Material

2 GHz

4 GHz

Reference

ε'

ε"

ε'

ε"

0.01 wt% CNT + epoxy + CoO (3.5 mm thick)

3.5

0.30

3.5

0.25

[26]

0.01 wt% CNT + epoxy + CuO (3.5 mm thick)

4.2

0.40

4.1

0.41

[26]

U-type barium hexaferrite-epoxy composite

4.5 - 5.2

<0.30

4.7 - 5.0

<0.30

[4]

α-Fe₂O₃ + OPEFB fiber + PCL multilayered composite (25 wt%, 6 mm thick)

3.7

0.54

3.5

0.64

This study