2.4GHz 無線區域網路低中頻接收器系統與設計

Abstract

傳統可攜式無線通訊系統主要以砷化鎵或是雙極性電晶體來實現射頻前端電路。為了避免高成本的製程以及多晶片電路板的製作成本﹐本論文提出了針對2.4GHz 無線區域網路單晶系統整合的低中頻接收器系統。 本論文依據 Weaver 及 Hartley 的鏡像消除架構提出四種適用於2.4GHz無線區域網路的低中頻接收器。並針對系統架構所包含的射頻混頻器以0.5um BiCMOS製程從事設計﹐其效能可達到8dBm OIP3﹐8dB增益。且利用0.35um CMOS 設計效能可達到4.3dBm OIP3﹐及6.7dB 增益的射頻混頻器;27dBm OIP3﹐及8dB 增益的中頻解調器;80dB增益﹐6度以內的相位失真的限制放大器;及+/-1度相位差的90度/180度相位移轉器等電路。經由系統鏈結分析﹐這樣的設計可以符合系統規格要求。

Conventionally, GaAs or BJT technology dictates the RF front-end circuit in the portable wireless communication system. To avoid the higher process cost and multi-chip board area, a 2.4Ghz to 22Mhz CMOS low IF receiver for wireless local area network application is chosen to realize receiver system integration. Based on Weaver's and Hartley's image rejection architecture, this thesis proposes four type of low-IF receiver architecture for 2.4GHz WLAN. And based on the system architecture, we have designed the 0.5um BiCMOS RF mixer with 8dBm OIP3, and 8dB conversion gain. In addition, by the 0.35um CMOS process, we have designed RF mixer with 4.3dBm OIP3 and 6.7dB conversion gain; and IF demodulator with 27dBm OIP3 and 8dB conversion gain; and IF limiter with 80dB gain and 6°phase distortion; and 0°/90° and 0°/180° phase shifter within 1°phase deviation. From the link budget simulation, these designs meet the specification of low-IF receiver system.