Konferenzbeiträge

A millimeter wave agile multi-beam front-end with an integrated 4 by 1 antenna array for 5th generation wireless communications is analyzed by antenna and digital communication measurements. The front-end core comprises a compact low-temperature co-fired ceramic multilayer module with a foot-print area of 74 mm × 74 mm. An over-the-air gain of 50.4 dB and a noise figure of 4.9 dB were measured. Link measurements with broadband single-carrier QAM and OFDM signals result in a data rate of 3.2 Gb/s for 400 MHz bandwidth SC-256QAM modulation with 1.2% error vector magnitude of the front-end determined by a detailed analysis.

Automotive radar systems in automobiles are key for automated and connected driving. Conventionally, functional tests and safety validation of automotive radar systems are carried out in field-operational tests, but are very resource-expensive and they offer neither reproducibility nor reliability. To improve efficiency and reliability, though at the expense of a partial loss of realism, a controlled test environment is required in which repeatability is guaranteed. We proposed previously a system concept for over-the-air testing of radar systems with a vehicle-in-the-loop approach in a virtual environment. For the test in a controlled environment, a realistic simulation of the radar scenario-under-test is necessary. Technological achievements in hardware, software, and computational power have made powerful radar target simulators and real-time capable control computers available. However, for the spatial degrees-of-freedom, which are key to emulate relevant test cases with dynamic evolution in the virtual environment, the illumination antennas of the radar target simulator must be positioned with high speed, accuracy, and over sufficient angular ranges. This paper describes our hybrid electronic-mechanical antenna positioner, offering three motional degrees-of-freedom. Initial trials with a modern commercially available automotive radar installed in a passenger car are presented and they indicate very promising results.

This paper focuses on a new Nano Fabrication Machine 100 (NFM-100) with a working range up to 100 mm in diameter and its integrated tip-based system, which can be used as an Atomic Force Microscope (AFM) as well as for Field-Emission-Scanning-Probe-Lithography (FESPL). The combination of both systems offers the possibility to fabricate and analyze micro- and nanostructures with high resolution and precision down to a single nanometer over a large area in one single configuration without tool or sensor change. After the description of the basic machine structure of the NFM-100, the demonstration of long range and large area AFM scans in combination with the NFM-100 will be shown. Additionally, the basic functionality of the FESPL manufacturing process is presented.

Compliant mechanisms with flexure hinges are well-suited for high-precision applications due to their smooth and repeatable motion. However, the synthesis of planar compliant mechanisms based on notch flexure hinges is mostly limited to the use of single-axis hinges due to the lack of certain multiple-axis flexure hinges. This contribution introduces a novel planar leaf-type notch flexure hinge with two coincident rotation axes based on circular pre-curved leaf springs. A generally suitable hinge geometry is determined through a parametric study using the finite element method (FEM). Finally, the two-axis flexure hinge is applied and investigated for the use in two planar micropositioning stages for the rectilinear guidance of an output link with a large centimeter stroke. The presented two-axis flexure hinge turns out to be a suitable approach to monolithically connect three links of a compliant mechanism in a planar and precise way.

Monolithic compliant mechanisms are often used in precision engineering applications for path-generating tasks due to their many advantages. They are mostly realized with concentrated compliance in form of notch flexure hinges and achieve their motion due to bending of the hinges. This contribution presents the non-linear analytical modeling of compliant mechanisms with power function-based notch flexure hinges and their efficient optimization of the elasto-kinematic path-generating properties using MATLAB. Different planar mechanisms are analytically characterized with the theory for large deflections of curved rod-like structures. A verification of the analytical model is exemplified by FEM simulations for a four-hinge Watt mechanism as a point guidance mechanism and for a 12-hinge pantograph mechanism as a plane guidance mechanism. Further, the exponents of the power function contours for each hinge are individually optimized on the example of an Evans and a Roberts mechanism. This is achieved with the goal of minimizing the straight-line deviation of their coupler points realizing a stroke of 10 mm.