Abstract :
The method described has the important advantage over known methods of Q-factor measurement in that the unloaded Q-factor of the resonator is obtained directly. It is derived from the reflection coefficient measured at the coupling cross-section of the resonator at resonance, and the frequency interval between two points of the response curve at which the reflection coefficient reaches a certain value obtained from the theory. At these two points the real and imaginary components of the impedance of the cavity are equal. The value of Q is calculated from the familiar equation Q = f/2¿f. Although the method was developed primarily for 2-terminal networks, it can also be used for transmission and reactance cavities. The loaded Q and the external Q can be calculated using the data obtained from the unloaded Q-measurement. An outline of the derivation of the formulae is also given.
