Lam Research Corporation
Inductive current sensor on printed circuit board

Abstract:

A first inductive loop is formed within a printed circuit board (PCB). The PCB is mounted in a fixed spatial relationship with a radiofrequency power supply structure. A second inductive loop is formed within the PCB. The second inductive loop is positioned in fixed spatial relationship with the first inductive loop such that a distance between the centerpoints of the first and second inductive loops has a fixed value and is precisely known. Each of the first and second inductive loops is formed in an essentially identical manner with regard to number of complete turns of the loops and a size of the loops. A first voltage signal present on the first inductive loop and a second voltage signal present on the second inductive loop and the distance between the first and second loops provide for determination of a radiofrequency current present on the radiofrequency power supply structure.