Bifilar Heating Resistor for Motor Vehicle EMI Reduction

The heating resistor is segmented into multiple sections arranged in a bifilar configuration, where adjacent sections carry current in opposite directions. This segmentation allows the electromagnetic fields from each section to cancel each other out, significantly reducing radiated electromagnetic interference while maintaining the heating function.

The conductor track is designed with asymmetric width variations along its length. The track width is adjusted in different regions to optimize current distribution and heat generation patterns, ensuring uniform temperature distribution across the substrate while minimizing electromagnetic radiation through strategic placement of wider and narrower sections.

The conductor track is designed with varying local properties, specifically varying width along its length. Certain sections have wider tracks to generate more heat in regions requiring higher temperature, while narrower sections provide less heat in areas that would otherwise overheat. This local quality variation ensures uniform temperature distribution across the substrate even at high power output levels.

Instead of using a uniform conductor track design, the patent inverts the conventional approach by deliberately creating non-uniform track widths. The wider and narrower sections are strategically positioned to compensate for heat distribution patterns, effectively inverting the problem of non-uniform heating by designing non-uniformity into the track itself to achieve uniformity in the final temperature distribution.