Propagation of electromagnetic waves in biological media: Refraction at interfaces

Wireless monitoring of the biological object state at microwave frequencies: A review

“…Therefore, the damping ratio of the signal determined by taking integrals in (6) and (7) equals A [dB] = 22.2 dB with regard to propagation losses in the first medium. At smaller values of the permittivity of medium 1, the limiting angles of incidence are higher [8] (Fig. 6).…”

“…Also, the results were presented in the European Microwave Week Conference (EuMC) [www.eumweek. com/conferences] and published in Russian and foreign journals [8,10,17,54,65].…”

“…Electrical component E z (y, z) is proportional to the derivative of f(y) with respect to y. The boundary condition for the electrical component on the metal surface (y = 0) has the form E z (y, z) y = 0 = 0, and function f(y) is given by (9) According to (8) and (9), the field components in the h-thick dielectric layer and in air (y ≥ h) have the form for (10) and for (11) From (10) and (11), we obtain, with regard to the continuity of the field tangential components at the interface with y = h, an equation for the transverse wavenumbers, (12) In addition, from the wave equation, we find a relationship between the longitudinal and transverse wavenumbers, (13) where k = ω . Substituting (13) into (12) yields a dispersion relation in k z [10], (14) From (13) and (14) one can find the transverse wavenumbers and longitudinal wavenumber k z , respectively.…”

“…It is assumed that the wave propagates in the z direction, the dielectric layer is sufficiently long in the x direction, and the field distribution is independent of coordinate x (that is, ∂/∂x = 0). The permeability of the EM wave is represented in the form (8) where function f(y) depends on boundary conditions imposed on the structure and k z is an arbitrary wavenumber. Electrical component E z (y, z) is proportional to the derivative of f(y) with respect to y.…”

“…Hence, the propagation of spherical EM waves that are obliquely incident on the interface between two insulators far away from the source can be described in simpler terms, i.e., in terms of plane waves. Refraction angle ψ of a plane EM wave is related to its angle of incidence θ as [8,9] …”