Automated and precise dielectric measurement systems at millimeter wavelengths using open resonator technique

As low loss dielectric materials, ZnS, MgAl
₂
O
₄
and MgF
₂
have a very important application in the millimeter-wave frequency range. However, there is little information about their dielectric properties in the millimeter-wave regions. To obtain their dielectric properties, an automatic open resonator measurement system at Ka-band is designed and constructed. The method of multi-frequency points measurement with frequency variation technique is adopted in order to realize the precision determination of cavity length over a broad band. After the checking of repeatability, credibility, reliability and stability, the stability and high accuracy of the measurement system are ensured. It is called certified measurement system and is used to measure the above materials. The results of lots of measurement show that the standard deviation of measurement error is less than 0.154% in permittivity and 19.61% in loss tangent. Meanwhile, some experimental summaries on the open resonator technique are provided. Software that controls the measurement systems is developed and it improves greatly the measurement efficiency.