TY - CHAP A1 - Rasp, Franziska A1 - Sahinbas, Burak A1 - Reisinger, Thomas A1 - Hipp, Susanne A1 - Leitgeb, Erich T1 - Experimental Validation of a Full Polarimetric Channel Model with Frequency-Dependent Antenna Gain for Polarization Diversity Studies T2 - 2025 19th European Conference on Antennas and Propagation (EuCAP), 30. March-04. April 2025, Stockholm N2 - Autonomous driving, child presence detection, and digital car keys rely on precise localization. Therefore, accurate simulation environments are essential for designing radio systems and optimizing their positioning algorithms. A critical aspect of developing a reliable localization system is modeling the physical radio channel, which includes the transmitting antenna, the propagation medium, and the receiving antenna. However, existing channel models often overlook important physical effects of antennas, such as frequency dependence and polarization, leading to discrepancies between simulations and real-world measurements. To address this, the paper enhances full polarimetric channel models by incorporating the frequency dependence of both antennas and propagation channels. The theoretical model is validated through Vector Network Analyzer channel sounding measurements using reference antennas. This approach provides a foundation for polarization-based post-processing, ultimately improving positioning accuracy. KW - Accuracy KW - Antenna Embedding KW - Antenna measurements KW - Antennas KW - Channel Modelling KW - Channel models KW - Channel Sounding KW - Frequency dependence KW - Frequency diversity KW - Location awareness KW - Polarization Diversity KW - Propagation KW - Receiving antennas KW - Transmitting antennas KW - Vectors Y1 - 2025 SN - 978-88-31299-10-7 U6 - https://doi.org/10.23919/EuCAP63536.2025.10999403 PB - IEEE ER - TY - CHAP A1 - Marterer, Verena A1 - Muhr, Franz-Xaver A1 - Soukup, Radek A1 - Hipp, Susanne A1 - Blecha, Tomáš T1 - Material Characterization Using Waveguide Measurement Technique for the Development of Textile Antennas T2 - 2025 19th European Conference on Antennas and Propagation (EuCAP), Stockholm, Sweden, 3/30/2025 - 4/4/2025 N2 - Significant advances in using conductive textiles have been made over the past two decades, particularly in knitted fabrics. The aim is to deepen understanding of how knitted structures, especially those with hybrid yarns containing fine conductive elements (microwires), interact with electromagnetic fields. To establish simulation models that align with subsequent measurements, it is crucial to determine the dielectric properties, specifically relative permittivity and loss tangent/conductivity. This research investigates whether knitted structures with hybrid yarns exhibit anisotropic permittivity, meaning different dielectric properties along orthogonal axes within the fabric plane. These properties were measured using a waveguide technique’ whereby the structures were rotated by 90° to observe changes. The results demonstrate that the knitted structure exhibits metallic-like reflective behavior in one direction, while rotation leads to dielectric material characteristics. This effect is influenced by the number of conductive microwires and the materials used for these wires, such as silver-plated copper or bronze. KW - Anisotropic KW - Anisotropic magnetoresistance KW - conductive textiles, anisotropy, polarization KW - Dielectric loss measurement KW - Electromagnetic interaction KW - Electromagnetic waveguides KW - Fabrics KW - Hybrid yarns KW - Knitted structure KW - Permittivity KW - Permittivity measurement KW - Textile antennas KW - Wires KW - Yarn Y1 - 2025 SN - 978-88-31299-10-7 U6 - https://doi.org/10.23919/EuCAP63536.2025.10999278 SP - 1 EP - 5 PB - IEEE ER - TY - THES A1 - Schön, Matthias T1 - Implementation and Evaluation of the ESPRIT Algorithm for DoA Estimation on an FPGA-based SDR Platform N2 - Environmental sensing using smart antennas and antenna arrays is a broad field with many applications in different areas. This thesis is part of the initial stage of a longer research project at the OTH Regensburg, with the goal of enhancing the antenna-array-based sensing capabilities of base stations. Existing technologies that utilize radio waves, such as radar, often require the generation of special signals to scan the environment. This project aims to utilize the existing mobile communication traffic instead, making the benefits of sensing capabilities available to a wider range of applications. Many of the array processing methods require high computational power and are used in environments with real-time constraints. Therefore, the use of field-programmable gate arrays (FPGAs) for hardware acceleration of these methods will be investigated, evaluating which methods are suitable for implementation on FPGAs. The focus in this thesis lies on the Estimation of Signal Parameters Via Rotational Invariance Techniques (ESPRIT) method for direction of arrival (DoA) estimation, as it is a popular and highly accurate method that does not rely on calibration. The accelerator is implemented for the RFSoC4x2 software-defined radio (SDR), using Vitis High-Level Synthesis (HLS) for implementation of the algorithm itself, Vivado for the hardware configuration, and Python Productivity on Zynq (PYNQ) for drivers and application code. Simulations for evaluation and verification, as well as test data generation, are implemented in Julia, using a custom array signal processing package. A measurement setup is used to collect experimental data for simulation and evaluation of the performance of the implemented ESPRIT. It is shown that the underlying assumption of equal subarrays does not hold for the array used for the measurements. This causes the estimates to be erroneous and can only be addressed by employing other algorithms that allow for the required calibration. KW - Field programmable gate array KW - Digitale Signalverarbeitung KW - Array signal processing KW - Direction-of-arrival estimation Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-86883 CY - Regensburg ER -