An apparatus for measuring parameters of plasma includes a cutoff probe. The cutoff probe includes: a first antenna having a line shape and configured to emit a microwave to the plasma in response to the signal provided by at least one processor; a second antenna having a line shape and configured to generate an electrical signal in response to receiving the microwave emitted by the first antenna and transferred through the plasma; a first insulating layer; a second insulating layer; a first shield; a second shield; an end protection layer covering an end of each of the first insulating layer, the second insulating layer, the first shield, and the second shield; a first antenna protection layer, of insulating nature, covering the first antenna; and a second antenna protection layer, of insulating nature, covering the second antenna.

A sensor system and method of reducing plasma-induced communication inhibition for a main antenna includes using auxiliary antennas for detecting a density of plasma that affects operation of the main antenna, and re-orienting an electromagnetic field around the main antenna in response to the density detected to reduce effect of the plasma on the main antenna. The auxiliary antennas are also operable for data link communication and switchable such if the density of the plasma inhibits receipt or sending of signals by one of the auxiliary antennas, another one of the auxiliary antennas may be used for data link communication.

An ignition apparatus is provided which ignites a mixture of air and fuel gas by plasma to generate an initial flame. The apparatus includes: a spark plug that includes an inner conductor, a cylindrical outer conductor that holds the inner conductor thereinside, and a dielectric that is provided between the inner conductor and the outer conductor, and that generates plasma in a plasma formation space between the inner conductor and the outer conductor; an electromagnetic wave power supply that generates an electromagnetic wave to apply electromagnetic wave power to the spark plug; an evaluation section that evaluates a state of formation of the plasma; a determination section that determines a matching object of the electromagnetic wave based on an evaluation result by the evaluation section; and a coupled state control section that controls a matching condition of the electromagnetic wave so that the electromagnetic wave matches the matching object.

A probe for measuring plasma parameters by means of active plasma resonance spectroscopy comprises an external coupling, a balun, an internal coupling, and a probe head. It is provided that the couplings, the balun, and the probe head are integrated in an electrically-insulating substrate cylinder, and the substrate cylinder has a layered structure made from multiple substrate layers along its rotational axis. In this way, a probe for measuring plasma parameters is provided which enables an improved measurement of the plasma parameters, wherein the plasma is influenced as little as possible during the measurement of the plasma parameters.

The present invention relates to a planar-type plasma diagnosis apparatus comprising: a transmission antenna for applying a frequency-variable microwave to plasma; a reception antenna for receiving the microwave from the plasma; and a body part encompassing the transmission antenna and the reception antenna so that same are insulated from each other, wherein the upper surface of the transmission antenna for applying the microwave and the upper surface of the reception antenna for receiving the microwave are planar, and side surfaces of the upper surfaces of the transmission antenna and the reception antenna face each other.

An ignition apparatus is provided which ignites a mixture of air and fuel gas by plasma to generate an initial flame. The apparatus includes: a spark plug that includes an inner conductor, a cylindrical outer conductor that holds the inner conductor thereinside, and a dielectric that is provided between the inner conductor and the outer conductor, and that generates plasma in a plasma formation space between the inner conductor and the outer conductor; an electromagnetic wave power supply that generates an electromagnetic wave to apply electromagnetic wave power to the spark plug; an evaluation section that evaluates a state of formation of the plasma; a determination section that determines a matching object of the electromagnetic wave based on an evaluation result by the evaluation section; and a coupled state control section that controls a matching condition of the electromagnetic wave so that the electromagnetic wave matches the matching object.

A sensor system and method of reducing plasma-induced communication inhibition for a main antenna includes using auxiliary antennas for detecting a density of plasma that affects operation of the main antenna, and re-orienting an electromagnetic field around the main antenna in response to the density detected to reduce effect of the plasma on the main antenna. The auxiliary antennas are also operable for data link communication and switchable such if the density of the plasma inhibits receipt or sending of signals by one of the auxiliary antennas, another one of the auxiliary antennas may be used for data link communication.

An apparatus for measuring parameters of plasma includes a cutoff probe. The cutoff probe includes: a first antenna having a line shape and configured to emit a microwave to the plasma in response to the signal provided by at least one processor; a second antenna having a line shape and configured to generate an electrical signal in response to receiving the microwave emitted by the first antenna and transferred through the plasma; a first insulating layer; a second insulating layer; a first shield; a second shield; an end protection layer covering an end of each of the first insulating layer, the second insulating layer, the first shield, and the second shield; a first antenna protection layer, of insulating nature, covering the first antenna; and a second antenna protection layer, of insulating nature, covering the second antenna.