The Design And Research Of Current Mode RF Receiver Front End Circuit

Nowadays,with the rapid development of wireless communication,the relationship with the daily life is becoming more and more closely.But the radio frequency(RF)front-end circuits used for various wireless communication protocol are incompatible,which brought inconvenience to people's portability.So the design of multi-mode multi-frequency RF receiver front-end which can be compatible with a variety of multimode wireless communication protocol has become the focus of the study,in addition,the current mode circuits because of its higher working speed and working frequency,lower working voltage and power.and simpler circuit structure is becoming a research hotspot.The purpose of this paper is to study and design the current mode RF receiver front-end circuit.The main work of this paper includes:1.After studying the basic design method of traditional low noise amplifier(LNA),this paper presents a broadband low noise transconductance amplifier(LNTA)which can be applied in current mode RF receiver.The LNTA is composed of broadband active balun input stage and current mirror amplifier stage.The single-ended RF voltage signal received from the previous circuit will be converted into a current signal and amplified through LNTA,the RF current differential output at last.This LNTA can directly drive the next stage current mode passive mixer.The LNTA has a high and stable S21 in 0.8 to 7.5 GHz frequency band,which is 16.5 to 18.1 dB.The S11 is less than-9 dB,S12 is less than-43 dB.the noise coefficients is less than 4 dB,the minimum noise figure is 3.5 dB,applied in this paper the current mode of rf receiver design requirements.The performance of LNTA can satisfy the design requirements of current mode RF receiver.2.A variable gain broadband current mode RF receiver front-end is presented in this paper,using the zero intermediate frequency receiver structure,covering the frequency band of 4-7.5 GHz,it can support the WLAN 802.11a communication protocol.The RF receiver front-end circuit is composed of low noise transconductance amplifier(LNTA),I/Q quadrature current mode passive mixer switch(Mixer)and transimpedance amplifier with variable transimpedance gain(TIA).Among them,the LNTA structure is presented in part 1.Mixing switch stage with 25%duty cycle local oscillator(LO)signal driving can avoid the IQ interaction problem,and the current mode passive mixing switches without DC bias current can reduce the flicker noise.The TIA adopts the structure of two levels of op-amp with variable resistor-capacitor feedback network.Variable gain can be obtained by adjusting the different resistance,at the same time the regulative feedback capacitance can stabilize the linearity of the circuit.After the circuit theory analysis and software simulation,results show that the RF front-end circuit of adjustable gain can be achieved in the 4-7.5GHz frequency range,and linearity and noise coefficient can meet the design requirements at the same time.3.A current mode direct conversion receiver front-end with gm-boosted common gate(CG)structure TIA is presented,it covers the 0.8-5 GHz frequency band,can support GSM,TD-SCDMA,RFID communication protocol.The key feature of the proposed receiver front-end is a broadband active-Balun low-noise transconductance amplifier(LNTA)driving a current-mode passive mixer terminated by a low-input-impedance transimpedance amplifier(TIA).TIA with common gate structure converts the IF current into the intermediate frequency voltage and amplify,the equivalent transconductance is enhanced by the addition of the gm-boosting technique,thereby reducing the input impedance,improving the current efficiency and the port isolation,but also makes the transimpedance increase,improving the gain of the circuit.It overcomes the limitation between power consumption,gain and bandwidth in the operational transconductance amplifier with resistance negative feedback,as well as the noise and RF signal feeding through to the output because of the load capacitor.The circuit was simulated and analyzed.The results show that the RF front-end circuit can achieve high gain and wide band with very small fluctuation in 0.8-5GHz frequency range,and has good linearity and noise performance,good isolation,simple circuit structure,it can satisfy the design requirements.4.Because of a lot of radio frequency applications such as:Wi-Fi-IEEE 802.11b/g,Bluetooth-IEEE 802.15.1.Zigbee-IEEE 802.15.4.Wireless USB and so on operating in the frequency range of 2.3GHz-2.4835GHz.In this paper,a RF receiver front-end circuit operating in the 2.4GHz frequency band is studied.The transconductance of the 2.4GHz passive mixer is combined with the low noise amplifier,and a 2.4GHz current mode direct down conversion receiver is formed with the bias current of the circuit reduced.The first stage is a fully differential LNTA,it has good input matching feature with source degeneration inductor,can convert RF vortage signal into RF current and amplified.The second stage is a current mode passive mixer switches which is driven by 25%duty cycle LO signal.The third stage is the transimpedance amplifier,its input impedance is reduced by using the transconductance enhancement technology,while using PMOS tube shunt technique to reduce the voltage margin occupied by the load resistance,stabilize the output quiescent point and improve the linearity.5.The layout design and verification of the proposed two wideband current mode direct down conversion receiver front-end are presented.Because of the same structure of the low noise transconductance amplifier stage and the switching mixer stage of the two circuits,the circuit can be shared in the layout design,the layout area is saved,and the power consumption is reduced.