CW Multifrequency K-Band Source Based on a Helical-Waveguide Gyro-TWT With Delayed Feedback

By means of reflecting the output radiation from a wideband Bragg reflector, a multifrequency radiation source was experimentally implemented based on a continuous wave (CW) helical gyroresonance traveling-wave tube (gyro-TWT) with an operating frequency of about 24 GHz. Oscillation regimes were obtained with distances between the spectral component at 93-122, 193-239, 311-376, 496, 624, and 736 MHz, corresponding to excitation of various combinations of longitudinal modes. Existence of regimes with the second spectral component in intensity at the same level as the intensity at the central frequency was demonstrated, which are of significant interest for multifrequency plasma heating applications.