Traditional and novel vacuum electron devices

Multiple-Beam Klystron Amplifiers: Performance Parameters and Development Trends

“…For example, in MBKs operating in the fundamental mode, the control electrode is a flat plate with holes that are concentric with the emitters in the multiple-beam cathode. The MBK can also provide very low noise figures in the Doppler frequency range, highly linear amplitude-frequency and phase-frequency responses, and broad amplification bandwidths [6], [9], [10]. These general features are summarized in Table III.…”

“…However, this design, as discussed earlier, leads in principle to a narrow amplification bandwidth. To overcome this very significant drawback, several designs have been suggested, most of them consisting of a hybrid of the FM and HM approaches [7], [9], [11], [15], [17], [21]. One idea is to put several multichannel drift tubes, each pierced by multiple electron beams, at the antinodes of the electric field of a higher-order oscillation mode of a multimode resonator [ Fig.…”

“…Additionally, the reduced cathode voltage of the tube leads to a shorter length of the magnetic gap. Both of these factors decrease the weight of the magnetic focusing system required by the MBK, resulting in a magnet system weight that is three to ten times lighter and substantially smaller than that of an equivalent SBK system of comparable output power [5], [6], [9].…”

“…One idea is to put several multichannel drift tubes, each pierced by multiple electron beams, at the antinodes of the electric field of a higher-order oscillation mode of a multimode resonator [ Fig. 4(a)] [7], [9], [11], [12]. Thus, we get a "multiple-trunk" klystron where each trunk acts as if it is a multiple-beam klystron operating in the fundamental oscillation mode of the resonator with a high perveance.…”

“…These features cannot be achieved in conventional single-beam amplifiers, but are inherent in MBKs [5]- [9]. Due to these desirable features, the impact of MBK technology has been substantial.…”