Single-Crystal BAW RF Filter Layout for 5.5 GHz Coexistence
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Solution Overview
Problem
Conventional RF technologies face limitations in producing high-performance bulk acoustic wave resonators for frequencies above 5 GHz due to degradation of polycrystalline piezoelectric films and challenges in using single crystal piezoelectric thin films in manufacturing BAWR and BAW filters.
Innovation Solution
A method and structure for bulk acoustic wave resonator devices using single crystal piezoelectric materials, such as aluminum nitride or gallium nitride, with a ladder or lattice configuration, incorporating capacitor devices and shunt resonators to achieve a pass-band centered around 5.5025 GHz with high rejection and low insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polycrystalline piezoelectric films are used for BAWR manufacturing, then ease of manufacture is improved, but manufacturing precision deteriorates due to film degradation at high frequencies above 5 GHz
Solution Approach 1:
The patent changes the material parameter from polycrystalline to single crystal piezoelectric films, which fundamentally alters the film's structural properties. This parameter change enables the film to maintain high quality and consistent performance at frequencies above 5 GHz, resolving the degradation issue while preserving manufacturability through established single crystal growth techniques
Solution Approach 2:
The patent employs composite material structures by combining single crystal piezoelectric films with specific substrate materials and device architectures. This composite approach leverages the superior properties of single crystal materials for high-frequency operation while integrating them into manufacturable device structures that maintain ease of production
2Manufacturing precision
If single crystal piezoelectric thin films are used for BAWR manufacturing, then manufacturing precision is improved, but device complexity increases due to challenges in manufacturing
Solution Approach 1:
The patent segments the manufacturing process into distinct stages: single crystal film growth on suitable substrates, followed by controlled transfer and integration onto the BAWR device structure. This segmentation allows each stage to be optimized independently, reducing overall device complexity while maintaining the precision benefits of single crystal materials
Solution Approach 2:
The patent introduces intermediary processes and materials, such as using compatible substrate materials as temporary carriers during film growth and transfer. These intermediaries facilitate the integration of single crystal films into BAWR devices without requiring direct complex manufacturing steps, thereby reducing device complexity while preserving manufacturing precision
3Ease of operation
If conventional RF technology is used for frequencies above 5 GHz, then ease of operation is maintained, but reliability deteriorates due to performance limitations
Solution Approach 1:
The patent adapts and copies the successful device architecture and operational principles of conventional RF technology, but implements them using single crystal piezoelectric materials. This allows the device to maintain the ease of operation familiar to conventional systems while achieving superior reliability through the enhanced material properties that enable stable high-frequency performance
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 solution provides an ultra-small form factor RF resonator filter with high rejection, high power rating, and low insertion loss, suitable for 5.5 GHz Wi-Fi and 5G applications, manufactured in a cost-effective manner using conventional materials and methods.
Implementation Method 1
Bulk acoustic wave resonators (BAWR) using crystalline piezoelectric thin films
Implementation Method 2
bulk acoustic wave resonator devices... single crystal resonator device for a communication device
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.