PIC/MCC Modeling and Validation of Split-Ring Resonator Microwave Microplasma Formation

Abstract

Microplasma discharges are of interest both in their fundamental understanding and in their applications – such as plasma sources, metasurfaces, and in emerging radiofrequency and microwave applications. One common topology for microplasma discharge formation is a split-ring resonator. Much work has investigated split-ring resonators as a platform for radiofrequency and microwave driven plasma [1] . Microwave circuit models for the behavior of such circuits have been developed, and electromagnetic simulations of the fields generated by these devices have provided an additional avenue of investigation. This foundation can be valuably extended by introducing particle-in-cell/Monte Carlo collision (PIC/MCC) modeling of the breakdown phenomena. We present the simulation and experimental validation of micro-plasma formation in split-ring resonator structures for frequencies in excess 5 gigahertz. Split-ring resonator devices with planar gap geometry were designed and fabricated at Purdue’s Scifres Nanofabrication Cleanroom. Nominal gap widths between 5 and 20 micrometers were considered as well as signal frequencies between 5 and 18 gigahertz. Breakdown potential was measured experimentally in an Argon environment over a range of ambient pressures less than 1 atmosphere. Finally, PIC/MCC simulations were created in XOOPIC to predict breakdown potential. Measurement-model correlation, and model predictive strength are discussed. Domain-specific modeling challenges and recommendation for future measurements are provided.