When a plane electromagnetic wave is incident on wave-absorbing structure（ such as frequency selective surface）

the structure that can interact with electromagnetic field and magnetic field component can be equivalent to inductance or capacitance. Since there is no electric field component and magnetic field component in the propagation direction（ direction of Poynting vector）

the capacitance in the propagation direction are difficult to realize. In order to solve this problem

an equivalent device is proposed which can generate an electric field parallel to the direction of the Poynting vector

so as to form a capacitance in the space parallel to the direction of Poynting vector. The equivalent circuit of the equivalent de

vice is obtained by using the equivalent circuit method

and the full wave simulation of the structure and its equivalent circuit is performed respectively. The simulation results show that S parameters of the device is in good agreement with equivalent circuit at 0

1 GHz

that is

the designed device can be equivalent device as capacitance in the direction of the Poynting vector.