Design Of Low Noise Amplifier And Down-Convert Mixer Based On 0.18μm CMOS Technologe Used In 5GHz WLAN

Along with the progress of science and technology and the transformation of living and working, the dependence and requests to Internet of people are getting more higher, the traditional local area network already could not satisfy the people to the demand of network flexibility, the wireless local area network (WLAN) arises at the historic moment. The characteristics of wireless local area network as removability, smartness and so on cause us to break the limit that we can use network only when we have the fixed network infrastructure. The most direct-viewing application of wireless local area network is the substitution of the existing wired ethernet. The many merits of wireless local area network make its application domain to expand unceasingly. The wireless local area network is gradually becoming the Internet which the people use most frequently.The main work of this paper is to design the front-end module circuits of radio frequency receiver used in 5GHz IEEE 802.11a wireless local area network based on 0.18μm CMOS technology, including low noise amplifier (LNA) and down conversion mixer. Low noise amplifier is the main part of radio frequency front-end receiver which amplifies the aerial input weak signal. It has a small noise factor, and a certain gain, so that can reduce the influence of noises to the received signal greatly from the behand stages of the system. The mixer is an important component of the wireless transceivers. In receivers, mixers are down converters generally, they are after low noise amplifiers, moving the signal from radio frequency to the intermediate frequency.Firstly, the development progress and standards of wireless local area network, especially the IEEE 802.11a standard on the 5GHz frequency band are introduced, and then the basic structures and the performance parameters and the use scopes of kinds of radio frequency receivers are analyzed, and the receiver structure which this article's designs as LNA and Mixer based on are introduced.The difference source inductance degenerate cascode structure is adopted in the design of LNA. The parameters of components are determined by power restrainted noise optimization formula. It introduces a taped capacitor resonant tank as output matching network. The design has achieved the linearity, gain and noise requests and so on. Finally the simulation result and chip layout photo is given. Finally, after introducing the basic principle of mixer and some kinds of mixer structures, the active double balance Gilbert mixer is studied emphatically especially the mixer noise origin in this article. With source feedback inductance used for the input matching network and a LC resonant tank as tale current, a L network as IF port and LO port matching network, the Gilbert mixer is achieved with good performance. Finally simulation results and chip layout diagram are given.