Extracting an accurate model for permittivity from experimental data : Hunting complex poles from the real line

TL;DR

This paper presents a versatile method for accurately modeling material permittivity from experimental data using minimal parameters, applicable across various materials and frequency ranges, with demonstrated numerical examples.

Contribution

It introduces a general, material- and frequency-independent procedure for causal permittivity fitting with few parameters, improving upon existing methods.

Findings

High accuracy in permittivity fitting demonstrated

Method applicable across different materials and frequency ranges

Compared favorably to existing expressions in literature

Abstract

In this letter, we describe a very general procedure to obtain a causal fit of the permittivity of materials from experimental data with very few parameters. Unlike other closed forms proposed in the literature, the particularity of this approach lies in its independence towards the material or frequency range at stake. Many illustrative numerical examples are given and the accuracy of the fitting is compared to other expressions in the literature.