Hybrid BAW Filter Circuit With IPD Integration for Sharp Rejection
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Solution Overview
Problem
Existing electronic filtering circuits suffer from drawbacks such as wide transition bands and inferior rejection performances, and often require separate mechanical protection and filtering functions.
Innovation Solution
An electronic filtering circuit design that integrates a bulk acoustic wave filter on an integrated passive device, with conductive pillars connecting electrodes, forming a cavity protected by a peripheral wall, combining the advantages of both filter types and reducing transition bands while enhancing rejection performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bulk acoustic wave filter is used, then rejection performance is improved, but transition bands become wider
Solution Approach 1:
The patent combines a bulk acoustic wave filter (BAW) with an integrated passive device (IPD) into a single hybrid filter circuit. The BAW filter provides superior rejection performance while the IPD contributes narrow transition bands. The two filter types are merged through conductive pillars that electrically connect the BAW filter electrodes to the IPD contact pads, creating a unified filtering system that achieves both high rejection and sharp transition characteristics simultaneously.
2Reliability
If separate mechanical protection and filtering functions are used, then reliability is improved, but device complexity increases
Solution Approach 1:
The integrated passive device substrate serves multiple functions simultaneously: it acts as the mounting platform for the bulk acoustic wave filter, provides electrical connection pathways through its contact pads, and serves as the structural housing that encloses and protects the cavity containing the BAW filter. This multi-functional design eliminates the need for separate protective housings and reduces overall device complexity while maintaining mechanical protection.
3Strength
If additional covers are added for mechanical protection, then strength is improved, but volume increases
Solution Approach 1:
The integrated passive device substrate is designed to serve as both the functional circuit carrier and the mechanical protective housing. By merging these two functions into a single component, the patent eliminates the need for additional protective covers that would increase device volume. The substrate's inherent structural integrity provides sufficient mechanical protection while maintaining a compact form factor.
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 integrated design achieves narrower transition bands and superior rejection performances, while providing mechanical protection and space savings, without the need for additional covers.
Implementation Method 1
a bulk acoustic wave filter superimposed on the integrated passive device
Implementation Method 2
at least one conductive pillar passing through the integrated passive device and connecting an electrode of the bulk acoustic wave filter to a contact recovery element
Data Source
Figure 1~2B
Figure 2C~3A
Figure 3B~4
AI summary
The present description relates to an electronic filtering circuit (100) comprising: - an integrated passive device (101); - a bulk acoustic wave filter (151) superimposed on the integrated passive device (101) on the side of a first face (103B) of the integrated passive device (101); and - at least one conductive pillar (181) passing through the integrated passive device (101) and connecting an electrode (157) of the bulk acoustic wave filter (151) to a contact recovery element (113) located on a second face (103A) of the integrated passive device (101) opposite the first face (103B) and intended to be connected to an external element (117).