SINOPSIS

The requirements to the electron beam quality in frequency multipliers are less strict as compared to those in the O-type backward wave tubes (BWT-O). Though having a lower output power than BWTs, multipliers are good candidates to be used in submillimeter waveband. Experimental research of frequency multipliers in millimeter waveband has been already undertaken. In these devices, the modulating function is performed by a klystron-type cavity fed by a powerful external cm-waveband oscillator. A slow-wave comb structure serves as a power take-off unit. In the submillimeter waveband, a two-stage klynotron-type oscillator seems to have all necessary characteristics to act as a multiplier, fulfilling two functions at the same time: a modulating oscillator and a power take-off. According to numerical theoretical studies, the electron bunching in a sheet beam in klynotrons occurs in a "layer-by-layer" manner: the more remote an electron layer from the comb surface, the more time is needed for electrons to bunch. In a remote layer electrons group into bunches after escaping the comb of the modulating structure; it means that a klynotron can be used as a beam modulator. The goal of this study was to justify this statement in experiments; we offer a description of a simple design of a multiplier klynotron and consider the outcome of its experimental performance research. In the modulating part of the klynotron the oscillations were generated at the wavelength λ ~ 2.8 mm, and the wavelength of a signal generated in the take-off unit has a wavelength λ ~ 0.93 mm. It was shown that it is possible to decrease the density of the focusing magnetic field in the device to 0.5 - 0.3 T, while a BWT of the same waveband requires a magnetic field of about 1.0 T.