RF Switch Module Ground Shielding for Terminal Isolation
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Solution Overview
Problem
There is a challenge in reducing the size of wireless communication terminal switch ICs while maintaining sufficient isolation between radio-frequency signal paths, as signal leakage occurs between the common and selection terminals, becoming more pronounced as the IC size decreases.
Innovation Solution
Incorporating a ground electrode between the common and selection terminals on a substrate, which can be disposed within the substrate and extend in the thickness direction, effectively blocking radio-frequency waves and enhancing isolation by using via-electrodes and wiring patterns to create a blocking plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of the switch IC is reduced, then the size of the wireless communication terminal is reduced, but the isolation between the common terminal and selection terminals deteriorates
Solution Approach 1:
A ground electrode is introduced as an intermediary element between the common terminal and selection terminals. This ground electrode acts as a mediator to block radio-frequency waves propagating between these terminals, thereby enhancing isolation without requiring changes to the terminal structures themselves. The ground electrode serves as a shielding barrier that prevents signal leakage while maintaining the compact IC design.
Solution Approach 2:
The ground electrode extends in the thickness direction (vertical dimension) of the substrate, creating a three-dimensional shielding structure. By utilizing the vertical dimension rather than only the planar dimensions, the patent achieves effective signal blocking without increasing the horizontal footprint of the IC. This dimensional approach allows compact IC design while maintaining isolation performance.
2Length of stationary object
If the distance between common terminal and selection terminal is reduced, then the IC size is reduced, but signal leakage increases
Solution Approach 1:
The ground electrode serves as a shielding intermediary positioned between the common terminal and selection terminals. Even when these terminals are placed close together to reduce IC size, the ground electrode blocks radio-frequency waves from propagating directly between them, preventing signal leakage that would otherwise occur due to the reduced distance.
Solution Approach 2:
The ground electrode is strategically positioned in the region between the common terminal and selection terminals where signal leakage occurs. By applying shielding only in this specific local region rather than throughout the entire IC, the patent effectively blocks signal leakage while maintaining compact terminal spacing and minimizing overall IC size.
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
This configuration significantly reduces radio-frequency signal leakage, allowing for improved signal-to-noise ratios and preventing radiation of unwanted waves, even when connected to directional couplers, thus enhancing the performance of radio-frequency modules.
Implementation Method 1
at least a portion of radio-frequency waves propagating between the common terminal and the plurality of selection terminals of the switch IC is able to be blocked
Implementation Method 2
radio-frequency waves propagating within the substrate are able to be blocked more reliably by the ground electrode
Data Source
AI summary
A radio-frequency module includes a substrate and a switch IC mounted on the substrate and including a common terminal and a plurality of selection terminals. The substrate includes ground electrodes disposed between the common terminal and the plurality of selection terminals in a plan view of the substrate.