Eigenanalysis of Multiferroics Using Finite-Difference Frequency Domain for Shielded Structures

This article introduces a novel multiphysics β-formulation eigenanalysis simulator designed for shielded multiferroic devices/transmission lines. The finite-difference frequency-domain (FDFD) method was selected to simultaneously address both the electromagnetic (EM) and elasto-mechanic (EL) aspects of the problem. Building on previous work, the mathematical formulation has been expanded and implemented using a finite-difference scheme to solve the coupled Maxwell and Newton equations through the constitutive relations of piezoelectric and piezomagnetic materials. Following the validation of the simulator, two types of printed planar transmission lines were tested for their potential use as tunable phase shifters or isolators. The ultimate goal is to utilize the proposed method as an initial design tool for electronically tunable microwave devices. Notably, this marks the first instance in the literature where a β-formulation eigenanalysis approach has been applied to arbitrary planar multiferroic structures, offering new insights and contributing to a deeper understanding of this complex multiphysics phenomenon.