S parameters six- point method of calculating the coupling coefficient between resonators

In this paper, S parameter six-point method is presented, and the influence of feeder on the result having been considered is removed when calculating. The microwave network model of coupling resonator with feeder on each side is established. Through theoretical analysis, the expression of calculating the coefficient with the use of the corresponding resonant frequencies of the six points on the S parameter transmission coefficient amplitude and phase curves is deduced. The six-point method is given concretely with the example of card micro-strip resonators. Coefficients of the two resonators with different spacing are calculated and they are compared with experimental data, the rightness of the method being proved under the condition of strong coupling, thereby proving that it is an accurate and proper method for calculating in engineering design.