RF Design of Simultaneous Dual-Mode Mobiles

The paper is to research on the RF design of GSM/ CDMA1X simultaneous dual-mode mobile terminals. The interference issue between GSM RF and CDMA RF units is emphasized, which consists of 4 interference scenarios. 1, interference of GSM Tx to CDMA Rx; 2, interference of GSM Tx spurious emissions to CDMA Rx; 3, interference of CDMA Tx to GSM Rx; 4, interference of CDMA Tx spurious emissions to GSM Rx. In the paper, the principle and implementation methods of eliminating and alleviating RF interference are introduced. The essential guideline is to effectively increase and maximize the RF isolation between GSM and CDMA RF units, of detailed methods e.g.: partly designing GSM and CDMA antennas to enhance spatial radiated isolation; separating the GSM and CDMA radio units to enhance board level conducted isolation. With all these methods adopted in the product design, the GSM/CDMA1X dual-mode mobile terminal was successfully developed finally.