J.L. ter Haseborg

Susceptibility of some electronic equipment to HPEM threats

In this paper, an overview of the susceptibility of a large number of different electronic devices like computer networks, computer systems, microprocessor boards, microcontrollers, and other basic integrated circuits (ICs) to different threats like electromagnetic pulse (EMP), ultrawideband (UWB), and high-power microwave pulses (HPM) is given. The presented data will include a comparison of the HPM and UWB susceptibility of some devices and a deeper look into the destruction effects in ICs. Therefore, the ICs were opened and the destruction effects were investigated. A norm based approach to describe the threat of different pulses to electronic devices gives a theoretical explanation for the measured susceptibility data.

Linear and nonlinear filters suppressing UWB pulses

In order to protect electronic systems against natural or man-made electromagnetic interferences with high energies and amplitudes nonlinear protection elements like spark gaps, varistors or Z-diodes are state-of-the-art countermeasures. Most of these protection circuits are designed for well studied transient interferences like lightning electromagnetic pulse, nuclear electromagnetic pulse or electrostatic discharge pulses. It is of special interest to investigate the response of common nonlinear protection elements at ultrawideband (UWB) pulses with significant amplitudes, rise times in the picosecond range and pulse durations of a few nanoseconds. It is discussed whether traditional protection concepts provide a sufficient protection against such extremely fast pulses. Furthermore the possibility of linear filtering is presented with focus on the protection of high frequency datalines.

Susceptibility of IT network systems to interferences by HPEM

Intentional electromagnetic interferences (IEMI) have become a threat to various kinds of technical applications. Different high power electromagnetic (HPEM) sources may cause a disruption or destruction of complex electronic systems like communications systems. Even a temporary breakdown of the data transfer is very critical in some applications. In this contribution a COTS IT network system is investigated under HPEM conditions. The susceptibility of the system to interferences by ultra wideband (UWB), damped sinusoid (DS) and high power microwave (HPM) sources is tested and the interference signals on the critical coupling paths are measured. The performance of the system with additional COTS protection devices is also taken into account. The results are to allow first statements about the potential of protecting complex electronic systems against HPEM interferences.

Double probe near field scanner, a new device for measurements in time domain

A double probe near field scanner for measurement in time domain is presented in this paper. The advantages of measurements in time domain compared with measurements in frequency domain are time efficiency and the simplified capture of frequency hopping signals. The double probe set-up allows measurements of the absolute value of the field strength as well as of the phase. It is also possible to measure occasionally appearing transient pulses. This allows not only the representation of field strengths on the measurement plane but also the illustration of wave propagation or radiation in form of an animated picture sequence. Results of various measurements are shown in this paper.

SPICE Simulations of UWB pulse stressed protection elements against transient interferences

This paper discusses the possibility of SPICE simulations of common protection elements against transient interferences by stressing with extremely fast high voltage ultra wideband (UWB) pulses. The focus of this investigation is the accuracy of the SPICE simulation relating to real measurements. Therefore different SPICE model implementations of protection elements are discussed also concerning numerical stability and complexity. Finally some UWB pulse effects on traditional protection elements are presented and discussed.

Simulation and measurement of the propagation of Bluetooth signals in automobiles

Due to the low costs of Bluetooth digital radio, wireless communication according to this standard increases popularity in the future. An interference free operation of wireless devices in cars among themselves and between these devices and sensitive car electronics has to be assured. In this paper fields originated by Bluetooth transmitters in personal cars are examined. Field distributions according to different transmitter positions are simulated with the method of moments (MoM) in order to get worst case results of the field strength as well as to characterize the radiation pattern of such configurations. To compare with the simulation, measurements of the field strength and the radiation pattern are made. Finally, measurements of coupling into cables within the passenger cabin are performed. Due to their increasing use as basic hardware within portable computers, also the coupling of WLAN is observed in this context.

Interdigital microstrip filters as protection devices against ultrawideband pulses

Standard protection concepts against transients employing nonlinear elements like sparkgaps or Zener diodes cannot provide an optimal protection against interferences caused by ultrawideband (UWB) pulses. Therefore this paper discusses the use of linear filters as protection against UWB-pulses. Due to advantages in several areas for example cost-effective production and high voltage capability this study focuses an implementation of microstrip bandpass filters with very steep edges. To reduce the overall size of the filters, their realization as interdigital structures has been investigated. Finally, the filters are characterized in frequency domain and with UWB-stress in time domain.

An estimation of the backdoor coupling of UWB pulses on commercial wireless USB adapters

This paper describes the performed measurements to estimate a possible backdoor coupling on commercial wireless USB adapters using the 2.4 GHz ISM band caused by UWB pulses. Different commercial adapters (Bluetooth and WLAN) have been stressed by UWB pulses in a GTEM cell by using different setups. The coupled voltage into the different USB conductors (Data+, Data- and VCC) has been measured and compared to the standard voltage levels of the USB connection. It has been shown that backdoor coupling of the UWB pulses can have wide influences on the wireless USB adapters.

Two dimensional simulation and measurement of the coupling of Bluetooth signals into conductive structures

In this work the near-field coupling of Bluetooth transmitters to a transmission line and a PCB loop is examined by high resolutional two dimensional simulations and measurements with different Bluetooth modules. Both simulations and measurements are compared, yielding good agreements in strength as well as in the topographic field-distribution.

Investigation of Hardening Measures for IT Equipment against Radiated and Conducted IEMI

Intentional electromagnetic interferences are a serious threat for electronic systems (e.g., IT communication systems) in military or civilian applications and structures. In this paper, different hardening measures for susceptible coupling paths of an IT system are developed and investigated under different high-power electromagnetic conditions. The behavior of adapted nonlinear protection circuits and linear filters, which are integrated into the test system, as well as modifications on an enclosure is investigated by measurements and simulations with radiated and conducted disturbance signals using ultrawideband, high-power microwave, and damped sinusoidal sources. The influence of the protection measures on the data transmission error rates during disturbance is additionally investigated. The results lead to statements about future protection concepts for IT equipment and other vulnerable electronic systems.