DIELECTRIC-CONSTANT CHARACTERIZATION OF LARGE-AREA SUBSTRATES IN MILLIMETER-WAVE BAND

A possibility of the dielectric constant epsilon' measurement for subs trates with permittivity epsilon = epsilon' + i epsilon'' without an e ssential restriction on their area has been shown experimentally. The method uses frequency measurement of quasioptical, dielectric resonato r (QDR) with two dole oriented along the QDR radius with a dielectric substrate in one of them. Taking QDR of teflon in 8mm waveband as an e xample it is found that measurable values of epsilon' can ran up 15 ep silon(q)', where epsilon(q)' is the QDR material permittivity. Absolut e error of the measurements is determined by an accuracy with which th e permittivity of calibrated (standard) samples is known. The relative measuring error is determined by the accuracy of the QDR frequency me asurement and can be quite a small. As an example the method is demons trated for LaAlO3 single crystals.