In recent years, usage of high power in modern technologies operating at microwave frequency range has been varying in research topics such as radar, plasma science, satellite communications and particle physics. Therefore, transmission of high power from a power generator to a specific target without loss is a key point of these research fields. In accordance with this purpose, a project has been started at the Kandilli Detector, Accelerator and Instrumentation (KAHVE) Laboratory of Bo˘gazic¸i University in Turkey which name is Design, Simulation and Production of an RF Circulator and Transmission Line. The aim of the project is to build a high power RF transmission line and circulator ope-rating at 800 MHz frequency. In order to perform this whole system after their installing, a simple pillbox cavity has been designed, simulated and fabricated. A cavity is not enough itself to test the system because an efficient high power transmission section from the RF power generator to the pillbox cavity is needed. In this regard, an input power coupler with a loop antenna has also been produced. Overall, several measurements have been performed to compare with simulation results and to determine whether the performance of the transmission line is adequate for high power applications and consistent results were obtained in accordance with the project targets.