Surface Waves in Oversized G-Band Slow-Wave Structures with Rectangular Corrugations

Abstract

Surface waves in oversized G-band slow-wave structure with rectangularly corrugated wall are analyzed numerically. The inner corrugation generates cylindrical surface wave. The outer corrugation also generates transverse magnetic surface wave. The upper cut-offs of surface waves are controlled by corrugation amplitude. In excitation of the surface waves by an annular electron beam, the slow cyclotron interaction as well as the Cherenkov interaction occur due to there-dimensional beam perturbations. The slow cyclotron interaction merges with the Cherenkov interaction at lower magnetic field. The merged growth rate is enhanced by 13 % as compared to the isolated Cherenkov growth rate. The surface waves on inner and outer corrugations can have different frequencies and can be excited selectively by adjusting the beam radius of the electron beam.

Experimental Study on W-Band (75 - 110 GHz) Oversized Surface Wave Oscillator Driven by Weakly Relativistic Electron Beams

“…The value of the magnetic field can be changed from zero to approximately 1 T; the field is 0.82 T in this study. The microwave output is picked up by rectangular horn antennas of F-and G-bands, which are EIA standard rectangular waveguides with cutoff frequencies of 74 and 116 GHz [15], respectively, located typically 600 mm away from the output window. After providing an adequate amount of attenuation, the output powers are detected by crystal detectors.…”

Enhancement of smith-purcell radiations by selfbunched electron beams in oversized backward wave oscillators

“…In this case, the distance between beam and corrugation surface is estimated as about 4 mm and all the radiations disappear. To excite the higher order modes as well as the surface wave, the beam should propagate within the interaction region of the oversized BWO [8].…”

“…The radius of SWS is about 30 mm to match the beam radius used in our experiments. We determine the corrugation parameters based on numerical analysis of the dispersion curves and the beam interactions presented in [7], [8]. The SWS parameters of K-and G-band BWO are listed in Table 1.…”

Experimental study of intense radiation in terahertz region based on cylindrical surface wave resonator

“…14, where the numerically obtained Dk z for the fundamental axisymmetric CSW is shown assuming an infinitesimally thin annular beam with radius R b . 31,32 In Fig. 14, the value of R b is 12.835 mm (12.769 mm) with corresponding distance from the corrugation wall of 0.1 mm for the A (B)-type CSWresonator.…”