A FDTD method for circuits on high-dielectric constant substrates

Most commercial computer aided design (CAD) software for microwave planar circuits is based on models of circuit elements that are valid for a limited range of dielectric constant. Therefore designing miniaturized circuits on high dielectric constant substrates requires a full wave analysis approach. This category of substrates mainly contains high dielectric ceramics stable with temperature and the substrates for high temperature superconducting (HTS) thin films. Despite the advances in the finite-difference time domain (FDTD) method applied to planar circuits the practical aspects of the case of high dielectric constant substrates have not been sufficiently studied. This paper presents a FDTD method which can be effectively applied for practical planar circuits on high dielectric substrates. The extension of the FDTD method to this case is very important for the design of high temperature superconducting devices for mobile and satellite communications.