Jovan Jevtic

Adjunct Associate Professor | Milwaukee School of Engineering

Milwaukee, WI, UNITED STATES

Dr. Jovan Jevtic is an expert in the areas of electromagnetic field theory, radio-frequency plasmas, and high-frequency circuits/antennas.

Education, Licensure and Certification (3)

Ph.D.: Electrical Engineering, Ohio State University 1999

M.S.: Electrical Engineering, Ohio State University 1994

Dipl. Ing.: Electrical Engineering, University of Belgrade-Yugoslavia 1991

Biography

Dr. Jovan Jevtic is an adjunct associate professor in the Electrical, Computer and Biomedical Engineering Department. He teaches courses in linear networks: steady-state and electric and magnetic fields.

Accomplishments (4)

James Clark Maxwell Foundation Award, Smith's Prize Competition

2008

Wisconsin Governor's Business Plan Contest, 2nd Prize

2006

National Research Council Award, Student Paper Competition

1995

Outstanding M.S. Thesis, The Ohio State University

1994

Patents (5)

Inductively Coupled High-density Plasma Source

US7482757B2

A high-density plasma source (100) is disclosed. The source includes an annular insulating body (300) with an annular cavity (316)formed within. An inductor coil (340) serving as an antenna is arranged within the annular cavity and is operable to generate a first magnetic field within a plasma duct (60) interior region (72) and inductively couple to the plasma when the annular body is arranged to surround a portion of the plasma duct. A grounded conductive housing (400) surrounds the annular insulating body. An electrostatic shield (360) is arranged adjacent the inner surface of the insulating body and is grounded to the conductive housing. Upper and lower magnet rings (422 and 424) are preferably arranged adjacent the upper and lower surfaces of the annular insulating body outside of the conductive housing. A T-match network is in electrical communication with said inductor coil and is adapted to provide for efficient transfer of RF power from an RF power source to the plasma. At least one plasma source can be used to form a high-density plasma suitable for plasma processing of a workpiece residing in a plasma chamber in communication with the at least one source.

Apparatus and Method of Improving Impedance Matching between an RF signal and a Multi-segmented Electrode

US7109788B2

An apparatus and method of improving impedance matching between a RF signal and a multi-segmented electrode in a plasma reactor powered by the RF signal. The apparatus and method phase shifts the RF signal driving one or more electrode segment of the multi-segmented electrode, amplifies the RF signal, and matches an impedance of the RF signal with an impedance of the electrode segment, where the RF signal is modulated prior to matching of the impedance of the RF signal. The apparatus and method directionally couples an output of the matching of the impedance of the RF signal and the electrode segment, and adjusts the output of the matching of the impedance of the RF signal such that a directionally coupled output signal and a reference signal representing the RF signal at the output of the master RF oscillator produces a demodulated signal of minimal amplitude.

Optical Interface for Local MRI Coils

US7345485B2

An implementation of an optical transmission path for NMR signals from local coils in magnetic resonance imaging employs a photomodulator that may be incorporated into a connecting optical cable to be shared among multiple local coils and to provide for connection and disconnection at an electrical interface eliminating the need for optical connectors.

Phased Array Local Coil for MRI Imaging Having Non-overlapping Regions of Sensitivity

US7091721B2

A capacitor decoupling network allows the production of a multi-loop local coil for magnetic resonance imaging without overlap of the loops and/or with decoupling between both adjacent and non-adjacent coils. The former design may

Addition of Power at Selected Harmonics of Plasma Processor Drive Frequency

US6917204B2

A method for controlling the non-uniformities of plasma-processed semiconductor wafers by supplying the plasma with two electrical signals: a primary electrical signal that is used to excite the plasma, and a supplemental electrical signal. The supplemental signal may be composed of a plurality of electrical signals, each with a frequency harmonic to that of the primary signal. The phase of the supplemental signal is controlled with respect to the phase of the primary signal. By adjusting the parameters of the supplemental signal with respect to the primary signal, the user can control the parameters of the resultant plasma and, therefore, control the non-uniformities induced in the semiconductor wafer.

Selected Publications (5)

Replacing the Argon ICP: Nitrogen Microwave Inductively Coupled Atmospheric-Pressure Plasma (MICAP)for Mass Spectrometry

Analytical Chemistry

Schild, M., Gundlach-Graham, A., Menon, A., Jevtic, J., Pikelja, V., Tanner, M., Hattendorf, B., Günther, D.

2018 We combine a recently developed high-power, nitrogen-sustained microwave plasma source—the Microwave Inductively CoupledAtmospheric-Pressure Plasma (MICAP)—with time-of-

New Inductively Coupled Plasma for Atomic Spectrometry: The Microwave-Sustained, Inductively Coupled, Atmospheric-Pressure Plasma (MICAP)

Journal of Analytical Atomic Spectrometry

Schwartz, A.J., Cheung, Y., Jevtic, J., Pikelja, V., Menon, A., Ray, S.J., Hieftje, G.M.

2016 A novel inductively coupled plasma (ICP), termed the microwave-sustained, inductively coupled, atmospheric-pressure plasma(MICAP) has been developed that operates at microwave frequency (2.45 GHz). To sustain the new plasma, a dielectric resonator ring (fabricated from an advanced technical ceramic) is coupled with a 2.45 GHz microwave field generated from a microwave-oven magnetron. The microwave field induces polarization currents (small shifts in the equilibrium positions of bound electrons) in the resonator that generate an orthogonal magnetic field, analogous to that produced by electrical current within a traditional ICP load coil. This magnetic field is capable of sustaining an annular plasma in either air or nitrogen that can readily accept solution samples in the form a wet aerosol produced from a conventional nebulizer and spray chamber. An initial analytical evaluation of the MICAP with radially viewed, optical emission spectrometry (OES) revealed that limits of detection ranged from 0.03−70 ppb with relative standard deviations from 0.7−2.0%. In addition, the new plasma exhibited good tolerance to solvent loading, and was found capable of accepting a wide variety of organic solvents directly and salt solutions up to 3% w/w concentration. Combined, the results suggest the MICAP could be a competitive, simpler alternative to traditional, radiofrequency argon ICP-OES.

A Generic Model of Memristors With Parasitic Components

Circuits and Systems

Sah, M.P., Yang, C., Kim, H., Muthuswamy, B., Jevtic, J., Chua, L

2015 In this paper, a generic model of memristive systems, which can emulate the behavior of real memristive devices is proposed. Non-ideal pinched hysteresis loops are sometimes observed in real memristive devices. For example, the hysteresis loops may deviate from the origin over a broad range of amplitude and frequency of the input signal. This deviation from the ideal case is often caused by parasitic circuit elements exhibited by real memristive devices. In this paper, we propose a generic memristive circuit model by adding four parasitic circuit elements, namely, a small capacitance, a small inductance, a small DC current source, and a small DC voltage source, to the memristive device. The adequacy of this model is verified experimentally and numerically with two thermistors (NTC and PTC) memristors.

Dielectric resonator antenna for high power RF plasma applications

IEEE International Conference on High-Power Particle Beams (BEAMS)

Jevtić, J., Menon, A., Pikelja, V.

2014 Some of the numerous applications of the inductively coupled plasma, at both atmospheric and low pressure, include plasma manufacturing, optical and mass spectroscopy, gasification and plasma reforming, semiconductor fabrication, in-space propulsion, gas lasers, ion sources, and fusion. A coil of copper or silver-plated tubing is typically used to couple the radio-frequency power into the plasma. Although this technology has been used extensively for many decades, an RF coil suffers from limitations which negatively affect the quality of the generated plasma and increase the complexity of the plasma source. These limitations include high ohmic losses in the antenna conductor which necessitate fluid cooling, high levels of capacitive coupling which necessitate RF shielding, high inter-turn voltage which limits the maximum power due to electric breakdown, external tuning capacitors which add to the size and cost, material properties of copper which demand a vacuum or thermal barrier between the coil and the plasma, etc.

Microwave Induced Plasma Source for Optical Emission and Mass Spectroscopy

SciX Conference

Jevtic, J., Menon, A., Pikelja, V.

2013