MEMS Phase Shifter Bridge Structure to Reduce Dielectric Charging
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Solution Overview
Problem
MEMS phase shifters face failure due to dielectric charging during electrostatic driving, causing adhesion of the film bridge and subsequent operational issues.
Innovation Solution
A MEMS phase shifter design featuring a substrate with a coplanar waveguide signal structure, insulating isolation layers, and a metal film bridge, where the insulating dielectric layer has concave parts facing the metal film bridge, reducing contact area and charge injection effects by separating the insulating dielectric layer from the driving electrode and using organic materials with long-chain cross-linking for reduced adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional insulating dielectric layer is used in the MEMS phase shifter, then the device structure is simple and manufacturing is easy, but dielectric charging occurs during electrostatic driving causing film bridge adhesion and device failure
Solution Approach 1:
The insulating dielectric layer is segmented into multiple separate insulating dielectric structures (first, second, third, and fourth insulating dielectric structures) positioned at different locations. This segmentation reduces the continuous contact area between the dielectric layer and the metal film bridge, thereby reducing dielectric charging effects and preventing film bridge adhesion while maintaining device reliability.
Solution Approach 2:
Different regions of the device have different insulating structures tailored to their specific needs. The insulating dielectric structures are selectively positioned at locations where dielectric charging is most problematic, while other regions maintain their original simple structure. This local optimization reduces overall device complexity while improving reliability at critical points.
2Reliability
If the insulating dielectric layer is removed completely to prevent dielectric charging, then dielectric charging effects are eliminated, but electrical insulation and signal transmission are compromised
Solution Approach 1:
The insulating dielectric layer is divided into separate structures that provide localized insulation only where needed for signal transmission, while leaving other areas open to prevent dielectric charging. This segmentation allows the device to maintain electrical insulation functionality while resisting dielectric charging effects.
Solution Approach 2:
The separate insulating dielectric structures act as intermediaries that provide electrical insulation between the metal film bridge and the substrate only at specific locations, while allowing the rest of the structure to remain free of dielectric charging. This intermediary approach balances insulation needs with charging prevention.
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 enhances the service life and response speed of the MEMS phase shifter by minimizing dielectric charging effects, maintaining stable operating voltage and reducing adhesion risks.
Implementation Method 1
the failure of the MEMS phase shifter caused by the charging of the insulating dielectric layer during the electrostatic driving of the MEMS phase shifter can be reduced
Data Source
AI summary
A MEMS phase shifter, including: a substrate; a coplanar waveguide signal structure on the substrate; two coplanar waveguide ground wires respectively at two sides of the coplanar waveguide signal structure; insulating isolation layers respectively on the two coplanar waveguide ground wires; and a metal film bridge across and over the coplanar waveguide signal structure and forming a gap with the coplanar waveguide signal structure, both ends of the metal film bridge respectively attached to the insulating isolation layers on the two coplanar waveguide ground wires, wherein an insulating dielectric layer is provided on the coplanar waveguide signal structure, and the insulating dielectric layer comprises at least one concave part, which is concave in the direction towards the substrate, on the surface facing the metal film bridge.