Research On Compact Model Of RF Transistor Based On Physical Characteristics

With the rapid development of integrated circuits,Si Ge HBTs are characterized by their short transit time,low temperature performance,large current gain,low cost,and compatibility with traditional silicon processes.It is widely used in radar systems and wireless communication circuits.Therefore,the modeling of RF transistor Si Ge HBT high-frequency noise model has always been a hot research topic.In order to greatly improve the accuracy of the model,people usually consider the physical characteristics of the transistor while modeling.However,the Si Ge HBT high-frequency noise model containing physical characteristics cannot be directly used by the simulation software because of its complex structure,which makes the high-frequency noise model has a very limited application.So in order to overcome this problem,we need to simplify the model to get its compact model,and then use Verilog-A language to embed it into the simulation software.This not only improves the practicality of the noise model,but also allows the model designer to greatly reduce the time required for the model to be updated later.This paper focuses on the Si Ge HBT high frequency equivalent noise compact model with non-quasi-static effect.The main content can be divided into the following aspects:The Si Ge HBT small-signal equivalent circuit model is the basis for establishing high frequency equivalent noise for Si Ge HBTs.Therefore,we determine the equivalent circuit structure of the non-quasi-static Si Ge HBT firstly,and then improve the existing Van vliet model.Finally,we determine the high frequency equivalent noise model of Si Ge HBT.Since the noise model can not be directly embedded in the simulation software by using Verilog-A language,we introduce the model parameters in the model,and the model is converted and approximated by using the noise power spectral density matrix to get the compact model.Finally,Verilog-A language is used to program the compact model.The compiled program is embedded into the simulation software ADS to simulate the four-noise parameters.The simulation results are compared with the results of the four noise parameters calculated based on the exact physical model and thesimulation results of the four noise parameters of several common models to verify the practicability and accuracy of the compact model.