Research On X-band Low Noise Amplifier In Deep-space Exploration Application

The low noise amplifier plays an extremely vital role in receiver front-ends,since it has direct impact on the receiver's dynamic range and the overall system noise figure.Currently,high-quality MMIC LNAs meeting specific specifications such as low noise figure,good impedance matching,and high gain are required urgently for microwave receiving system for achieving the best performance.For the commands of X-Band receivers in deep-space exploration application,this paper completes the design of an X-Band MMIC LNA with the desired RF characteristics.Based on the 0.15 ?m GaAs pHEMT process,a 3-15 GHz ultra-wideband MMIC low noise amplifier with flat high gain and low noise figure is presented,fabricated and measured,which has demonstrated excellent RF characteristics like bandwidth,return loss,gain and gain flatness.The RC feedback network and source inductive degeneration topology have been used to achieve the desired RF characteristics like bandwidth,return loss,gain and gain flatness for this four-stage LNA.The measured results show that the average small signal gain is 31 dB and the maximum gain is 34.8 dB over the range of 3-15 GHz.The noise figure of the LNA is less than 2.5 dB and the input return loss is more than 10 dB as well as the output return loss are obtained with chip size of 2 mm × 1 mm.Consisting of overall input/output return loss,power gain and noise figure characterization,the measured results match quite well with the simulation results over the whole band.Measurements especially demonstrate that the input return loss is better than 19 dB,output return loss is better than 16 dB and the measured NF is less than 2 d B across the 8-10 GHz.Experimental results illustrate that the designed 3-15 GHz ultra-wideband LNA exhibits a low input/output reflection coefficient,low noise figure,high flat gain,and unconditional stabilization,which can be employed directly in the S/C/X/Ku-band heterodyne receivers or inside the IF module for millimeter and sub-millimeter wave receivers.