Enhanced Microwave Magnetic and Attenuation Properties for Barium Ferrite Flaky-Filler Composites

Microwave reflection characteristics as well as high frequency magnetic and dielectric properties have been studied for composites filled with Z-type barium ferrite flakes. Results show that both μ
₀
^'
and μ
_max
^''
are enhanced, while ε
^'
is almost the same, as compared to conventional composites. Therefore, the percentage bandwidth
W
_P
is significantly widened for the flaky-filler composites;
W
_P
achieves 130%-150% for reflection loss
RL
<; -10 dB. In addition, for all composites, two matching frequencies are found. The first matching frequency is attributed to the quarter-wavelength resonator and the second matching frequency is mainly controlled by the values of both μ
^'
(
f
) and ε
^'
(
f
) , where μ
^'
/ε
^'
=1/3 .