Phase Calibration Of The Ⅵ Probe And Application In Pulse-modulated RF Atmosphere Discharge

In recent years, low pressure low temperature plasma has rapid development, but some of its inherent shortcomings limit its wide application, such as the need to vacuum, operation complex, and not suitable for continuous production in industry, the atmospheric pressure discharge can avoid these drawbacks of the low-pressure plasma discharge,it do not need to buy vacuum equipment, can effectively reduce production costs, therefore, the atmospheric pressure discharge plasma is more suitable for industrial production, although atmospheric pressure corona discharge and dielectric barrier discharge applied to the surface treatment of a variety of metal materials and polymer materials.but the area of the corona discharge is small, the current is week and the efficiency is low, dielectric barrier discharge is easy to form filamentary discharge, burning to the surface of the processed material, and the discharge is uneven. Low pressure glow discharge can handle these materials, but it remains impossible to treat a variety of materials’surface scalely, people has long been for the efforts to achieve atmospheric pressure glow discharge.the atmospheric pressure glow discharge at the same time both the advantages of large area uniform and relatively high processing speed, but is likely to have a glow discharge into arc discharge; the breakdown and sustaining voltage of the RF discharge at atmospheric pressure is low, you can obtain a more stable, higher intensity of the glow discharge; pulse modulation of the output signal of the signal source is a relatively new means of plasma production and control process, the signal pulse modulation can suppression the thermal stability, to prevent the contraction, you can get a higher intensity of the glow discharge. in order to more accurately calculate the modulation power under RF conditions, the need for current and voltage probes for phase calibration.In this thesis, the phase calibration of the discrete voltage and current probes, the current probe and voltage probe output signal collected by the oscilloscope, you can get the wave of the voltage and current signals change over time, this signal into the computer by a Matlab-FFT program to calculate the phase difference across the load measured by the current and voltage probes, compared with the phase difference of the capacitance or inductance selected by the network analyzer, come up with the phase delay of the current and voltage probes,the loop current and voltage probes measured has a great influence on the measured phase error, My group made the situ calibration thought; in the calibration process, current and voltage probes to the ground, ground loop interference, oscilloscope stalls,oscilloscope temperature rise and other factors affect the measurement of phase angle, and exclude the impact of these factors, the better the results of calibration experiments. calibration phase error for the calculation of the power in pulse modulated radio frequency atmospheric pressure discharge, and compared with the photomultiplier tube measured data, the result is it is very accurate calculation of high-power power,but low-power, the power calculation is not accurate; analysis showed that small amplitude signals exist interference on the oscilloscope, it can not accurately capture small signal, the signal to a small value of phase deviation from-90degrees and we can not accurately calculate the power in the pulse modulation frequency atmospheric pressure discharge,the breakdown point of the small value signal can get from the photomultiplier tube.