Generalized Scattering Matrix Framework for Modeling Implantable Antennas in Multilayered Spherical Media

TL;DR

This paper introduces a fast, versatile modeling framework for antennas in multilayered spherical media, enabling rapid design and analysis of implantable biomedical antennas and radome systems.

Contribution

A unified scattering matrix approach that decouples antenna characterization from medium properties, allowing quick reevaluation for various spherical media configurations.

Findings

Achieves significant speedups over traditional methods.

Accurately models multilayer and anisotropic media.

Validated with extensive comparisons to full-wave solutions.

Abstract

This paper presents a unified and computationally efficient framework for modeling antennas embedded in spherically stratified media, applicable to implantable biomedical antennas and radome-enclosed systems. The method separates the characterization of the radiator from that of the surrounding medium by combining the antenna's free-space generalized scattering matrix (GSM) with a set of extended spherical scattering operators (SSOs). This decoupling enables rapid reevaluation under arbitrary changes of the spherical medium without re-simulating the antenna, yielding orders-of-magnitude speedups over traditional DGF-based MoM approaches. The SSO formulation accommodates multilayer, radially inhomogeneous, and radially uniaxial anisotropic profiles, and the GSM can be obtained from diverse numerical solvers or far-field data, supporting array-level synthesis and measurement-driven modeling. Extensive examples confirm excellent agreement with full-wave and DGF-based solutions, demonstrating the accuracy, generality, and practical versatility of the proposed framework.