A Low-Voltage Microwave Plasma Ionizer With Reduced Electric Overstress Due to Displacement Current Coupling From a High-AC Voltage Source

A low-voltage microwave plasma ionizer was proposed as an ac-type ionizer. A structure to improve the ionizing performance and stability of the plasma ionizer was proposed. A dedicated source module was also designed to generate microwave power for the ionizer. The ionizing performance of the proposed ionizer was experimentally investigated using a charged plate monitor, and the factors required to achieve good performance were found. The risk of electric overstress due to displacement current coupling from the ac voltage source in the ionizer was then investigated. It was experimentally confirmed that the proposed microwave plasma ionizer has a much lower risk of electric overstress at a close distance than a conventional ac-type corona ionizer.