| Summary: | 碩士 === 國立東華大學 === 電機工程學系 === 104 === The research and implement of low noise amplifiers (LNA) for wireless applications are presented in this thesis. There are two low noise amplifiers design which are low power dissipation, low noise, high gain.
The first chip is a single-to-differential LNA with low power consumption for 2.4GHz bluetooth system. The LNA uses common-source (CS) stage before active balun stage for input matching , also it utilizes compensatory capacitor to make the gain error to a minimum. The balun LNA is designed and fabricated by a standard 0.18m CMOS technology. The noise figure of the LNA is 4.2dB with 3.8mA current consumption in a 0.8V supply. The core area of the LNA is 1.457mm×1.092mm.The experimental results show that the architecture has a good performance in power consumption.
The second LNA using positive feedback is presented in this thesis. The circuit structure utilizes common-source amplifier as an input stage to enhance the gain and to reduce the noise figure. By employing a positive feedback technique, the gain can be enhanced. Besides, a body-biasd technology is added to the transistors. The proposed LNA is designed and fabricated by a standard 0.18um CMOS technology. The results show that the LNA achieves a noise figure of 3.645dB and a gain of 17.888 dB. Operated at a supply voltage of 0.7V, the LNA consumes a dc power of 2.54mW.The core area of the LNA is 0.823×0.736mm2. The LNA has been demonstrated for 5.8 GHz frequency band applications. It can be used in applications of wireless communication(Wi-Fi, WLAN, WiMAX ,and WBANS). The results show that this circuit has low power consumption, suitable both gain and noise figure.
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