BAW Resonator Matching Network for 6.5 GHz Wi-Fi 6E Filters
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Solution Overview
Problem
Current bulk acoustic wave resonators using polycrystalline piezoelectric thin films face degradation issues at frequencies above 5 GHz due to poor crystalline quality as thickness decreases below 0.5 um, limiting their performance in high-frequency applications.
Innovation Solution
The use of single crystalline or epitaxial piezoelectric thin films grown on compatible substrates, combined with advanced manufacturing processes, to create high-quality bulk acoustic wave resonators with enhanced electro-mechanical coupling and quality factor for high-frequency applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polycrystalline piezoelectric thin films are used in BAW resonators, then manufacturing is easier and cost is lower, but crystalline quality degrades quickly as thickness decreases below 0.5 um, limiting performance at frequencies around 5 GHz and above
Solution Approach 1:
The patent changes the material parameter from polycrystalline to single crystal structure, enabling the piezoelectric film to maintain high crystalline quality at thicknesses below 0.5 um. This parameter change allows the resonators to operate at frequencies above 5 GHz while preserving acoustic wave propagation characteristics and electro-mechanical coupling.
Solution Approach 2:
The patent employs a composite structure combining single crystal piezoelectric material with compatible crystalline substrates. This composite approach leverages the superior crystalline quality of single crystal materials while using substrate integration techniques to achieve manufacturability and device performance at high frequencies.
2Reliability
If single crystal piezoelectric thin films are used, then crystalline quality and electro-mechanical coupling are improved for high-frequency applications, but manufacturing complexity increases
Solution Approach 1:
The patent uses compatible crystalline substrates as intermediaries to grow single crystal piezoelectric thin films. These substrates serve as a bridge between the manufacturing process and the final high-frequency device, enabling the growth of high-quality single crystal layers while simplifying the overall manufacturing complexity through established substrate-based growth techniques.
3Speed
If piezoelectric film thickness is reduced to achieve higher resonant frequencies, then operating frequency increases, but quality factor degrades due to poor crystalline quality in polycrystalline films
Solution Approach 1:
The patent changes the crystalline structure parameter from polycrystalline to single crystal, which fundamentally alters the relationship between film thickness and quality factor. This parameter change enables the quality factor to be maintained at high levels even as thickness is reduced to achieve higher operating frequencies above 5 GHz, overcoming the degradation issue inherent in polycrystalline films.
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 approach enables the production of high-performance RF filters with improved quality factor and crystalline quality, effectively addressing the limitations of polycrystalline films at high frequencies and enabling efficient acoustic wave control in RF filters.
Implementation Method 1
Bulk acoustic wave resonators (BAWR) using crystalline piezoelectric thin films are leading candidates for meeting such demands
Implementation Method 2
Single crystalline or epitaxial piezoelectric thin films grown on compatible crystalline substrates exhibit good crystalline quality and high piezoelectric performance
Implementation Method 3
bulk acoustic wave resonators with enhanced electro-mechanical coupling and quality factor for high-frequency applications
Data Source
AI summary
A multi-stage matching network filter circuit device. The device comprises bulk acoustic wave (BAW) resonator device having an input node, an output node, and a ground node. A first matching network circuit is coupled to the input node. A second matching network circuit is coupled to the output node. A ground connection network circuit coupled to the ground node. The first or second matching network circuit can include an inductive ladder network including a plurality of series inductors in a series configuration and a plurality of grounded inductors wherein each of the plurality of grounded inductors is coupled to the connection between each connected pair of series inductors. The inductive ladder network can include one or more LC tanks, wherein each of the one or more LC tanks is coupled between a connection between a series inductor and a subsequent series inductor, which is also coupled to a grounded inductor.