| Summary: | 碩士 === 中正理工學院 === 電機工程研究所 === 87 === The laptop computers and the portable communications excite the development of the products in wireless local area network in recent years. Additionally, MMICs for reducing the cost, size, and weight used in the related products have been prompted by the great advance of semi-conductor technologies. We propose a new approach for the design of MMICs low noise amplifier since it is necessary in the products.
GaAs transistors have better noise performances in microwave band than Si transistors. We thus design a GaAs MMIC low noise amplifier to verify the effectiveness of the approach. The traditional design approach is applied in the beginning to obtain suitable matching networks as well as their element values in the light of Smith chart manipulation and the characteristics of devices. The matching networks in MMICs generally include the integrated low Q inductors. The added loss can not be ignored and may be more than that added by FETs. Therefore, after the design of traditional approach, these inductors must be reexamined and adjusted through the noise matching.
Two-stage amplifiers operated at 2.4 and 5.7GHz are simulated by SuperCompact. The applied models are obtained, via the help of CIC, from the cell library provided by Haxewave Inc. The noise figures are 2.7dB(2.4GHz) and 3.6dB(5.7GHz) under a single power supply of 4V.
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