Radar System Engineering

322 THE MAGNETRON AND THE PULSER [SEC. 10.1
The dimensions of the interaction space depend upon the wavelength
and voltage at which the magnetron is to operate and also upon the
number of resonant cavities, or oscillators. The ratio of cathode diameter
to- anode diameter is determined principally by the number of
oscillators, no matter what the wavelength or operating voltage is to be.
For a 12-oscillator magnetron the diameter of the cathode is about onec\
H
s
FIG. 1O.1.—Atypical ca},ity magnetron.
half the anode diameter. For fewer oscillators, it is somewhat smaller
than one-half, and for more than twelve oscillators, somewhat larger.
The anode and cathode diameters for any given type are propofiional to
the wavelength and to the square root of the anode voltage.
The particular resonant system shown consists of eight side cavities.
Each of these cavities is similar to a simple oscillating circuit consisting
of a lumped L and C. Although the inductance and capacity of the
magnetron cavity are not strictly lumped, the inductance of the oscil-