Electromagnetic behavior of radar absorbing materials based on Ca hexaferrite modified with Co-Ti ions and doped with La
doi: 10.5028/jatm.2009.0102255263

Valdirene Aparecida da Silva
Institute of Aeronautics and Space
São José dos Campos - Brazil
valapsilva@yahoo.com.br

José Jesus Pereira
University of Taubaté
Taubaté – Brasil
jesusp_99@yahoo.com.br

Evandro Luís Nohara
University of Taubaté
Taubaté – Brasil
evandro@unitau.br

Mirabel Cerqueira Rezende*
Institute of Aeronautics and Space
São José dos Campos - Brazil
mirabel@iae.cta.br

*author for correspondence

Abstract:

Radar Absorbing Materials (RAM) are compounds that absorb incidental electromagnetic radiation in tuned frequencies and dissipate it as heat. Its preparation involves the adequate processing of polymeric matrices filled with compounds that act as radar absorbing centers in the microwave range. This work shows the electromagnetic evaluation of RAM based on CoTi and La doped Ca hexaferrite. Vibrating Sample Magnetization analyses show that ion substitution promoted low values for the parameters of saturation magnetization (123.65 Am²/kg) and coercive field (0.07 T) indicating ferrite softening. RAM samples obtained using different hexaferrite concentrations (40-80 per cent, w/w) show variations in complex permeability and permittivity parameters and also in the performance of incidental radiation attenuation. Microwave attenuation values between 40 and 98 per cent were obtained.

Keywords:

Radar absorbing materials, Electromagnetic characterization, Hexaferrite, Reflectivity.