Efficient optimal design of mosaic-like PPDW devices for THz application using the adjoint variable method.

In the development of THz-wave circuits, parallel plate dielectric waveguide (PPDW) is a promising platform and recently some fundamental devices have been reported. In order to realize high performance PPDW devices, optimal design methods are crucial and as out-of-plane radiation does not occur in PPDW, mosaic-like optimal design appears to be appropriate for PPDW platform. In this paper, we present a novel and efficient mosaic-like design approach based on gradient method with adjoint variable method (AVM) to realize high performance PPDW devices for THz circuit applications.