Switchable SAW Reflector Electrodes for Frequency-Agile Filters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current SAW devices for telecommunications lack frequency agility, requiring separate components for each frequency band, leading to increased volume and cost, as their frequency response is fixed by design and geometry, making it impossible to produce frequency-agile filters or oscillators.
Innovation Solution
A surface acoustic wave device with transducers and acoustic reflectors featuring electrodes with mixed connection types (grounded and floating) and a switching circuit to dynamically modify electrode connections, allowing for frequency agility without altering geometric parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate SAW components are used for each frequency band, then each band can be processed by a specific component, but the occupied volume and cost increase
Solution Approach 1:
The patent implements a single SAW device that can process multiple frequency bands by dynamically reconfiguring the electrical connections of reflector electrodes between grounded and floating states. This multi-functional capability allows one device to replace multiple frequency-specific components, reducing overall device volume while maintaining the ability to handle different RF bands through electrical control rather than physical redesign
2Adaptability or versatility
If separate SAW components are used for each frequency band, then each band can be processed by a specific component, but the cost increases
Solution Approach 1:
The patent implements a single SAW device that can process multiple frequency bands by dynamically reconfiguring the electrical connections of reflector electrodes between grounded and floating states. This multi-functional capability allows one device to replace multiple frequency-specific components, reducing overall device volume while maintaining the ability to handle different RF bands through electrical control rather than physical redesign
3Device complexity
If the frequency response is fixed by design and geometry, then the device structure is simple, but frequency agility is lost
Solution Approach 1:
The patent introduces dynamic reconfigurability to the SAW device by enabling electrical connections of reflector electrodes to switch between grounded and floating states through switching circuits. This dynamic control allows the device to adapt its frequency response in real-time without altering the physical geometry or material structure, achieving frequency agility while maintaining structural simplicity
Solution Approach 2:
The patent achieves frequency tuning by changing the electrical boundary conditions (grounded vs. floating connections) of the reflector electrodes rather than altering physical dimensions or material properties. This parameter change approach allows frequency agility to be achieved through electrical control, preserving the simplicity of the physical device structure while enabling adaptive frequency response
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 frequency-agile operation while preserving the integrity of filter figures of merit, reducing device size and energy consumption by allowing frequency adjustment through electrical boundary condition modification, facilitating the production of filters and oscillators with shifted nominal frequencies.
Implementation Method 1
The operation of these devices is based on the conversion of electrical energy into at least one elastic wave via a transducer typically comprising two combs of interdigitated electrodes deposited on the surface of a piezoelectric material
Implementation Method 2
The acoustic reflectors are Bragg mirrors arranged on either side of this transduction zone. They are formed from periodic networks of electrodes R1 and R2 deposited on the surface of the same Mat substrate, and provide a high reflection coefficient for the surface acoustic waves in a certain range of frequencies, called the forbidden band
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
The invention relates to a surface acoustic wave device (10) comprising: - at least one transducer (T1, T2); - two acoustic reflectors (M1, M2) disposed on either side of the at least one transducer so as to form a cavity, each acoustic reflector comprising an array of electrodes (R1, R2) in the form of lines (21) parallel with each other, each array comprising a subset of electrodes connected to a reference potential denoted mass (M) defining a first connection type (CC), and a subset of electrodes that are not connected to any potential, i.e. that have a floating connection defining a second connection type (CO); - at least one switching circuit (CCOM) configured to modify the distribution of the connections of at least one part of the electrodes of each array between the different connection types.