2．4-6．0GHz超宽带低噪声放大器的设计

采用标准0．5μmGaAsPHEMT工艺设计了工作频段在2．4—6GHz可应用于无线局域网（WLAN）和超宽带（UWB）接收机的超宽带低噪声放大器。从宽带电路的选择、高频电路设计的器件选择和电路结构的选择等方面讨论了如何进行超宽带低噪声放大器的设计。结果表明，通过合适的电路结构和器件参数选择，可以采用0．5μmGaAsPHEMT工艺制备满足超宽带系统要求的低噪声放大器。在UWB3．1～5．15GHz低频带内，该LNA增益20．8～21．6dB，噪声系数低于0．9～1．1dB，输入输出驻波比均小于一10dB。在2．4～3GHz频带（涵盖802．11b／g的使用范围）内，该LNA增益20．8～21．5dB，噪声系数低于2dB，输入输出驻波比均小于-10dB。在频带5．2—6GHz，该LNA的噪声系数增大到1．332dB。增益则从21．4dB下降到19．7dB。电路的工作电压为3．3V。

Design of a 2.4～6 GHz Ultra Wideband Low Noise Amplifier

A 2.4 - 6 GHz ultra wideband LNA for Wireless Local Area Network （ WLAN ） and Uhra-wideband （UWB） receiver was designed using standard 0. 5 μm GaAs PHEMT process. The simulation result shows that, with careful selection of circuits structure and device parameters,it is possible to fabricate a UWB LNA using standard 0.5 μm GaAs PHEMT process. In the UWB low-band （3 to 5. 15 GHz）, the broadband LNA achieves a power gain of 20.8 - 21.6 dB, a noise figure of 0. 9 - 1.1 dB and input/output return loss less than - 10 dB. From frequency 2. d to 3 GHz （ covering a 802. 11 b/g band） , the LNA achieves a power gain of 20. 8 - 21.5 dB and a noise figure less than 2 dB. From frequency 5.2 to 6 GHz,the noise figure of the LNA becomes higher than 1.33 dB. The gain decrease to 19. 7 dB. The DC supply is3.3 V.