Patent ID: 9552965
Date: 2017-01-24
CPC Classifications: H01F,H01J

Claim:
1. An inductively coupled coil, comprising: an internal coil and an external coil which are distinct from each other and coaxially arranged with respect to each other, the internal coil comprising a plurality of distinct internal branches having a same configuration which are nested together, the plurality of distinct internal branches being electrically connected in parallel and arranged symmetrically with respect to an axis of the inductively coupled coil, the configuration of the distinct internal branches including a radius from a point on each distinct internal branch to the axis, and currents flowing through the distinct internal branches being of a same direction; the external coil comprising a plurality of distinct external branches having a same configuration which are nested together, the plurality of distinct external branches being electrically connected in parallel and arranged symmetrically with respect to the axis of the inductively coupled coil, the configuration of the distinct external branches including a radius from a point on each distinct external branch to the axis, and currents flowing through the distinct external branches being of the same direction; an input end of each internal branch and each external branch being connected to an RF (radio frequency) source through a variable capacitor in series; output ends of the distinct internal branches and the distinct external branches being connected to a same grounding capacitor; and the variable capacitors and the same grounding capacitor being configured to adjust an impedance of each internal branch and each external branch and positions of maximum and minimum currents and voltages on the internal branches and the external branches.