DESIGN OF A MINIATURIZED DUAL-BAND DOUBLE-FOLDED SUBSTRATE INTEGRATED WAVEGUIDE BANDPASS FILTER WITH CONTROLLABLE BANDWIDTHS

One miniaturized multilayer dual-band bandpass filter (BPF) is developed using standard low temperature co-fired ceramic (LTCC) technology. The filter makes use of four double-folded substrate integrated waveguide (SIW) resonators. Two sets of coupling paths between the source and load are implemented to generate dual-band responses. Utilizing this method, the two passbands can operate at independent frequencies and the bandwidth can be easily controlled. High isolation is obtained between two passbands, and two pairs of transmission zeros close to the passband edges are generated by source-load coupling, resulting in high skirt-selectivity. Good agreement between the simulated and measured results of the filter sample is obtained, with its high electrical performance validated.