Design Of High Linearity Mixer Chip Based On 0.18μm CMOS Process

The wireless communication transceiver system is closely related to the human living environment and is widely used in GPS,satellite telephone,WLAN,RFID,satellite positioning navigation,and radar etc.With the continuous development of communication technology,people are increasingly demanding the size,power consumption and performance of integrated transceiver chips.Frequency conversion is indispensable in the transceiver system chip.In the receiver,in order to realize signal processing and information acquisition,the radio frequency signal needs to be converted to a medium and low frequency to operate;in the transmitter,the low frequency signal is adjusted to a radio frequency signal for transmission purposes.The mixer is a module for performing spectrum shifting and has an essential function in the wireless transceiver system.The importance of the mixer design is also reflected in its linearity determines the dynamic range of the transceiver system,its noise figure affects the sensitivity of the entire system,and the conversion gain also helps to increase the gain of the entire system.This thesis designs a downconverting mixer chip in a wireless communication RF receiving chip based on the TSMC 0.18μm CMOS standard process,which mainly includes a mixer circuit,a local oscillator buffer,and an inverter circuit.The mixer circuit adopts a hybrid circuit and the working mode is similar to that of the active mixer.The current-controlled switching tube and the front-stage transconductance are injected with signals from the balun,which reduces the requirement for the input power of the local oscillator while ensuring linearity.The structure is passive,which reduces the loss across the conduit,improves the conversion gain,and reduces the noise figure.The local oscillator buffer converts the single-ended signal into a differential signal,increases the local oscillator signal amplitude and reduces the loss of the local oscillator signal transmitted to the mixer module,and adjusts its performance;the inverter transforms the waveform of the local oscillator signal into The standard square wave output signal enters the mixer.In the cadence software environment,the pre-circuit simulation,layout design and post-simulation of the mixer chip were carried out,and the mixer chip was produced by TSMC.The area of the chip was 0.8*0.52 mm~2.The post-simulation results show that it works at 1.8V supply voltage,RF input frequency range is 2000MHz-5000MHz,IF output is 200MHz,the minimum gain is 5.5dB,Double-side Noise Figure is 8.8dB,input1dB Compression Point typical value is 13.4dBm.