A novel, fast and accurate approach for coupling factor computation between square open loop resonators using fuzzy inference method

Coupling factor computation is the first and most important step in filter design process. Extraction of the coupling factor curves versus physical parameters of the coupled resonators, especially when there is no analytical solution, make this process very time consuming and cumbersome. In this paper in order to over come this draw back, a surprisingly fast, accurate and general approach based on fuzzy inference method is introduced to model the coupling factor. The developed method is applied to the coupled square open loop resonators to extract the coupling factor curves. The extracted coupling factor curves are used to design a four pole band pass Chebychev filter. The simulated response of the designed filter is compared with an ideal four pole Chebychev one. There is good agreement between the response of an ideal Chebychev filter and the designed one, while the computing time is vanishingly short.