Mousavinia, M. Afarideh, H. Ghergherehchi, M. JACoW Geneva, Switzerland 978-3-95450-167-0 10.18429/JACoW-Cyclotrons2016-WEB03 English 267-269 WEB03 cavity coupling cyclotron simulation impedance Contribution to a conference proceedings 2017 2017-01 http://dx.doi.org/10.18429/JACoW-Cyclotrons2016-WEB03 http://jacow.org/cyclotrons2016/papers/web03.pdf RF system is the key part of cyclotron and cavity is the key part of RF system. The basic parameters of cavity design are the resonant frequency , dee voltage , RF phase and RF power. Proper operation of cavity depends on the suitable voltage distribution in accelerating gap, phase stability in cavity and as well as optimal scattering parameters. In this simulation by using CST MWS, different parts of cavity such as stam and dee are optimized to achieved optimum dimesnsions for desired resonant freq, dee voltage and RF power. Properties of designed cavity including: resonant frequency at 64.3 MHz, dee voltage is 45 kV and RF power is 11 kW.