Design And Implementation Of Low Intermediate Frequency Receiver Based On Sub-GHz Wireless Communication Technology

In the present world, wireless products are ubiquitous. A lot of wireless terminals and a variety of applications have scattered around us, such as meteorological station, smart home, automatic meter reading, car keyless (RKE) into the system, sprinkler system, lighting system, wireless body area network, etc. Sub-GHz wireless technology is widely applied in above wireless devices and the application systems. The main research work of this paper is to design a low intermediate frequency receiver with GSMC0.18μm CMOS technology, which can be used for wireless body area network or automatic meter reading system, working at the Sub-GHz wireless technology.Firstly, the thesis introduces the Sub-GHz wireless technology and analyzes the advantages and disadvantages of its different applications. This thesis also summarizes mainstream architectures of receiver for wireless communication, and compares advantages and disadvantages of different structures. To meet the application requirements, we chose low intermediate frequency receiver structure, and determine the performances matrix of the receiver.Secondly, we design the main circuits, in the low intermediate frequency receiver, which includes low noise amplifier (LNA), mixer, and active filter. Respectively in the third chapter, we design a narrow-band LNA (for400MHz) and a dual band LNA (used in the400MHz and900MHz). The DC power supply voltage is1.8V:the DC current consumption of LNA is less than5mA,(1) the400MHz LNA, NF=1.55～1.69dB, and the gain19dB<S21<40dB,(2) for the dual band LNA, NF is less than2dB, and the gain=23-26dB; mixer DC current consumption is less than0.7mA, its conversion gain is about17dB, the linearity performance IIP3-4dBm; the DC current consumption of the active filter is less than8mA, it has a center frequency of2MHz, and the image rejection of active filter is more than40dB and its gain is approximately ldB.The paper describes other circuits simultaneously, used for low intermediate frequency receiver in the sixth chapter, including gain variable IF amplifier, bias circuit and frequency divider circuit. The whole receiver’s DC current consumption is less than17mA, working in the400MHz band, its gain is41-60dB, and noise range of2.8～6dB. Finally this IF receiver design has been taped out and tested, the test results shows that the amplitude range of the input signal is-50～-10dBm.Finally, this paper summarizes the research and design work for the low intermediate frequency receiver, and makes the outlook of the design based on the existing design circuits.