Konferenzbeiträge

To efficiently extract estimates about the propagation behavior of electromagnetic waves in a radio environment it is common to invoke the narrowband-assumption. It essentially states that the relative bandwidth of the measurement system is so low that the frequency response of a single propagation path only depends on it Time-of-Flight and the response of the measurement device can be calibrated independently of the measured channel. Recent advances into higher relative bandwidths and antenna arrays with larger spatial aperture render this assumption less likely to be satisfied, which leads to a model mismatch during estimation. In this case estimates are inherently biased and have a special statistical behavior. This behavior can be captured by the so-called Misspecified Cramér-Rao Bound, which formulates a lower bound for the variance of estimates that are biased due to model mismatch. We analyze this bound in contrast to the traditional Cramér-Rao Bound and show the shortcomings in the setting of joint ToF-DoA estimation in the mmWave spectrum. The conducted numerical studies also show that planar array geometries inherently suffer from violation of the narrowband assumption irrespective of the individual elements' frequency response, whereas circular structures show it to a lesser degree.

For decades, chipmakers brought digital logic ICs (integrated circuit) with an exponentially increasing complexity and computing power to market. This was made possible by continuously shrinking the size of the basic component of logic ICs, i.e., by MOSFET scaling. Over the years, MOSFET scaling passed through several stages with a new stage beginning when the scaling method used at the previous stage was approaching its limits. In the present paper, we provide an overview of these stages of scaling, discuss the transition from the conventional planar MOSFET to the FinFET architecture in the early 2010s, and converse about the upcoming introduction of another new MOSFET architecture, the SNC (stacked nanosheet channel) MOSFET. Here, special emphasis is put on transistors using two-dimensional (2D) materials for the stacked channels.

5G low-earth orbit (LEO) satellite communication plays a crucial role in enhancing the reliability and coverage of wireless connectivity for automated and connected driving. Compactness of user equipment antennas presents a key requirement for automotive mass-market applications offering non-terrestrial connectivity in addition to terrestrial mobile communications. Latest studies reveal the potential for moderate-gain antenna terminals for such applications. We present a circularly polarized 4 × 4 patch antenna array operating at a center frequency of 2S GHz in the 5G new-radio band n257 suitable for LEO satellite communications. The antenna is feasible for integration into the rear spoiler of a car, roof-top shark-fin antenna, or other plastic-covered antenna mounting locations. The embedded array offers 12 dBi measured realized gain and 4 GHz of -10 dB impedance bandwidth. It offers a 3-dB axial-ratio bandwidth of 900 MHz, demonstrating its circular polarization purity along the broadside direction. Realistic link budget calculations predict an uplink data rate of 6 Mbit/s, promising for various automotive mobility applications.

Wireless devices supporting global navigation satellite systems (GNSS) services have become an essential tool in different areas of technology such as agriculture, construction, automotive, etc. Therefore the performance and reliability of such devices are important aspects that need to be addressed in the testing stage during the development of the units. The integration of the Over-the-Air (OTA) testing method with the 3D Wave Field Synthesis (3DWFS) technique offer not only the benefit of having tests under controllable and repeatable conditions but also the ability to recreate complex and realistic scenarios in a controlled environment with full polarimetric support for the testing of wireless devices. This contribution applies this technology to emulate a GNSS scenario within an anechoic chamber. For the results validation, a realistic GNSS outdoor scenario was recorded and compared with the emulated scenario where 3DWFS was applied for each individual satellite. This represents a significant step for the GNSS community and also for the future development and testing of wireless devices.

Virtual validation methods strive to reduce the testing efforts of automated driving functions significantly. However, assuring the fidelity of deployed sensor models based on objective criteria remains an unsolved challenge, especially for radar target detection point clouds, since they are subject to major stochastic fluctuations.This work focuses on the scenario-based derivation of requirements for synthetic radar target detections, which are deduced from sensor data recorded in real-world test drives. Based on these reference data, deviations between the radar point clouds from different recordings are quantified using metrics for both point clouds from single measurement cycles and relative probability distributions for accumulated point clouds. Finally, the suitability of the calculated reference values as adequate metrics of deviations between recorded and simulated sensor data is evaluated.