Theses

Objectives: In contrast to multiprobe antenna measurement systems with fixed angular resolution of 1° to 5°, the gantry arm-based BIRA system installed in the "virtual road - simulation and test area - VISTA" provides adjustable resolutions better than 1°. Up to now, the arm carrying the measurement probe is operated in a stepped mode, meaning that it holds the position during the measurement. This, however, is time consuming and should be optimized by a swept-mode operation where the probe is moving continuously. This mode should be implemented and tested with special consideration of the inevitably resulting angular smoothing.

Methods: Python programming, choice of suitable test antennas, antenna pattern measurements, data post-processing, design of time- and accuracy-optimized measurement procedures

Supervisor: Dr. Tobias Nowack

Objectives: Design of a feed structure for a single-aperture antenna terminal that operates at S-band frequencies for terrestrial networks, as well as in the S- and Ka-band frequency ranges for non-terrestrial networks, tailored to 5G wireless automotive applications.

Methods: Literature study of feed networks, design and electromagnetic full-wave simulations, parametric optimization, manufacturing of a lab version, experimental evaluation, comparison of experimental and numerical results

Supervisor: M.Sc. Ehtisham Asghar

Objectives: Design of a compact antenna for operation in 5G and 6G frequency bands, suitable for integration into bicycle frames. The antenna shall support both terrestrial and non-terrestrial V2X communication links, ensuring continuous connectivity in urban mobility applications. It should achieve sufficient field-of-view and high radiation efficiency.

Methods: Literature study of compact antenna designs for centimeter and millimeter wave ranges. Identification of required parameters with respect to relevant urban traffic scenarios. Antenna design and optimization using full-wave electromagnetic simulations for key parameters like gain, beamwidth, and bandwidth requirements (matching, pattern, polarization). Development of a lab demonstrator, experimental evaluation, comparison of experimental and numerical results.

Supervisor: M.Sc. Ehtisham Asghar, M.Sc. Yumna Gillani (from February 2025)

Objectives: Development and training of machine learning algorithms to classify detected objects into categories such as vehicles, pedestrians, cyclists, and static objects based on radar point cloud data extracted from the daily CAMIL operation.

Methods: Literature study of millimeter-wave automotive radar sensors and signal processing, concepts for data structuring, signal processing, and target classification using machine learning techniques

Supervisor: M.Sc. Isabella Varga

Objectives: Design, simulation, and dual-polarimetric radar reflectivity measurements of dummies of vulnerable road users over a selected range of illumination and observation angles

Methods: Literature study of bi-static radar cross-section (RCS) in the millimeter-wave range, electromagnetic simulation for the evaluation of bi-static RCS of objects using suitable solver, bi-static dual-polarized reflectivity measurements in VISTA using the robotic BIRA extension, comparison of simulated and measured results

Supervisor: M.Sc. Isabella Varga

Objectives: Many empirical or numerical wave propagation models are available for the determination of electromagnetic fields around mobile radio base stations. The agreement between simulated and measured data depends on model parameters and, particularly for deterministic models, on the accuracy of the underlying digital twin. A digital twin includes a geometric replica of the real environment, the electromagnetic material parameters of the objects and the radiation patterns of the transmit and receive antennas. Studies are needed to optimize the parameter settings, to evaluate the usefulness and accuracy of high-resolution geometrical models.

Methods: Literature study on electromagnetic wave propagation models, numerical simulation of electromagnetic exposure around mobile radio base stations (e.g. ray tracing solvers from Remcom XGtd, ADTI HTZ Communications, Ansys HFSS), comparison with measured data.

Supervisor: M.Sc. Lisa-Marie Schilling

Objectives: To evaluate the maximum exposure at 5G massive MIMO systems, data traffic can be provoked. To date, measurements have been carried out only at the center frequency of the transmission channel and then extrapolated to the entire channel bandwidth. However, frequency-selective fluctuations can corrupt the assessment of the actual maximum exposure, so that other methods need to be devised. In addition, especially in indoor and NLOS scenarios, the uplink exposure of the user equipment may be stronger than the downlink exposure of the base station and hence corrupt the measurements, so that methods are to be investigated to minimise this uplink interference.

Methods: Literature study of the assessment of maximal exposure at 5G massive-MIMO base stations, measurement of the maximum exposure using provoked data traffic, considering frequency-selective effects, derivation of recommendations for reducing the interfering uplink exposure of the user equipment

Supervisor: Dr.-Ing. Christian Bornkessel

Objectives: To determine the maximum exposure at 5G massive-MIMO systems, code-selective measurements of the signaling signals with subsequent extrapolation to full load of the base station can be applied. In massive MIMO systems, however, signaling and data traffic are radiated via two different antenna patterns, implying location-dependent gain correction factors. Under line-of-sight (LOS) conditions, this approach yields satisfactory results. However, gain correction under NLOS conditions requires more advanced approaches.

Methods: Literature study of the assessment of maximal exposure at 5G massive-MIMO base stations, measurement of the gain correction factor between signaling and data traffic in NLOS scenarios, derivation of recommendations for the assessment of maximum exposure at massive MIMO systems. As a reference, the exposure at full load with provoked data traffic via a mobile phone shall be used.

Supervisor: M.Sc. Lisa-Marie Schilling

Objectives: As the progressive market penetration of V2X will lead to an increasing number of communicating nodes, it will also affect the electromagnetic exposure. The electromagnetic emission from mobile V2X communication nodes shall be investigated for different driving profiles. Based on these exposure settings, scalable results shall be derived for different types of traffic flow and V2X market penetration rates.

Methods: Literature study of V2X systems and its electromagnetic field exposure assessment. Implementation of electromagnetic exposure assessment for V2X nodes. Emission-critical comparison of different vehicle driving profiles and traffic flows.

Supervisor: M.Sc. Tobias Struck

Objectives: In this research topic, ITS-enabled traffic nodes shall be identified and quantified in terms of their individual contribution to the overall electromagnetic exposure. The exposure from different V2X nodes shall be aggregated and evaluated in terms of areal field distribution in selected stationary and moving scenarios by simulation and measurement.

Methods: Literature study of V2X systems and related RF exposure assessment. Identification and quantification of relevant V2X messages and their electromagnetic exposure contribution. Implementation of location-specific exposure assessment using computational algorithms (e.g. electromagnetic full-wave simulations) and confirmation by measurements in VISTA.

Supervisor: M.Sc. Tobias Struck

Objectives: Derive a concept for a statistical modelling approach considering the distance dependence of bi-static reflectivity patterns of electrically large vulnerable road user (VRU) objects like pedestrians or bicyclists between nearfield and far-field situations

Methods: Literature study of existing bi-static reflectivity and radar cross-section (RCS) models, analytical differentiation of nearfield and far-field situations, electromagnetic simulations of the transition from nearfield to far-field, using selected VRU objects in Ansys HFSS, comparison and validation using selected bi-static reflectivity measurements in VISTA

Supervisor: M. Sc.Sc. Isabella Varga

Objectives: Implement selected real-world scenarios in our scenario simulator and perform measurements using our unique research laboratory VISTA. Compare the results with real-world measurement data and characterize them with suitable test metrics.

Methods: Study of previous major research on automotive radar testing and test metrics, scenario simulation and testing using existing toolchain, OTA/ViL-based radar testing in VISTA, evaluation of results in the framework of suitable test metrics.

Supervisor: M.Sc. Luqman Nazar

Objectives: Focus of this work is the design of a discrete broadband bias-tee circuit covering a frequency range from about 50 kHz to about 10 GHz using commercially available components, to provide the DC power supply for a monolithic microwave integrated circuit (MMIC). Practical implementation on a suitable RF substrate and verification by measurements are planned.

Methods: Literature and research and conceptual studies, simulation and comparison of the concepts identified using Keysight ADS design software, design, layout, and RF measurements using network analysis.

Supervisor: Dipl.-Ing. Uwe Stehr

Objectives: Comparison of single-ended and differential transmission lines for low-voltage differential signaling (LVDS) in the microwave frequency range. Practical comparison of both concepts on a suitable RF substrate, design of single-ended to differential and differential to single-ended converters.

Methods: Familiarization with transmission line theory for RF and microwave signals (line impedance, propagation constant, field distribution, frequency range of operation, mixed-mode S-parameters), design of different transmission lines and signal converters using Keysight ADS design software and RF verification measurements using vector network analyzer or digital oscilloscope

Supervisor: Dipl.-Ing. Uwe Stehr

Objectives: For the generation of high voltage (HV) pulses at high frequencies (HF) to drive Pockels cells, gallium nitride (GaN)-based integrated circuits (IC) present a promising solution. The Interuniversity Microelectronics Centre (IMEC) offers a GaN multi-project service (MPW) process to realize complex GaN ICs. The GaN transistors provided by the IMEC shall be evaluated regarding their capability to realize ultra-fast Pockels cell drivers by circuit design and simulation of a half-bridge circuit. Design focus is on the reduction of parasitic elements.

Methods: Familiarization with the requirements of Pockels cell driver electronics and circuit topologies to realize high voltage and high frequency driver circuits based on GaN transistors, analysis of the influence of parasitic elements as main source of switching losses, circuit simulation with Cadence design software and optimization of GaN transistor layout with respect to the switching frequency.

Supervisor: M.Sc. Robert Neumann