Synthesis of Wideband Multicoupled Resonators Filters

A method for the synthesis of multicoupled resonators filters with frequency-dependent couplings is presented. A circuit model of the filter that accurately represents the frequency responses over a very wide frequency band is postulated. The two-port parameters of the filter based on the circuit model are obtained by circuit analysis. The values of the circuit elements are synthesized by equating the two-port parameters obtained from the circuit analysis and the filtering characteristic function. Solutions similar to the narrowband case (where all the couplings are assumed frequency independent) are obtained analytically when all coupling elements are either inductive or capacitive. The synthesis technique is generalized to include all types of coupling elements. Several examples of wideband filters are given to demonstrate the synthesis techniques.

[1]  K. Kurokawa,et al.  An introduction to the theory of microwave circuits , 1969 .

[2]  R. J. Wenzel,et al.  Synthesis of Combline and Capacitively Loaded Interdigital Bandpass Filters of Arbitrary Bandwidth , 1971 .

[3]  Ali E. Atia,et al.  Synthesis of multi-coupled resonator filters with frequency-dependent couplings , 2010, 2010 IEEE MTT-S International Microwave Symposium.

[4]  Jr. R. Wyndrum.  Microwave filters, impedance-matching networks, and coupling structures , 1965 .

[5]  A. E. Atia,et al.  Narrow-band multiple-coupled cavity synthesis , 1974 .

[6]  Yunchi Zhang,et al.  Analytical Synthesis of Generalized Multi-band Microwave Filters , 2007, 2007 IEEE/MTT-S International Microwave Symposium.

[7]  Jean-Charles Faugère,et al.  Coupling matrix synthesis for a new class of microwave filter configuration , 2005, IEEE MTT-S International Microwave Symposium Digest, 2005..

[8]  E. Guillemin.  The mathematics of circuit analysis , 1965 .

[9]  R. Cameron.  General coupling matrix synthesis methods for Chebyshev filtering functions , 1999 .

[10]  Gabor C. Temes,et al.  Filter Design Using Transformed Variables , 1968 .

[11]  Smain Amari,et al.  Notes on bandpass filters whose inter-resonator coupling coefficients are linear functions of frequency , 2008, 2008 IEEE MTT-S International Microwave Symposium Digest.

[12]  R. J. Wenzel.  Exact Design of Wideband Equal-Ripple Bandpass Filters with Non-Adjacent Resonator Couplings , 1976 .

[13]  Smain Amari,et al.  Theory of Coupled Resonator Microwave Bandpass Filters of Arbitrary Bandwidth , 2010, IEEE Transactions on Microwave Theory and Techniques.