Periodically Allocated Reentrant Cavity Klystron

A novel klystron topology is proposed to overcome the frequency limits of conventional klystrons. In contrast to the conventional klystron approach, where the distance between the cavities placed along the drift tube is a function of the plasma frequency wavelength, the new configuration exploits the interaction property of a sequence of numerous cavities allocated at fixed short distance along the drift tube. The remarkable advantage is to obtain good performance by the use of cavities with low R/Q, as in the case of high-frequency and high-order mode operation. A frequency operation up to 136 GHz with 20-dB gain and an output power up to a few tens of watts are demonstrated. The promising performance of the periodically allocated reentrant cavity klystron makes it attractive for millimeter-wave applications.