A broadband free-space dielectric properties measurement system at millimeter wavelengths

Abstract

A free-space system operating in the 75 GHz to 95 GHz range for measurement of the complex permittivity of matter is presented. The complex transmission coefficient of a parallel polarized quasiplane wave through a planar sample is determined for different incidence angles. The quasiplane wave is realized by a collimated Gaussian beam. The complex permittivity is subsequently calculated from the measured data by applying a nonlinear least-squares method. Errors induced by multiple reflections between the transmitting and receiving horn antennas are removed by a time-domain gating technique. The design of the quasioptical measurement setup is based on Gaussian beam optics. A dielectric lens collimates the beam of the transmitting horn antenna for minimization of diffraction effects at the edges of the sample. In order to verify the Gaussian beam and thin lens approximations at millimeter wavelengths, the farfield pattern of the horn antenna and the dielectric lens system has been measured. The performance of the measurement setup has been tested using glass samples.

Measurement of Complex Permittivity of Lossy Materials in Free Space Using Matched THz Power Meter

“…As a result of minimization the best values of " 0 r and " 00 r satisfying a least-squares criterion are determined. Examples of measurements based on the frequency domain formulation were reported in [7].…”

W-band Silicon dielectric measurement

“…In free space method, the dielectric constant is measured based on either the transmission method or metal backed method [2][3]. Metal backed method is better for very thin dielectric samples.…”

Propriétés électromagnétiques matériaux par la mesure des paramètres S sur ligne de transmission

“…Plusieurs méthodes de mesures ont ainsi été développées afin d'extraire les caractéristiques électromagnétiques de matériaux jusqu'au terahertz. On distingue ainsi des techniques résonnantes [1], en espace libre [2], capacitives [3], en lignes de transmission [4] et en spectroscopie terahertz [5]. La méthode présentée dans cette étude utilise une topologie en ligne de transmission coaxiale classique dans le but de réaliser un kit de mesure métrologique étalon pour la caractérisation électromagnétique de matériaux diélectriques et/ou magnétiques jusqu'à 18 GHz.…”