The Research And Design Of LNA In RF Front-end For IOT And WSN

The Internet of Things and Wireless Sensor Network is a cutting edge andinterdisciplinary field which combines sensor, wireless communication, integratedcircuits and other aspects of the technology. IOT and WSN provide a new mean formarine research and utilization. One of the main problems in the ocean to establishIOT and WSN is the wireless communication system. Wireless communication inthe sea and land are significantly different, especially because in the ocean eachcommunication node is often far apart. This put forward a very high request to thewireless communication distance. In this study, low noise amplifier in RF front-endsystem is researched and designed. And through the analysis of the noiseperformance of the receive system, the communication distance of wirelesscommunication system is estimated. Finally, application of IOT and WSN in theocean is discussed.Different frequencies and different types of LNA are researched and designedin this study. Design and simulation use UMC0.18μm process.For2.4GHz band, a narrow band LNA is designed, which is improved fromcommon narrow band LNA structure by use additional inductors to partly cancel outthe influence of the parasitic capacitance of the transistor, and thus improved gainwithout increasing power consumption. According to the post simulation result, thisnarrow band LNA can achieve a18dB power gain and about1.4dB noise figureunder1.8V supply. The DC power consumption is10.8mW. The circuit also has agood gain and noise performance under1.2V supply.For433MHz and860~960MHz band, a wideband LNA is presented. Noisecancelling and local feedback is used in this design, as well as a gate inductor isused in order to compensate the gain loss at high frequency. These lead to an LNAwith high gain and low noise, and achieve a flat gain in pass-band. According to thepost simulation result, consuming9.45mW from a1.8V supply, the LNA achieves amaximum power gain of22dB and an NF of1.7~5dB over a3dB bandwidth of0.1~1.65GHz. The circuit also shows a good gain and noise performance under1Vsupply.The LNA designed in this study show a good gain and noise performance,which provide a reference for the design of a wireless communication system in theocean, as well as a basis for the application of IOT and WSN in ocean. Longdistance communication system in433MHz and915MHz band can be used to build wireless sensor network on the ocean observing system. Short distancecommunication system in2.4GHz band can be used to build IOT system in ship orRFID system. Both of them have broad application prospects in ocean.