Design And Realization Of Mobile Communications Front-end Module Based On LTCC Technology

With the rapid development of mobile communication technology, multiplecommunication services are prevalent in our daily lives, there are growing demands onthe development mobile communication terminal for miniaturization, high performance,multi-band, multi-mode and low cost. LTCC (Low Temperature Co-fired CeramicLTCC) technology is becoming the first choice of modular communication front-end,which is including a large number of passive components, as it’s has multi-dimensionalwiring characteristics and advantages of the mechanical, thermal characteristics.This thesis, based on LTCC multilayer technology, designed a dual-modemulti-band mobile communications front-end module for GSM/UMTS, work of thepaper mainly for the following aspects:Firstly of all, the research typical architecture of LTCC mobile communicationfront-end, finding the development direction of the current mobile communicationsfront-end several bottlenecks. Summed up the typical architecture defects, thus theLTCC mobile communications front-end module architecture design programs in thepaper is proposed.Secondly, the passive devices, in the ceramic substrate of mobile communicationmodule, are designed for suppressing the higher harmonic of the transmitting end andfor selecting the reception band. For high stop-band-rejection requirements andreducing the process realization difficulty of the filter, based on the parasitic effects ofthree-dimensional capacitor and the transmission zeros of LC resonant, a lumpedlow-pass filter is designed in this paper. Distributed band-pass filter is based on thethree-dimensional cross finger resonance, and it’s quickly optimize designs can realizeby N+2order coupling matrix assistant adjustment. Further, the more parameter ofresonator is easier to achieve a controllable adjustment of the transmission zeros, toinhibiting characteristics of the band of the band-pass filter is easier to achieve.The mobile communications front-end module is designed and fabricated finally.The module consist a large number of passive components buried LTCC substrate and microwave switch finally the GSM module, the final package size of only15mm×15mm×1.5mm. The electromagnetic coupling suppression for passive devices inthe ceramic substrate is focused in the designing of mobile communications FEM.Transmission line transition mode and design for text (DFT) must be discussed andresearched. Reuse of software to optimize the design of the module as a whole, until theperformance indicators are to meet the requirements. Finally, the LTCC module isfabricated and tested, to verify the feasibility of the design.