Filters

20193

More filters

2020 - 20213
Reset filters

Settings

End date: 2021 × Start date: 2020 × End date: 2019 × Start date: 2019 × DDC: 530 × Publisher: Basel : MDPI AG ×

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    The equivalent circuit approach for the electrical diagnostics of dielectric barrier discharges: The classical theory and recent developments
    (Basel : MDPI AG, 2019) Pipa, Andrei V.; Brandenburg, Ronny
    Measurements of current and voltage are the basic diagnostics for electrical discharges. However, in the case of dielectric barrier discharges (DBDs), the measured current and voltage waveforms are influenced by the discharge reactor geometry, and thus, interpretation of measured quantities is required to determine the discharge properties. This contribution presents the main stages of the development of electrical diagnostics of DBDs, which are based on lumped electrical elements. The compilation and revision of the contributions to the equivalent circuit approach are targeted to indicate: (1) the interconnection between the stage of development, (2) its applicability, and (3) the current state-of-the-art of this approach. © 2019 by the authors.
  • Thumbnail Image
    Item
    Resonant terahertz light absorption by virtue of tunable hybrid interface phonon-plasmon modes in semiconductor nanoshells
    (Basel : MDPI AG, 2019) Nika, D.L.; Pokatilov, E.P.; Fomin, V.M.; Devreese, J.T.; Tempere, J.
    Metallic nanoshells have proven to be particularly versatile, with applications in biomedical imaging and surface-enhanced Raman spectroscopy. Here, we theoretically demonstrate that hybrid phonon-plasmon modes in semiconductor nanoshells offer similar advantages in the terahertz regime. We show that, depending on tm,n,nhe doping of the semiconductor shells, terahertz light absorption in these nanostructures can be resonantly enhanced due to the strong coupling between interface plasmons and phonons. A threefold to fourfold increase in the absorption peak intensity was achieved at specific values of electron concentration. Doping, as well as adapting the nanoshell radius, allowed for fine-tuning of the absorption peak frequencies.
  • Thumbnail Image
    Item
    Compact differential-fed planar filtering antennas
    (Basel : MDPI AG, 2019) Hassan, Emadeldeen; Martynenko, Denys; Wadbro, Eddie; Fischer, Gunter; Berggren, Martin
    This paper proposes novel low-profile differential-fed planar antennas with embedded sharp frequency selectively. The antennas are compact and easy to integrate with differential devices without matching baluns. The antenna design is formulated as a topology optimization problem, where requirements on impedance bandwidth, directivity, and filtering are used as the design objectives. The optimized antennas operate over the frequency band 6.0-8.5 GHz. The antennas have reflection coefficients below -15 dB, cross-polarization levels below -42 dB, a maximum gain of 6.0 ± 0.5 dB, and a uniform directivity over more than 130° beamwidth angle in the frequency band of interest. In addition, the antennas exhibit sharp roll-off between the operational band and frequencies around the 5.8GHz WiFi band and the 10 GHz X-band. One antenna has been fabricated with a good match between simulation and measurement results. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.