Cheng Yang

Technische Universität Hamburg | TUHH · Institute of Electromagnetic Theory

In this work, an efficient iterative dataset generation strategy is proposed, considering prediction accuracy and high impact input parameters as figures of merit to define a sufficient number of samples for reliable machine learning (ML) results. Parameter prioritization in combination with artificial neural networks (ANNs) is designed for examina...

This article introduces an algorithm for transient simulation of electromagnetic structures loaded by lumped nonlinear devices. The reference application is energy-selective shielding, which adopts clipping devices uniformly spread along shield apertures to achieve a shielding effectiveness that increases with the power of the incident field, there...

In this article, we introduce a robust procedure for the extraction of passive rational macromodels of low-loss electromagnetic structures with massive port counts. Such structures pose inherent challenges that make standard macromodeling tools and approaches inadequate, mainly due to complexity and sensitivity at low frequency. The proposed approa...

This article presents a novel waveform relaxation scheme to solve electromagnetically large structures loaded with lumped linear and nonlinear elements. The scheme partitions the problem into a linear electromagnetic structure and a possibly nonlinear lumped circuit, which are coupled using Thévenin interfaces across the steps of an iterative wavef...

In this article, for the first time, the shielding of orbital angular momentum (OAM) waves by a cavity with apertures is evaluated. This is particularly interesting because the distinguishing feature between the OAM modes is their phase distribution in space, and, hence, shielding effectiveness is a mode-dependent phenomenon. A perfectly electrical...

There have been considerable efforts devoted to the study of topological phases in certain non-Hermitian systems that possess real eigenfrequencies in the presence of gain and loss. However, it is challenging to experimentally realize such non-Hermitian topological insulators in either quantum or photonic systems, due to the difficulties in introdu...

In this article, the orbital angular momentum (OAM) mode system, known from antenna communication, is applied and extended to various multiconductor transmission lines. In the context of this work, an OAM mode describes the excitation of a multiport system with a voltage distribution that is an eigenmode of a cyclic system. The OAM mode system is t...

Lumped-element grids provide an attractive option for wave propagation control in electromagnetic compatibility (EMC) engineering. This article investigates the peak shielding effectiveness (SE) of a diode grid used for protection of enclosures with apertures against high-intensity radiation fields (HIRFs). The nonlinearly loaded aperture is invest...

A recently developed concept for designing passive microwave components using functional vertical interconnect accesses (vias) for vertical integration in printed circuit boards (PCBs) is extended and transferred to the low temperature co-fired ceramic (LTCC) technology. Given the changed material properties and new technology constraints, it is sh...

This paper proposes a hierarchical adaptive sampling scheme for passivity characterization of large-scale linear lumped macromodels. Here, large-scale is intended both in terms of dynamic order and especially number of input/output ports. Standard passivity characterization approaches based on spectral properties of associated Hamiltonian matrices...

Low temperature cofired ceramics (LTCCs) refer to a mature technology with low-loss dielectric materials, high quality conductors, and high dimensional accuracy. This class of ceramics-based substrates is a popular choice for integration of a variety of electronics with active and passive components in both single- and multilayered environments. Ve...

This paper proposes a hierarchical adaptive sampling scheme for passivity characterization of large-scale linear lumped macromodels. Here, large-scale is intended both in terms of dynamic order and especially number of input/output ports. Standard passivity characterization approaches based on spectral properties of associated Hamiltonian matrices...

Higher-order topological insulators (HOTIs) represent a new family of topological materials featuring quantized bulk polarizations and zero-dimensional corner states. In recent years, zero-dimensional corner states have been demonstrated in two-dimensional systems in the form of quadrupole modes or dipole modes. Due to the challenges in designing a...

In this article, we present a hybrid numerical scheme to compute the transient electromagnetic fields scattered by a metallic structure loaded with lumped nonlinear loads. The proposed scheme is based on three successive steps. First, the field coupling problem to the structure with the nonlinear loads removed is solved in the frequency domain usin...

Radio waves carrying orbital angular momentum (OAM) have been intensively studied in recent years with respect to generation, propagation, and communication. In this article, the effect of an infinite ground on OAM wave propagation and communication is investigated numerically using the method of moments (MoM). A circular array of half-wavelength d...

There have been considerable efforts devoted to the study of topological phases in certain non-Hermitian systems that possess real eigenfrequencies in the presence of gain and loss. However, it is challenging to experimentally realize such non-Hermitian topological insulators in either quantum or photonic systems, due to difficulties in introducing...

Intelligence at either the material or metamaterial level is a goal that researchers have been pursuing. From passive to active, metasurfaces have been developed to be programmable to dynamically and arbitrarily manipulate electromagnetic (EM) wavefields. However, the programmable metasurfaces require manual control to switch among different functi...

The crosstalk suppression of multichannel coupled drivelines is studied for high performance integration of micro-electro-mechanical system (MEMS) arrays. By using traditional drivelines, for example, microstrip lines, the distance between adjacent drivelines should be large enough to reduce the multichannel coupling effects. As a result, the size...

Digital coding metasurfaces have attracted attention due to their advantages compared to metamaterials. Many devices have been proposed by encoding the phase responses on metasurfaces such as orbit angular momentum generation, prefect absorbers, and holography. For complete manipulation for propagation of electromagnetic waves, it would be benefici...