Error Correction in Variable-Temperature Characterization of Material Complex Dielectric Spectrum

We present a method for temperature-dependent calibration of a multichannel measurement system for 0.05-3 GHz characterization of material complex dielectric-spectrum. This system, described elsewhere, is based on one-port vector-network-analyzer measurements of a two-port coaxial-cell terminated with a variable load. The nominal system calibration uses multiple coaxial transmission-line sections terminated with a variable termination, and due to a large number of calibration standards is difficult to implement in a multichannel system at multiple temperatures. Therefore, we devised a new variable-temperature calibration approach. In this approach we assume that the temperature variation causes only small changes of the system calibration coefficients, and determine those changes with an approximate calibration technique requiring a lower number of calibration standards. We verify our approach based on measurements of PTFE samples at temperatures from 0 to 40 degrees Celsius.