INCREASE OF THE SENSITIVITY AND ACCURACY OF QUASIOPTICAL METHODS OF MEASURING THE ELECTROMAGNETIC RESPONSE IN THE MILLIMETER WAVELENGTH RANGE

摘要

The quasi-optical method [1] is promising for investigation of the material parameters and electromagnetic properties of sheet materials in millimeter and submillimeter wavelength ranges. The measurable parameters here are the complex reflectance (R) and transmittance (T) that depend on the magnetodielectric layer thickness (d) and values of the complex permeability μ = μ′ – iμ″ and permittivity ε = ε′ – iε″. In the plane wave approximation, expressions for the reflectance and transmittance can be written in the form R=ρ(1-e~(-2iγd))/1-ρ~2e~(-2iγd),T=(1-ρ~2)e~(-iγd)/1-ρ~2e~(-2iγd)(1)Here ρ = (Z-1) / (Z+1) is the reflectance from the magnetodielectric open face, Z =(μ/ε) is the wave impedance,γ = k_0(με) is the electromagnetic wave propagation constant in the magnetodielectric layer, k_0 = ω/c is the wave number in the free space, and ω = 2πf is the circular frequency of the electromagnetic process.