Coupling coefficients of irregular microstrip resonators and selective properties of filters on their basis

Frequency-dependent coefficients of coupling between irregular microstrip resonators and their role in the formation of a filter´s frequency response are studied on the basis of an energetic approach. Two-resonator segments and filters are used as the samples under investigation. A theoretical analysis carried out in the quasi-static approximation shows good agreement between calculated and experimental frequency responses and, thus, allows us to conclude that the attenuation poles in the frequency response are due to compensation of the capacitive and inductive interaction between resonators. The data obtained show the possibility of controlling the steepness of filter skirt slopes by appropriate choice of structural parameters