Kellermeier, M.J. Aßmann, R.W. Flöttmann, K. Hillert, W. Lemery, F. JACoW Publishing Geneva, Switzerland 2673-5490 978-3-95450-227-1 10.18429/JACoW-IPAC2022-TUPOMS044 English 1526-1529 Contribution to a conference proceedings 2022 2022-07 https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS044 https://jacow.org/ipac2022/papers/tupoms044.pdf Emerging high power THz sources pave the road for THz- driven acceleration of ultra-short bunches, and enable their manipulation for diagnostic purposes. Due to the small feature sizes of THz-guiding devices new methods are necessary for their electromagnetic characterization. A new technique has recently been developed which characterizes THz waveguides with respect to their dispersion relations and attenuation. Here, the method is applied to circular waveguides, partially filled with polymer capillaries of different thicknesses, to find a suitable size for THz driven streaking at 287 GHz. Further, rough 3d-printed metallic waveguides are measured to study the effect of roughness on attenuation and phase constant. In general, additive manufacturing techniques show promise for advanced integrated designs of THz driven structures.