Single- Supply Voltage PHEMT LNAs and Direct Conversion Mixers with Flicker Noise Improvement
|Keywords:||假晶高電子遷移率電晶體製程;低雜訊放大器;主動式混頻器;閃爍雜訊;顫動雜訊;PHEMT LNA;CMOS active mixer;PHEMT active mixer;flicker noise|
Noise is an important issue for the WLAN front-end applications, especially in the direct-conversion system. This thesis focuses on the two topics of PHEMT LNAs and low flicker-noise mixer. The first is to design a single biasing PHEMT LNAs by our proposed self-bias technique. Under a single supply of 3 V, the 2.4 GHz LNA achieves the noise figure of 1.43 dB and the gain of 15.7 dB. The other LNA operating at the dual band of 2.4 GHz/5 GHz has noise figure about 3.4dB at these two bands. The current consumption of them are 10 mA and 12.6 mA, respectively. The next studies the flicker noise of mixer, which is closely related to the biasing current of the switch core, and the circuit parasitic capacitance. We approach this issue in the three different methods, including the static curent bleeding, dynamic current bleeding and static curent bleeding with two series resonant inductors. Moreover, the technique of low-frequency noise measurement will be discussed in detail. It is because the surrounding noise will degrade the measurement quality seriously. How to make a clean environment is another challenge in the flicker-noise research. From the measured results, the dynamic current bleeding mixer implemented in 0.13um CMOS process achieves 12.8 dB noise figure and 4 MHz corner frequency, and the 0.15m□ PHEMT mixer with static-current injection has an obvious improvement in lowering the corner frequency (from 80 MHz to 40 MHz).
|Appears in Collections:||Thesis|
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