Bare-Chip Acoustic Wave Filter Layout for Low-Profile RF Modules
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Solution Overview
Problem
Existing RF modules face challenges in reducing the height of their mount board while maintaining effective component placement and signal processing capabilities.
Innovation Solution
The RF module design includes a mount board with electronic components on one surface and an acoustic wave filter, along with external connection terminals on the opposite surface, utilizing a bare-chip acoustic wave filter configuration to minimize height while ensuring signal processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If components are mounted on both principal surfaces of the mount board to downsize the board, then the board area is reduced, but the height along the thickness of the mount board increases
Solution Approach 1:
The patent transitions from planar component arrangement to three-dimensional stacking by placing components on both principal surfaces of the mount board. This dimensional change allows efficient use of board area while managing height through strategic component placement and interconnection via through-hole electrodes.
Solution Approach 2:
The patent embeds through-hole electrodes within the mount board structure to connect components between the two principal surfaces. This nesting approach integrates the interconnection mechanism into the board itself, reducing the need for external connectors and minimizing overall height.
2Reliability
If a packaged acoustic wave filter is used, then the filter is protected and easy to mount, but the overall module height increases
Solution Approach 1:
The patent extracts the acoustic wave filter from its traditional packaged form and implements it as a bare-chip configuration. This removes the protective packaging that contributes to height while relying on the mount board structure and bonding techniques to provide necessary protection and support.
Solution Approach 2:
The patent merges the acoustic wave filter chip directly with the mount board through bonding techniques, eliminating the separate packaging layer. This integration reduces height while maintaining functionality by directly connecting the filter to the board's electrical infrastructure.
3Length of stationary object
If a bare-chip acoustic wave filter is used, then the module height is reduced, but the filter becomes more vulnerable to foreign particles and damage
Solution Approach 1:
The mount board structure serves multiple functions: it provides mechanical support, electrical interconnection through through-hole electrodes, and environmental protection for the bare-chip filter. This multi-functionality allows the board to compensate for the lack of traditional filter packaging.
Solution Approach 2:
The patent positions the bare-chip filter in a protected location on the mount board and uses the board's structure to shield it from foreign particles before they can cause damage. This preventive approach cushions the vulnerable chip against environmental hazards.
Data Source
AI summary
A radio-frequency module includes a mount board, an electronic component, an external connection terminal, and an acoustic wave filter. The mount board has a first principal surface and a second principal surface facing each other. The electronic component is arranged on the first principal surface of the mount board. The external connection terminal is arranged on the second principal surface of the mount board. The acoustic wave filter is arranged on the second principal surface of the mount board. The acoustic wave filter is a bare-chip acoustic wave filter. The radio-frequency module is suppressed in height along a thickness of the mount board.