Design Of LTCC Front-end Module GSM900MHz Band

With the rapid development of wireless communication system, the handsets in our daily use become one of the hotspots for researching and developing. More and more integration technology advanced driven by the demand for small-size and high performance, so was the Low temperature co-fired ceramic (LTCC) technology.Taking advantage of multilayer circuit design, LTCC technology is increasingly catching more and more eyes in the field of RF integration. The handsets occupy the main part of the LTCC product application areas, approximately 80 percents or more. And the LC filters, the diplexers, front-end modules (FEM) are its main application.This paper presents the design of the LTCC Tri-band front-end modules. On the premise that we have cleared the basic design theory, we work on the design of the GSM900MHz band in accordance with the design process of LTCC module. First make the circuit design that meet the demand suggested, the process includes transmitting mode and receiving mode. On this basis, fully utilizing LTCC 3D design advantages, think out the 3D layout in all the determined cubage, then make the choice of substrate material, firing thickness, layer thickness, width, the layout of each layer before fine-tune to improve the various unpredictable parasitic and coupling effects. Besides, the match and segregation problems with the DCS1800MHz/PCS1900MHz should be considered. Then the 3D design work in this frequency band is accomplished, the final module's volume is 6.5mm×5mm×0.62mm.Before the design of this Tri-band front-end module, we have completed a design of a dual-band module, including the testing work. In the end, a corresponding conclusion is given out using these sample's results.