Theoretical investigation of a miniature microwave driven plasma jet

M. Klute1, H.-E. Porteanu2, I. Stefanovic3, W. Heinrich2, P. Awakowicz3 and R.P. Brinkmann1

Published in:

Plasma Sources Sci. Technol., vol. 29, no. 06, pp. 065018, DOI: 10.1088/1361-6595/ab9483 (2020).

Copyright © 2020 The Author(s). Published by IOP Publishing Ltd. Printed in the UK.
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.


Radio frequency driven plasma jets are compact plasma sources which are used in many advanced fields such as surface engineering or biomedicine. The MMWICP (miniature micro wave ICP) is a particular variant of that device class. Unlike other plasma jets which employ capacitive coupling, the MMWICP uses the induction principle. The jet is integrated into a miniature cavity structure which realizes an LC-resonator with a high quality factor. When excited at its resonance frequency, the resonator develops a high internal current which - transferred to the plasma via induction - provides an efficient source of RF power. This work presents a theoretical model of the MMWICP. The possible operation points of the device are analyzed. Two different regimes can be identified, the capacitive E-mode with a plasma density of ηe≈5×1017m-3, and the inductive H-mode with densities of ηe≥1019m-3. The E to H transition shows a pronounced hysteresis behavior.

1 Theoretical Electrical Engineering, Ruhr University Bochum, Germany
2 Microwave Department, Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Berlin, Germany
3 Electrical Engineering and Plasma Technology, Ruhr University Bochum, Germany


plasma jet, inductively, microwave, miniature, ICP, RF