Wang, J. Mihalcea, D. Piot, P. JACoW Geneva, Switzerland 978-3-95450-192-2 10.18429/JACoW-IBIC2017-TUPCC10 English 172-175 TUPCC10 ion electron cavity wakefield GUI Contribution to a conference proceedings 2018 2018-03 https://doi.org/10.18429/JACoW-IBIC2017-TUPCC10 http://jacow.org/ibic2017/papers/tupcc10.pdf The development of future free electron lasers (FELs) requires reliable time-resolved measurement of variable ultra-short electron-bunchs characteristics. A possible technique is to streak the bunch in the transverse direction by means of time-dependent external fields. In this paper we explore the possible use of self-generated electromagnetic fields *. A passive deflector, consisting of a dielectric-lined waveguide, is used to produce wakefields that impart a time-dependent transverse kick to the relativistic electron bunch passing off-axis. We investigate the technique and its performances and explore its possible application at the Fermilab Accelerator Science & Technology (FAST) facility.