Compact Self-Packaged Dual-Band Bandpass Filters Based on FSIW With Embedded CRLHR and MLR

This letter proposes and analyzes two novel self-packaged hybrid-structure folded substrate integrated waveguide (FSIW) bandpass filters (BPFs). For the first time, the meander-line resonator (MLR) and composite right-/left-handed resonator (CRLHR) are embedded in the middle layer to avoid the reduction in unloaded quality factors (QU) caused by surface etching slot lines. Meanwhile, the embedded MLR and CRLHR not only achieved excellent shielding performance, but also could contribute a pole to each passband, respectively. Additionally, both TE0.5,0,1and TE1,0,1modes of the inline right and left FSIW cavity (FSIWC) contribute two poles for each passband, respectively. Two compact dual-band BPFs with five poles and six poles, featuring controllable passband frequency ratios, have been fabricated and measured.