Planar Balun Layout for Compact mm-Wave Radar Packaging

The patent transitions from a planar hairpin-shaped path to a three-dimensional folded path that utilizes vertical spacing between package layers. The half-wavelength path is routed through multiple layers using vias, creating a compact structure that achieves the required electrical length while minimizing the footprint on each individual layer. This dimensional transformation allows the balun to maintain its electrical characteristics while occupying significantly less package area.

The patent embeds the half-wavelength path within the vertical structure of the package by routing it through intermediate layers between the differential and single-ended sides. The path is nested within the multilayer package structure, utilizing the vertical space between layers to accommodate the required path length without increasing the horizontal footprint. This nesting approach allows the balun structure to be integrated compactly within the package volume.

The patent uses vertical layering to achieve the required half-wavelength path length without increasing horizontal dimensions. By routing the signal through multiple layers with controlled via transitions, the design maintains precise signal routing while keeping the overall package footprint small. The vertical dimension provides the necessary path length while the horizontal dimensions remain compact.

The patent divides the half-wavelength path into multiple segments routed through different layers of the package. Each segment is precisely controlled in length and position, with vias providing controlled impedance transitions between layers. This segmentation allows the total path length to be achieved through cumulative segments rather than a single long trace, maintaining manufacturing precision while reducing overall package size.