Estimating Relative Permittivity of Material Filled in Waveguide Using Compressed Sensing

This paper proposes a compressed-sensing based method to estimate the relative permittivity of a material filling up a waveguide. Two monopole antennas are placed at both ends of the waveguide, and the S-parameters between the antennas are measured. Relative permittivity is estimated by applying compressed sensing to the frequency characteristics of the S21, where two-dimensional bins for distance and relative permittivity are defined to find unknown parameters. The simulation result showed that this technique can estimate the relative permittivity within a 7.3% error.