Design Of High Lineatrity Beidou Navigation Receiver

With the continuous development of wireless communication technology,wireless spectrum becomes more and more crowded.A large number of interference signals will seriously affect the signal processing of the radio frequency receiver.Due to its strong anti-interference ability,high linearity receiver has become a hot spot in modern RF design.This thesis mainly introduces the design of the receive chain in a high linearity RF receiver applied in Beidou navigation system.The receive chain mainly consists two main modules: RF front-end and baseband complex filter.A passive mixer-first front-end is applied as the first stage of the receiver to achieve better linearity performance.After downconversion,the current signal is converted into voltage form by transimpedance amplifier and then sent to the baseband complex filter.The complex filter is a 6 order Chebyshev filter and is used to provide band selection and image rejection.A feedforward compensation op-amp is chosen in the design of integrator to improve the gain of passband,thus ensuring the linearity of the filter.The receiver is implemented in 0.18μm CMOS process and the supply voltage is 3.3V.It has been demonstrated by measurement that the current consumption of RF front-end is 24 mA,while the baseband complex filter consumes 18 mA.The intermediate frequency of receiver is 15.53 M.The default gain is 14.4dB and the receiver has an adjustment gain range of approximately 44 dB.The input 1dB compression point of receiver is-3dBm and the input third-order intercept point is 7dBm.The results show that the receiver has a good linearity performance,which can meet the design requirements of high linearity.The NF is 33.8dB for the default gain and 24 dB for the maximum gain.After calibration,the in band ripple is less than 1.8dB,the out-band rejection at 1.5 times BW is 30 dB,and the image rejection is 43.3dB.