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Dissertation
Microfluidics Based 3D Printed Reconfigurable Antenna for K-Band Applications
(2023)
In dieser Arbeit werden neuartige mikrofluid-basierte, rekonfigurierbare Antennen für Mikrowellen-Anwendungen vorgestellt. Ebenfalls vorgestellt wird eine kosteneffektive Methode zur ultra-breitbandigen Erhöhung (definiert als Bandbreite von 20% oder höher als die zentrale Frequenz) des Antennengewinns basierend auf dielektrischen Linsen. Zunächst wird dabei ein fest-verdrahtetes Design entwickelt. Diese Antenne verwendet kapazitive Lasten, um die -10 dB Bandbreite um den Faktor 2.5 (+150%) zu erhöhen. Die vorgeschlagene ...
Dissertation
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Highly Selective Gas Sensors using GaN Nano Wires
(2023)
Over recent years, a variety of nanostructure gas sensor designs have been published, utilizing structures such as planar high electron mobility transistors (HEMTs) and one-dimensional structures like nanorods, nanowires, and nanotubes. Even though these sensors have demonstrated responses to certain target gases, generally all designs also showed cross-sensitivites to other gases in the same order of magnitude. However, a concept for developing highly selective nanowire sensors that are sensitive to only one specific ...
Dissertation
Mechanically consistent scaling of historical stone columns
(2023)
A number of sites inscribed on the World Heritage list have sustained damage to their stone columns as a result of seismic events that have occurred over a period of thousands of years. Despite the acknowledged risk posed by seismic activity to such structures, there remains a paucity of scientific knowledge concerning the behaviour of stone block structures under seismic loading.
The present study focused on the rocking motion between two stone drums, besides the sliding and torsion motions. This mechanism is the ...