Wolfgang Mathis
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View article: On Gustav Robert Kirchhoff’s contributions to electrodynamics
On Gustav Robert Kirchhoff’s contributions to electrodynamics Open
Purpose This work is dedicated to the two-hundredth anniversary of the birth of German physicist Gustav Robert Kirchhoff. The purpose ot the article is to point out that Kirchhoff’s research includes an impressive number of fundamental pub…
View article: The Long Road to Entertainment Radio Broadcasting in Germany
The Long Road to Entertainment Radio Broadcasting in Germany Open
In 2023, the 100th birthday of “Unterhaltungs-Rundfunk” (Entertainment Radio Broadcasting) in Germany was celebrated with numerous special exhibitions and contributions in the press, radio and television. In this context, details on the hi…
View article: Egbert von Lepel and the Invention of the Spark-Gap Transmitter
Egbert von Lepel and the Invention of the Spark-Gap Transmitter Open
On 29 October 1923, radio broadcasting or “Rundfunk” was officially opened in the Voxhaus in Berlin and thus the new communication medium was now also available in Germany, but later than in other countries such as the US and the UK. Howev…
View article: Heinrich Hertz [Pioneers in CAS]
Heinrich Hertz [Pioneers in CAS] Open
Heinrich Rudolf Hertz discovered in 1887 the electromagnetic waves experimentally. Independent of Oliver Heaviside and Josiah Willard Gibbs, he formulated Maxwell's equations in the form known today. Therefore, Hertz became one of the foun…
View article: Gustav Robert Kirchhoff [Pioneers]
Gustav Robert Kirchhoff [Pioneers] Open
In the 19th century, new electrical, magnetic, and thermal phenomena were observed, eventually leading to the development of electromagnetic theory and thermodynamics as new theories of physics. These theories were mainly developed by p…
View article: Wilhelm Cauer [Pioneers in CAS]
Wilhelm Cauer [Pioneers in CAS] Open
Wilhelm Cauer belonged to a very respected family in the German capital of Berlin. His father was a professor railway engineering at the Technical University of Berlin and several other family members were scientists or artists. Cauer's re…
View article: 100 Years of Wireless Telephony in Germany: Experimental Radio Transmission from Eberswalde and Königs Wusterhausen
100 Years of Wireless Telephony in Germany: Experimental Radio Transmission from Eberswalde and Königs Wusterhausen Open
In this contribution, we examine the development of radio technology before 1921 and the emergence of the broadcasting concept during the World War I. We consider in detail the experiments in the transmitter stations located in Eberswalde …
View article: Guest editorial
Guest editorial Open
The first symposium took place in 1981 in Bratislava and has been followed by conferences held in various parts of Europe.It is traditionally devoted to research and education in theory and applications of electromagnetic fields, electrica…
View article: Modeling and Simulation of stochastically deformed Waveguides using Schelkunoff's Method
Modeling and Simulation of stochastically deformed Waveguides using Schelkunoff's Method Open
This paper deals with the propagation of electromagnetic waves in cylindrical waveguides with irregularly deformed cross-sections. The general theory of electromagnetic waves is of high interest because of its practical use as a transmissi…
View article: Order reduction of hierarchical interconnected dynamical systems
Order reduction of hierarchical interconnected dynamical systems Open
The simulation of large scale nonlinear dynamical interconnected systems, as they arise in all modern engineering disciplines, is a usual task. Due to the high complexity of the considered systems, the principle of thinking in hierarchical…
View article: A Low-Power, Low-Noise 37-MHz Photoreceiver for Intersatellite Laser Interferometers Using Discrete Heterojunction Bipolar Transistors
A Low-Power, Low-Noise 37-MHz Photoreceiver for Intersatellite Laser Interferometers Using Discrete Heterojunction Bipolar Transistors Open
Intersatellite laser interferometers feature quadrant photoreceivers to produce electrical signals from the interfered optical beams. In the particular case of LISA, the expected optical AC beat note has an amplitude of the order of nW. Th…
View article: Analysis of Dissipative Nambu Systems with Limit Cycles Using a Self-consistent Carleman Linearization
Analysis of Dissipative Nambu Systems with Limit Cycles Using a Self-consistent Carleman Linearization Open
In this contribution a canonical dissipative Nambu system with limit cycles is analyzed with a self-consistent Carleman linearization in order to obtain an approximation of the emerging limit cycle. In contrast to a numerical simulation, t…
View article: Behavioral modeling of nonlinear transfer systems with load-dependent <i>X</i>-parameters
Behavioral modeling of nonlinear transfer systems with load-dependent <i>X</i>-parameters Open
In this contribution, different approaches based on the X-parametersTM to model the behavior of mismatched nonlinear transfer systems are examined. The X-parameters based on the PHD1-principle introduced by Verspecht and Root (2006) as an …
View article: Electrostatic sensor modeling for torque measurements
Electrostatic sensor modeling for torque measurements Open
Torque load measurements play an important part in various engineering applications, as for automotive industry, in which the drive torque of a motor has to be determined. A widely used measuring method are strain gauges. A thin flexible f…
View article: Discretization analysis of bifurcation based nonlinear amplifiers
Discretization analysis of bifurcation based nonlinear amplifiers Open
Recently, for modeling biological amplification processes, nonlinear amplifiers based on the supercritical Andronov–Hopf bifurcation have been widely analyzed analytically. For technical realizations, digital systems have become the most r…
View article: Eine selbstkonsistente Carleman Linearisierung zur Analyse von Oszillatoren
Eine selbstkonsistente Carleman Linearisierung zur Analyse von Oszillatoren Open
Die Analyse nichtlinearer dynamischer Schaltungen ist bis heute eine herausfordernde Aufgabe, da nur selten analytische Lösungen angegeben werden können. Daher wurden eine Vielzahl von Methoden entwickelt, um eine qualitative oder quantita…
View article: Elektronenröhren (Internet)
Elektronenröhren (Internet) Open
Anmerkung: Dieser Abschnitt kann aus dem Internet als PDF-File geladen werden; Einzelheiten dazu findet man im Vorwort zu diesem Buch. Die Hinweise auf Abschnitte, Gleichungen und Abbildungen beziehen sich auf den vorliegenden Text. Die Se…
View article: Adapting the range of validity for the Carleman linearization
Adapting the range of validity for the Carleman linearization Open
In this contribution, the limitations of the Carleman linearization approach are presented and discussed. The Carleman linearization transforms an ordinary nonlinear differential equation into an infinite system of linear differential equa…
View article: Implementation of a digital evaluation platform to analyze bifurcation based nonlinear amplifiers
Implementation of a digital evaluation platform to analyze bifurcation based nonlinear amplifiers Open
Recently, nonlinear amplifiers based on the supercritical Andronov–Hopf bifurcation have become a focus of attention, especially in the modeling of the mammalian hearing organ. In general, to gain deeper insights in the input-output behavi…
View article: Ambiguities in input-output behavior of driven nonlinear systems close to bifurcation
Ambiguities in input-output behavior of driven nonlinear systems close to bifurcation Open
Since the so-called Hopf-type amplifier has become an established element in the modeling of the mammalian hearing organ, it also gets attention in the design of nonlinear amplifiers for technical applications. Due to its pure sinusoidal r…
View article: Modeling and simulation aspects of AC machines
Modeling and simulation aspects of AC machines Open
In the field of power and drive systems, electrical AC machines are mostly modeled using a set of explicit ordinary differential equations in a state space representation. It is shown, that by using other equation types for simulation, alg…
View article: A novel ZePoC encoder for sinusoidal signals with a predictable accuracy for an AC power standard
A novel ZePoC encoder for sinusoidal signals with a predictable accuracy for an AC power standard Open
In this paper we present an analytical formulation of a Zero Position Coding (ZePoC) encoder for an AC power standard based on class-D topologies. For controlling a class-D power stage a binary signal with special spectral characteristics …
View article: Antenna Array Pattern Synthesis via Coordinate Descent Method
Antenna Array Pattern Synthesis via Coordinate Descent Method Open
This paper presents an array pattern synthesis algorithm for arbitrary arrays based on coordinate descent method (CDM). With this algorithm, the complex element weights are found to minimize a weighted L2 norm of the difference between des…