Acoustic Filter with MEMS Switches for Parallel Resonance Tuning
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Solution Overview
Problem
Conventional silicon-on-insulator (SOI) switches in wireless devices exhibit higher on-resistance and off-capacitance, leading to degraded RF efficiency and performance due to higher figure-of-merit, which can be improved by replacing them with microelectromechanical systems (MEMS) switches.
Innovation Solution
An acoustic filter apparatus incorporating a microelectromechanical systems (MEMS) switch circuit that dynamically reconfigures parallel resonance frequencies by selectively controlling MEMS switches, reducing insertion loss and enhancing performance by employing MEMS switches with improved figure-of-merit over conventional SOI switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SOI switches are used in wireless devices, then device complexity is reduced and ease of manufacture is improved, but RF efficiency and performance degrade due to higher on-resistance and off-capacitance
Solution Approach 1:
The patent replaces conventional silicon-on-insulator (SOI) electronic switches with microelectromechanical systems (MEMS) switches. This substitution transitions from a purely electronic switching mechanism to a mechanically actuated microswitching mechanism, achieving lower on-resistance and off-capacitance values that improve RF efficiency and performance while maintaining manageable device complexity through established MEMS fabrication processes
Solution Approach 2:
The patent changes the fundamental switching parameters by transitioning from SOI to MEMS technology, achieving a figure-of-merit (FOM) that is at least 1/3 lower than conventional SOI switches. This parameter change results in reduced on-resistance and off-capacitance, directly improving RF efficiency without proportionally increasing device complexity
2Loss of energy
If MEMS switches are used to reduce insertion loss, then RF efficiency improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent integrates multiple functions into the acoustic filter apparatus, including signal filtering, dynamic reconfiguration of parallel resonance frequencies, and switching operations, all within a single device structure. This multi-functionality reduces the need for separate components, thereby improving RF efficiency while managing manufacturing complexity through consolidation
Solution Approach 2:
The patent employs dynamically reconfigurable parallel resonance frequencies through MEMS switches, allowing the acoustic filter to adapt its characteristics in real-time. This dynamic capability reduces insertion loss across varying operating conditions while maintaining manufacturing feasibility through programmable control of MEMS switch states
3Adaptability or versatility
If acoustic filter apparatus with MEMS switches is used, then parallel resonance frequencies can be flexibly configured, but device complexity increases
Solution Approach 1:
The patent segments the acoustic filter apparatus into distinct functional modules: acoustic resonators for frequency determination, MEMS switches for dynamic reconfiguration, and control circuitry for frequency management. This segmentation enables flexible configuration of parallel resonance frequencies while managing overall device complexity through modular design and independent optimization of each segment
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 acoustic filter apparatus effectively reduces insertion loss and improves RF efficiency and performance by flexibly configuring parallel resonance frequencies using MEMS switches, offering better performance compared to conventional SOI switches.
Implementation Method 1
The acoustic ladder network is configured to resonate in a series resonance frequency to pass a signal from an input node to an output node
Implementation Method 2
The acoustic ladder network is also configured to block the signal from the output node in a number of parallel resonance frequencies different from the series resonance frequency
Implementation Method 3
The MEMS switches may be selectively controlled (e.g., closed and/or opened) to cause a modification to a selected parallel resonance frequency(s) among the parallel resonance frequencies
Data Source
AI summary
An acoustic filter apparatus is provided. In examples discussed herein, the acoustic filter apparatus includes an acoustic ladder network configured to pass a signal in a series resonance frequency and block the signal in a number of parallel resonance frequencies. The acoustic ladder network is coupled to a microelectromechanical systems (MEMS) switch circuit that includes a number of MEMS switches. The MEMS switches may be selectively controlled (e.g., closed and/or opened) to cause a modification to a selected parallel resonance frequency(s) among the parallel resonance frequencies. As such, it may be possible to flexibly configure the parallel resonance frequencies of the acoustic ladder network based on application scenarios. Further, by employing the MEMS switches having improved figure-of-merit (FOM) over conventional silicon-on-insulator (SOI) switches, it may be possible to reconfigure the parallel resonance frequencies with reduced insertion loss, thus helping to improve performance of the acoustic filter apparatus.