  Corrugated structures have recently been widely used for manipulating
electron beam longitudinal phase space and for producing THz radiation. Here we
report on time-resolved measurements of the quadrupole wakefields in planar
corrugated structures. It is shown that while the time- dependent quadrupole
wakefield produced by a planar corrugated structure causes significant growth
in beam transverse emittance, it can be effectively canceled with a second
corrugated structure with orthogonal orientation. The strengths of the
time-dependent quadrupole wakefields for various corrugated structure gaps are
also measured and found to be in good agreement with theories. Our work should
forward the applications of corrugated structures in many accelerator based
scientific facilities.
