Design Of Anti-blocker RF Receiver Front-end Without Surface Acoustic Wave Filters

With the superiorities of high flexibility,high integration and low cost,anti-blocker surface-acoustic-wave-less(SAW-less)receiver is a potential solution in multimode and multiband applications today.Receiver front-end is the key part in an anti-blocker SAW-less receiver,because it is burdened with the task of attenuating the out-of-band blockers without sacrificing other performances.An anti-blocker SAW-less receiver front-end is proposed in this thesis,which consists of a low-noise amplifier(LNA),4-path filters,radio-frequency(RF)transconductance amplifiers,a current-switching passive mixer and intermediate-frequency(IF)transresistance amplifiers.By organically combining the feedforward blocker cancellation architecture,4-path filtering architecture and cascaded current-mode architecture,high suppression ratio for out-of-band(OOB)blockers is obtained at the cost of relatively low power dissipation and complexity.Capacitors are used as the low-frequency networks of the 4-path filters,which leads to the band-pass input impedance of the filters.The 4-path filters are conbined with the LNA and the RF transconductance amplifiers to suppress the OOB blockers.The class-AB structure is employed in the designs of the LNA and the RF transconductance amplifiers to enhance the linearity.The two RF transconductance amplifiers constitute a feedforward canceling structure,which amplifies the wanted signals while cancels the OOB blockers.The input impedance and transresistance of the IF transresistance amplifier is designed based on calculations and analyses,to further eliminate the OOB blockers.In addition,a 25%duty-cycle clock generator is designed in this thesis to provide the clock signals for the mixer and the 4-path filters.The schematic and layout of the receiver front-end is designed in TSMC 130 nm CMOS technology.The post simulation results show that the conversion gain of the front-end is 43.6 dB and the noise figure is 6.2 dB.The in-band and OOB third-order input intercept point is-7.7 dBm and +21.6 dBm respectively.The OOB blocker suppression ratio measured at the frequency points 20 MHz and 95 MHz away from the center frequency of the wanted signal are 45.3 dB and 63.6 dB respectively.The quiescent power dissipation of the receiver front-end is 20.2 mW.Considering the relatively low power dissipation,high OOB blocker suppression ratio and high noise figure,the anti-blocker SAW-less receiver front-end is fit for a receiver that asks for a good ability of restraining blockers and a relatively low power dissipation,instead of a very high sensibility.