LTCC-MLC duplexer for DCS-1800

A low-temperature cofired-ceramic (LTCC) multilayer-ceramic (MLC) duplexer is presented in this paper. The duplexer is designed for a DCS-1800 handset. It is constructed using a multilayer laminated bandpass filter and a multilayer laminated bandstop filter. These two filters are capable of easy tuning after duplexer manufacture. The computer-aided design flowchart is also presented. Additionally, the tuning method and loss improvements of the duplexer are discussed. Measured results show the performance of the LTCC-MLC duplexer is acceptable for DCS-1800 applications.