Surface Acoustic Wave Filter With Movable Electrode for Multi-Band RF
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Solution Overview
Problem
Electronic devices equipped with multiple filters for passing specific frequency bands face space constraints due to the need for fixed transducer electrodes with varying gaps and thicknesses for different frequency bands, leading to a lack of mounting space.
Innovation Solution
The electronic device employs a filter with a first and second substrate, first and second transducer electrodes, and a power supply to apply voltages, allowing the second transducer electrode to move and change its position based on signal frequency, thereby adjusting the frequency band passed without the need for multiple filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple filters are disposed in the electronic device to pass signals of several frequency bands, then the frequency band coverage is improved, but the mounting space is reduced
Solution Approach 1:
A single filter structure is designed to perform multiple functions by selectively passing different frequency bands. The filter includes a first transducer electrode and a second transducer electrode that can be selectively connected to process signals of different frequency bands, allowing one filter to replace what would traditionally require multiple separate filters.
Solution Approach 2:
The filter employs dynamic switching capability where the second transducer electrode can be selectively connected or disconnected based on the frequency band of the incoming signal. This dynamic reconfiguration allows the same physical filter structure to adapt to different frequency requirements, enabling multi-frequency band processing without requiring multiple fixed filters.
2Reliability
If fixed transducer electrodes with varying gaps and thicknesses are used for different frequency bands, then the signal filtering performance is improved, but the device complexity increases
Solution Approach 1:
The filter structure is divided into distinct functional segments: a first transducer electrode with specific gap and thickness characteristics for a first frequency band, and a second transducer electrode with different gap and thickness characteristics for a second frequency band. These segmented elements can be independently optimized for their respective frequency bands while being integrated into a single filter structure.
Solution Approach 2:
The filter utilizes changes in physical parameters (gap distance and electrode thickness) of the transducer electrodes to achieve different filtering characteristics for different frequency bands. By varying these parameters in the second transducer electrode relative to the first, the filter can selectively process different frequency bands without requiring completely separate filter structures.
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 configuration allows the device to pass signals of multiple frequency bands using a single filter, increasing the mounting space and reducing the physical space occupied by the filter, thereby addressing the space constraint issue.
Implementation Method 1
a piezoelectric substrate, a first transducer electrode and a second transducer electrode
Implementation Method 2
a piezoelectric substrate, a first transducer electrode and a second transducer electrode
Implementation Method 3
a power supply configured to apply voltages to the first group of electrodes and the second group of electrodes such that at least one of the second group of lines is separated from the first substrate
Data Source
AI summary
An electronic device according to an embodiment includes: an antenna, a filter configured to pass a signal of a specific frequency band among signals transmitted and received through the antenna, and a processor configured to control the filter to pass the signal of the specific frequency band. The filter includes: a first substrate, a second substrate facing the first substrate, a first group of electrodes disposed inside the first substrate, a second group of electrodes disposed inside the second substrate, a first transducer electrode including a first group of lines, a second transducer electrode including a second group of lines disposed to alternate with the first group of lines, and a power supply configured to apply voltages to the first group of electrodes and the second group of electrodes. The processor is configured to cause at least one of the second group of lines to be separated from the first substrate, by controlling the power supply based on a frequency of a signal to be passed through the filter.