Design of a compact wide-stopband bandpass filter using meandering uniform-impedance resonators

A compact wide-stopband bandpass filter using meandering uniform-impedance resonators is proposed. The filter consists of a pair of uniform-impedance resonators and feeding lines. By bending the designated positions of resonators, the first harmonic and second harmonic can be suppressed to achieve a wide stopband. The proposed filter shows harmonic suppression to exceed 3f₀ for a rejection better than 22 dB, where f₀ is the fundamental frequency. Due to the multi-path effect between resonators and feeding lines, the attenuation poles are realized near the passband edges to improve the filter selectivity. The full-wave simulator IE3D is used to design the meandering structure of the proposed filter to suppress the first and second harmonics.