Miniaturized and high-selectivity substrate integrated waveguide (SIW) bandpass filter loaded by complementary split-ring resonators (CSRRs)

Abstract

This paper presents an effective technique to obtain miniaturized and high-selectivity substrate integrated waveguide (SIW) bandpass filters by loading complementary split-ring resonators (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 simulated ones.

Acknowledgment

This work was supported by the National Basic Research Program of China under Grant 2009CB320206 and the National Natural Science Foundation of China 60901024.