A novel compact dual-band bandpass filter using dual-mode resonators

The paper reports a compact and high performance dualband bandpass filter (BPF) using two types of dual-mode resonators. The dual mode,cross shaped resonator and the three dual mode ring resonators in the designed dual-band BPF are excited to control the first and second passband, respectively. It is shown that the designed and fabricated dualband BPF has narrow bandwidths and very sharp attenuation rate due to the existence of the transmission zeros. The frequency response of the designed dual-band BPF shows good agreement between the simulations and experiments.