Assessment of FDTD accuracy in the compact hemielliptic dielectric lens antenna analysis

TL;DR

This paper evaluates the accuracy of FDTD methods in analyzing small dielectric lens antennas, highlighting limitations near resonances and confirming adequacy for practical mm-wave applications.

Contribution

It provides a systematic assessment of FDTD accuracy against boundary integral methods for dielectric lens antennas, identifying resonance-related inaccuracies and practical applicability.

Findings

FDTD accuracy is limited near half-bowtie resonances.

Denser meshing improves accuracy but is constrained by boundary conditions.

FDTD is sufficiently accurate for small-size hemielliptic lenses in mm-wave applications.

Abstract

The objective of the paper is to assess the accuracy of a standard FDTD code in the analysis of the near and far-field characteristics of two-dimensional models of small-size dielectric lens antennas made of low or high-index materials and fed by the line sources. We consider extended hemielliptic lenses and use the Muller boundary integral equations method as a suitable reference solution. Inaccuracies of FDTD near so-called half-bowtie resonances are detected. Denser meshing reduces the error of FDTD only to a certain level determined by the type of absorbing boundary conditions used and other fine details of the code. Out of these resonances, FDTD code is demonstrated as capable of providing sufficient accuracy in the near and far-field analysis of small-size hemielliptic lenses typical for the mm-wave applications.