Measuring Scattering Parameters in the Time Domain

The terahertz pulses can be transferred to the component under investigation through a waveguide. After the pulses have passed through the component, they can then be detected optically in the time domain.

Network Analyzer Tera-VNA

The application of network analyzers plays an important role in the development of high frequency components and circuits. By developing extender modules, it has been possible to boost the bandwith up to 1.1 THz. In order to boost the bandwith up to 2 THz, we developed a new procedure: S-parameters of components are not measured in the frequency range, but in the time domain.

A THz TDS system was developed in a way, that the terahertz pulses can be transferred to the component under investigation through a waveguide. After the pulses have passed through the component, they can then be detected optically in the time domain. After the data, which has been obtained in this way, has been transferred to the frequency range, it is then possible to determine the required vectorial S parameters of the component under investigation. This has been demonstrated for frequencies from 100 GHz to 2THz.

The new technology affords many advantages in comparison to classical network analysis in the frequency range.This new technology permits working with very high bandwidths at relativeley low-cost system prices, compared to common VNAs. Another advantage of the Tera-VNA is: only the waveguide components in each case need to be changed for shifting between various frequency bands. An exchange of extension modules is not necessary. Moreover, it is even possible to determine the propagation times of the pulses through a network directly. It is thus possible to detect invisible flaws or discontinuities in the network directly and identify their positions directly.