Untersuchung der Einkopplungen von UWB-Pulsen auf Funksysteme im 2,4-GHz-ISM-Band

Dieser Bericht fasst die durchgeführten Messungen zur Abschätzung möglicher Kopplung elektromagnetischer Energie ausgehend von abgestrahlten UWB-Pulsen auf Funkübertragungssysteme im 2,4-GHz-ISM-Band zusammen. Dabei wird genauer auf die sogenannte Frontdoor- und Backdoorkopplung eingegangen. Während für die Abschätzung der Frontdoorkopplung generische PCB-Antennen untersucht wurden, sind für die Backdoorkopplung Standard-USB-Funkmodule zum Einsatz gekommen. Es wird im Gesamten eine Abschätzung gegeben, inwieweit UWB-Pulse Funkübertragungssysteme beeinflussen können. Die durchgeführten Messungen wurden mit Hilfe einer GTEM-Zelle in Verbindung mit dem UWB-Pulsgenerator PBG3 der Firma Kentech durchgeführt. Weiterhin sind die Auswirkungen von UWB-Pulsen auf ein reales Funkübertragungssystem im 2,4-GHz-ISM-Band untersucht worden

Linear and nonlinear filters under high power microwave conditions

The development of protection circuits against a variety of electromagnetic disturbances is important to assure the immunity of an electronic system. In this paper the behavior of linear and nonlinear filters is measured and simulated with high power microwave (HPM) signals to achieve a comprehensive protection against different high power electromagnetic (HPEM) threats

HPEM protection on HF transmission lines

Traditional protection concepts against electromagnetic interferences are combinations of nonlinear elements like spark gaps, varistors or suppressor diodes. Due to parasitic capacitances and inductivities and the general behavior of the elements, a trade off has to be made between the frequency bandwidth and the energy absorption capability of the protection circuit. For high frequency applications with signal frequencies above about 500MHz a sufficient protection can not be given without changing the transmitted signals itself. Additionally this kind of protection concept is designed and optimized against transient interferences with rise times down to some nanoseconds, for example the LEMP, the NEMP or the ESD. Current researches focus on transient interferences with rise times in the picosecond range and pulse widths of a few nanoseconds, the so called ultra wideband (UWB) pulses, combined with a significant voltage amplitude of some kilovolts. In this paper investigations on nonlinear protection elements and linear filters against line-coupled UWB pulses with high voltage amplitudes will be done with special focus on the protection of high frequency data-lines

Investigation of the behavior of protection elements against field radiated line coupled UWB-pulses

To protect electronic systems against electromagnetic interferences in general nonlinear protection circuits are used. These protection circuits are optimized mostly against special transient interferences such as lightning electromagnetic pulses (LEMP) or electromagnetic pulses caused by nuclear explosions (NEMP). Previous investigations have shown that these protection elements could be undermined by so-called ultra wideband (UWB) pulses. Thereby a direct charge of the UWB-pulse to the elements has been assumed. This assumption was a worst case approximation because in practice UWB-pulses only get into systems by coupling effects. In this investigation the behavior of typical nonlinear protection elements has been tested with field radiated line coupled UWB-pulses. For that line coupled UWB-pulses have been defined depending on the coupling behavior of typical electronic systems and a possibility of generation of this kind of pulses is presented. After it typical nonlinear protection elements such as spark gaps, varistors and protection diodes have been tested with the previously defined test pulses. Finally the measured behavior of the elements has been compared with the behavior by direct charged UWB-pulses and the protection effect of the elements against field radiated line coupled UWB-pulses is re-evaluated