Determination of Loaded, Unloaded, and External Quality Factors of a Dielectric Resonator Coupled to a Microstrip Line

In the case of a dielectric resonator coupled to a microstrip line, the relations for the determination of unloaded, loaded, and external quality factors, in terms of directly measurable reflection or transmission coefficient at the resonant frequency, have been derived and represented on the corresponding vectorial and scalar planes. Construction of a linear frequency scale and a graphical method to accurately determine the unloaded Q from the loaded Q measurement presented.