Extraction of Generalized Coupling Coefficients for Inline Extracted Pole Filters With Nonresonating Nodes

This paper presents the procedure for extracting the generalized coupling coefficients between resonating and nonresonating nodes of extracted pole sections. The extraction allows obtaining key design parameters for inline extracted pole filters directly from results of full-wave simulations. A third-order waveguide E-plane bandpass filters with λ/4-wavelength resonators is designed to prove feasibility of the proposed concept. The bandpass filter with a generalized Chebyshev response has 300-MHz bandwidth at 9.45 GHz and reveals wide stopband due to three transmission zeros arranged at predicted frequencies. Performance of the fabricated filter is evaluated through measurements, the experimental results obtained show very good agreement with simulations.