無線區域網路雙頻低雜訊放大器設計

Abstract

本文提出可供IEEE 802.11a與802.11b兩頻段之無線區域網路(wireless local area network, WLAN)使用之低雜訊放大器(low noise amplifier)設計方法。此串接兩級雙頻低雜訊放大器是設計在2.441 GHz和5.772 GHz兩頻段，使有最佳的雜訊指數及足夠的增益。電路的設計是採用補償匹配(compensated matching)、微帶傳輸線(microstrip transmission lines)及諧振匹配(resonance matching)法完成雙頻段的特性，補償匹配電路的電感與電容零件均採用TDK公司所生產之零件；而諧振匹配電路是使用微帶線。在此雙頻低雜訊放大器的供應電壓，使用直流3 V的電源，將有42 mA的耗電流產生，提供了2.441 GHz頻段27.7 dB之增益及1.4 dB的雜訊指數，在5.772 GHz頻段15 dB的增益及2.3 dB的雜訊指數。

This thesis studies design of dual-band low-noise amplifiers (LNA) for use in the IEEE802.11a and 802.11b wireless local area networks (WLANs). This cascaded two-stage dual-band LNA is designed at 2.441 GHz and 5.772 GHz, with high gains and optimized noise figures. The circuit design uses compensated matching networks, microstrip transmission lines, and resonance matching networks. The lumped inductors and capacitors use those manufactured by the TDK company. The resonance matching network is implemented using microstrip lines. This dual-band LNA uses DC 3.3 V and consumes 42 mA. The circuit achieves 27.7 dB power gain and 1.4 dB NF at 2.441 GHz, and 15 dB power gain and 2.3 dB NF at 5.772 GHz.