Investigation On Cold And Hot Cavity Characteristics Of Overmoded Coaxial Swss With Inner Corrugations Designed For Tm02 Mode Operation At 60 Ghz

Coaxial O-type Cerenkov devices usually operate in the quasi-TEM or TM01 mode, but for the purpose of operating at 60 GHz, the coaxial slow-wave structures (SWSs) operating in the TM02 mode were investigated in this paper. To elucidate the working mechanism of coaxial SWSs in the TM02 mode, the cold and hot cavity characteristics are analyzed by numerical calculations. The analysis results suggest that the long periodic length and the short distance between the inner and outer conductors can be adopted to make the group velocity of the TM02 mode at the intersection point close to zero and guarantee single-mode operation. In addition, SWSs with these geometry parameters can achieve high power capacity and high wave-beam interaction conversion efficiency. The starting current is low and the temporal growth is close to the low order modes. Published by AIP Publishing.