Compact Ku‐band LTCC bandpass filter using folded dual‐composite right‐ and left‐handed resonators.

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. [ABSTRACT FROM AUTHOR]