Study of X-Band Microwave Attenuation by Array of Filamentary Air Plasma

In this paper, a filamentary air plasma array is explored for attenuation of a transmitting X-band microwave (MW) beam at reduced atmospheric pressure, P = 3-9 kPa. Discharge parameters such as voltage-current characteristics, gas temperature, and the plasma filament diameters are measured; the electron density and electron-molecular collision frequency are calculated. The attenuation of a 10 GHz microwave is measured for parallel and perpendicular polarizations with respect to the plasma filament direction. It was found that the maximal attenuation of an MW beam with perpendicular polarization can be as high as 25 dB at P = 3 kPa. The processes of plasma contraction and expansion are considered an important factor of the plasma's impact on transmission characteristics. A simulation of the interaction between the MW and a plasma array was performed using the method of finite difference time domain.