5 GHz the regression equations above estimate propagation loss at 8.
They suggest that granite aggregate reduces propagation loss by a factor of 2, roughly the amount of volume filled.
So unlike bulk water, which undergoes a drastic reduction in propagation loss in the microwave range when it freezes to ice crystals, the water absorbed in concrete is clearly too segmented and has too many interactions with the polycrystallite surfaces and embedded salts to actually form crystals.
Furthermore, the propagation loss of the fabricated polycarbonate slab waveguide was also measured by Prism-Coupler (SPA4000) for TE mode at 632.
As is known, the quality of the margin part of film is poorer than the central part because of the spin-coating, leading to the high propagation loss as well.
The relation between scattered light intensity and propagation loss can be expressed as the following (20):
Therefore, the propagation loss of the optical waveguide can be nondestructively measured by monitoring the intensity of the scattered light along the propagation direction and fitting this variation with a monoexponential formula.
From the linear least-square fit of this plot, the propagation loss coefficient for the central part of the slab waveguide was measured to be 0.