Project: A general theory of the synthesis and design of coupled-cavity microwave band-pass filters with frequency-dependent couplings

The goal of this project was to develop a rigorous and comprehensive theory and methodology for an as yet unresolved problem of synthesis and design of microwave bandpass filters with frequency dependent couplings. The research plan for the project consisted of:

  1. theoretical analysis of the synthesis problem including the construction of polynomials of the filtering function,
  2. formulation of the coupling matrix synthesis in terms of matrix pencils and a generalized eigenvalue problem,
  3. the solution of the coupling matrix synthesis by means of quadratic programming with zeroes and poles of the short circuit admittance parameters derived from the filtering function used as reference,
  4. developing new software for coupling matrix synthesis allowing arbitrary frequency dependent coupling topology including dispersive source-load coupling,
  5. developing new software for extraction of coupling matrix with frequency dependent couplings form measured data or electromagnetic simulations,
  6. series of simulations using the new software to find new topologies which lead to more selective or more compact microwave band pass filter construction,
  7. design, numerical modeling and optimization of selected filter topologies including in-line configurations with finite transmission zeros and filters with more transmission zeros than poles which are impossible to achieve using existing filter synthesis techniques,
  8. fabrication of selected filters designs,
  9. experimental verification of the theory, coupling matrix synthesis and extraction and new design methodology.