Terahertz radiation with its non-ionizing property can be potentially employed in many fields, for example, medical imaging, security scanning, spectroscopy, and communication. In this thesis, we investigate one of the potential terahertz generators based on the cylindrical corrugated waveguide.

We show that by applying the Mathieu equation in Maxwell's equations specifically for our symmetric corrugated waveguides, we can find the explicit approximate solution of the electromagnetic fields. Moreover, we define the coincident inflection point (CIP) which is the point on the dispersion relation where particles would interact with the broad frequencies range of the electric fields. With this approximation and the CIP, the design of the symmetric corrugated waveguides is easier compared to other slow-wave structures e.g., radio frequency cavity.

We utilize the CST studio to compare our analytical results with numerical results from the CST simulation. The results show good agreement in the longitudinal electric field graphs and the dispersion relation between these two results, confirming that our analytical results are good enough to use in practice.

The study in the cylindrical corrugated waveguide is the developed work from the rectangular corrugated waveguide. Not only did we observe better agreement between analytical results and numerical results, but also an easier in manufacturing process. We expect that the optical fiber extrusion technique for making the cylindrical corrugated structure will be relatively easier and cheaper than the CNC (Computer Numerical Control) technique for the rectangular corrugated structure.