Research on WCDMA RF front-end technology

A kind of WCDMA RF front-end of mobile table is designed in this paper. The main building blocks of this RF front-end are receiving circuit, transmitting circuit, duplexer and regulator. A cascade mode with three LNAs is used in the receiving circuit, and a traditional cascade mode with driver amplifier and power amplifier is used in the transmitting circuit. The final measurement results show that this RF front-end provides maximum transmitting power of 23 dBm, power conversion gain of receiving circuit of 40 dB, power conversion gain of transmitting circuit of 25 dB, gain flatness of less than 1 dB, input and output return loss of more than 10 dB, output P1dB of 32 dBm, ΔIMD3 of -48 dBc, and ACLR of -46.29 dBc (lower sideband) and -48.56 dBc (upper sideband). Therefore, this RF front-end completely meet the standards of WCDMA, which could be installed in the mobile table to use.