Microwave characterization of dielectric materials from 8 to 110 GHz usinga free-space setup

In this paper, we present a free-space setup for the high-and low-temperatu re dielectric characterization of materials from 8.0 to 110 GHz along with the measured results. Using am HP 8510 XF single-connection, single-sweep n etwork analyzer along with three pairs of spot-focused horn lens antennas, it is possible to perform broadband in-situ and real-time dielectric charac terization of materials. Presently, all other methods have the disadvantage s of either being narrowband or single-frequency measurement, and the diffe rences associated with accurate sample preparation for different frequency bands. This method, based on a microwave beam focused to a measurement plan e, is noncontact, so it can be adapted easily for measurements in high-temp erature and hostile environments. The frequency dependence of the complex d ielectric properties of a number of common samples is measures as a functio n of temperature and frequency, and is compared with existing data. (C) 200 0 John Wiley & Sons, Inc.