Refine
Year of publication
Document Type
- Article (71)
- Conference Proceeding (17)
- Book (8)
- Part of a Book (1)
- Patent (1)
Keywords
- Hot S-parameter (2)
- 3-D printing (1)
- Antennen (1)
- Automotive application (1)
- Circuit simulation (1)
- Elektrotechnik (1)
- FPGA (1)
- Feldsimulation (1)
- Frequency Doubler (1)
- Furnace (1)
- Fusion (1)
- Harmonic Radar (1)
- Hochfrequenztechnik (1)
- Mode converter (1)
- Modeling (1)
- Plasma (1)
- Plasma diagnostics (1)
- Plasmatechnik (1)
- Radar (1)
- Rescue System (1)
- Tag (1)
- Transponder (1)
- batteries and fuel cells (1)
- electrospinning (1)
- fibers (1)
- harmonic radar (1)
- harmonic radar tags (1)
- ignition (1)
- irradiation (1)
- metrological characterization (1)
- microplasma (1)
- microwave (MW) plasma (1)
- microwave measurements (1)
- nonlinear VNA measurements (1)
- passive inter-modulation (1)
- plasma jet (1)
- porous materials (1)
- power integrity (1)
- signal integrity (1)
Institute
- Fachbereich Elektrotechnik und Informationstechnik (98) (remove)
Design and Development of a Hot S-Parameter Measurement System for Plasma and Magnetron Applications
(2020)
This paper introduces a new maritime search and rescue system based on S-band illumination harmonic radar (HR). Passive and active tags have been developed and tested while attached to life jackets and a small boat. In this demonstration test carried out on the Baltic Sea, the system was able to detect and range the active tags up to a distance of 5800 m using an illumination signal transmit-power of 100 W. Special attention is given to the development, performance, and conceptual differences between passive and active tags used in the system. Guidelines for achieving a high HR dynamic range, including a system components description, are given and a comparison with other HR systems is performed. System integration with a commercial maritime X-band navigation radar is shown to demonstrate a solution for rapid search and rescue response and quick localization.
Carbon nanofiber nonwovens represent a powerful class of materials with prospective application in filtration technology or as electrodes with high surface area in batteries, fuel cells, and supercapacitors. While new precursor-to-carbon conversion processes have been explored to overcome productivity restrictions for carbon fiber tows, alternatives for the two-step thermal conversion of polyacrylonitrile precursors into carbon fiber nonwovens are absent. In this work, we develop a continuous roll-to-roll stabilization process using an atmospheric pressure microwave plasma jet. We explore the influence of various plasma-jet parameters on the morphology of the nonwoven and compare the stabilized nonwoven to thermally stabilized samples using scanning electron microscopy, differential scanning calorimetry, and infrared spectroscopy. We show that stabilization with a non-equilibrium plasma-jet can be twice as productive as the conventional thermal stabilization in a convection furnace, while producing electrodes of comparable electrochemical performance.
Dieses Lehr- und Fachbuch vermittelt anschaulich die Grundlagen der HF-Technik, gibt konkrete Beschreibungen für den Entwurf von linearen Komponenten aus Bauteilen wie auch Leitungen für High-Speed- und HF-Schaltungen. Dem Leser wird vermittelt, wie Bauteile modelliert und Schaltungen synthetisiert und optimiert werden. Mit Hilfe frei verfügbarer Simulationssoftware können GHz-Schaltungen selbst entwickelt werden. Viele Übungsbeispiele ermöglichen die Eigenkontrolle des Wissensstandes. Weiterhin werden komplexe nichtlineare Komponenten wie Hochfrequenzmischer, Oszillatoren und Synthesegeneratoren in ihrer Funktionalität dargestellt. Die neuen Mixed-Mode-Streuparameter sowie deren Leitungs- und Schaltungstechnik für Anwendungen der schnellen Digital- und der modernen HF-Technik sind ausführlich beschrieben. Es wird auf Systeme für folgende Bereiche eingegangen: Streuparametermesstechnik, verschiedene Funktechniken, UHF-RFID und Lokalisierung- und Ortung. Dem Leser wird somit ermöglicht, komplexe GHz-Schaltungen insbesondere mit Halbleiter-, SMD- und LTCC-Schaltungen zu entwickeln.
A novel method to determine the extruded length of a metallic wire for a directed energy deposition (DED) process using a microwave (MW) plasma jet with a straight-through wire feed is presented. The method is based on the relative comparison of the measured frequency response obtained by the large-signal scattering parameter (Hot-S) technique. In the practical working range, repeatability of less than 6% for a nonactive plasma and 9% for the active plasma state is found. Measurements are conducted with a focus on a simple solution to decrease the processing time and reduce the integration time of the process into the existing hardware. It is shown that monitoring a single frequency for magnitude and phase changes is sufficient to achieve good accuracy. A combination of different measurement values to determine the length is possible. The applicability to different diameter of the same material is shown as well as a contact detection of the wire and metallic substrate.
This article addresses the need for an innovative technique in plasma shaping, utilizing antenna structures, Maxwell’s laws, and boundary conditions within a shielded environment. The motivation lies in exploring a novel approach to efficiently generate high-energy density plasma with potential applications across various fields. Implemented in an E01 circular cavity resonator, the proposed method involves the use of an impedance and field matching device with a coaxial connector and a specially optimized monopole antenna. This setup feeds a low-loss cavity resonator, resulting in a high-energy density air plasma with a surface temperature exceeding 3500 o C, achieved with a minimal power input of 80 W. The argon plasma, resembling the shape of a simple monopole antenna with modeled complex dielectric values, offers a more energy-efficient alternative compared to traditional, power-intensive plasma shaping methods. Simulations using a commercial electromagnetic (EM) solver validate the design’s effectiveness, while experimental validation underscores the method’s feasibility and practical implementation. Analyzing various parameters in an argon atmosphere, including hot S -parameters and plasma beam images, the results demonstrate the successful application of this technique, suggesting its potential in coating, furnace technology, fusion, and spectroscopy applications.