LTCC Bandstop Filters With Controllable Bandwidths Using Transmission Zeros Pair

Abstract

This brief presents compact low temperature co-fired ceramic (LTCC) bandstop filters (BSFs) using internal coupled lines. The inband transmission zeros pair (TZP) is generated by introducing internal coupling. According to the guidelines obtained by theoretical analysis, the bandwidth could be flexibly controlled. Furthermore, the roll off and the passband performance can be improved. To demonstrate the proposed method, LTCC BSFs with narrow and wide stopbands are implemented and measured. The broadside couplings on LTCC multilayers technology are employed to realize the internal couplings and the TZPs. The good consistency of the simulated and measured results supports that the proposed method is suitable not only for the narrow- but also for the wide-band BSF designs.