.3 ~ 5 Ghz Broadband Cmos Low Noise Amplifier Research And Design,

High speed wideband communication and low cost are significant directions of the development of wireless communication technologies nowadays. On the other hand, as the first stage of wireless receiver, low noise amplifier plays an important role in the communication system. So the research of wideband CMOS LNA is imperative under this situation.The filter wideband CMOS LNA is deeply studied in this thesis, and several optimize methods are proposed for the wideband impedance matching, noise figure, gain, gain flatness and so on. At last, a 3⁵GHz wideband CMOS LNA is designed for the application of Wireless Personal Area Network.The thesis analyzed the high frequency (HF) noise model of MOSFET and the HF characteristics of devices in the RF CMOS process, which is helpful for the design and optimization of LNA.The wideband impedance matching principle of LNA is researched, and the wideband input matching network is designed in the consideration of effective bandwidth, device number and the sensitivity to devices. The topology of input network is improved for the sake of eliminating the conflict between the bandwidth and noise. A new noise optimization method is proposed for the new input network, from which the optimal size of input transistor is obtained. The noise characteristic of common-gate transistor is calculated from the point of signal noise rate, and minimized from an improved topology and an optimal transistor dimension.The common single stage filter output mode and source follower output mode are explored in this thesis. And it compares the advantage and disadvantage from wideband impedance matching, gain and gain flatness between the two output modes. Then, a new tow stage cascode output mode is proposed, which combined the band-pass filter and the full band impedance transform. The proposed output mode transfers some gain pressure of the first stage to the output stage, so it improves the gain and gain flatness of the LNA.This thesis also discusses the linearity of LNA. The main origin of non- linearity in this two stage LNA is analyzed, and the linearity of LNA is correspondingly optimized through the second stage.Finally, the LNA is designed under TSMC 0.35μm RF CMOS process, and the Spectre RF simulation results show that, in the full work band of 3～5GHz, the input and output impedance matching s11&s22<-11dB, the forward gain s21>12.1dB, the gain fluctuating range△s21<2.6dB, the noise figure NF<4.45dB, and the input referred IP3 IIP₃>-5.82dBm.