Distributed Amplifier Circuit Design Based On 0.18?m CMOS Process

With the rapid development of wireless broadband communication technology,broadband amplifiers have more important value in the field of wireless broadband communication.Distributed amplifiers are widely used in wideband amplification systems due to their wide operating frequency range,moderate gain,and good matching.This paper studies the design and optimization of monolithic distributed amplifiers based on the0.18?m CMOS process.The specific research work is as follows:Firstly,a non-uniform four-stage distributed amplifier based on tapped inductor was designed using 0.18?m CMOS process.The distributed amplifier uses a tapped inductor to replace the traditional two-port inductor,which reduces the number of on-chip inductors,thereby reducing chip area,and maintains good port impedance matching characteristics.The simulation results show that the amplifier gain is 8.6 d B,the gain flatness is±1.25 d B,and the layout area is(1.1×0.59)mm~2in the range of 1.48?15.5 GHz.Then,the genetic algorithm was used to optimize the distributed amplifier in Python language,and the inductance of the transmission line was optimized based on the circuit structure of the gain unit,so that the gain of the circuit was maximized while maintaining impedance matching.The comparison of algorithm optimization and circuit simulation results shows that the S-parameters at10 GHz have little difference under different impedance matching conditions,and the error is less than 0.9 d B.Finally,a 0.18?m CMOS process is used to design a uniform distributed amplifier with modulation function.Utilizing the structural characteristics of the distributed amplifier circuit,the multi-ary modulation function of the amplifier is realized by adding three groups of switches,that is,the octal modulation is used to achieve eight changes in the carrier signal amplitude while maintaining good impedance matching characteristics.Simulation results show that the distributed amplifier with modulation function has an input and output return loss of less than-10 d B in the range of 1.938?22.43 GHz,and the circuit can perform octal amplitude modulation on signals with a transmission rate of 1.2 Gb/s.The energy consumption per bit is 16.78 pJ,and the circuit area is(1.8 × 0.52)mm~2.