MEMS Switch Recta-Coax Actuator for Low Insertion Loss
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Solution Overview
Problem
Current broadband MEMS switches face challenges in achieving low insertion loss, high isolation, and return loss at ultra-high frequencies, with existing technologies struggling to meet the stringent requirements of broadband communications systems, particularly in satellite applications.
Innovation Solution
The design incorporates an electrically-conductive ground housing with suspended conductors and an actuator system that includes an electrically-conductive arm to move a third conductor between isolated and contact positions, utilizing a recta-coax configuration and electrostatic attraction to facilitate low-loss signal transmission, with a configuration that includes multiple layers of conductive material and insulative tabs for efficient electrical isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional thin film technology is used for MEMS switches, then manufacturing is simpler, but insertion loss and isolation performance deteriorate at ultra-high frequencies
Solution Approach 1:
The switch structure is divided into distinct segments including separate ground housing, signal conductors, and actuator components. Each segment is optimized independently for its specific function, allowing the overall device to achieve low insertion loss through precise geometric control of each component while managing complexity through modular design.
Solution Approach 2:
The patent transitions from planar thin-film structures to three-dimensional microstructures with vertical stacking and suspended geometries. This dimensional change enables better control of electromagnetic field distribution, reducing insertion loss at ultra-high frequencies while the modular 3D architecture manages complexity through spatial organization.
2Volume of moving object
If miniaturized switch designs are used, then size constraints are satisfied, but achieving low insertion loss and high isolation at ultra-high frequencies becomes difficult
Solution Approach 1:
The design nests multiple functional elements within a compact volume, including suspended conductors within ground housings, and integrating actuators with contact structures. This nesting achieves miniaturization while maintaining low insertion loss through optimized electromagnetic field confinement in the nested geometries.
Solution Approach 2:
The patent uses thin-film deposited conductive and dielectric layers to create flexible suspended structures and actuators. These thin-film-based flexible components enable miniaturized switch designs that maintain low insertion loss by controlling field distribution through precise thin-film geometry and material properties.
3Manufacturing precision
If conventional switch structures are used, then manufacturing processes are simpler, but isolation and return loss performance worsen at 20 GHz and above
Solution Approach 1:
The switch is segmented into separately manufacturable components including ground housings, suspended conductors, and actuators. This segmentation enables precise control of isolation-critical interfaces through independent manufacturing and assembly, achieving 46.8 dB isolation at 20 GHz while managing manufacturing complexity through modular component fabrication.
Solution Approach 2:
The transition to three-dimensional microstructures with vertical stacking and suspended geometries enables superior isolation performance at ultra-high frequencies through enhanced field confinement. The 3D architecture provides additional spatial dimensions for managing electromagnetic fields, improving isolation while the modular 3D components facilitate systematic manufacturing approaches.
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 results in significantly improved insertion loss, return loss, and isolation, with predicted values of approximately 0.12 dB, 17.9 dB, and 46.8 dB at 20 GHz, respectively, representing substantial improvements over existing technologies, along with enhanced power-handling capability and linearity for both DC and RF signals.
Implementation Method 1
utilizing a recta-coax configuration and electrostatic attraction to facilitate low-loss signal transmission
Data Source
AI summary
Embodiments of switches (10) include electrically-conductive housings (30, 60), and electrical conductors (34, 64) suspended within and electrically isolated from the housings (30, 60). Another electrical conductor (52) is configured to move between a first position at which the electrical conductor (52) is electrically isolated from the electrical conductors (34, 64) within the housings (30, 60), and a second position at which the electrical conductor (52) is in electrical contact with the electrical conductors (34, 64) within the housings (30, 60). The switches (10) further include an actuator (70, 72, 74, 76) comprising an electrically-conductive base (80) and an electrically-conductive arm (82a, 82b) having a first end restrained by the base (80). The electrical conductor (52) is supported by the arm (82a, 82b), and the arm (82a, 82b) is operative to deflect and thereby move the electrical conductor (52) between its first and second positions.