Analysis of Electromagnetic Nearfield Disturbances on Printed Circuit Board and IC Level

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The data transmission speed and packaging density of modern electronic systems are continuously increasing. Furthermore signal and supply voltage levels are reduced to decrease power dissipation. This results in a small signal-to-noise ratio and an increasing sensitivity against electromagnetic interference. The electromagnetic susceptibility of a device under test (DUT) is usually conducted in the far field of an antenna, as for example in a semi anechoic chamber. In cases where the DUT fails the test, information about the corresponding frequency and amplitude of the interference field is available. However, the localization of the critical coupling path and the sensitive components is usually not obvious. For such fault diagnostics especially on printed circuit boards (PCB) near-field scanning using small electric or magnetic probes has been suggested as a complementary test method. However, a systematic method for comparing near- and far field measurement results is not available so far. For this reason the aim of the research request is to expand and generalize the fundamental results from the running project. The quantitative relationship between near- and far field disturbances should be expressed in terms of a correlation factor, concerning the coupled voltage into a transmission line. The already developped analytic relation for electrically small probes should be expanded to bigger (resonant) antenna probes. Attention will be paid on the wave polarization relative to the transmission line as well as the influence of the line terminations. To validate the model, numerical field simulations and measurement configurations close to reality are intended. For this purpose the disturbance should not be restricted to pure CW signals or trapezoidal pulses. Also more realistic modulated signals, as used for example in mobile communication systems or WLAN networks should be employed. Suitable antenna geometries have to be found, constructed and tested. The disturbance influence will be measured in terms of the bit error ratio (BER) of a digital data transmission line.