Experimental and Numerical Investigations on Microwave Absorption by the Cold Collisional Capacity-Coupled-Plasma
The absorption of electromagnetic (EM) wave in the cold collisional capacity-coupled-plasma (CCP) is studied in this paper. First, the time-dependent fluid model is used to gain the spatial variation of electron number density when discharge tends to be in steady state in CCP. The pure argon gaseous electronics conference cell reactor type is used in the model where the diameter is 4 cm, the interelectrode distance is 2.5 cm, the operating frequency is 13.56 MHz, the gas pressure is 1-2 torr, and the applied voltage is 500-1500 V. Second, EM attenuation of 7-12 GHz is studied theoretically for CCP using the plasma parameter obtained from the first step. When the EM wave passes through the plasma, the transmission attenuation is -4.5 dB at 7 GHz, which deduces while EM frequency raises. In addition, the transmission attenuation increases with the applied voltage and gas pressure, respectively. Finally, microwave measurement system is used to measure the transmission attenuation of CCP in anechoic chamber. This paper shows that the theoretical and experimental results have a good agreement on the transmission attenuation.