Patent ID: 7750572

Claim:
A microwave power tube comprising: an electron gun having a cathode that generates an electron beam in a microwave structure of the tube, a collector for collecting electrons from the beam, and a magnetic device for spreading the beam, which generates a magnetic spread field in the collector, wherein the magnetic spread field is periodic and amplitude modulated, wherein the magnetic device for spreading the beam comprise a solenoid fed with a beam-spreading electric signal, of angular frequency ω 1 , which is amplitude modulated by two other modulating signals, of angular frequencies ω 2 and ω 3 respectively, the spread signal being normalized at a unity amplitude S given by the equation: S=(1+m sin ω 3 t·sin ω 2 t)/(1+m); wherein m being the modulation parameter, with the value of m being between 0 and 1.