A COMPACT WIDEBAND BANDPASS FILTER USING MODIFIED NB-SRRs WITH WIDE UPPER BANDSTOP

摘要

A new type of compact wideband bandpass filter using modified non-bianisotropic split-ring resonators is proposed to have wideband performance and suppress spurious responses. With the proposed resonators, size reduction of ～15% and 20% when comparing single outer and inner constituent rings has been obtained. Embedded-slot-loaded resonators are placed at both input and output feed lines for extra stopband rejection modes to suppress spurious frequencies with attenuation losses over than 15 dB for a frequency range up to 3.1 f_0 without affecting the operation band. In addition, due to the zero-degree feed structure, the appearance of two transmission zeros, thereby suppressing the second harmonic response has been obtained. This filter has not been only compact size but also a wider upper stopband caused by slot-loaded resonator bandstop characteristics. Good agreement is obtained between simulations and measurements.