Substrate With Superposed Electrodes For Duplexer Isolation
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Solution Overview
Problem
Existing duplexer designs face challenges in maintaining isolation characteristics between high-frequency and low-frequency signal paths due to electromagnetic coupling caused by inductor patterns and wiring lines within the circuit board, leading to degradation of transmission and reception isolation.
Innovation Solution
A substrate design with superposed mounting electrodes on opposite surfaces, electrically connected to each other, which reduces the need for lengthy wiring lines and prevents electromagnetic coupling by ensuring the signal paths of transmission and reception signals are not close to each other, thereby improving isolation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inductor patterns and wiring lines are provided inside the circuit board to connect filter components, then the electrical connection between components is achieved, but electromagnetic coupling occurs between transmission and reception signal paths causing degradation of isolation characteristics
Solution Approach 1:
The patent transitions from planar wiring layout to three-dimensional stacked electrode arrangement. First mounting electrodes on the first main surface and second mounting electrodes on the second main surface are superposed in the thickness direction, creating vertical electrical connections that eliminate the need for lengthy inductor patterns and reduce electromagnetic coupling between signal paths.
Solution Approach 2:
The patent combines multiple functions into the substrate structure itself. The substrate body with superposed mounting electrodes serves both as the mounting platform for filter components and as the electrical connection medium, eliminating separate inductor patterns and wiring lines that cause electromagnetic coupling.
2Area of stationary object
If wiring lines are routed close together to achieve compact layout, then the device size is reduced, but electromagnetic coupling increases causing signal interference
Solution Approach 1:
The patent resolves the conflict between compactness and signal interference by moving electrical connections from the planar dimension to the vertical dimension. Superposed mounting electrodes on opposite surfaces of the substrate provide direct vertical connections, achieving compact layout without requiring closely routed wiring lines that would cause electromagnetic coupling.
3Reliability
If lengthy wiring lines are used to connect components on opposite surfaces, then the electrical connection is established, but the signal path length increases causing more electromagnetic coupling
Solution Approach 1:
The patent eliminates lengthy wiring lines by establishing direct vertical electrical connections through the substrate thickness. First mounting electrodes and second mounting electrodes superposed on opposite surfaces are connected through the substrate body, providing the shortest possible path and minimizing electromagnetic coupling.
Solution Approach 2:
The patent extracts and removes the harmful inductor patterns and wiring lines from the circuit board design. Electrical connections are achieved directly through the substrate structure with superposed mounting electrodes, eliminating the intermediate wiring elements that cause electromagnetic coupling and signal interference.
Data Source
AI summary
In a substrate that improves isolation characteristics of a high-frequency-side signal path and a low-frequency-side signal path, a duplexer, and a substrate module, a package substrate includes two SAW filters mounted thereon and defines a portion of the duplexer. A substrate body includes main surfaces that oppose each other. Land electrodes are provided on one of the main surfaces and are used to connect either of the two SAW filters. Land electrodes are provided on one of the main surfaces and are used to connect a mounting substrate on which the duplexer is mounted and are respectively superposed with the land electrodes when viewed in plan from a z-axis direction. The land electrodes and the land electrodes, which are superposed with each other when viewed in plan from the z-axis direction, are electrically connected to each other.