Rounded MEMS Switch Membrane for Sticking and Deformation
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Solution Overview
Problem
RF MEMS switches face challenges in maintaining mechanical and thermal stability, preventing permanent deformation, contact degradation, and sticking phenomena, especially during prolonged activation and high-temperature packaging processes.
Innovation Solution
A microelectromechanical switch design featuring a deformable conductive membrane with a rounded shape and radial opening, anchored at its periphery, an activation electrode matching the membrane's shape, and stop pads to ensure high localized contact force and reduced electrical capacitance, minimizing sticking and deformation, and utilizing materials from the platinum group for enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the deformable conductive membrane is made flat and rigid for stable electrical contact, then contact reliability improves, but temperature sensitivity increases and permanent deformation occurs during prolonged activation
Solution Approach 1:
The deformable conductive membrane is designed with a rounded convex shape instead of being flat. This curvature allows the membrane to deform elastically under activation forces and return to its original shape, preventing permanent deformation while maintaining stable electrical contact. The rounded geometry distributes stress more evenly, reducing temperature sensitivity and preventing contact sticking during prolonged activation.
2Reliability
If the contact area between the deformable conductive membrane and signal supply line is increased for stable electrical contact, then contact stability improves, but electrical capacitance increases reducing switch isolation
Solution Approach 1:
The signal supply line is positioned to extend slightly beyond the contact pad, creating a localized contact area. This configuration provides sufficient contact stability while minimizing the overlapping area between the deformable conductive membrane and the signal supply line, thereby reducing parasitic electrical capacitance and maintaining good switch isolation.
3Use of energy by moving object
If the deformable conductive membrane is made thin and flexible for low activation voltage, then power consumption decreases, but mechanical strength reduces leading to permanent deformation
Solution Approach 1:
The deformable conductive membrane is constructed as a multi-layer composite structure combining materials with different properties. This composite design provides the necessary mechanical strength to prevent permanent deformation while maintaining flexibility for low-voltage activation. The layered structure allows optimization of both structural integrity and electrostatic actuation characteristics.
4Duration of action of stationary object
If repeated activation cycles are performed to ensure component longevity, then durability improves, but contact zone aging accelerates causing performance degradation and sticking
Solution Approach 1:
The rounded shape of the deformable conductive membrane enables elastic deformation during repeated activation cycles, allowing the contact to return to its original position without permanent set. This elastic behavior prevents contact sticking and reduces aging effects, maintaining reliable electrical contact over extended operational lifetimes.
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 achieves reduced temperature sensitivity, stable electrical contact, and extended longevity with minimal sticking, maintaining performance across a wide range of frequencies and temperatures.
Implementation Method 1
an activation electrode, formed on the substrate under the deformable conductive membrane, said activation electrode being intended to deform the said deformable conductive membrane to make electrical contact
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present invention relates to a switch (1) of a microelectromechanical system, said switch including: - a signal input line (4); - a signal output line (5); - a conductive membrane (2) that is capable of changing shape when conductively linked with the line (5) and includes a contact pad (9) facing the line (4); and - an electrode (3) for activating the membrane (2). Said switch is characterized in that the membrane (2) has a planar, rounded shape with a radial opening (2a) in the direction of the signal input line (4) that tapers from the periphery to the center of the membrane (2). The contact pad (9) is formed in the central region of the membrane (2). The activation electrode (3) has the same shape as the membrane (2), and there is nothing but an air space between the membrane (2), facing the activation electrode (3), and the activation electrode (3).