Research And Implementation Of A Multi-mode Wideband Rf Receiver

Exploding development of wireless communication technique brings various communication protocols which are working in different frequency bands,data rates and distance.Therefore,a single communication terminal compatible with multiple protocols is more and more attractive.The key point is the design of multi-mode transceiver.For the above consideration,the main content of this work includes:The communicating protocols have been firstly analyzed thus to give the index of receiver design,including DVB-T,GSM,W-CDMA,TD-SCDMA,GPS,ZigBee,Bluetooth,802.11b/g and so on.The architecture and index of the multi-mode reconfigurable receiver have been studied.Basing on the index and modeling of the receiver,the parameters of each module(such as LNA,mixer and so on)have been calculated.Since the tradeoff among gain,noise figure and input third-order intercept point(IIP3)is difficult in LNA design,this work gives two solutions which combine noise cancellation,cross capacitor coupling(CCC)and multiple gated transistors(MGTR).Both designs achieve wideband matching and low noise figure at the first stage.At the second stage,the gain is promoted while the IIP3 is not decreased as the MGTR technique is implemented.Measured result shows both LNAs have advanced performance compared to the references.Moreover,this work has a deep research in the limitation of conventional MGTR technique and presents an improved MGTR technique.The conventional MGTR only increases the IIP3 of the circuit but has no benefit for input 1 dB compression point(CP1dB).In order to solve this problem,this work implements two pairs of transistors to compensate both gm and gm" of the transconductance stage of the circuit,thus to improve both IIP3 and CP1dB.The newly proposed technique has been implemented in the active down conversion mixer and the measured result shows that the design achieves high gain and low noise without reduction of IIP3 and CP1dB.Basing on the designs of LNA and mixer,two designs of RF front-end(RFE)are presented.Compared to the references,both of the RFEs have obvious advantage on die size,power consumption and noise figure.Finally,on the basis of system analysis and RF front-end design,a wideband reconfigurable RF receiver has been proposed.The measured result shows that the receiver can work in the frequency band from 45MHz to 2.5GHz.The bandwidth can be adjusted from 0.28MHz to 40MHz.The maximum gain is 87dB and the noise figure is 3.8-7.9dB.The maximum out-of-band IIP3 is-14dBm without a SAW filter.The EVM test is successful under several protocols.The chip area is 4.1x4.1 mm2 the power consumption is 233mW under the maximum gain.