Multilayer Branching Filter Shielding for Compact Band Isolation
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Solution Overview
Problem
Existing branching filters face challenges in maintaining isolation between filters when reduced in size, as the conductive members used for shielding become insufficient.
Innovation Solution
A multilayered branching filter design incorporating a stack of dielectric layers with integrated conductors and inductors, featuring a first and second path for different frequency bands, and a third path for a higher frequency band, with a structure body connected to ground, ensuring isolation through a plurality of first sub-structure bodies and through holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the branching filter is reduced in size, then the device becomes more compact and space-saving, but isolation between the first filter and the second filter is degraded
Solution Approach 1:
The conductive member is divided into multiple segments (first conductive member, second conductive member, third conductive member) arranged at different positions and orientations. This segmentation allows each conductive member to shield specific regions between the filters, maintaining isolation even when the overall filter size is reduced.
Solution Approach 2:
The conductive members are arranged not only in the stacking direction (vertical dimension) but also in the horizontal direction, creating a three-dimensional shielding network. This multi-dimensional arrangement maximizes the shielding effect within a compact volume, preventing signal leakage between filters while maintaining a small form factor.
2Volume of moving object
If a columnar conductive member is used for shielding, then some isolation is achieved, but when the branching filter is further reduced in size, the shielding becomes insufficient
Solution Approach 1:
Instead of relying on a single columnar conductive member, the shielding function is segmented into multiple conductive members positioned at different locations. This distributed shielding approach maintains effectiveness even when individual members are smaller due to overall size reduction of the filter.
Solution Approach 2:
Multiple conductive members are combined to form a comprehensive shielding system. The first, second, and third conductive members work together to provide coverage across different regions between the filters, creating a more robust shielding effect than a single columnar member could provide in a compact configuration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design maintains effective isolation between frequency bands, even in a compact form, enhancing the performance of branching filters in smaller mobile communication devices.
Implementation Method 1
a first structure body that is arranged in a vicinity of a boundary between the first region and the second region and is connected to a ground. The first structure body includes a plurality of first sub structure bodies that are stacked in a direction parallel to a stacking direction of the plurality of dielectric layers
Implementation Method 2
a stack for integrating the common terminal, the first signal terminal, the second signal terminal, the first path, the second path, and the first inductor, the stack including a plurality of dielectric layers being stacked
Data Source
AI summary
A stack of a branching filter includes a first region and a second region, and includes a first structure body that is arranged in a vicinity of a boundary between the first region and the second region and is connected to the ground. The first structure body includes a plurality of first sub structure bodies that are stacked in a direction parallel to a stacking direction of a plurality of dielectric layers. Each of the plurality of first sub structure bodies include a plurality of first through holes and a first conductor layer that connects the plurality of first through holes. A first inductor is arranged in the second region, and is connected to the first structure body.