needles in that direction, whereas the lower connectivity of the metallic phase in all other directions delays the onset of percolation in those directions. As f increases, percolation Ε½ . occurs last in any direction perpendicular to u z . In Figure t 3, the intertransition f-regime is most clearly evident as 0.4 Q f Q 0.6 in the plot of R , which becomes virtually LR constant at a high magnitude for f R 0.6.
Although only two different absorbing-dielectric-to-metal transitions are evident in the plots of β and β in Figure 3 a b because of the assumption that β s β , three different tranc a sitions will occur for a metallic TFHBM for which β / β .
c a
As f will increase from 0, the first transition will be exhibited by β . The second and third transitions will be located at b higher values of f as a consequence of the columnar microstructure being locally aciculate. The latter two transitions will coincide for columns with circular cross sections, but not for noncircular columns. However, the reflection of normally incident plane waves by metallic TFHBM half spaces and layers will show evidence of only two transitions because . . only: 1 β and 2 the combination β or β and β enter the c d a b
Ε½ . Ε½ . expressions 10 α 14 . We also conclude from the presented results that metallic TFHBM with only low metallic volumetric fractions appear desirable if the aim is to exploit the CBP for a certain application.