Wang, D. JACoW Publishing Geneva, Switzerland 2226-0366 978-3-95450-194-6 10.18429/JACoW-LINAC2018-MOPO016 English 65-67 MOPO016 electron radiation wakefield simulation impedance Contribution to a conference proceedings 2019 2019-01 https://doi.org/10.18429/JACoW-LINAC2018-MOPO016 http://jacow.org/linac2018/papers/mopo016.pdf We studied through analysis and numerical simulations the use of a relativistic electron bunch to drive a metallic beam pipe with helix wire inside, for the purpose of gen-erating narrow-band terahertz radiation. we have shown that the frequency is related to the radius of the pipe and that of the wire, thus one can generate a narrow-band radiation pulse with frequency tunable through this scheme with different pipes and wires. The total energy of a few milli-Joules. The pulse length tends to be on the order of hundreds of picoseconds. We have also shown that, if the pipe radius is tapered along its length, the generated pulse will end up with a frequency chirp.