Design of compact dual-passband LTCC filter exploiting stacked QMSIW and EMSIW

A dual-passband low-temperature co-fired ceramic (LTCC) filter with a stacked quarter-mode substrate-integrated waveguide (QMSIW) and an eighth-mode SIW (EMSIW) on LTCC substrates is presented. By exploiting the QMSIW and EMSIW cavities, the filter has a dual passband with high selectivity and compact size. The experimental filter exhibits two passbands, one is centred at 5.4 GHz with an insertion loss of <;1.7 dB, and a 3 dB bandwidth of 13%. The other is centred at 8.3 GHz with an insertion loss of <;1.5 dB, and with a bandwidth of 12.9%. The volume of the filter is only 6.5 × 6.5 × 1.2 mm³.