Modeling of integrated microstrip bend structures on silicon substrates up to 110 GHz

This work describes an equivalent circuit model for microstrip bend structures on silicon substrates targeted for integrated millimeter wave circuits. The values of the lumped elements are extracted from 3D electromagnetic simulations for three different bend shapes and strip widths in the range of W=5-50 µm up to 110 GHz. The width dependence of the element values are derived using curve fitting algorithms and the integration of the model equations in circuit simulation environments is demonstrated. The developed model is compared with measurement results of several bend test structures fabricated in a high performance 0.25 µm SiGe BiCMOS technology. Excellent agreement has been obtained.