Modelling Aspects of Planar Multi-Mode Antennas for Direction-of-Arrival Estimation

TL;DR

This paper compares two modeling methods, AIT and WM, for accurately representing the radiation pattern of a planar multi-mode antenna, and evaluates their impact on direction-of-arrival estimation accuracy.

Contribution

It introduces and compares AIT and WM modeling techniques for multi-mode antennas, optimizing parameters for high-resolution EMF data interpolation.

Findings

Both models accurately interpolate EMF data.

Model errors influence DoA estimation bias.

Optimized parameters improve interpolation accuracy.

Abstract

Multi-mode antennas are an alternative to classical antenna arrays, and hence a promising emerging sensor technology for a vast variety of applications in the areas of array signal processing and digital communications. An unsolved problem is to describe the radiation pattern of multi-mode antennas in closed analytic form based on calibration measurements or on electromagnetic field (EMF) simulation data. As a solution, we investigate two modeling methods: One is based on the array interpolation technique (AIT), the other one on wavefield modeling (WM). Both methods are able to accurately interpolate quantized EMF data of a given multi-mode antenna, in our case a planar four-port antenna developed for the 6-8.5 GHz range. Since the modeling methods inherently depend on parameter sets, we investigate the influence of the parameter choice on the accuracy of both models. Furthermore, we evaluate the impact of modeling errors for coherent maximum-likelihood direction-of-arrival (DoA) estimation given different model parameters. Numerical results are presented for a single polarization component. Simulations reveal that the estimation bias introduced by model errors is subject to the chosen model parameters. Finally, we provide optimized sets of AIT and WM parameters for the multi-mode antenna under investigation. With these parameter sets, EMF data samples can be reproduced in interpolated form with high angular resolution.