Investigation of return loss of 15 bonding wires fabricated on a test board by FDTD method

Return losses of 1~15 bonding wires fabricated on a test board for RF and microwave circuit applications are studied by the finite-difference time-domain (FDTD) method. In order to fit a cell size of 0.25 mm, an equivalent material obtained by the effective material property technique is applied to model bonding wires, the top metallic patch, and the bottom metallic layer. Simulation results of return losses obtained by the FDTD method are presented and compared with those obtained by the HFSS software at frequencies of 0.04~6 GHz. It is found that simulation results calculated by the FDTD method make a good agreement with those obtained by the HFSS software. It is also found that the return loss of bonding wires can be improved by using multiple wires placed in parallel in bonding wire arrays.