Programmable SAW Filter Switching for Adjustable Frequency Response
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Solution Overview
Problem
Existing SAW filters have fixed filtering characteristics determined during manufacturing and cannot be changed post-manufacturing, which limits their adaptability to changing signal requirements.
Innovation Solution
A programmable SAW filter is designed with a piezoelectric substrate, comb-structured ground and output electrodes, and a switching unit comprising transistors that can selectively transmit output signals to an output or ground node based on switching control signals, allowing dynamic adjustment of filtering coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SAW filter is configured as passive filter with fixed electrode structures, then power consumption is reduced, but filtering characteristic cannot be changed after manufacturing
Solution Approach 1:
The patent applies the dynamics principle by introducing switching units that can dynamically change the connection state of output electrodes. The switching units include switches that can be controlled to connect or disconnect specific output electrodes, enabling the filtering characteristics to be adjusted after manufacturing without changing the physical electrode structures. This resolves the contradiction by making the filter adaptable while maintaining the passive power-saving design.
Solution Approach 2:
The patent implements multi-functionality by designing a single SAW filter device that can perform multiple filtering operations. The switching units allow the same filter structure to be reconfigured for different filtering requirements by selectively connecting different output electrodes. This enables one filter to serve multiple functions and adapt to different signal processing needs, resolving the adaptability limitation.
2Adaptability or versatility
If electrode positions and structures are fixed during manufacturing, then manufacturing precision is maintained, but filtering characteristic cannot be adjusted during use
Solution Approach 1:
The patent makes the filter reconfigurable by introducing controllable switching units. These switches can be controlled through control signals to change the connectivity of output electrodes dynamically. The electrode structures themselves remain fixed (maintaining manufacturing precision), but their electrical connections become dynamic, allowing filtering characteristics to be adjusted during operation without physical repositioning.
Solution Approach 2:
The switching units act as intermediaries between the fixed electrode structures and the output signals. By introducing these intermediate switching elements, the patent enables control over which electrodes are connected to the output, providing reconfiguration capability without requiring changes to the underlying electrode positions or structures manufactured on the substrate.
3Adaptability or versatility
If switching units are added to enable selective transmission of output signals, then filtering characteristic can be changed, but device complexity increases
Solution Approach 1:
The patent introduces dynamic switching capability through switching units that can be controlled to connect or disconnect output electrodes. These switches enable the filter to be reprogrammed for different filtering characteristics by changing the connectivity configuration. The dynamic nature of the switches allows adaptability while keeping the base filter structure passive.
Solution Approach 2:
The switching units are applied locally at specific points in the filter circuit where output electrodes connect to the output. Rather than making the entire filter active or complex, the switching capability is introduced only where needed to control signal transmission. This localized approach enables reprogrammability with minimal impact on overall power consumption.
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
Enables the SAW filter to programmatically change its filtering characteristics as needed, enhancing its adaptability and functionality in applications like communication terminals for signal allocation and processing.
Implementation Method 1
a piezoelectric substrate; a ground electrode formed in a comb structure on the piezoelectric substrate
Implementation Method 2
Surface Acoustic Wave (SAW) filters, and more particularly, to programmable SAW filters
Data Source
AI summary
A programmable surface acoustic wave filter and methods thereof including a piezoelectric substrate, a ground electrode formed in a comb structure on the piezoelectric substrate, a plurality of output electrodes formed in comb structures on the piezoelectric substrate and alternately disposed together with the ground electrode, and a switching unit performing a switching operation so as to selectively transmit output signals output from the plurality of output electrodes to an output node. As a result, a filtering characteristic of the programmable surface acoustic wave filter can be programmed in a desired format.