| Since entering the 21 st century,China has made breakthroughs in 5G technology research.Compared with today’s mainstream 4G mobile communication,5G network has a larger communication capacity and faster data transmission rate.Rf front-end is an important part of wireless communication system.Its technical bottleneck is mainly the low-noise amplifier(LNA),Mixer,etc.These components largely determine the performance of the receiving system.However,transistor voltage and current margins and high-frequency parasitic effects limit the overall performance of LNAs and mixers,which cannot meet the requirements of future communication systems.Therefore,the study of low-noise amplifiers and mixers in RF front-end components is of great significance.In this study,Ga As pseudocrystalline high electron mobility transistor(p HMET)advanced process was adopted and the design methods of broadband low-noise amplifier and high-isolation mixer were explored.In this study,the main results were obtained as follows:1)For the demand of civil communication system,an ultra-wideband low-noise amplifier was designed on 0.15 μm Ga As process using cascode topology,thus completing schematic simulation,EM simulation and flowing chip and subsequent batch testing.During the design process,the frequency response characteristics and low-frequency stability of the cascode amplifier structure were discussed by deriving the transfer matrix.The R-C negative feedback structure and the selection of a suitable offchip RF choke device were adopted to improve the low-frequency stability of the amplifier.A suitable output matching structure was selected using load-pull while the linearity and input return loss of the LNA were optimized.Finally,the frequency of ultra-wideband LNA ranges from 0.02 to 6 GHz with the average gain of 21 d B and the gain flatness of 1 d B.The simulation results shows that the lowest noise coefficient was 0.6 d B.The low-noise amplifier also had good linearity.Its output 1 d B compression point was 21 d Bm,the output IP3 was 33.5 d Bm,and the chip size was 1.3 mm × 1.1mm × 0.1 mm.2)For electronic countermeasures and monitoring applications,a high-frequency ultra-wideband low-noise amplifier was designed on a 0.1μm Ga As process using a common-gate structure as the input stage,and schematic simulation,layout EM simulation and flow of the chip were completed.During the design process,the potential instability region of the common-gate structure was investigated by small-signal equivalent analysis and combined with simulation software,and the attenuation and feedback structure was used to avoid it.At the same time,the common-gate structure and load modulation technology were used to improve the high frequency gain.The final design of the ultra-wideband low-noise amplifier had a frequency range of 8 to 50 GHz,an average gain of 20 d B in the bandwidth,a gain flatness of 1 d B,a minimμm noise coefficient of 4 d B,an output 1 d B compression point of 15 d Bm,and a chip size of 1.3 mm × 1.1 mm × 0.05 mm.3)For the satellite communication field,a passive balun with high amplitude phase coherence over ultra-wideband was uesd and a passive mixer was designed in 0.25μm Ga As process.During the design process,the passive balun in this work was compared with the commonly-used Marchand balun,and its characteristics of good amplitude-phase coherence and low fluctuation with port impedance variation were verified,thus designing a passive double-balanced mixer with high-isolation and highlinearity.The final design of the mixer RF operating frequency range was 0.7 to 1.1GHz,the local oscillator operating frequency range was 0.8 to 1.2GHz,the frequency loss was 9 d B,the LO to IF isolation was greater than 20 d B,the LO to IF isolation was greater than 40 d B,the input P1 d B was greater than 22 d Bm,the input IP3 was greater than 3 1d Bm,and the chip size was 3.5 mm × 3.5 mm×0.1 mm. |
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