RF-MEMS Switch Collapsible Portion Lateral Offset Design
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Solution Overview
Problem
RF-MEMS switching devices face the risk of self-actuation when exposed to high-power RF signals, which can lead to unintended actuation and reduced reliability.
Innovation Solution
The method involves designing a micro electromechanical device with a collapsible portion that is laterally offset from the region of maximum actuation liability, requiring a higher attraction force for actuation and ensuring the device can withstand higher RF-induced forces, thereby reducing the risk of self-actuation. This is achieved by determining the characteristics of the collapsible portion to be movable between distant and proximate positions and ensuring the device can withstand RF-induced forces above a given value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the collapsible portion is positioned directly over the first conductor to maximize actuation efficiency, then the actuation voltage is minimized, but the device becomes susceptible to self-actuation under high-power RF signals
Solution Approach 1:
The patent introduces a lateral offset in the horizontal plane between the first conductor and the region of maximum actuation liability on the collapsible portion. This dimensional displacement moves the conductor away from the vertically aligned position that would maximize actuation efficiency, thereby reducing RF-induced forces while maintaining sufficient actuation capability through the offset geometry.
Solution Approach 2:
The patent creates a non-uniform distribution of actuation liability across the collapsible portion by designing it with a specific geometry that concentrates maximum liability in a region laterally offset from the first conductor. This local concentration allows the device to withstand RF forces at the conductor location while remaining actuatable through the offset region.
2Productivity
If the collapsible portion is designed with high actuation sensitivity, then switching efficiency is improved, but the device cannot withstand high RF-induced forces
Solution Approach 1:
The patent employs asymmetric positioning where the region of maximum actuation liability is deliberately placed at a lateral offset from the first conductor rather than directly above it. This asymmetric configuration creates different force distribution characteristics: high sensitivity to controlled actuation forces while presenting reduced vulnerability to RF-induced forces at the conductor location.
3Force
If the first conductor is positioned at the center of the collapsible portion's projection, then actuation force is minimized, but RF-induced forces cause self-actuation
Solution Approach 1:
The patent resolves the force contradiction by moving the first conductor laterally offset from the vertical projection of the maximum actuation liability region. This horizontal displacement in another dimension reduces the overlapping area between the conductor's electromagnetic field and the most sensitive region of the collapsible portion, thereby reducing RF-induced attraction forces while maintaining actuation capability through the offset geometry.
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 design effectively reduces the risk of self-actuation and allows for higher RF power transmission, as the device is capable of withstanding higher RF-induced forces, enhancing its operational reliability and stability.
Implementation Method 1
it is the collapsible portion of the second conductor which may be attracted by the first conductor as a result of RF induced forces
Implementation Method 2
The displacement is induced via a micro-actuator for which various actuation mechanisms exist including, electrostatic, electrothermal, piezoelectric, and electromagnetic means
Data Source
AI summary
A method is described for designing a micro electromechanical device in which the risk of self-actuation of the device in use is reduced. The method includes locating a first conductor in a plane and locating a second conductor with its collapsible portion at a predetermined distance above the plane. The method also includes laterally offsetting the first conductor by a predetermined distance from a region of maximum actuation liability. The region of maximum actuation liability is where an attraction force to be applied to activate the device is at a minimum.