Harmonic and subharmonic filter
US5187457A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1991 |
| Grant date | Feb 16, 1993 |
| Priority date | — |
| Expiry date | Sep 12, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H7/1775
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A harmonic and subharmonic filter is coupled between a high power RF energy source and a non-linear RF load via a matching network, such as a plasma chamber. The filter passes high power RF energy in a band centered on a predetermined radio frequency, i.e., 13.56 MHz, but blocks and attenuates out-of-band energy at frequencies which are multiples of or fractions of the predetermined frequency. The harmonic and subharmonic filter comprises an input terminal, an output terminal, a series LC resonance path connected between the input and output terminals, and tuned to the predetermined radio frequency, a series resistive path formed of first and second resistors, and a parallel LC resonance path between the junction of the two resistors and ground.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.