Low Noise Amplifier And Mixer Design For Bluetooth Receiver Systems

With the development of modern wireless communication technology,mobile wireless products have become more and more widely used.This has put increasing demands on handheld wireless communication chips with small size,low power consumption,and high integration,which is also a current research hotspot.This thesis is mainly based on the Bluetooth low-frequency RF receiver system.The low-IF receiver structure is selected to design the core circuit module of the receiver:Low Noise Amplifier(LNA)and Mixer.In the design of the low-noise amplifier module,the chip has a non-inductive structure,and the input matching inductor uses a chip's external lead parasitic inductance,which can save the chip's internal area.The low-noise amplifier uses two pairs of cascode structures.The purpose is to implement the function of single-ended input differential output.The constant current source method is used to bias the transistor to avoid the problem of the transistor's working state caused by the constant voltage source.In this case,the circuit function cannot be realized.In order to achieve the function of gain control,after comparing the advantages and disadvantages of changing the transistor size,changing the gate bias voltage,and changing the load resistance value,then based on the principle of negative feedback,two sets of inversion are controlled by two signals.The voltage gain of the three modes is designed,that is,the voltage gain is 7.83dB,15.28dB and 26.19dB.In the low-noise amplifier,in the high gain mode,the noise figure is 2.26dB,the input reflection coefficient is-14.52dB,and the voltage gain is 26.19dB.In the post simulation,the noise figure is 2.9dB,and the input reflection coefficient is-23.57dB.Front and rear simulations show that the performance parameters of the low noise amplifier are excellent.In mixer design,the design of orthogonal down conversion is mainly based on the classic Gilbert active mixer circuit structure.The mixer designed in this paper uses two Gilbert Mixer units,and the circuit architecture of the constant current source is used to design the bias circuit.The actual performance parameters obtained from the simulation,the double-sideband noise figure is 13.58dB,the output voltage gain is 6.11dB,and the input third-order intermodulation point is-1.4dBm,which all meet the design index requirements.The mixer compensates and calibrates the phase and amplitude balance problems of the low-noise amplifier.The amplitude difference of the differential signal is 0,and the phase difference is 179.82deg.Finally,the low-noise amplifier and mixer are jointly simulated.The simulation results show that in the high-gain mode,the input reflection coefficient is-17.46dB,the double-sideband noise coefficient is 2.91dB,and the voltage gain is 34.79dB.The tuning point is-21.89dBm,and the performance parameters meet the design index requirements.