| Radar has the ability to detect,track,and identify targets.As technology advances,it plays a vital role in defense and civilian use.With the complexity of the application environment,people's requirements for radar performance are getting higher and higher,and narrow-band radar can no longer meet the demand.UWB radars with stronger information collection,higher resolution,and stronger anti-interference ability have been developed.Due to the small size and light weight requirements,MMIC is widely used in radar transceiver components.The first stage low noise amplifier after receiving the antenna determines the performance of the entire receiver,including the operating frequency band,linearity,sensitivity,and so on.Therefore,the noise,gain,flatness,and stability of the ultra-wideband low noise amplifier MMIC are studied.In this paper,the equivalent model of the passive matching device and active device transistor is studied in detail based on 0.25?m Ga As p HEMT process.Introduced the types of noise and studied the mechanism of various types of noise generation.Combining the classical analysis method of two-port network noise with the various indicators of the amplifier,we studied how to achieve the balance between the various indicators of the amplifier in the design.This paper studies key LNA design techniques such as noise power simultaneous matching,wideband matching,DC bias network design and circuit topology selection.The difference between noise matching and power matching is analyzed.Combined with the topology commonly used in recent years,the source series inductive feedback structure is designed to reduce the gap between the two.The implementation method of broadband matching is studied.The design of the lossy matching network reduces the quality factor to achieve broadband matching.The feedback loop formed by the cascade of two-stage amplifiers is studied to crosstalk the signal and cause instability of the amplifier.A suitable DC bias network is designed to eliminate the oscillation.This paper studies the advantages and disadvantages of resistor/reactance,feedback,balanced and distributed amplifiers.The design specifications of the ultra-wideband LNA studied in this paper are analyzed,and the appropriate topology is selected.Three ultra-wideband LNAs with C-band,X-band and K-band are designed.The 4-8GHz ultra-wideband LNA gain is 23±0.6d B,the noise figure is better than 1.4d B,the output P1 d B is greater than 12 d Bm,and the DC power consumption is less than 0.37 W.The 6-18 GHz ultra-wideband LNA noise figure has a maximum value of 1.9d B,a gain of 19±0.5d B,a P1 d B of more than 10.6d Bm,and a DC power consumption of 0.378 W.The 18-40 GHz ultra-wideband LNA noise figure is typically 4d B,the gain is 8.9±0.4d B,the P1 d B is greater than 9d Bm,and the DC power consumption is 0.24 W.The three ultra-wideband LNAs are self-biased,designed with the layout and joint simulation results to meet unconditional stability in the 0-300 GHz band. |
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