RF Switch Common-Ground Shunt Layout for Better Isolation

The common ground pad is segmented into multiple isolated ground regions (first ground region, second ground region, third ground region) using isolation structures. Each shunt path is assigned to a separate ground region, effectively dividing the shared ground pad into electrically isolated segments. This allows multiple shunt paths to share the physical ground pad area while maintaining RF isolation between them, resolving the contradiction between compact size and isolation performance.

Isolation structures (such as isolation trenches or dielectric layers) are introduced as intermediary elements between adjacent ground regions. These isolation structures act as mediators that prevent RF signal coupling between different shunt paths while allowing each path to maintain its connection to the common ground pad. This enables compact design with maintained isolation by mediating the interaction between shared ground resources and isolation requirements.

Multiple ground regions that provide isolation are merged into a single common ground pad structure. Instead of using physically separate ground pads for each shunt path (which would increase area), the invention combines multiple isolated ground regions within one shared ground pad footprint. The isolation is achieved through internal segmentation rather than external separation, thus maintaining compact device area while providing effective RF isolation.

The isolation between shunt paths is achieved by introducing a vertical or subsurface dimension through isolation structures (such as trenches extending downward or through-layer dielectric layers). Rather than separating ground pads in the horizontal plane (which would increase area), the isolation is implemented in another dimension, allowing compact 2D layout while maintaining 3D isolation effectiveness.

Isolation structures are applied locally only where needed between adjacent ground regions, rather than throughout the entire device. The isolation is concentrated at specific interfaces between shunt paths, minimizing the overall addition to device complexity. This localized approach provides necessary RF isolation while avoiding unnecessary complexity in regions where isolation is not required.

The isolation between ground regions is achieved by changing material parameters (such as introducing high-resistivity dielectric materials or conductive isolation layers) rather than by complex structural arrangements. By modifying the electrical parameters of the isolation structures, effective RF isolation is obtained with relatively simple geometric configurations, thus improving isolation while minimizing increases in device complexity.