Via hole modeling in Ka-band MMIC

Via hole in the monolithic microwave integrated circuit (MMIC) is very critical for the circuit performance in high frequency. Based on Maxwell equation by Ansoft HFSS simulation, the 3D electromagnetic (EM) model of conical via hole is established in Ka-band GaAs MMIC application. The relationship between the structural parameters and performance of circuit is investigated. Through the simulation, length and width of microstrip line connected to the via hole can make a great influence on the S parameter of via hole. Based on the fabricated chip, the model parameters matched the measurement results well.