On the synthesis of coupled-lossy resonator filters with unloaded quality factor control

A technique for fast synthesis of coupling matrix low-pass prototypes of generalized Chebyshev bandpass filters with lossy resonators is presented in this paper. The coupling matrix is found by solving a nonlinear least squares problem based on zeros and poles of filter´s transfer functions. Additional constraints are introduced that allow one to control the level of unloaded quality factor of resonators.