A RF sensor for sensing and analyzing parameters of plasma processing. The RF sensor is provided with a plasma processing tool and an antenna for receiving RF energy radiated from the plasma processing tool. The antenna is located proximate to the plasma processing tool so as to be non-invasive. Additionally, the RF sensor may be configured for wideband reception of multiple harmonics of the RF energy that is radiated from the plasma processing tool. Further, the RF sensor may be coupled to a high pass filter and a processor for processing the received RF energy. Additionally, the antenna may be located within an enclosure with absorbers to reduce the interference experienced by the RF sensor. Additionally, a tool control may be coupled to the processor to provided to adjust and maintain various parameters of plasma processing according to the information provided by the received RF energy.