powerful low-voltage multi-beam traveling wave tubes
characteristic of chains of coupled multi-gap resonators of «a single multi-storey ladder» type
Yu.V. Gulyaev, Yu.F. Zakharchenko, N.I. Sinitsyn, V.A. Cherepenin
Characteristics of linear chains of coupled multi-gap resonators (CCMGR) for a new class of powerful low-voltage multi-beam traveling wave tubes are theoretically considered. Amplifier includes two-cascade section of voltage amplification and two-cascade section of power amplification. In sections of voltage amplification, resonators of «a winding multi-storey ladder» type are used, and in sections of power amplification, chains of resonators of «a single multi-storey ladder» type are used. In CCMGR, multi-beam electron beams interact with a traveling wave field in the direction, perpendicular to the direction of super high frequency (SHF) power flow. In the result, the extended and cross interaction is realized simultaneously.
Output SHF power is defined by a total energy exchange of all beams with a wave at synchronism of phase velocities of the waves traveling along the CCMGR of input and output cascades. It is reached at the identity of their dispersion characteristics realized at the expense of identity of their basic sizes. Suppression of a backward wave in CCMGR, excluding interaction electron from it, is provided by the realization of the conditions providing an anti-phase interference of backward waves radiated of two adjacent resonators.
In the voltage amplification section, it is reached automatically due to the use of CCMGR of «a winding multi-storey ladder» type. The latest has a long length of the interaction space in the direction of electrons movement when phase synchronism conditions of SHF-current in the beam and fields in the gaps are provided only in this direction Thus, the frequency band Δfe/f0 of electronic amplification is 3-10%.
In the power amplification section, resonators of «a single multi-storey ladder» type have short lengths of the interaction space in the electrons movement direction. Therefore the anti-phase interference of backward waves is provided only at optimum pass-bandwidth of resonators in relation to operating bandwidth of amplified frequencies, and also at an optimum position of operating bandwidth of amplified frequencies on the dispersion characteristic of CCMGR. For this purpose, the section a×bS of the basic rectangular wave guide, which provides in-phase synchronism of SHF voltage in SHF backlashes, and the section a×bE of rectangular waveguides with flying channels is necessary to be correspondent to propagation of H10 waves. For a pass-band of the resonator of «a single multi-storey ladder» type will be exceeding of 50%, the ratio of the lattices length lE of waveguides forming SHF gaps to the cross size «a» of the waveguide should be equal to 0,1-0,15, and the ratio of lE to the length lW of the period of wave guides lattice arrangement along the basic waveguide should be equal to 0,5. And a phase shift of a traveling wave field between adjacent resonators should be equal to π/2 at a frequency f0.