The main body of work presented in this thesis is precise frequency and phase control of
a 1.2 kW CW cooker magnetron (National 2M137) locked to a 10 MHz reference injected
with a very small RF signal (of the order of -40 dBc) creating a suitable RF source for
particle accelerators and other sophisticated applications. We will go on to discuss the
characterization of the magnetron with differing heater powers and load conditions when
operated with a low cost switched mode power supply. We similarly identify three
different regimes of the magnetron operation with respect to the heater power: firstly low
noise operation for small heater powers (up to 15W), secondly unstable operation for
mid-range heater powers (15W to 30W) and thirdly high noise operation at high heater
powers (30W to 54W). We then introduce a novel method to lock the magnetron output
frequency to the 10 MHz reference using a digital frequency synthesizer IC (Analog
Devices ADF4113) in a negative feedback loop, with this method we exploit the use of
the pushing mechanism where the ADF41113 controls the power supply output to vary
the magnetron’s anode current, keeping its natural frequency locked to the reference. We
next investigate the injection locking of the frequency locked magnetron with small
injection levels (-29 dBc to -43 dBc) under differing operating conditions and observe a
phase jitter performance of the order of+/-13
o
for very small heater power and
-29 dBc injection level. We then fast switch/ramp the injection phase and establish the
maximum rate of change of the magnetron output phase. This rate was found to be 4p/us
for -29 dBc injection level and 44W heater power. We finally discuss the implementation
of a fast DSP based feedback control on the injection phase to improve the magnetron
phase jitter performance to below 1o r.m.s.