In this contribution we compare the back-projection algorithm with our recently developed modified range migration algorithm for 3D terahertz imaging using sparse multistatic line arrays. Numerical and experimental investigations show that imaging results from the proposed range migration algorithm approximates very nicely these of the back-projection algorithm, yet with a significant computational saving. These results are appealing for time critical 3D terahertz imaging.

We present the design of an optical modulator for amplitude modulation in a special silicon-on-insulator technology with 250 nm silicon layer thickness. The design of the modulator is optimized by simulating different parameters like dimension of the structure and doping of the silicon to improve the performance of the device. In addition, a prototype is fabricated and successfully measured to demonstrate the functionality of the technology.

In this paper, a novel approach (using metamaterials) is used to enhance the XPD for a dual linear polarization patch antenna at the frequency of 10 GHz. This improvement is obtained by placing two S-RRs close to the microstrip patch antenna, placing a SRR between two microstrip feed lines, and etching two pairs of CSRRs in the ground plane. An improvement in the XPD by 8.8 dB as compared to the conventional dual linear polarization antenna is noticed.

We discuss the results of an intercomparison for electric field strength measurements within the DKD. The comparison has been carried out on the field strength value required to reach a display reading of 20 V m⁻¹ of the field probes. While the results agree well for the small field probe and when the larger commercial 3-axis field probe is oriented in the direction of the magnetic field, larger deviations occur, when the larger 3-axis field probe is oriented into the direction propagation.

This paper presents a guided wave Six-Port interferometric radar system with integrated I/Q offset cancelation. An intelligent algorithm is proposed which optimally adjusts three voltage controlled attenuators and one voltage controlled phase shifter in the radio frequency part of the system. By minimizing the I/Q offset, the standard deviation as well as the relative error are decreased in comparison to an uncompensated measurement setup.

A cost-effective and universal FMCW radar is developed for the RF characterisation of wind turbine plants. This radar is modular and can be easily adapted for different measurement tasks. A long-term goal is to investigate high-frequency characteristics of wind turbines at different locations by their Doppler spectrum. The results obtained will be used to derive a statistical model.

Meta-sheets open up new opportunities in the design of radomes for microwave antennas. A meta-sheet typically consists of a periodic array of small resonators embedded in a thin dielectric layer. The smallness of unit cells and the large electrical size of microwave radomes significantly complicate full-wave numerical simulations as a very fine sampling over a large area is required. This paper proposes an efficient simulation approach, which combines Physical Optics and Finite Element methods.

Recently, for modeling biological amplification processes, nonlinear amplifiers based on the Andronov–Hopf bifurcation have become a focus of attention. In this contribution, we analyze discrete-time implementations of this type of amplifiers. The effects of the time-discretization by explicit integration methods are discussed. A novel discrete-time system based on the Neimark–Sacker bifurcation is introduced, that outstandingly approximates the behavior of a particular Hopf-type amplifier.

This paper reports on an effective root-cause analysis method of memory effects in power amplifiers, as well as introduces compensation techniques on a circuit design level. Despite conventional memory-effect approaches, the discussed method uses a two-tone scan over a wide operation and modulation range. The approach is demonstrated on a 65-nm CMOS power amplifier with an OIP1 of 27 dBm and a PAE of over 30 % using WCDMA and LTE signals.

This work investigates the errors, numerically and analytically, which occur due to the discretization of surveillance space in a multi-sensor radar system. The result of these investigations help to imprve the efficiency of the well-known compressed sensing algorithms. The improvement is critical for the cases where the signal processing algorithms must deliver the results within very short time intervals, e.g. 5 milliseconds or less.

This paper presents a novel algorithm for traffic monitoring applications, where the powerful post-Doppler space-time adaptive processing (PD STAP) is combined with the OpenStreetMap database. The road map is applied after the PD STAP for recognizing and rejecting false detections, and for repositioning off-road vehicles. The algorithm was tested using real multi-channel data acquired by DLR’s airborne F-SAR. The experimental results are shown and discussed, and the novelties are highlighted.

This paper presents a comparative overview of models for lithium-ion batteries from an electrical Engineering Point of view. The comparison criteria and the different models are presented. After this comparison, a model is used to establish a new communication concept.

Currently, the electrification of the drive train of passenger cars takes place, and the task of obtaining precise knowledge about the condition of the on board batteries gains importance. Due to internal characteristics, several existing methods cannot be used. This work describes an impedance based approach using the Taylor Fourier transformation. The parameters extracted by the method can be used as features in machine learning algorithms.

By analyzing the behavior of a self-mixing receiver, an appropriate model with a squre-law device can be obtained. This model is analyzed and a novel transmission technique with higher spectral efficiency is deduced by the formulation of the signal reconstruction problem as a phase retrival problem. Simulation results show the good performance of the proposed method.

Power consumption in wireless networks is crucial. In most scenarios the transmission time is short compared to the idle listening time for data transmission, the most power is consumed by the receiver. In low latency systems there is a need for low power wake-up receivers (WuRx) that reduce the power consumption when the node is idle, but keep it responsive. This work presents a WuRx designed out of commercial components to investigate the needs of a WuRx when it is embedded in a WPAN.

This paper presents a new generalized design methodology based on simplified gain estimations for multi-stage Cherry–Hooper amplifiers. With the proposed approach, a limiting amplifier with 14.6 THz gain-bandwidth-product and 0.5 ps maximum group delay variation is designed.

A flexible Hybrid System-in-Foil (HySiF) is designed to be used as an electronic skin for robotic applications. At IMS CHIPS, we believe that the future of flexible electronics relies on the integration of multiple electronic components on a single substrate. Our system comprises of an array of printed strain gauges and ultrathin flexible silicon chips, which demonstrates the complementary benefits of combining the low-cost printed electronics and the high performance silicon technologies.

Recent advances in Josephson junction based parametric amplifiers (JPA) have reached quantum limited amplification. In the quantum regime, dissipation and thermal fluctuations play a significant role. We outline the classical treatment of the Josephson parametric amplifier and derive a quantum mechanical formalism of the lossy JPA. We investigate the influence of dissipation and fluctuations on the dynamics of the amplification mode and show limitations of the applied quantum Langevin approach.

We present a novel silicon-organic hybrid modulator based on an single waveguide interferometer, which can be used for optical communications. A prototype modulator showing a voltage dependent transmission spectrum is obtained by cladding a dual-mode waveguide in a 250 nm silicon-on-insulator technology with a customized organic electro-optic layer. The presented prototype is to the best of the authors’ knowledge the first integrated single waveguide silicon-organic hybrid modulator.

The next generation DDR5 memory operates at double the frequency of DDR4 memory. At 6.4 Gbit s⁻¹ per port, the transmitted symbols are severely distorted at the receiver. Equalisation can be used to partly recover the distorted signal. In this work, a back-plane channel is analysed to derive the requirements for receiver-side equalisation. Based on these results, different correction methods for DDR5 data buffer front-ends are discussed. The results of the equalisation are shown.

Analog environmental signals must be converted to digital for processing and transmitting. This analog to digital conversion is usually done with a constant rate. To save energy during conversion and transmission this conversion rate can be made adaptable to the signal form, which is called asynchronous A-to-D conversion. Before digital processing the asynchronous sampled data must be interpolated to a constant rate. This interpolation is subject of the article. The work was funded by the DFG.

Electric equipment can be shielded against high power electromagnetic fields via metallic cavities. At certain frequencies, called resonances, the shielding effectiveness collapses. In this paper the impact of different sized windows in the shield is analyzed. The results is: at a certain size of the window, approximately one third of the shield's size, the shielding effectiveness is at its minimum. Furthermore, the quality factor of shields with different windows sizes is analyzed.

In this article the modeling of electromagnetic field coupling to nonlinear devices is studied. This is of benefit in the context of Electromagnetic Compatibility where the interaction between sensitive electronics within complex systems and electromagnetic interference is investigated.

In this paper, the optimization of the power transfer over wireless channels having multiple-inputs and multiple-outputs (MIMO) is studied. As a result, an optimization framework is proposed, which yields the maximum achievable power transfer efficiency over a given MIMO channel and the corresponding operating point, i.e., the complex amplitudes of the optimal incident and reflected waves. The optimization framework can be used to gain insights in the WPT over arbitrary MIMO channels.

Nowadays, faced with the ever-increasing dependence on diverse electronic devices and systems, the proliferation of potential electromagnetic interference (EMI) becomes a critical threat for reliable operation. A typical issue is the electronics working reliably in power-line networks when exposed to electromagnetic environment. In this paper, we consider a conducted ultra-wideband (UWB) disturbance, and perform the impact evaluation at the loads in a network.

There is continuous interest in coupling processes between the lower and middle atmosphere. Here we analyse midlatitude winds measured by radar at 82–97 km and find that especially in February they are positively correlated with El Niño. The signal is strong for the upper altitudes accessible to the radar, but weakens below. The observations can be qualitatively reproduced by numerical experiments using a mechanistic global circulation model.

We describe the design of an exposure setup used to study possible non-thermal effects due to the exposure of human hematopoietic stem cells to GSM, UMTS and LTE mobile communication signals. The experiments are performed under fully blinded conditions in a TEM waveguide located inside an incubator to achieve defined environmental conditions as required for the living cells.

An algorithm to perform a sensitivity analysis for electromagnetic eigenvalue problems is presented. By computing the sensitivity of the eigenvalues und eigenvectors of the problem, a couple of information can be derived with only a single calculation, which normally requires multiple computations. The results for the sensitivity of a specific parameter is presented and show good agreement with other methods. It’s a basic algorithm which can be applied to similar problems.

In diesem Beitrag wird eine selbstkonsistente Carleman Linearisierung zur Untersuchung von Oszillatoren vorgestellt. Anstelle einer linearen Näherung um einen Arbeitspunkt, erfolgt mit Hilfe der selbstkonsistenten Carleman Linearisierung eine Approximation auf einem vorgegebenen Gebiet. Um in Anschluss das stationäre Verhalten von Oszillatoren zu beschreiben, wird die Berechnung einer Poincaré-Abbildung durchgeführt. Mit dieser ist eine anschließende Analyse des Oszillators möglich.

This paper proposes a dual-baseline framework for the unwrapping of large-baseline interferometric SAR data. The algorithm aims at the efficient retrieval of absolute phase measurements regardless the very high frequency of the phase variations associated with large-baseline data. Hence, it promotes the recovery of digital elevation models with very high vertical accuracy, claim which is corroborated by the results obtained from two experiments using data acquired with the TanDEM-X sensor.