Matching circuit for delivering radio frequency electromagnetic energy to a variable impedance load
US4679007A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 20, 1985 |
| Grant date | Jul 7, 1987 |
| Priority date | — |
| Expiry date | May 20, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H7/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A matching circuit is provided for delivering radio frequency electromagnetic energy from a radio frequency power supply to a variable impedance load such as a gas plasma. The matching network couples and impedance matches the power supply to the load. The matching network includes a ratio circuit for establishing a voltage ratio between the power supply and the load and a tuning circuit for tuning out a complex portion of the reactance of the load. Separation and control of the ratio and tuning variables is achieved through provision of a ratio control circuit comprising a lumped quarter wave transformer and a tuning control circuit comprising a variable tuning capacitance and a tuning inductance electrically connected in parallel to the load. The lumped quarter wave transformer comprises first and second ratio inductances electrically connected parallel to the load; a first variable ratio capacitance electrically connected in series with the load; and second and third variable ratio capacitances electrically connected parallel to the load. Ratio and tuning inductances are provided comprising toroidal-shaped forms having layers of electrically conductive material deposited or appl…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.