Publication: Rekabentuk penguat hingar rendah (lna) cmos beraruhan merosot bebezaan penuh untuk penerima wcdma
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Date
2005-03-01
Authors
Law, Eng Hui
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Abstract
A 2.1 GHz low noise amplifier (LNA), intended for use in a Wide-band Code Division Multiple Access (WCDMA) receiver has been implemented in 0.18μm RF process. The amplifier provides a forward gain (S21) of 11.42dB with a noise figure of only 1.7dB and drawing 12.66mA from a 1.8V supply voltage. The 1dB-compression point of the LNA is -9.82dB. In this thesis, detailed analysis of the LNA architecture will be presented. The LNA employed an inductive source degeneration topology, that is, a degenerative inductor is used to provide 50Ω input impedance matching. An advantage of this method is that unlike other methods, it does not bring with it the thermal noise of an ordinary resistor because a pure reactance is noiseless. This LNA uses differential architecture rather than single-ended architecture to provide better common-mode rejection ratio. The main problem faced in the project was to obtain a 50Ω input and output impedance while maintaining the gain to be in the range of 10dB to 15dB. This gain specification is to ensure that the LNA provide enough gain but not too high as to avoid nonlinearity that can cause distortion. LNA should not consume too much power to have good portability. Finally, the performance of the designed low noise amplifier meets all of the specification.