Topology optimization of Optical and Millimeter-wave Circuit Devices Using Finite Element Method and Function Expansion Method

To develop optical and millimeter-wave circuit devices with desired transmission properties, various kinds of design optimization methods have been proposed so far. Among them, topology optimization, which can automatically generate device structures with arbitrary topology, is the most powerful design method. We have originally developed function-expansion-based topology optimization technique and have applied it to design of optical and millimeter-wave circuit devices. In this paper, we present this method in view of some practical aspects.