Research On Ultra-wideband Low Noise Amplifier Based On Noise Canceling Technique

Low noise amplifier, as an important module in electronic communicationreceiver system, is inevitably evolving toward lower noise, wider band.Ultra-wideband low noise amplifiers (UWB LNAs) are researched in this paper, themain work are as follows:Firstly, an ultra-wideband low noise amplifier circuit topology is presented. Atinput stage, the use of complementary gate structure achieves a good input matching,gm-boosted structure is employed to improve the gain of this stage; noise cancelingtopology which is constituted of adjusted complementary common gate structurecancels the noise generated by channel of complementary common gate MOStransistors, the UWB LNA has very low noise figure over a wide frequency range; theinserted inductor Linimproves the gain flatness of the UWB LNA. At intermediatestage, the bandwidth is extended by shunt inductor; source inductor degenerationstructure is utilized to improve the linearity. The output stage is a source followerwhich provides a good output impedance matching easily. Based on0.18μm CMOSprocess provided by TSMC, the UWB LNA is verified by Agilent Advanced DesignSystem (ADS) simulator. The results show that the UWB LNA has a3dB bandwidthover4-10GHz, the voltage gain (S21) is19.2±0.3dB, noise figure (NF) ranges from2.1dB to2.4dB, the input intercept point (IIP3) is-7dBm at9GHz. The LNAconsumes28.6mW with a1.8V power supply. Finally, the layout of UWB LNA isgiven.Secondly, a board-level broadband low noise amplifier module is designed. TheRogers4350B is selected as the substrate, murata’s discrete inductors, capacitors andresistors are determined as passive components. Infineon BFP740is chosen as activedevice. The structure of open stub series capacitance and inductance is used to realizeinput matching. Open stub series capacitor is set to achieve the output matching. Byusing ADS, the simulation circuit is drawn, pre-placement is finished by loadingcomponents model, the layout is generated and optimized. The electromagneticco-simulation of layout and components on PCB is performed by using Momentummodule of ADS. The results show that, the amplifier is absolutely stable in the wholerange of3-5GHz, the power gain S21swings from18to20.67dB, S11and S22are bothless than-10dB, the whole circuit noise figure lies between1.1-3dB. The simulationresults coincide with the design target.At last, Altium Designer circuit design software is used to draw layout. Thedesign and fabrication of board-level broadband low-noise amplifier is implemented.Finally, S-parameters of LNA is measured by Agilent N5230A vector networkanalyzer.