Design Of GaAs PHEMT Wideband Low NoiseAmplifier Based On The Feedback Topology

With the development of information society and the explosive growth of information transmission,broadband wireless communication technology has become one of the essential trends.As a key component of RF receiver front-end,the wideband technology of low-noise amplifier design and manufacture has become a research hotspot.In this paper,based on the negative feedback broadband topology and combined with the parasitic capacitance offset technique,we design two different band broadband low noise amplifiers,which are successfully taped out.Firstly,the article introduces the series feedback model and parallel negative feedback model of common source amplifier.The theoretical formula to determine the theoretical value of each device in the series-parallel feedback amplifier model is derived by using the parasitic capacitance offset technique,which provides theoretical guidance for the simulation design of the wideband amplifier.We also propose an improved active bias circuit,which has temperature compensation and voltage fluctuation compensation,ensuring the working stability of LNA in severe environment.Therefore,with the use of ADS(Advanced Design System),an EDA tool of Agilent Company,we complete the circuit design,Momentum simulation and layout design of UHF wide-band LNA chip and C band broadband low noise amplifier MMIC chip.In addition,we design the test substrate,evaluation board for the two broadband low-noise amplifier chips debugging and testing.Finally,the two chips are packaged into a complete module with the SIP package technology.With the power supply voltage of 3.3 V,we test two chips.The result shows UHF band broadband low noise amplifier operating from 0.2 GHz to 2.5 GHz,covering GSM,GPS,and 2.4 G WLAN and other frequency bands.The operating band gain is over 15 dB while gain flatness is about 1.3 dB.The noise figure is less than 1.3 dB,and the total size of amplifier is 3 mm x 3 mm x 1 mm.The result also shows C-band broadband low-noise amplifier chip operating from 4.8 GHz to 5.8 GHz,covering multiple bands of 5.8 GHz WLAN technology.The chip gain is over 11.6 dB,the gain flatness is 1 dB,the noise figure is less than 1.2 dB and the total size is 3 mm×3 mm×1 mm.