Accurate design of pseudoelliptic inline SIW filters with frequency-dependent couplings

This paper presents an accurate synthesis method for inline SIW (Substrate Integrated Waveguide) generalized Chebyshev bandpass filters with frequency-dependent couplings. The technique is based on the synthesis of a coupling matrix that takes into account the impedance of the frequency-dependent stub. Thus, a loading effect compensation in adjacent resonators (via resonant frequency adjustment) and coupling elements (via coupling-value modifications) is possible. The application of this method of synthesis is illustrated through an experiment in which a third-order filter consisting of rectangular half-wavelength resonators is implemented in substrate integrated waveguide (SIW) technology. The resonators are separated by inductive irises and a parallel shorted stub. The stub acts as a dispersive inverter and produces the transmission zero. A substantial improvement in design accuracy is thus obtained. The measured and simulated results for this method are in good agreement.

[1]  Raafat R. Mansour,et al.  Microwave Filters for Communication Systems: Fundamentals, Design and Applications , 2007 .

[2]  Lukasz Szydlowski,et al.  Generalized Chebyshev Bandpass Filters With Frequency-Dependent Couplings Based on Stubs , 2013, IEEE Transactions on Microwave Theory and Techniques.

[3]  R. Cameron.  Advanced coupling matrix synthesis techniques for microwave filters , 2003 .

[4]  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.

[5]  W. Menzel,et al.  Diplexer design using pre-synthesized waveguide filters with strongly dispersive inverters , 2001, 2001 IEEE MTT-S International Microwave Sympsoium Digest (Cat. No.01CH37157).

[6]  S. Amari,et al.  Synthesis of cross-coupled resonator filters using an analytical gradient-based optimization technique , 2000 .

[7]  A. Lamecki,et al.  Coupled-Resonator Filters With Frequency-Dependent Couplings: Coupling Matrix Synthesis , 2012, IEEE Microwave and Wireless Components Letters.

[8]  A. Lamecki,et al.  A Substrate Integrated Waveguide (SIW) Bandpass Filter in A Box Configuration With Frequency-Dependent Coupling , 2012, IEEE Microwave and Wireless Components Letters.

[9]  J. Kuo,et al.  Quasi-Elliptic Function Bandpass Filter with Upper Stopband Extension and High Rejection Level Using Cross-Coupled Stepped-Impedance Resonators , 2011 .

[10]  Jens Bornemann,et al.  Using frequency-dependent coupling to generate finite attenuation poles in direct-coupled resonator bandpass filters , 1999 .

[11]  Jian Guo,et al.  A NOVEL QUASI-ELLIPTIC WAVEGUIDE TRANSMIT REJECT FILTER FOR KU-BAND VSAT TRANSCEIVERS , 2011 .