Citation: Przybyl, W.; Mazurczuk, R.; Kalinowski, A.; Bogdanowicz, K.A. Gaussian Model of Anti-Radar Properties for Coatings Based on Carbonyl Iron Powder. Materials 2023, 16, 3050. https://doi.org/ 10.3390/ma16083050 Academic Editor: Nicholas Fantuzzi Received: 7 March 2023 Revised: 30 March 2023 Accepted: 11 April 2023 Published: 12 April 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). materials Article Gaussian Model of Anti-Radar Properties for Coatings Based on Carbonyl Iron Powder Wojciech Przybyl 1, * , Robert Mazurczuk 1 , Artur Kalinowski 2 and Krzysztof A. Bogdanowicz 1, * 1 Military Institute of Engineer Technology, Obornicka 136, 50-961 Wroclaw, Poland 2 Faculty of Mechatronics and Mechanical Engineering, Kielce University of Technology, Al. 1000-lecia P. P. 7, 25-314 Kielce, Poland * Correspondence: przybyl@witi.wroc.pl (W.P.); bogdanowicz@witi.wroc.pl (K.A.B.) Abstract: The article presents the Gaussian model of the electromagnetic radiation attenuation properties of two resin systems containing 75% or 80% of a carbonyl iron load as an absorber in the 4–18 GHz range. For the attenuation values obtained in the laboratory, mathematical fitting was performed in the range of 4–40 GHz to visualize the full curve characteristics. The simulated curves fitted up to a 0.998 R 2 value of the experimental results. The in depth analysis of the simulated spectra allowed a thorough evaluation of the influence of the type of resin, absorber load, and layer thickness on reflection loss parameters such as the maximum attenuation, peak position, half-height width, and base slope of the peak. The simulated results were convergent with the literature findings, allowing a much deeper analysis. This confirmed that the suggested Gaussian model could provide additional information, useful in terms of comparative analyses of datasets. Keywords: radar absorption; carbonyl iron coatings; military application; epoxy resin 1. Introduction Today’s armed conflicts, especially full-scale ones, confirm that the use of armored weapons, gun and rocket artillery, and aviation is essential to achieve operational and tactical goals. The basis for the effectiveness of these types of weapons is effective recon- naissance [1]. Thanks to the widespread use of various sensors, recognition is carried out with a wide range of electromagnetic radiation (Figure 1). Figure 1. Scheme of the spectrum of electromagnetic radiation. Optical and thermal bands are usually used for closer ranges, whilst radar bands are commonly used for longer ranges. The radar range covers wavelengths from a few millimeters to several meters and is divided into a number of bands, depending on the propagation properties (Table 1). Materials 2023, 16, 3050. https://doi.org/10.3390/ma16083050 https://www.mdpi.com/journal/materials