Design Of Low Noise Amplifier For WLAN And RF Transceiver Front-end Integration

People can connect to the Internet by using a mobile terminal within the coverage of wireless local area network (WLAN), and wireless local area network has a lower cost than the wired network, which makes WLAN be used broader, and WLAN plays a more and more irreplaceable role in our daily communication. With the expanding application of WLAN and the using environment becoming more and more complicated, the demand for wireless transceiver chip rise sharply as well as the high quality of the chip. Lower power consumption and smaller chip area become the key considerations of the commercial chip designs. Based on the design method of power constraints, a low noise amplifier applying for wireless local area network (LAN) is designed by using the sharing level source inductance feedback source grid structure. Finally, the RF front-end chip that integrates PA, LNA, T/R switch circuit, meets the need of frequency function for wireless local area network radio.This article analyzes the passive components of the RF circuit and CMOS device’s physical characteristics at first, so that we can design it better according to the radio frequency characteristic of inductance capacitance resistance, analyze and improve the device diagram, especially the inductance in landscape painting and the layout. Inductance has always been a key part of the RF circuit design, for that it is formed by a certain width of the metal coils winding, and the width of the metal, the distance between the metal and the circle number and shape of metal around affect the sense of inductance value and Q value. It has always been a challenge of RF circuit design to design a suitable inductance for design requirements. After analyzing the design method of low noise amplifier, based on the source inductance feedback source grid structure, using the images to provide bias circuit structure, and optimizing the input and output matching method, improves the performance of the low noise amplifier by analyzing the simulation result of the low noise amplifier. Designed a satisfying current WLAN transceiver RF front-end required for performance of low noise amplifier. The noise coefficient of low noise amplifier determines the lowest limitation of the receiver noise coefficient, while linearity of low noise amplifier determines the linearity of the receiver that can achieve limitation in theory, and both of them determine the sensitivity of the receiver. The circuit diagram of RF transceiver front-end layout is implemented as a key bridge of chip design. The design of entire system is strictly compliance with the rules of layout design, and gets the physical performance parameters of the whole RF front-end by optimizing the layout of the diagram, ultimately integrating the low-noise amplifier, power amplifier, RF transceiver in a diagram switch for streaming on tablets, testing the WLAN RF transceiver after taped, and building a test platform. And the differences between the simulation results and test results of the circuit design and the reasons for these differences are analyzed.