A novel dual-mode dual-band bandpass filter with simple defected ground struc-ture (DGS) is proposed. A dual-mode dual-band bandpass filter is obtained by combining the microstrip square loop on the top layer and another square loop constructed with DGS on the bottom layer, which achieve dual-mode single-band bandpass characteristic, respectively. Ex-cited with common feed lines, the proposed
... [Show full abstract] filter is compact and easy fabrication. The design is confirmed by simulation and experiments with good agreement.