MEMS Phase Shifter Structure With Air-Suspended Waveguide
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Solution Overview
Problem
MEMS phase shifters experience significant dielectric loss due to signal transmission in substrate media and phase shift errors caused by substrate bonding packaging methods, which introduce stresses.
Innovation Solution
The design includes a first substrate with a coplanar waveguide and capacitance bridges arranged in a groove, where the conductive wire is suspended above the groove, reducing dielectric loss by transmitting signals primarily in air and eliminating packaging-induced stresses through a second substrate with intersecting capacitance bridges that change distributed capacitance upon voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If signals are transmitted in the substrate medium, then the transmission line is compact and easy to manufacture, but the dielectric loss increases significantly
Solution Approach 1:
The patent extracts the signal transmission path from the substrate medium by creating a groove that suspends the conductive wire in air. The groove removes the substrate material from beneath the transmission line, allowing signals to propagate primarily in air rather than through the lossy substrate, thereby reducing dielectric loss while maintaining manufacturing simplicity
Solution Approach 2:
The patent introduces a vertical dimension by etching a groove into the substrate, transitioning from a planar transmission line to a three-dimensional structure. This dimensional change allows the conductive wire to be suspended above the groove, creating an air-filled transmission path that reduces dielectric loss while maintaining compact integration
2Reliability
If substrate bonding packaging methods are used, then the device is well-protected and packaged, but stresses are introduced that cause phase shift errors
Solution Approach 1:
The patent segments the substrate into two separate substrates with a groove between them, allowing independent processing and packaging of each substrate. This segmentation enables the transmission line to be isolated from packaging-induced stresses, maintaining phase shift accuracy while still providing protected packaging through the bond between substrates
Solution Approach 2:
The groove acts as an intermediary element between the two substrates, providing mechanical support and stress isolation. By suspending the conductive wire in the groove rather than bonding it directly to the substrate surface, the structure mediates between the need for protected packaging and the requirement for stress-free phase shift operation
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 significantly reduces dielectric loss and phase shift errors by minimizing substrate involvement in signal transmission and eliminating packaging-related stress, resulting in a low-loss, stable, and high-integration phase shifter.
Implementation Method 1
a plurality of capacitance bridges being located on a side of the coplanar waveguide away from the first substrate, the plurality of capacitance bridges being arranged at intervals and insulated from the first conductive wire and the second conductive wires, and each of the plurality of capacitance bridges being disposed in an intersecting manner with the first conductive wire
Data Source
AI summary
The present disclosure provides a MEMS phase shifter and a manufacturing method thereof. The MEMS phase shifter includes a first substrate having a first surface, a coplanar waveguide on the first surface of the first substrate and including a first conductive wire and two second conductive wires on two sides of the first conductive wire and insulated from the first conductive wire, and a plurality of capacitance bridges on a side of the coplanar waveguide away from the first substrate. The plurality of capacitance bridges are arranged at intervals and insulated from the first conductive wire and the second conductive wire, and each of the plurality of capacitance bridges intersects the first conductive wire. The first surface of the first substrate includes a first groove, and the first conductive wire is suspended above the first groove.