Intercomparison of permittivity measurements using the transmission/reflection method in 7-MM COAX

Summary form only given. To aid in standardizing the transmission/reflection (T/R) method, the National Institute of Standards and Technology (NIST) organized a nationwide intercomparison of permittivity measurements in the 50 MHz to 187 GHz frequency range. The T/R method involves calculation of relative permittivity ( in /sub r/) and permeability ( mu /sub r/) from transmitted and reflected scattering parameters measured by a network analyzer. Three sample kits have been circulated among fifteen participating organizations. Each kit will be circulated to five different participants. All three sample kits contain four materials with in /sub r/ ranging from approximately 5 to 20, and one sample kit contains a fifth, high-permittivity sample with in /sub r/ somewhere between 35 and 60. Measurement results are compared with each other and with high-accuracy cavity resonator measurements made by NIST. The commonly implemented Nicholson/Ross algorithm is shown to be less accurate and much more unstable than the Baker-Jarvis algorithm, especially when the sample is longer than a half wavelength.<>