Topology Optimization of Metallic Waveguides Loaded with Ferrite

Abstract

This paper presents a structural design method of metallic waveguides loaded with ferrite material using the level set-based topology optimization method. Metallic waveguides are widely used to control the wave propagation, especially in microwave application, such as waveguide filters, T-junctions. Ferrite materials display a frequency-dependent permeability due to magnetic resonance phenomenon that can be altered by changing the magnitude of an externally applied DC magnetic field. Thus, metallic waveguides with ferrite inclusions are expected to offer some advantages, such as tunable operating frequencies. Anisotropic permeability tensor of ferrite is modeled using Landau-Lifshitz model in analysis. The optimization problem is formulated as to maximize the transmission power at prescribed frequencies using S-parameters. To confirm the validity and utility of the presented method, we apply it to the waveguide filter design problem and T-junction design problem, and the results show that the presented method successfully finds optimized configurations that maximize transmission power of waveguides.