Connected cars will be equipped with several wireless transmission technologies. The corresponding exposure of the general public will be significantly influenced by these technologies and must be correctly evaluated. A new measurement procedure suitable for the European vehicle communication standard ITS-G5 together with exposure measurements performed in different cars are described. In comparison with WiFi and Bluetooth, ITS-G5 generated the highest exposure inside a car.

This paper presents the implementation of two easy-to-implement methods for radar imaging with a radar system on a linear drive for educational purposes. This method is a so-called synthetic aperture radar (SAR) approach which is commonly used in the space and aeronautical earth observation. In this paper the two methods are compared with each other and drawbacks and advantages are discussed.

In the upper (FR2) mm-wave 5G frequency band, the coverage area of a single antenna is very limited. Therefore, many antennas with electronical steering capability are needed for a good quality of service. These antennas have to be cost-effective and reliable, such as reflectarray antennas. The developed 10x10 reflectarray antenna has a gain of approximately 10 dBi and a continuous steering range from -30° to 30°.

D-VOR transmitters are used as navigation aids in aviation. In an airborne navigation receiver, a directional information (azimuth angle) related to the position of the aircraft and the location of the transmitter can be derived. In this work, the bearing accuracy of current methods is investigated. The proposed new method reduces noise and thus yields a significant increase in accuracy. Finally, the application of this new method to real measured signals confirms the theoretical expectations.

In this artice two loopantennas in freespace are modeled and simulated in a numerical field calculation program. To verify the results, two approaches based on equivalent electrical circuit diagrams (ECD) were investigated. One approach based on the ECD of a real coil and another is based on the input impedant of the antenna. The comparison of the results of the simulation and the analytical calculation of the ECD from the input impedance of the antenna showed a very good agreement.

This Paper introduces a low-cost vector network analyzer with a large frequency range made of commercial off-the-shelf components. Its architecture reduces complexity while maintaining many features of more complex designs. The design and some characteristic data is shown. The performance is better than currently available low-cost VNAs. The research was conducted as a Masters Thesis. The goal was creating a device hobbyists can afford and engineers can have on their desk for quick measurements.

In this contribution, a radar system for measuring the height profile of bulk solids in silos, is presented. By utilizing six integrated radar chips, a compact 3D imaging radar system with an novel fractal antenna layout is realized. The performance of the system has been evaluated by test measurements on a sand heap, showing an improved measurement accuracy compared to conventional radar level systems.

In this contribution, similarities and differences between electrical and thermal effects on cables are investigated. In the electrical transmission line theory, a wide variety of methods is known to describe the voltage and current along cables. The potential for the adaption of some of those methods to thermal problems is discussed. An example is given.

Quantification and minimization of uncertainty is an important task in the design of electromagnetic devices, which comes with high computational effort. We propose a hybrid approach combining the reliability and accuracy of a Monte Carlo analysis with the efficiency of a surrogate model based on Gaussian Process Regression. Further, we present a genetic multi-objective approach to optimize performance and robustness of a device at the same time.

According to the Guide to the Expression of Uncertaintyin Measurement (GUM), uncertainties must be specified for each measurement. Therefore, this work's primary objective is to examine the effect of irregular deformed boundaries on the electromagnetic field and the resonance frequencies of a field generator (TEM-cell). Using a semi-analytical approach, the wave characteristics can be determined and the uncertainty contribution of the field generator can be estimated.

Carrier synchronization is a crucial part of any wireless receiver, which is required due to frequency and phase offset. In this work, we compare interpolation techniques with different FFT-based carrier synchronization methods. Applied to reference burst types specified in the DVB-RCS2 standard, trade-offs between communication performance and hardware implementation efficiency are shown. Furthermore, we present and analyze a flexible IP core implemented on FPGA.

In the paper we describe how the detection of living objects, such as people and animals, can be significantly improved. It is particularly important to detect people in dangerous environments to protect them. For such a detection task we use a radar system. Radar, because the detection also has to work at night and if it rains or snows, these are the situations when other systems, i.e. cameras, fail. Our experiments showed that many radar applications can benefit from our approach.

This paper demonstrates a squaring circuit, which is a key element in many low-power receivers, designed in a low-cost technology. For its functionality, the circuit exploits the typical characteristics of a transistor. To enhance the speed of the circuit and consequently to enable higher data rates for the receiver, a novel “boosting circuit” is implemented. An additional control circuit regulates the output and simplifies the detection of an incoming signal.

In recent years, many simulation tools emerged to model the communication of connected vehicles. Thereby, the localization accuracy due to satellite navigation systems was treated as perfect. The effect of inaccurate positioning, however, was neglected so far. This paper presents a new simulation framework that can estimate the localisation accuracy of navigation systems like GPS, GLONASS or GALILEO, based on ray optical path loss predictions (ray tracing) considering 3D building data.

In this article, we examined the emergence of the new broadcast medium Radio in Germany shortly after World War I which is called Rundfunk in this country and consider the early radio transmitter stations in Eberswalde and Königs Wusterhausen.

This paper discusses modern applications for high performance analog and hybrid computer. In the first part, we do a theoretical prediction concerning the properties of these machines. In the second part, we compare such a computer against a standard laptop CPU. We find that the even a rather simple analog computer is actually on a par. In the third part, we give an outlook how future highly integrated analog computers could be used to tackle very large computational problems.

In high-frequency technology, devices for filtering signals in the frequency domain are often based on resonant structures. As a result, the physical dimensions of a filter generally increase with decreasing frequency of operation. In this work, bandstop filters are built from special resonant elements with small physical dimensions to reduce the filter size. The small sizes result from the large permittivity of the used ceramic, increasing the electrical length of the resonant elements.

A typical logistical RFID use-case is presented. The signal coverage is computed using accurate simulation techniques. A subsequent evaluation of the simulation results is performed. Emphasis is put on the derivation of expressive quantities to facilitate the evaluation and interpretation of the simulation results. Accurate simulations of the planned environment are essential to predict the real behavior and uncover flaws in the planned system, to avoid costly a-posteriori modifications.

The publication presents an EMI safeguarding approach from an Automotive Ethernet ECU to the vehicle antenna, which allows the emission signal calculation at the antenna in an early vehicle development stage. The approach shows a more accurate safeguarding method than the state of the art approach by a system level test. In combination with the considered simulation in this work, a more efficient safeguarding process of communication systems is possible.

Radar cross-section measurements require the background reflections to be much lower than the reflections of the device under test. Although, anechoic chambers with special target holders meet this requirement, they are expensive and still have imperfections. To reduce background reflections in environments where an anechoic chamber is not suitable, digital signal processing can be used. A complete signal processing realized in Matlab and a compact RCS measurement setup is presented.

Our research on the performance analysis of 300 GHz backhaul links considering historic weather data can show the feasibility of wireless backhaul links at the frequency range of 300 GHz under the general mid-term weather changes in Hanover area or the area whose general climate conditions are similar to Hanover.

On the way to autonomous driving a safety proof is inevitable. Here simulators can help, but their accuracy is not good enough, yet. In order to improve such simulations, we analyzed the behaviour of road surfaces on radar sensors. Therefore, laboratory measurements and open space measurements were performed. Differences depending on material and roughness could be proved. Furthermore, material parameters were calculated, which can be mapped to roads in existing simulation setups.

Large numbers of unexploded World War II bombs are recovered from the ground every year. However, it is often not clear whether an anonamly in the ground is actually dangerous goods or scrap. In this thesis an application of borehole radar is investigated, with which first a 2D image and then a 3D representation of the buried object is to be generated. Both performed simulation and field measurements show good results, even if optimizations are still necessary in the 3D representation.

This paper evaluates a method for reconstructing the phase and amplitude of superimposed signals with a frequency separation smaller than the DTFT frequency resolution would allow to differentiate.

We compare winds and tidal amplitudes in the upper mesosphere/lower thermosphere region for cases with disturbed and undisturbed geomagnetic conditions. The zonal winds in both the mesosphere and lower thermosphere tend to be weaker during disturbed conditions. The summer equatorward meridional wind jet is weaker for disturbed geomagnetic conditions. The effect of geomagnetic variability on tidal amplitudes, except for the semidiurnal tide, is relatively small.

A radar working in the 24 GHz ISM-band in a frequency modulated continuous wave mode has been used for vital sign monitoring of the heart beat and the breathing rate. The observation is hereby contactless with the patient sitting straight up in a distance of 1–2 m to the radar. A mathematical method to calculate the heart beat and breathing rate is presented. The results are compared with classical ECG measurement equipment.

For wireless capsule endoscopy (WCE), precise localization is an open research topic. In this study, a novel differential magnetic localization method for WCE is proposed. The differential method prevents interference of the geomagnetic field. Therefore, the mean position and orientation errors were significantly reduced by three orders in magnitude to less than 0.1 mm and 0.1°, respectively. In the future, the simulation-based results will be validated in experiments.