“…In contrast to the classical magnetron, the operation conditions (operation mode, chosen harmonic, DC voltage, and magnetic field strength) in SHMs are selected in a way that the operation frequency of these sources can be easily extended into the mm-wave band, and even recently also into the sub-THz range [22][23][24]. With this goal in mind, in [20,21], and also in this report, we have investigated this specific class of magnetrons. Several results have already been published in our paper [25] which is an extension of the conference paper [13], however, because of limited space, just gross results without any detailed derivation have been summarized and partially also discussed.…”