Design Of Ultra Wideband Receiver RF Front-End

Wireless communication with high speed, reliable and convenient features satisfy people’s needs, and UWB systems are to the advantages of wide-band, high speed, low power consumption became the object of researchers contend for successively in recent years. So the research of UWB system is of great importance. RF front-end with CMOS process integrated with the band part of large scale, with the increasing cut-off frequency of CMOS process, could achieve the purpose of the single chip receiver.RF front-end is a linkage between the antenna with the base part. While the wireless communication system is developing rapidly in recent years, designing the RF receiving front-end has brought the huge challenges. RF front-end are including low noise amplifier and mixer, and RF front-end’s main function are to amplify the weak signal of radio frequency spectrum, and move RF signal into the intermediate frequency spectrum. The performance of two modules affect directly the sensitivity of the receiving system, namely the receiving system could receive the smallest signal amplitude. So we need to design logically of two modules.This paper has designed two kinds of circuits of UWB low noise amplifier, working within the3GHZ-5GHZ frequency band, based on CMOS process, respectively for LC matching UWB LNA and low complexity UWB LNA. LC matching UWB LNA uses second-order Butterworth band-pass filter as input matching structure, and the CS-CG structure as core circuit. Power consumption is13.2mW under1.8V power supply voltage, and this circuit can realize high gain, low noise coefficient, etc. Low complexity LNA circuit has strong reliability. Because of reducing the inductance in the circuit, so the chip design area is reduced. At the same time, we need to consider fully peripheral circuit’s influences to the UWB LNA. Power consumption of this circuit is13.2mW under1.8V power supply voltage.In this paper, we design a double balanced mixer circuit on the basis of the classical Gilbert structure working for3GHz-5GHz. The RF port and the LO port are added to the impedance matching circuits, and load circuit employs with the method of resistance and capacitance in parallel. Power consumption of this circuit is6.9mW under1.2V power supply voltage. And this circuit can realize high conversion-gain, low power consumption, low noise, etc.