Design Of A RF Front-end For Multi-mode Multi-standard SAW-less Receiver

In recent years,with new communication standards and functions continue to emerge,wideband receivers which can support multiple communication modes have gradually replaced the multi-narrowband parallel receivers due to their advantages of flexibility and become the current research focus.Compared with the traditional narrowband receiver,the wideband receiver is more susceptible to be jammed by out-of-band(OOB)blockers without off-chip filters because the forestage circuit needs to receive the signal within the wideband operating frequency.SAW-less anti-blocker receiver front-ends is studied in the thesis to improve the anti-blocking ability of the receiver without sacrificing other performances.An improved RF front-end for a wideband SAW-less receiver is proposed in this thesis,which consists of a low-noise amplifier(LNA),radio-frequency(RF)transconductance amplifiers,4-path filters,a current-switching passive mixer and intermediate-frequency(IF)transresistance amplifiers(TIA).Based on the traditional current mode architecture,N-phase filtering technology is introduced.Combining the advantages of voltage mode and current mode architecture to effectively improve the OOB suppression capability of the receiver.LNA improves the traditional Colgate structure by introducing positive and negative feedback technology,which can achieve greater equivalent transconductance while ensuring the wideband input matching,so as to improve the circuit noise performance.Meanwhile,The LNA and RF transconductance amplifier both adopt push-pull structure,which can resist larger OOB blockers while improving linearity.The operational transconductance amplifier(OTA)uses a dual feedback compensation method to extend the bandwidth of OTA effectively in the TIA,so that the input impedance of the TIA is still lower at higher frequencies,and the out-of-band linearity of the circuit is improved.The promotion of the OOB suppression and linearity of the receiver circuit indicates the enhancement of its anti-blocking ability.The schematic and layout is designed in TSMC 40 nm CMOS technology.The post simulation results show that the conversion gain of the front-end is 37.7d B～41.5d B and the noise figure is 5.13 d B～5.57 d B Within the operating frequency of 0.9GHz～2.5GHz.The in-band and OOB third-order input intercept point is-4.03 d Bm and11.78 d Bm respectively.The circuit achieves higher than 26.7d B blocking inhibition ration(BRR)at 100 MHz offset and tolerates-8d Bm blockers acceptable 7.22 d B NF.Thus,this receiver RF front-end has high linearity and good anti-blocker ability.