Compact Ku-band LTCC bandpass filter using folded dual-composite right- And left-handed resonators

Abstract

A compact Ku-band bandpass filter is proposed by using low-temperature cofired ceramic (LTCC) technology in this Letter. For miniaturisation, the folded dual-composite right- and left-handed (D-CRLH) resonator is introduced. By folding the inter-digital capacitor and microstrip section inductor in multiple metal layers, the circuit size of D-CRLH resonator can be reduced to one third of the planner one. Furthermore, the additional transmission loss caused by reverse currents is also investigated. To this end, a very compact LTCC filter is designed, fabricated, and measured, with the core circuit size smaller than 0.91 × 0.95 × 0.29 mm3. The minimum insertion loss is 1.95 dB at 13 GHz while with wide stopband suppression from 14.3 to 33.1 GHz.