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This paper presents an effective technique to obtain miniaturized and high-selectivity sub-strate integrated waveguide (SIW) bandpass filters by loading complementary split-ring res-onators (CSRRs) at the SIW cavities. The existence of the CSRR enables a considerable reduction of the resonance frequency of a conventional SIW cavity thanks to the coupling effect between CSRR and SIW cavity. Besides, a sharp roll-off is generated in a higher stopband due to the characteristics of CSRRs. To demonstrate the operation principal, the second- and third-order SIW bandpass filters are fabricated using standard printed circuit board technology, showing advantages of compact size, good selectivity, easy fabrication, and integration with other circuits. The measured ¿'-parameters agree well with the simu-lated ones. [ABSTRACT FROM AUTHOR] more...

A compact dual-band bandpass filter is proposed using asymmetrical dual stepped-impedance stub-loaded open-loop resonators, where additional transmission zeros are introduced so as to improve its upper rejection. Its mode characteristics and generation of its transmission zeros are analyzed theoretically. In such a filter, double resonators have different configurations, with their individual transmission zeros generated at different frequencies. It is demonstrated that the realized filter has good performance in frequency selectivity and spurious suppression. Also, good agreement is obtained between its simulated and measured S-parameters. Its -20 dB upper stopband is improved up to 2.57 times of the first central frequency, which is much better than its previous dual-band counterparts with small frequency ratios. [ABSTRACT FROM AUTHOR] more...

A compact substrate integrated waveguide (SIW) transversal filter using microstrip dual-mode resonator is proposed, with its coupling scheme given to predict its desired performance. The microstrip dual-mode resonator is introduced to achieve compact size, which is etched on the top metal layer of the SIW cavity. An additional transmission zero, contributed by bypass coupling due to the higher order mode of SIW cavity, is used to suppress its first spurious passband. A filter sample was fabricated using standard printed circuit board (PCB) technology, with good agreements obtained between its measured and simulated S-parameters. [ABSTRACT FROM AUTHOR] more...

A novel third-order substrate integrated waveguide (SIW) filter incorporated with a coplanar waveguide (CPW) is presented in this paper. The CPW not only acts as a resonator, but also brings mixed coupling between two SIW resonators. It is shown that the filter has two transmission zeros and wide stopband, which is very compact in comparison with conventional third-order SIW counterpart. Good agreement is obtained between its measured and simulated S-parameters. [ABSTRACT FROM AUTHOR] more...