| Summary: | 碩士 === 元智大學 === 通訊工程學系 === 95 === Return losses of large number of bonding wires structures for RF and microwave circuit applications are studied with the finite-difference time-domain (FDTD) method. The FDTD model is validated first by comparing the simulation results of bonding wires fabricated on a test board with those obtained by the HFSS model with finite element method (FEM) and measurements using a vector network analyzer at 0.04~6 GHz band. After checking its accuracy, the FDTD method is used to investigate the return loss for large numbers of bonding wires with numerous geometrical parameters. From simulation results, it is found that the return loss of bonding wires can be improved by using multiple wires placed in parallel in the bonding wire array. It is also found that operation frequency shifts of bonding wire array can be achieved by changing the wire numbers in bonding wire array. It is also revealed that the return loss of bonding wire structures is a function of the bonding wire geometry such as the spacing between adjacent wires, wire number, wire height above the substrate, and wire length. In order to predict the electrical performance of high-power RF amplifiers with large numbers of bonding wires, a ??-type equivalent circuit is proposed for modeling 1~15 short bonding wires. Elements in the equivalent circuit are obtained by employing a curve fitting technique together with Newton’s Iteration method to fit the equivalent circuit’s series impedance and shunt admittance responses obtained from transforming the S-parameters computed by HFSS. This equivalent circuit with series impedance and shunt admittance is a function of frequency and wire number.
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