Applying negative-ε media to bandpass filters for harmonic suppression

A novel meandered parallel coupled line bandpass filter incorporating CSRRs to suppress second higher order passband is presented. The stopband characteristic of the CSRR is integrated into the filter design and is easily implemented. The size of the proposed filter is marginally smaller compared with the conventional structure. Experimental results show that the passband characteristics are preserved and the second higher order passband is suppressed to below -10 dB compared with that of the conventional meandered parallel coupled line filter.