Helmut Schreiber

Virtual reality for automotive radars

Car manufacturers spend quite a lot on the development of driver assistance systems and subsequently on autonomous driving functionality. To ensure the safety and reliability of these functions meet industrial standards it is necessary to verify and validate their functionality. While tests on the road are still the ultimate evidence of correct operation they are associated with huge efforts and risks. Therefore, they have to be complemented by other means like simulations and tests on specialised testbeds. For the latter the car’s sensors have to be stimulated in a way that they perceive a desired – but only virtual – environment. An important type of sensor in cars is the radar due to its various advantages. This article describes the development of a stimulator generating virtual radar targets in order to enable the testing of autonomous driving functions.ZusammenfassungAutohersteller investieren eine hohe Summe in die Entwicklung von Fahrerassistenzsystemen und in autonomes Fahren. Es ist daher notwendig, die sichere und zuverlässige Funktion dieser Systeme zu verifizieren und zu validieren. Dies kann mit Testfahrten auf der Straße erfolgen, was aber mit großen Kosten und hohem Aufwand verbunden ist. Es wird daher daran gearbeitet, zumindest Teile dieser notwendigen Tests mit Simulationen auf Prüfständen durchzuführen. Das Radar ist ein wichtiger Sensor für die erwähnten Systeme, deshalb ist dessen Stimulation von entscheidender Bedeutung. Dieser Beitrag beschreibt die Entwicklung eines Stimulators zur Erzeugung von virtuellen Radarzielen, um autonome Fahrfunktionen auf dem Prüfstand zu testen.

A preliminary result on development of analog broadband tapped delay line for L-band applications

This paper presents a brief comparison of delay line elements to develop a tapped delay line system. The comparative study includes surface integrated waveguide (SIW)-based delay line elements and coaxial cables. For SIW-based delay line elements, we divide the analysis into two scenarios based on the used transition line configuration, namely microstrip-to-SIW transition and grounded coplanar waveguide (GCPW)-to-SIW transition. This transition line is required to ensure impedance matching between transmission line and SIW component. Based on numerical analysis, it can be seen that the return loss of a SIW-based delay line with microstrip-to-SIW transition is better than the one with GCPW-to-SIW transition. Furthermore, the time delay of SIW-based delay line with microstrip-to-SIW transition is longer than the one with GCPW-to-SIW transition. In addition, for the whole design of 6-taps delay line system, a flat time delay of around 1 ns is achieved which reasonable insertion loss and isolation between two neighboring taps.

Frequency dividers in radar target stimulator applications

More and more driver assistance systems are integrated into modern vehicles. This development results in a continuous rise in the complexity of these vehicles, as the functions have to comply to the corresponding safety standards. Testing and validating these functions on an automotive test bench instead of driving tests at closed proving grounds requires comprehensive stimulation of the involved sensors. In this article we are focusing on an approach for stimulating short-range radar sensors of a vehicle located on such a test bench. Coping with the requirements imposed by these types of sensors we investigate the usage of frequency multipliers and dividers in the frequency translation section of the radar stimulator. For this purpose, we provide an overview on different concepts for these multipliers and dividers. After reviewing the advantages and disadvantages of these devices, we provide measurement results of a stimulator setup applying this type of frequency translation.ZusammenfassungFahrassistenzsysteme spielen eine immer größere Rolle in modernen Fahrzeugen. Die Integration dieser Systeme und die damit verbundene Einhaltung der nötigen Vorschriften und Sicherheitsstandards erhöhen die Komplexität der Fahrzeuge enorm. Um die Funktionsprüfung von Fahrassistenzsystemen auf dem Prüfstand durchführen zu können, ist eine umfassende Stimulation der Sensoren des Systems notwendig.Dieser Beitrag behandelt einen Zugang zur Stimulation automotiver Radarsensoren für den Nahbereich auf einem Prüfstand. Dabei wurde die Verwendung von Frequenzmultiplikatoren und Dividierern im Frequenzumsetzungspfad des Radar-Stimulators untersucht. Der Artikel gibt einen Überblick über verschiedene Konzepte zur Realisierung dieser Funktionsblöcke. In der Folge werden die Vor- und Nachteile der in Verbindung mit einem Radar-Target-Stimulator verwendeten Konzepte aufgezeigt und Messergebnisse präsentiert.

Size reduction and bandwidth enhancement of aperture coupled based microstrip antenna by using Meander line slot

In this paper, a development of aperture coupled based microstrip antenna using meander line slot is presented. The proposed antenna constitutes of 2 substrate layers which are separated by a common ground plane. A Meander line slot is loaded to the antenna patch to reduce the dimension of the proposed antenna design. The antenna characteristics before and after applying a meander line slot are numerically investigated. Compared to the reference antenna design, using a meander line slot loaded to the antenna patch, it can achieves several performance improvements. These improvements are not only in terms of size reduction, but also in terms of bandwidth enhancement and antenna efficiency.

Numerical characterization of a SIW-based time delay line element with meandered slots structure

This paper presents a delay line element with meandered slots being part of a substrate integrated waveguide (SIW) structure and its numerical analysis. The proposed delay line element is designed by using a coplanar waveguide (CPW) configuration due its low dispersion compared to other transition configurations. The proposed delay line element is designed on a substrate of Rogers RO4360 with a thickness of 1.524 mm. Its numerical characterization is conducted in terms of return loss, insertion loss and group delay time. By numerical analysis and synthesis, the optimum delay line element can be designed and the desired characteristics can be achieved for operation in the frequency range of 1.4-2.8 GHz with a return loss up to 40 dB at a frequency around 1.75 GHz. Additionally, an almost flat insertion loss with values around 0.5 dB and a likewise nearly constant time delay around 1 ns is achieved over the desired frequency band.