Study And Design Of W-band MMIC LNA

In recent years,wireless communication technology has developed rapidly.Limited by restricted bandwidth and transmission rate,the current frequency range has been unable to meet the needs of science and technology development.Higher frequency(millimeter and sub-millimeter waves)and higher performance are the inevitable trends of future communication technology.Thus,as one of the most excellent band resources,W-band has attracted extensive and deep attention of researchers.As the first active stage of wireless receiver,Low Noise Amplifier(LNA)largely determines the performance of the receiver system,and has been widely used in the W-band applications,involving millimeter-wave imaging,radar,communications,radio astronomy and so on.The development direction of LNA is high frequency,high gain and low noise figure because of the shortage of frequency resources and the improvement of wireless receiver performance.Therefore,in this paper,the realization process and research significance of W-band LNA are introduced first,meanwhile the related reports on W-band LNA at domestic and abroad in recent years are investigated and summarized.Then,the basic theory of low noise amplifier is introduced,including noise theory,design parameters,basic structure of amplifier and matching theory.On this basis,with the Ommic 70 nm Ga As m HEMT process and ADS simulation platform,the design of W-band MMIC LNA has been studied.The main results are summarized as follows:1.According to the Process Design Kit(PDK)provided by Ommic Corp.,the Ga As m HEMT is simulated,and the gate width of 2×25?m and the operation point of Vgs=0V and Vds=1.2V are selected.The general design flow of LNA is presented by the design of single-stage microstrip line LNA,and the deviation of passive components of library models at W-band is analyzed,which shows the importance of Momentum EM simulation.At the design frequency of 94 GHz,single-stage microstrip line LNA has a noise figure of 2.48 d B and a small signal gain of 5.00 d B,with the chip-size of 0.9×1.0mm2.2.Based on the single-stage microstrip line LNA,the W-band four-stage microstrip line LNA is designed.This paper puts forward some improvement measures on the frequency offset and high frequency gain attenuation of multi-cascade amplification structure.At the same time,the single drain bias network and the method of reducing the size of matching network are implemented to minimize the layout area greatly.The simulation results show that in the 85GHz~100GHz frequency range,the small signal gain is larger than 19 d B and the noise figure is less than 3.8d B and they achieve the maximum of 23 d B at 93 GHz and the minimum of 3.23 d B at 94 GHz respectively.This design achieves absolutely stability at the whole frequency band and meets the design requirements,with the chip-size of 2×1.5mm2.3.The advantages of coplanar waveguide(CPW)in high frequency MMIC design and its related theory are briefly introduced,and the differences between CPW circuit layout design and microstrip line layout design are studied and analyzed.The single-stage CPW LNA is designed and the layout is optimized,which shows a 7.1d B gain and a 2.27 d B noise figure at 94 GHz design frequency,and the layout area is 0.6×0.9mm2.For simplicity,the two-stage CPW LNA is cascaded by two single-stage CPW LNAs.In the band of 85~100GHz,the gain and the noise figure of the two-stage CPW LNA is greater than 10 d B and less than 3d B respectively.The gain is 12.35 d B and the noise figure is 2.76 d B at 94 GHz.A full band stability is realized and the chip-size is 1.15×0.9mm2.