Joint communication and radar sensing: an overview. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
This paper provides an overview of recent developments in Joint Communication and Radar Sensing (JCRS) systems and networks. Our discussion will focus on radio system and network architectures that can be used for JCRS and on approaches to select, generate and process waveforms suitable for both communication and sensing. In addition, advantages and challenges of assembling a network out of several JCRS nodes are addressed. Finally, we give an outlook to possible applications of JCRS networks, which we see in autonomous driving and low altitude air traffic control.
https://doi.org/10.23919/EuCAP51087.2021.9411178
Realistic emulation of GNSS testing scenarios using 3D wave field synthesis in an OTA testbed. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
While traditional testing methods as conducted and open field tests have their limitations in terms of realism and repeatability of the scenario's conditions, Over-the-Air (OTA) testing enhances the way that GNSS and mobile communications systems with integrated antennas are tested, since it provides the freedom to accurately emulate an impinging wave with arbitrary polarization and direction radiated from any source/reflection such as GNSS satellites and terrestrial base stations. Therefore, real world scenarios can be precisely reproduced with total control of the environment's conditions. In this context, this paper describes the process to implement full polarimetric 3D Wave Field Synthesis (WFS) in an OTA testbed, from the principle to characterize the electromagnetic (EM) field in three dimensions to the system calibration and correspondent verification measurements inside the anechoic chamber, which will provide a deeper insight on the quality and reliability of the EM field for testing purposes.
https://doi.org/10.23919/EuCAP51087.2021.9411259
Nano-imprinted subwavelength gratings as polarizing beamsplitters. - In: Journal of the European Optical Society, ISSN 1990-2573, Bd. 17 (2021), 1, 4, S. 1-13
Polarizing beamsplitters have numerous applications in optical systems, such as systems for freeform surface metrology. They are classically manufactured from birefringent materials or with stacks of dielectric coatings. We present a binary subwavelength-structured form-birefringent diffraction grating, which acts as a polarizing beamsplitter for a wide range of incidence angles -30˚…+30˚. We refine the general design method for such hybrid gratings. We furthermore demonstrate the manufacturing steps with Soft-UV-Nanoimprint-Lithography, as well as the experimental verification, that the structure reliably acts as a polarizing beamsplitter. The experimental results show a contrast in efficiency for TE- and TM-polarization of up to 1:18 in the first order, and 34:1 in the zeroth order. The grating potentially enables us to realize integrated compact optical measurement systems, such as common-path interferometers.
https://doi.org/10.1186/s41476-021-00149-8
Determination of biocompatibility and antimicrobial efficacy of a new ceramic micro-plasma source. - In: Experimental dermatology, ISSN 1600-0625, Bd. 30 (2021), 3, S. e113
P232
https://doi.org/10.1111/exd.14263
Bestimmung der Biokompatibilität und der antimikrobiellen Wirksamkeit einer neuen keramischen Mikroplasmaquelle. - In: Journal der Deutschen Dermatologischen Gesellschaft, ISSN 1610-0387, Bd. 19 (2021), S. 87-88
P148
https://doi.org/10.1111/ddg.14459
Picometer-scale positioning of a linear drive system via feedforward-feedback control. - In: 2021 IEEE International Conference on Mechatronics (ICM), (2021), insges. 6 S.
This paper deals with the controller design of a linear drive system with potential applications in picometer-scale positioning. The displacement is measured using a high-precision differential plane-mirror laser interferometer. However, this measured signal must be filtered for control purposes and performance validation. For tracing picometers, we adopt a model-based 2-DOF control architecture with a feedforward stage for model-following and a feedback stage for stabilization and compensation of constant disturbances. A straightforward way to deal with noise is to use a feedback controller based on estimated (and filtered) states, which can be generated by a Kalman-Bucy filter. The effectiveness of the presented control strategy is verified via real-time experimentation, where the overall control scheme allows positioning in the picometer level. Moreover, comparative tests in the frequency domain were conducted using the so-called PI-LQR feedback controller based on estimated states.
https://doi.org/10.1109/ICM46511.2021.9385699
Friction stir welded AISI 304 metal sheets for application in food implants. - In: THERMEC 2021, (2021), S. 63-68
Stainless steels are indispensable materials in many industrial fields. They can be easily shaped and joined by traditional welding methods. Some problematics such as possible decrease in corrosion resistance at the welding bead and in the heat-effected zone, residual stress, crack formation and distortions may take place after welding. Friction Stir Welding (FSW) may be used for joining stainless steels in a single pass and for optimising microstructure and mechanical properties of the processed region. The application of FSW to the widely used AISI304 stainless steel is investigated in food implants. The mechanical properties together with corrosion resistance and surface finishing are characterized. A high energy input is chosen for the welding (2000 rpm tool rotational speed and 50 mm/min advancing speed). The stirred zone (SZ) is characterized by optical microscopy. Vickers microhardness in the SZ results 37% higher than in the base material. Tensile tests highlight elongations up to 40% keeping maximum stress values at 600 MPa. All samples pass accelerated corrosion tests that simulate 20 years of cleaning cycles in a typical food implant.
Light-field imaging of the human optic nerve head at different wavelengths - a case study. - In: Acta ophthalmologica, ISSN 1755-3768, Bd. 99 (2021), S265, insges. 1 S.
https://doi.org/10.1111/j.1755-3768.2020.0140
Fundus image quality assessment for an eye model with cataract using adapted illumination patterns. - In: Acta ophthalmologica, ISSN 1755-3768, Bd. 99 (2021), S265, insges. 1 S.
https://doi.org/10.1111/j.1755-3768.2020.0150
Light-field imaging for glaucoma diagnosis - reproducibility on one patient. - In: Acta ophthalmologica, ISSN 1755-3768, Bd. 99 (2021), S265, insges. 1 S.
https://doi.org/10.1111/j.1755-3768.2020.0193