Date of Award

12-2010

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Electrical and Computer Engineering

Advisor

Hubing, Todd H

Committee Member

Pearson , Wilson L

Committee Member

Xu , Xiao-Bang

Committee Member

Pisu , Pierluigi

Abstract

This dissertation describes three independent studies related to the design of reliable automotive electronics. The topics covered are: the estimation of the radiated emissions from power bus structures, EM propagation of tire pressure monitoring systems (TPMS), and examinations of corrosion-induced faults in a connector.
The first chapter describes a method for estimating the maximum possible radiated emissions from a printed circuit board power bus. An analysis based on a lossy cavity model is performed to determine the maximum possible radiated field corresponding to a given power bus noise voltage. A closed-form expression relating the maximum power bus noise voltage to the radiation peaks is then derived. This expression is solved in reverse to determine the minimum power bus voltage necessary to generate a radiated field and can be applied to measured values of power bus noise voltage to determine whether radiation directly from the power bus is potentially the emissions source.
The second chapter identifies transmission parameters from a rotating tire and the vehicle body's effect on tire sensor transmission and propagation; relates these effects to receiver antenna packaging requirements; and then, based on these results, proposes the antenna design of employing car body as a part. In the new proposed TPMS design, a 20mm x 5mm loop antenna with a 40mm x 10mm slot beneath it is added to capture the surface currents of the car body and block the current path to increase the current density around the loop antenna. The simulation results show that this design exhibits a propagation factor 150 times larger than the traditional design.
The third chapter investigates the effects of different contaminants (salt, oil, grease) on the shunt resistance between pins of a cable connector. The test results show that salt-induced corrosion and moisture may cause intermittent shunting resistances capable of affecting the normal operation of automotive systems. One important test result is that the induced shunting resistances are a nonlinear function of the applied voltage. An equivalent circuit based on measurements is developed to model the behavior of various salt-water/metal electrode interactions.

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