Empirical relationship between δ and ferromagnetic resonance frequency in hexagonal ferrite‐based microwave absorbing paint

This paper reports the development of an empirical relationship between δ and f r for a Mn‐Ti‐substituted barium hexagonal ferrite‐based paint. The previously available empirical relation 1 is not valid beyond δ = 1.1, after which anomalous results are being obtained. An attempt has been made to overcome this limitation by preparing different samples of ferrite using δ = 1.6, 1.7, 1.8, 1.9, 2.7, and 3.1 and experimentally determining their respective complex permeability. A plot has been obtained between δ and f r (resonant frequency) and, using the curve fitting techniques, a best‐fitted curve was found. From this an empirical relation could easily be derived. This relation was found to be valid for a wide frequency range from 8 GHz to 18 GHz. Results show that a maximum absorption on the order of 8 dB can be obtained at the resonance frequency of the various samples, thus successfully validating the relation. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 352–355, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10762