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Plasma generation systems represent a particularly challenging load for radio-frequency power amplifiers owing to the combination of high operating frequency (e.g., 13.56 MHz) and highly variable load parameters. We introduce a dynamic matching system for inductively coupled plasma (ICP) generation that losslessly maintains near-constant driving point impedance (for low reflected power) across the entire plasma operating range. This new system utilizes a resistance compression network (RCN), an impedance transformation stage, and a specially configured set of plasma drive coils to achieve rapid adjustment to plasma load variations. As compared to conventional matching techniques for plasma systems, the proposed approach has the benefit of relatively low cost and fast response, and does not require any moving components. We describe suitable coil geometries for the proposed system, and treat the design of the RCN and matching stages, including design options and tradeoffs. A prototype system is implemented and its operation is demonstrated with low pressure ICP discharges with O $_{2}$ , C $_{4}$ F $_{8}$ , and SF $_{{6}}$ gases at 13.56 MHz and over the entire plasma operating range of up to 250 W.

Single-Switch inverters such as the conventional Class-E inverter are often highly load sensitive, and maintain zero-voltage switching over only a narrow range of load resistances. This paper introduces a design methodology that enables rapid synthesis of Class E and related single-switch inverters that maintain ZVS operation over a wide range of resistive loads. We treat the design of Class-E inverters for variable resistance operation and show how the proposed methodology relates to circuit transformations on traditional Class-E designs. We also illustrate the use of this transformation approach to realize Φ[subscript 2] inverters for variable-resistance operation. The proposed methodology is demonstrated and experimentally validated at 27.12 MHz in a Class E and Φ[subscript 2] inverter designs that operate efficiently over 12:1 load resistance range for an 8:1 and 10:1 variation in output power, respectively, and a 25-W peak output power., Massachusetts Institute of Technology. Center for Integrated Circuits and Systems, MIT Energy Initiative, Skolkovo Institute of Science and Technology, Warsaw University of Science and Technology (Poland). Center for Advanced Studies