Approximation of the Range Ambiguity Function in Near-field Sensing Systems

Fuente: arXiv
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Main Authors: Wachowiak, Marcin, Bourdoux, André, Pollin, Sofie
Format: Preprint
Published: 2025
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author Wachowiak, Marcin
Bourdoux, André
Pollin, Sofie
author_facet Wachowiak, Marcin
Bourdoux, André
Pollin, Sofie
contents This paper investigates the range ambiguity function of near-field systems where bandwidth and near-field beamfocusing jointly determine the resolution. First, the general matched filter ambiguity function is derived and the near-field array factors of different antenna array geometries are introduced. Next, the near-field ambiguity function is approximated as a product of the range-dependent near-field array factor and the ambiguity function due to the utilized waveform and bandwidth. An approximation criterion based on the aperture-bandwidth product is formulated, and its accuracy is examined. Finally, the improvements to the ambiguity function offered by the near-field beamfocusing, as compared to the far-field case, are presented. The performance gains are evaluated in terms of resolution improvement offered by beamfocusing, peak-to-sidelobe and integrated-sidelobe level improvement for a few popular array geometries. The gains offered by the near-field regime are shown to be range-dependent and substantial only in close proximity to the array.
format Preprint
id arxiv_https___arxiv_org_abs_2509_22423
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Approximation of the Range Ambiguity Function in Near-field Sensing Systems
Wachowiak, Marcin
Bourdoux, André
Pollin, Sofie
Signal Processing
This paper investigates the range ambiguity function of near-field systems where bandwidth and near-field beamfocusing jointly determine the resolution. First, the general matched filter ambiguity function is derived and the near-field array factors of different antenna array geometries are introduced. Next, the near-field ambiguity function is approximated as a product of the range-dependent near-field array factor and the ambiguity function due to the utilized waveform and bandwidth. An approximation criterion based on the aperture-bandwidth product is formulated, and its accuracy is examined. Finally, the improvements to the ambiguity function offered by the near-field beamfocusing, as compared to the far-field case, are presented. The performance gains are evaluated in terms of resolution improvement offered by beamfocusing, peak-to-sidelobe and integrated-sidelobe level improvement for a few popular array geometries. The gains offered by the near-field regime are shown to be range-dependent and substantial only in close proximity to the array.
title Approximation of the Range Ambiguity Function in Near-field Sensing Systems
topic Signal Processing
url https://arxiv.org/abs/2509.22423