Common-Mode Noise Filter Coil Shape for High-Frequency Differential Signals

The patent applies asymmetry by changing the coil conductor cross-section from a symmetric rectangular shape to an asymmetric triangular shape with a tapered profile. The cross-section has a wider base and a narrower apex, creating an asymmetric geometry that reduces the overlapping area between adjacent coil conductors. This asymmetric design directly addresses the capacitance problem by minimizing the effective area through which electric field coupling occurs, thereby reducing differential signal attenuation while maintaining structural integrity.

The patent applies local quality by varying the cross-sectional dimensions of the coil conductors along their length. The conductors have a tapered profile where the width changes from base to apex, creating different local properties. The wider base provides strong magnetic coupling where needed, while the narrower apex regions reduce capacitance. This localized variation in geometry allows the conductor to simultaneously achieve strong magnetic coupling in critical areas while minimizing capacitance effects, thereby maintaining high cut-off frequency.

The patent applies parameter changes by modifying the geometric parameters of the coil conductor cross-section from rectangular to triangular. Specifically, the width parameter varies continuously from the base to the apex, creating a tapered profile. This parameter change is achieved through standard manufacturing techniques such as precision molding or extrusion processes that can produce triangular cross-sections. The continuous variation in width parameter allows optimization of capacitance reduction while using conventional manufacturing methods, balancing performance improvement with ease of fabrication.