The effect of reactive loads on the frequency-modulation characteristics of reflex klystrons

From an analysis of the behaviour of a reflex klystron coupled to a reactive load, a relationship can be obtained between the frequency of operation, the phase of the bunches in the electron beam (or the reflector voltage) and the phase and magnitude of the standing wave on the line between valve and load. In the light of this relationship and of the effect of other associated variables, consideration is given to the known method of improving the range of linearity of frequency modulation by suitably adjusting the load impedance. Finally, the conditions under which the modulation sensitivity of a valve does not change by more than a predetermined amount with a load mismatch are found. These conditions are important in ensuring that the performance of the valve is not impaired when fitted to its associated high-frequency system. Measurements on a 4 cm-wavelength transmitting valve are included.