Fast Modeling and Design of Marchand Balun Based on Two-Conductor Coupled Line*

In view of the low efficiency and time consuming problem of the parameter extraction of the Marchand balun，a fast method for extracting the parameters of the model is proposed. In traditional ways，the model parameters must be extracted again when the line width，space or length are changed. Therefore，the electromagnetic（EM）simulation can be time consuming and wasting of resources. Based on the c- mode and π- mode theory，the model of Marchand balun is built in the first. The relationship between the model parameters and the size of balun is studied by analyzing a large number of simulated data. Then a series of dependent equations are fit out in Matlab. By using such equations，the model parameters can be calculated quickly instead of extracting from EM simula? tion. Thus，the design period for balun can be reduced. To verify the model，a 2.4GHz Marchand balun is designed on PCB board. Com? pared with the measurement results，the model shows good accuracy and can be a fast solution for Marchand balun design.