  In this paper we will show a cavity and higher order mode (HOM) coupler
designing scheme for the Circular Electron-Positron Collider (CEPC) main ring.
The cavity radio frequency (RF) design parameters are showed in this paper. The
HOM power is calculated based on the beam parameters in the Preliminary
Conceptual Design Report (Pre-CDR). The damping results of the higher order
modes (HOMs) and same order modes (SOMs) show that they are reached the damping
requirements for beam stability.
