**
On Calculation
of R/Q Ratio of Microwave Vacuum Tubes Multiple Beam Cavities**

** **

**Boris V.****
Prokofyev**^{ 1}
,
Alexander V.^{
}
Konnov ^{1},^{ }
Vladimir L.Savvin ^{2}

^{
1 }
FSUE
“R&P Corp. ”Toriy”, Moscow

^{
2 }
M.
V. Lomonosov Moscow state university, physics faculty, chair of photonics and
microwave physics

Received November
22, 2011

** **

**Abstract.
**A formula for calculation of
R/Q ratio of microwave vacuum tubes multiple beam cavities by arbitrary
perturbation of the gap RF electric field is derived. It is shown that the
wide used R/Q ratio formula based on the small perturbation and homogeneity of
the gap RF electric field leads to conservative values of R/Q ratio. ** **The
results obtained by refined formula are in good correspondence with these
computed by macros developed for CST Microwave Studio code.

**Key
words: **cavity
R/Q ratio, multiple beam cavity, microwave vacuum tubes, perturbation method,
macros.