Hybrid Filter Layout With 3D Spiral Inductor for Low Parasitics
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Solution Overview
Problem
Existing hybrid filters face challenges with large size and parasitic effects due to separate film bulk acoustic resonators and passive filters, and silicon-based substrates with high loss angles and conductivity issues limit performance in high-frequency applications.
Innovation Solution
A hybrid filter design with a first and second substrate oppositely disposed, featuring a film bulk acoustic resonator connected to a passive filter with a three-dimensional spiral inductor structure, using glass substrates and a sealed space for improved integration, and incorporating a three-dimensional spiral inductor structure for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate film bulk acoustic resonators and passive filters are used in existing hybrid filters, then the filter can achieve basic filtering function, but the size becomes large and parasitic effects increase
Solution Approach 1:
The patent merges the film bulk acoustic resonator and passive filter into a single integrated structure where the resonator is disposed within the sealed space formed by the substrates and the passive filter components are integrated on the same substrate. This integration reduces the overall filter size while maintaining the filtering function by combining previously separate components into a unified assembly.
Solution Approach 2:
The film bulk acoustic resonator is nested within the sealed space formed by the first and second substrates, with the resonator positioned inside the cavity created by the substrates and connection blocks. This nesting arrangement allows the resonator to be housed within the structural framework of the filter itself, reducing the need for separate mounting spaces and minimizing overall device volume.
2Reliability
If separate film bulk acoustic resonators and passive filters are used in existing hybrid filters, then the filter can achieve basic filtering function, but parasitic effects increase
Solution Approach 1:
By integrating the passive filter components directly on the substrate and positioning the film bulk acoustic resonator in close proximity within the sealed space, the patent reduces the length of interconnect paths between components. This merging approach minimizes parasitic inductance and capacitance that would otherwise be introduced by long external connections, thereby reducing overall parasitic effects while maintaining filtering performance.
3Strength
If silicon-based substrates are used, then the substrate provides mechanical support, but the high loss angles and conductivity issues limit performance in high-frequency applications
Solution Approach 1:
The patent changes the material parameter of the substrate from silicon-based to glass-based material. This parameter change addresses the high-frequency performance limitation by selecting glass, which has lower loss angles and better electrical insulation properties at high frequencies, while still providing adequate mechanical support for the filter structure.
4Reliability
If three-dimensional spiral inductor structure is used, then the bandwidth and roll-off coefficients are improved, but the manufacturing complexity increases
Solution Approach 1:
The patent employs a three-dimensional spiral inductor structure that utilizes vertical stacking and multi-layer construction to achieve superior electromagnetic performance. By transitioning from a planar two-dimensional layout to a three-dimensional configuration, the inductor achieves higher bandwidth and improved roll-off coefficients through enhanced magnetic coupling and reduced parasitic effects, despite the increased manufacturing complexity.
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 achieves reduced size and parasitic effects, with improved bandwidth and roll-off coefficients, addressing the limitations of existing hybrid filters for high-frequency applications.
Implementation Method 1
a piezoelectric layer disposed on a side of the first electrode away from the first base substrate
Implementation Method 2
the filtering inductor has a three-dimensional spiral inductor structure
Implementation Method 3
the passive filter includes a filtering inductor and a filtering capacitor
Data Source
AI summary
The present disclosure provides a hybrid filter, a preparation method thereof, and a filtering apparatus. The hybrid filter includes a first substrate (100) and a second substrate (200) disposed oppositely, a first space (300) is disposed between the first substrate (100) and the second substrate (200), at least one of the first substrate (100) and the second substrate (200) is provided with a film bulk acoustic resonator (30), at least one of the first substrate (100) and the second substrate (200) is provided with at least one passive filter (40), the film bulk acoustic resonator (30) is disposed in the first space (300) and is connected with the passive filter (40), the passive filter (40) includes a filtering inductor and a filtering capacitor, and the filtering inductor has a three-dimensional spiral inductor structure.