BAW RF Filter Topologies for 5.2 GHz Wi-Fi Coexistence
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional bulk acoustic wave resonators using polycrystalline piezoelectric thin films degrade quickly at thicknesses below 0.5 um, limiting their performance at frequencies above 5 GHz, while single crystalline films maintain quality but are challenging to manufacture and transfer effectively.
Innovation Solution
The development of a method and structure for bulk acoustic wave resonator devices using single crystalline or epitaxial piezoelectric thin films, employing techniques like sacrificial layers and transfer processes to achieve high-quality factor and electro-mechanical coupling for RF filters operating at high frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polycrystalline piezoelectric thin films are used in bulk acoustic wave resonators, then manufacturing is easier and cost is lower, but quality factor degrades quickly at thicknesses below 0.5 um and frequencies above 5 GHz
Solution Approach 1:
The patent changes the material parameter from polycrystalline to single-crystal piezoelectric thin films, which fundamentally alters the quality factor characteristics at high frequencies and thin thicknesses while maintaining manufacturability through established single-crystal growth techniques
Solution Approach 2:
The patent employs composite material structures combining single-crystal piezoelectric layers with carefully engineered electrode and substrate materials to achieve both high quality factor and manufacturability in bulk acoustic wave resonators
2Reliability
If single crystalline piezoelectric thin films are used to maintain quality at high frequencies, then quality factor and electro-mechanical coupling improve, but manufacturing and transfer processes become more complex
Solution Approach 1:
The patent performs preliminary actions by pre-growing single-crystal piezoelectric thin films on sacrificial substrate structures before final device assembly, allowing complex single-crystal material preparation to be completed in advance using specialized techniques while simplifying the main manufacturing process
Solution Approach 2:
The patent uses sacrificial substrate structures as intermediary elements that facilitate the transfer and integration of single-crystal piezoelectric thin films onto the final device architecture, enabling complex material handling through a mediating temporary support structure
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 reduced manufacturing complexity, effectively addressing the limitations of polycrystalline films at high frequencies and enabling efficient RF filtering for 5G and Wi-Fi applications.
Implementation Method 1
Bulk acoustic wave resonators (BAWR) using crystalline piezoelectric thin films
Implementation Method 2
bulk acoustic wave resonator devices
Data Source
AI summary
An RF circuit device using modified lattice, lattice, and ladder circuit topologies. The devices can include four resonator devices and four shunt resonator devices. In the ladder topology, the resonator devices are connected in series from an input port to an output port while shunt resonator devices are coupled the nodes between the resonator devices. In the lattice topology, a top and a bottom serial configurations each includes a pair of resonator devices that are coupled to differential input and output ports. A pair of shunt resonators is cross-coupled between each pair of a top serial configuration resonator and a bottom serial configuration resonator. The modified lattice topology adds baluns or inductor devices between top and bottom nodes of the top and bottom serial configurations of the lattice configuration. These topologies may be applied using single crystal or polycrystalline bulk acoustic wave (BAW) resonators.