| Wireless sensor network (WSN) has attracted much attention for low cost, flexible and wide range of applications and considerable prospects. As the development of the micro-electronics technology, CMOS RF transceiver chip with high integrity and low cost is being widely used in electronic equipment for industry and daily life, and it has a large potential market. In this paper, the key module of the Low Noise Amplifier (LNA) in the 2.4GHz WSN low-power RF receiver is conducted in the research. For WSN application requirements, a low-noise amplifier (LNA) is designed in 0.18μm RF CMOS process.In the paper, the design methods of LNA with different structures are analyzed, and the cascaded common-gate (CG) LNA structure is applied to design. Meanwhile, the design of the low power technique is carried out, the technique include the gain-boosting technique and noise optimization technique such as crossing-coupling, positive feedback, further subthreshold bias technique is chosen to reduce power consumption. The paper descripted the design of LNA circuit based on 0.18μm RF CMOS technology, including the circuit structure, input and output matching, gain enhancement and noise optimization technique, gain controlling and so on. The paper presented the analysis and results of the schematic simulation, the key points of layout design and the analysis and results of post simulation. The result of post simulation showed that in the conditions of typical process corner and room temperature, LNA has high gain and low gain of 15dB and 0dB respectively. In the high gain of 15dB, NF changes in 4.65～4.85dB, S11 changes in-20～-18.85dB, S22 changes in -22～-11.3dB; In the low gain of 0dB, IP1dB is-15.5dBm, S11 changes in -27.0～-26.1dB, S22 changes in -13.4～-13.28dB; The current is about 0.54mA under 1.8V power supply. The performance meets the design requirements.The LNA module which is designed in the paper can be used in the WSN RF chips after the further optimization and the chip verification. |
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