Hybrid Modeling Of GaN HEMTs Small Signal Equivalent Circuit Based On Particle Swarm Optimization

As a third-generation semiconductor device,GaN HEMTs are not only an important part of power amplifier control circuit,but also an ideal RF power device in 5G wireless communication circuit in the era of millimeter-wave.Therefore,it is a very important requirement to embed precise SSMS model of GaN HEMTs in computer aided design(CAD)software and use it to design power amplifier control circuit and RF power circuit.The latest research on GaN HEMTs small signal model shows that the SSMS hybrid modeling method based on algorithm optimization has the advantages of high efficiency and accuracy.Therefore,the advanced particle swarm optimization(PSO)algorithm and direct extraction technology in the control system were used to conduct SSMS hybrid modeling of GaN HEMTs.The main contents of this paper are as follows:Firstly,by investigating the research status of small signal equivalent circuit modeling of GaN HEMT devices at home and abroad,the hybrid modeling method using particle swarm optimization algorithm is defined to conduct hybrid modeling of the devices.Then,according to the structure and properties of GaN HEMTs and the current application requirements of high frequency and high power,a GaN HEMTs small-signal equivalent circuit topology with19 parameters is proposed.At the same time,the principle and significance of elementary particle swarm optimization algorithm are expounded,and its superiority in solving constrained continuous or discrete design variables is proved.On this basis,the elementary particle swarm optimization(PSO)algorithm is improved,and the improved PSO algorithm is applied to extract the external parasitic parameters of the hybrid model.The external parasitic parameters of the small signal equivalent circuit model of GaN HEMTs were extracted by the hybrid technology of particle swarm optimization(PSO)and direct extraction.The specific process of parameter extraction by PSO algorithm is as follows: First,the S parameter of the device is measured under the cold field condition(the leakage voltage is 0V,the gate voltage is less than the threshold voltage),the total value of parasitic capacitance is extracted,and the search boundary is set for the PSO algorithm.Secondly,the S parameter of the device is measured under the condition of no bias,the parasitic capacitance is deembed,and the parasitic resistance and inductance are extracted.Thirdly,the S parameter of the model is simulated in cold field,and the error between the simulation and the measured S parameter is calculated.The whole process includes direct extraction technology,algorithm optimization,and error analysis to obtain the optimal solution of model parameters.The comparison between the results of particle swarm optimization(PSO)algorithm and similar work shows that the proposed method has a strong advantage in modeling speed.The comparison of S parameters between simulation and measurement shows that the hybrid modeling method can efficiently and accurately extract external parasitic parameters of GaN HEMTs in a wide range of frequency bands.Finally,the reliability of the hybrid model was verified.The intrinsic parameters of the device were extracted by direct extraction method,and the hybrid modeling of the device was carried out.The hybrid modeling method was applied to GaN HEMT devices with four gate widens of 2×50?m,8×125?m,16×250?m and 8×250?m,and the validity of this paper was verified by comparing the S parameters of model simulation in ADS with the measured S parameters.