Comparison of the single reflection and total reflection TDS techniques

The single reflection TDS technique is compared with the total reflection technique on the basis of measurements performed on ethanediol and formamide over the frequency range of 10 8 -10 10 Hz. While confirming that single reflection TDS does indeed offer superior precision for measurements on high permittivity materials, such as water and formamide, at gigahertz frequencies, the results also illustrated the extent of the problem caused by timing errors. They showed that if the extra performance offered by single reflection TDS is to be realised then the effect of the timing errors must be corrected for by using suitable measurements from an independent technique. The main conclusion from this work, however, is that the two TDS techniques complement each other rather well. Total reflection TDS can be used for the measurements on the lower permittivity materials over the whole range 10 6 -10 10 Hz, as well as the measurements on the higher permittivity materials up to about 10 9 Hz. Single reflection TDS can then be used to extend these latter measurements up to at least 10 10 Hz.