Research Of Ultra-Wideband Low Noise Amplifier Based On Coupled Lines And Negative Feedback

The development trend of wireless communication affects the development of RF transceiver systems towards wider bandwidths and higher frequencies.As the core module of RF receivers,the design of wideband low-noise amplifiers is of great significance for the implementation of wideband receivers.Thesis mainly focuses on the design of broadband low-noise amplifiers,starting with an introduction to the domestic and international research progress in this field.The basic principles of broadband low-noise amplifier design are then elaborated,including the fundamentals of low-noise amplifier design and some common broadband structures.Finally,four ultra-wideband low-noise amplifier chips were designed based on the0.15μm Ga As p HEMT process,all employing distributed architectures.The research work in Thesis can be summarized as follows:1.The first amplifier uses a common-source configuration as a distributed basic gain unit,utilizing coupled lines for gate-drain coupling to reduce the impact of transistor parasitic capacitance on signal transmission.This expands the amplifier bandwidth and reduces the high-frequency noise figure.The amplifier layout achieves matching from 1to 40 GHz and demonstrates a gain level of 9.9?0.7d B within this frequency range,with minimal gain variation.The noise figure within the frequency band ranges from 1.3 to3.1d B,and at 40 GHz,the noise figure is only 2.6d B,with an output 1d B compression point of 9.4-13.6d Bm.2.The second amplifier cascades two units of the first amplifier,improving the overall gain level.It also incorporates an RC negative feedback structure and an input gate terminal resistor for amplifier input matching,thereby improving the low-frequency noise figure.The amplifier layout achieves matching from 1 to 40 GHz and attains a gain level of 19.6?1d B within this frequency range.The noise figure within the frequency band ranges from 1.5 to 2.6d B,with a decrease of approximately 0.5d B in the lowfrequency noise figure compared to the first amplifier.The output 1d B compression point is 8.9-13.4d Bm.3.The third amplifier utilizes a common-source common-gate structure as the basic gain unit,replacing the gate input terminal resistor with an active feedback terminal to enhance input matching and significantly reduce the low-frequency noise figure.The amplifier layout achieves matching from 0.6 to 35 GHz and attains a gain level of15.2?1.3d B within this frequency range.The noise figure within the frequency band ranges from 1.2 to 3d B,with a low-frequency noise figure below 1.8d B in the 0.6-10 GHz range.Compared to the traditional structure,the low-frequency noise figure is improved,and the output 1d B compression point is 10.4-13.5d Bm.4.The fourth amplifier also adopts a common-source common-gate structure as the basic gain unit,employing an RC negative feedback structure and an input gate terminal resistor for input matching,thus improving the low-frequency noise figure of the amplifier.The amplifier layout achieves matching from 0.6 to 35 GHz and attains a gain level of 15?1d B within this range.The noise figure within the frequency band ranges from 1.3 to 3.1d B,with a noise figure below 2d B in the 0.6-10 GHz range.The lowfrequency noise figure is improved,and the output 1d B compression point is 11-13.2d Bm.