Measuring the unloaded, loaded, and external quality factors of one- and two-port resonators using scattering-parameter magnitudes at fractional power levels

A simple and fast technique for measuring resonator quality factors is presented, in which only the magnitudes of the s-parameters are used. For the first time, the equations are presented for all of the basic topologies, including one-port reflection, two-port transmission, and two-port absorption resonators, and for all three quality factors, including the unloaded, loaded and external Q. The method is flexible and suitable to a large number of resonators because the required bandwidth may be measured at almost any level, not only at the classical half-power points. These levels are clearly identified as fractions of the absorbed power at resonance. The technique is then demonstrated by analysing a two-port microstrip ring transmission resonator.

[1]  Carol Gray Montgomery,et al.  Technique of microwave measurements , 1947 .

[2]  Y. Garault,et al.  Determination of Loaded, Unloaded, and External Quality Factors of a Dielectric Resonator Coupled to a Microstrip Line , 1983 .

[3]  D. Kajfez,et al.  Q-Factor Measurement with Network Analyzer , 1984 .

[4]  Robert Beringer.  Resonant cavities as microwave circuit elements , 1987 .

[5]  D. Pozar.  Microwave Engineering , 1990 .

[6]  X.-B. Wu,et al.  Axial slot antenna on an anisotropic dielectric-coated circular cylinder , 1994 .

[7]  J. Carroll,et al.  New technique to measure transmission line attenuation , 1995 .

[8]  Shuh-Han Chao,et al.  Unloaded Q measurement-the critical points method , 1995 .

[9]  Darko Kajfez,et al.  Q-factor measurement with a scalar network analyser , 1995 .

[10]  William T. Joines,et al.  Determining Q using S parameter data , 1996 .

[11]  Ji-Fuh Liang,et al.  Comments on "Characterization of high-Q resonators for microwave-filter applications" [with reply] , 1999 .

[12]  Raymond S. Kwok,et al.  Characterization of high-Q resonators for microwave filter applications , 1999 .

[13]  Janina Mazierska,et al.  Precise measurements of the Q factor of dielectric resonators in the transmission mode-accounting for noise, crosstalk, delay of uncalibrated lines, coupling loss, and coupling reactance , 2002 .

[14]  Langis Roy,et al.  Microwave characterization of a microstrip line using a two-port ring resonator with an improved lumped-element model , 2003 .