Mobile Phones With Bluetooth, Wifi, And Analog Television Rf Front-end Technology Research

When designing a mobile terminal, the RF front-end circuits and the EMC issues of multi-RF-systems are critical and difficult to deal with。Both in2G era and3G era, the EMC issues between RF front-end circuits are the very hot research foci.In this thesis, the key techniques on the design of RF front-end circuits are analyzed in depth and all the necessary RF circuits of the GSM mobile phone with WiFi、BT and ATV functions and a novel penta-bands antenna with a flexible structure are designed and tested. At last, a novel useful method is given to solve the radiated spurious emission (RSE) problem caused by the ATV antenna. The main results are as follows:Firstly, offset phase-locked loop of the up-conversion transmitters and direct down-conversion of the receivers are anaryzed in depth and selected.Secondly, According to the requirements for RF specifications of GSM mobile phones and the related functions specification of BT、WiFi and ATV, a series of multi-functions ICs made by MTK are presented. The performances of the chips selected are described in detail and the schematic diagrams involved are shown in this thesis.According to the characteristics of the internal antenna and the theory of small antenna, a novel structure PIFA with penta-bands is designed and the fifth operation frequency band of the antenna can be adjusted easily. The penta-bands (covering the GSM4-bands and WCDMA band1) PIFA made in FPC is manufactured and tested. The antenna has a compact volume and the size is only42mm×11mm×6mm.All the RF functions are verified and some problems such as GSM Rx sensitivity problems and WiFi Tx power issue are solved well. A novel method of decreasing RSE is proposed and at last all the test results meet the requirements of the involved specifications.