Research And Design Of Interference-Resilient Radio Frequency Receiver Front-End

The emergence of multiple wireless communication protocol standards has arisen the demand for wideband receivers operating in multiple frequency bands.Normal performance of these receivers is required under strong out-of-band（OOB）interference signals which are usually attenuated through off-chip surface acoustic wave（SAW）filters.Because of its non-tunability,the SAW filters is not suitable for wideband receiver scenario.In this thesis,a wideband receiver front-end that can tolerate strong OOB interference signals is studied.A CMOS interference-resilient radio frequency（RF）receiver front-end researched and designed in this thesis consists of interference-resilient low noise amplifier（LNA）,mixer and clock generation circuit.Adopting the top-down approach,many structures of the interference-resilient receiver are compared while the advantages and disadvantages are respectively illustrated.After the front-end structure is selected,the interference-resilient LNA and mixer are specifically designed,including the analysis of module structure and parameter calculation.An interference-resilient LNA is designed and taped out.With the interference cancellation structure,the N-path filter is adopted as feedback network to suppress strong OOB interference signals.Wideband input matching is achieved by using resistive feedback.Noise performance is optimized by applying noise cancellation and feedforward noise cancellation technology.Good differential performance is obtained by a balanced output buffer.The N-path filter is driven by a designed clock generation circuit.Post-simulation results indicate that in the range of 0.4～3 GHz,the LNA gain(S₂₁)is 15.33～20.24 dB,the noise figure（NF）is 2.21～5.73 dB,the blocker NF simulated under a 0 dBm interference located at 80 MHz offset is 6.29 dB@1GHz,and OOB IIP3 is 6.97 dBm@1 GHz,the input matching(S₁₁)is less than-10 dB.Based on the designed LNA,a passive mixer is integrated,thus an interference-resilient RF receiver front-end circuit is completed.In 0.4～3 GHz band,the post-simulation results show that the voltage conversion gain is greater than 20.34 dB,the NF is less than 5.67 dB,the blocker NF simulated under a 0 dBm interference located at 80 MHz offset is 6.95 dB@1 GHz,the interference rejection is greater than 47.28 dB,the OOB IIP3 is 6.41 dBm@1 GHz.