%0 Journal Article %A Hopwood, Jeffrey A. %A Iza, Felipe %A Coy, S. %A Fenner, D.B. %D 2008 %T A microfabricated atmospheric-pressure microplasma source operating in air %U https://repository.lboro.ac.uk/articles/journal_contribution/A_microfabricated_atmospheric-pressure_microplasma_source_operating_in_air/9546647 %K untagged %K Mechanical Engineering not elsewhere classified %X An atmospheric-pressure air microplasma is ignited and sustained in a 25μm wide discharge gap formed between two co-planar gold electrodes. These electrodes are the two ends of a microstrip transmission line that is microfabricated on an Al2O3 substrate in the shape of a split-ring resonator operating with a resonant frequency of 895 MHz. At resonance, the device creates a peak gap voltage of ~390V with an input power of 3W, which is sufficient to initiate a plasma in atmospheric pressure air. Optical emission from the discharge is primarily in the ultraviolet region. In spite of an arc-like appearance, the discharge is not in thermal equilibrium as the N2 rotational temperature is 500–700 K. The intrinsic heating of the Al2O3 substrate (to 100°C) causes a downward shift in the resonant frequency of the device due to thermal expansion. The temperature rise also results in a slight decrease in the quality factor (142 > Q > 134) of the resonator. By decreasing the power supply frequency or using a heat sink, the microplasma is sustained in air. Microscopic inspection of the discharge gap shows no plasma-induced erosion after 50 h of use. %I Loughborough University