Abstract:

To improve the performance and selectivity of filter, a complementary openloop resonator (COLR) is proposed. A compact planar lowpass filter with COLR is designed, where the cascading filters consist of two COLRs and three open stubs. In this technique, the proposed filter has low insertionloss, good stopband characteristic and high selectivity up to 73.91 dB/GHz. To show the potential of the proposed approach, a compact S-band microstrip lowpass filter with COLRs was designed, fabricated and measured. The measured results well agree with the simulations.

Key words: complementary split-ring resonators (CSRR), complementary open-loop resonator (COLR), lowpass filters, microstrip, open stubs