A technique for the measurement of the frequencyhyphen;dependent complex dielectric constant egr;=egr;rsquo;minus;jegr;lsquo;of liquids applicable to frequencies up to at least 20 GHz is described. The technique utilizes a coaxial probe dipped into the liquid. The reflection coefficient of the probe was measured using a network analyzer between 45 MHz and 20 GHz. A new dehyphen;imbedding procedure for eliminating the connector and coax mismatches is described, during which the impedanceZ(egr;) of the probe end was determined. The dielectric constant egr; was determined fromZ(egr;) by modeling the coaxndash;liquid interface as a capacitance. The dehyphen;imbedding procedure, which utilizes three calibrations, directly eliminates the (unknown) fringehyphen;field impedance. Radiation effects were minimized by using narrow (0.047hyphen;in.) semirigid coax. The technique yields accurate results for egr;rsquo;and egr;lsquo;of liquids such as methanol and water over the entire frequency range up to 20 GHz, and can be used to determine the relaxation spectra of liquid and liquidlike samples.
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