The self-consistent time-dependent code MAGY is presently being used for de
signing and modeling gyrodevices, In this paper, the code's self-consistent
capability is used to investigate three different issues relating to the o
peration of gyroklystron amplifiers. These are the effect of window reflect
ion on the properties of the output waves, higher order made excitation in
nonlinear output tapers, and excitation in cutoff drift sections. The first
two effects can potentially have major impacts on the gyroklystron output
radio frequency (RF) in terms of bandwidth po,ver ripple, phase ripple acro
ss the band, and mode purity. In fact, strong correlation between simulatio
n results and experimental data indicates that the observed bandwidth rippl
e in a recently tested W-band gyroklystron can be attributed to a small (-2
0 dB) window reflection. The last effect, excitation in cutoff drift sectio
ns, is found to result in a high level of RF fields at the drive frequency
in drift sections. This effect impacts the design and use of lossy ceramics
in the drift section because of thermal considerations, particularly in hi
gh average power devices.