Research And Design Of Radio-frequency Front-end Of Receiver Baesd On ADS

In recent decades, wireless technology with mobile communication applications as theleading, including Wirelss Local Area Network(WLAN), Global Positioning System(GPS),Satellite Communication(SATCOM), Remote Sensing And Mapping(RSM), Radio FrequencyIdentification Systems(RFID) and so on, have developed quickly and gained tremendoussuccess. RF front-end as their whole indispensable component part of the system, directlyimpact on the performance of the system. Then the RF front-end of the superheterodynereceiver structure selected as the model in the thesis, it involved microstrip bandpass filter,broadband low noise amplifier, improved version of Gilbert unit mixe.In the paper, after the structural features and the working principle of several commonreceivers being contrasted and analysed, the technical parameters of influencing receivers alsowas introduced. Then, according to this thesis research content, the superheterodyne receiverwas selected as the model to study its RF front-end.Secondly, the bandpass filter of the first component of this structure of the receiver RFfront-end was studied and designed. After the detailed description and analysis of theperformance of the filter, the parallel coupling structure of microstrip bandpass filter whosecenter frequency being3.05GHz was designed by using microstrip lines, and then it wasoptimizated and simulated by using ADS (Advanced Design System). According to the resultsof stamulation, the design met the requirements.Thirdly, the low noise amplifier which was connected after the bandpass filter wasresearched and designed. The operating principle and the function index sign of the low noiseamplifier were detailedly analysed, and the designed method which can match the impedencein a band was introduced. This method can fill the target of low noise amplifier such as gain,noise figure ect in a wide band. Based on the design of ADS software, a2.9~3.1GHz lownoise amplifier was designed by using the high electron mobility transistor ATF54143as thekey. According to the optimized simulation results, the technical parameters of the low noiseamplifier met the design index.Finally, the mixer of the receiver RF front-end was studied particularly in the thesis.Base on the structural features and the technical parameters of the mixer being introduced, theworking principle and the performance of the basic Gilbert cell mixer was analyzed in detail. Then transconductance stage structure was improved with innovation in the mixer. The mainidea is to replace the original structure of the basic mixer with a cross-connected one.Through ADS simulation measurement, on condition that other each target met the designrequirements, the linearity and the conversion gain of the mixer both were improved after thestructure being improved.