FBAR Resonator Tuning With Deformable Drivers for Multiband RF Filters
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Solution Overview
Problem
Conventional film bulk acoustic resonators (FBARs) are limited in their ability to tune resonance frequency, making it difficult to achieve multiband operations and result in the need for multiple filters, which complicates the realization of compact-sized wireless communication devices.
Innovation Solution
A tunable resonator is designed using a film bulk acoustic resonator (FBAR) with drivers that can be deformed by external signals to change the resonance frequency, including cantilever, bridge, or bimetal structures, allowing for stepwise tuning of the resonance frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a general FBAR is used with fixed thickness, then the resonance frequency is determined, but the frequency cannot be tuned and multiband operation cannot be fulfilled
Solution Approach 1:
The patent introduces drivers that can be deformed by external signals to change the resonance frequency of the FBAR. The drivers are arranged at sides of the FBAR and can be brought into contact with the FBAR through deformation, enabling dynamic frequency adjustment and multiband operation without requiring multiple fixed-frequency filters
Solution Approach 2:
The patent changes physical parameters of the resonator system by deforming the drivers through external signals. This deformation alters the effective resonance frequency of the FBAR, allowing the same device to operate across multiple frequency bands by changing structural parameters rather than using multiple fixed devices
2Adaptability or versatility
If multiple filters are used to achieve multiband operation, then frequency coverage is improved, but device size increases and compact-sizing becomes difficult
Solution Approach 1:
The patent merges multiple filter functions into a single FBAR device by adding deformable drivers. Instead of using separate fixed-frequency filters for different bands, the invention combines frequency selection and frequency tuning capabilities in one integrated structure, reducing the overall device volume while maintaining multiband operation
Solution Approach 2:
The FBAR with deformable drivers serves multiple functions: it acts as both a resonator and a frequency-tunable element. The same device can operate across multiple frequency bands by adjusting driver deformation, eliminating the need for multiple specialized filters and reducing device complexity and size
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 tunable resonator enables multiband operations by adjusting the resonance frequency, allowing for the realization of compact-sized RF filters and duplexers, improving insertion and skirt properties.
Implementation Method 1
If an electric energy is applied to both the electrodes, an acoustic wave is generated due to the piezoelectric effect and accordingly a resonance is generated.
Implementation Method 2
The at least one driver may be thermally expanded and deformed when being heated by the external signal.
Implementation Method 3
The at least one driver may be of a bimetal structure that comprises two metals having different coefficients of thermal expansion.
Data Source
AI summary
A tunable resonator is provided. The tunable resonator includes a film bulk acoustic resonator (FBAR) for performing a resonance, and at least one driver which is arranged at a side of the FBAR and is deformed and brought into contact with the FBAR by an external signal, thereby changing a resonance frequency of the FBAR. Accordingly, a multiband integration and a one-chip manufacture can be implemented simply using a micro electro mechanical system (MEMS) technology and a mass production is possible.