Patent ID: 7061184

Claim:
A plasma electron density measuring and monitoring device, the device comprising: a chamber filled with plasma having varying electron density; electromagnetic wave transmitting/receiving means having an antenna structure, one end of which is mounted in the chamber, such that the density of the plasma and the frequency of radiated electromagnetic waves have a correlation between them; an electromagnetic wave generator electrically connected to the electromagnetic wave transmitting/receiving means, for continuously radiating electromagnetic waves by frequency bands to the electromagnetic wave transmitting/receiving means; a frequency analyzer electrically connected to the electromagnetic wave transmitting/receiving means, for scanning the frequency of electromagnetic waves received by the electromagnetic wave transmitting/receiving means and analyzing the scanned frequency by amplitudes of the received electromagnetic waves; and a computer connected to the electromagnetic wave generator and the frequency analyzer via an interface unit, for instructing the electromagnetic wave generator to transmit the electromagnetic waves by frequency bands and obtaining a correlation between the frequency and the electron density of the analyzed electromagnetic wave through operation, wherein the electromagnetic wave transmitting/receiving means is a frequency probe comprising: a first waveguide electrically connected to the electromagnetic wave generator; a second waveguide located in parallel with the first waveguide and electrically connected to the frequency analyzer; a transmission antenna coaxially connected to one end of the first waveguide for radiating electromagnetic waves; and a receiving antenna coaxially connected to one end of the second waveguide for receiving electromagnetic waves.