Low-loss magnetodielectric spinel-ferrite based ceramic with constant permeability and permittivity in the UHF range - Université de Bretagne Occidentale Access content directly
Conference Papers Year : 2009

Low-loss magnetodielectric spinel-ferrite based ceramic with constant permeability and permittivity in the UHF range

Abstract

Present antennas are too large to allow satisfactory integration into such devices, and the present techniques used to reduce their size degrade the performances of the antennas [1]. The present study aims to investigate materials for electromagnetic applications in the UHF range. Actually, materials that show low electromagnetic signature, that is reduced impedance-matched to free space ( =1, with µ'=ε', and where µ' and ε' are real parts of relative permeability and permittivity), and a refractive index (n= ) large enough, could be useful to the design of antennas with reduced physical dimensions. Our laboratory synthesized spinel ferrite powders with the composition Ni0.5ZnxCo0.5-xFe2O4, using co-precipitation technique. From SEM, mean grain size is found to be ~50nm. Focusing on the composition with x=0.3, no relaxation phenomenon is found below 0.5GHz. Complex permeability and permittivity are almost constant in the range from 100MHz to 0.5GHz and equal to ~4.9+j0.15 (loss tangent~0.03) and ~4.8+j0.075 (loss tangent~0.015) respectively. The refractive index n is 4.8, and Z/Z0 is 1. Hysteresis loop (DC) shows initial permeability value that we ascribe to spin rotation phenomenon only. These EM performances can be advantageously compared with data from literature [3-5]: to date, to our best of knowledge, no such performances were reported in this frequency range and that by using spinel ferrites.
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Dates and versions

hal-00488963 , version 1 (14-06-2010)

Identifiers

  • HAL Id : hal-00488963 , version 1

Cite

Atul Thakur, Jean-Luc Mattei, Alexis Chevalier, Patrick Queffelec. Low-loss magnetodielectric spinel-ferrite based ceramic with constant permeability and permittivity in the UHF range. Hybrid Materials 2009, Mar 2009, Tours, France. pp.B2.1.75. ⟨hal-00488963⟩
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