Microwave Processing Laboratory - Other 98-3

Open-Ended Coaxial Probe for High-Temperature and Broad Band Dielectric Measurements

D. L. Gershon,¹ J. Calame,² Y. Carmel,¹ and T. Antonsen¹
¹ University of Maryland, College Park, Maryland 20742
² Naval Research Laboratory, Washington, DC 20375

American Ceramic Society Annual Meeting, May 1998

ABSTRACT. A stainless steel open-end coaxial probe was developed to measure the complex permittivity of solid dielectric materials at elevated temperatures. The spring loading of the inner conductor insured that the probe maintained contact with the sample up to 1000^oC and eliminated errors due to differential thermal expansion of the probe. Comparison with an industry standard probe demonstrated that the spring loaded probe accurately and reproducibly measured the complex permittivity of several samples over a broad frequency range of 0.3 to 6 GHz. Differences between the spring loaded probe and a resonant cavity for a glass ceramic and a porous alumina composite were ~8% for the real part and ~15% for the imaginary part. Finally, optimization of an open-ended probe by varying the probe dimensions is presented.