The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 2000
Filed:
Jun. 15, 1998
Michael Hopkins, Dublin, IE;
Scientific Systems Research Limited, Dublin, IE;
Abstract
An apparatus for sensing RF current delivered to a plasma includes an RF conductor along which the current is delivered to the plasma and which is divided into two parts along part of its length so that substantially equal currents flow in each part. A sensor device is inserted into the gap between the two parts of the conductor and includes first and second inductive loops disposed one n each side of the gap such that when an RF current flows along the RF conductor t magnetic flux surrounding the conductor which is generated by the RF current couples with the loops respectively in opposite directions relative to the sensor device. If a stray magnetic flux normal to the current direction couples with the loops in the same direction relative to the sensor device it will induce voltages in the loops which respectively add to the voltage induced by the RF current in one loop and subtract from the voltage induced by the RF current in the other loop. Thus by adding the voltages induced in the loops, for example by connecting them in series, the voltages induced by the stray magnetic flux tend to cancel.