Smith-Purcell Radiation with Different Grating Parameters and Beam Bunching Frequencies

Smith-Purcell radiation (SPR) is generated when electrons travel close to a metallic periodic grating [1] . In this work, we study the dispersion relation of SPR at different grating parameters (groove’s heights and widths) with a fixed grating period. The operating point is determined at the intersection of the SPR dispersion and the beam mode, which emits SPR radiation at the second harmonics of this frequency. According to the SPR equation, the SPR frequency depends on the period of the metallic grating. The dispersion relation, on the other hand, shows that, in addition to the grating period, the frequency of SPR varies significantly with grating parameters [2] , [3] . Numerical analysis using CST Particle Studio shows that when the grating is excited with a beam having a bunching frequency close to the SPR frequency calculated from the dispersion relation, the radiation field has significantly higher strength than excited with beams of other bunching frequencies.