MEMS Membrane-Bridge Phase Shifter for Fast Low-Loss Tuning
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Solution Overview
Problem
Conventional phase shifters, such as those using ferrite materials or liquid crystals, face limitations due to complex processes, high costs, large volume, and inadequate performance in high-speed applications like 5G MIMO, with liquid crystal phase shifters having narrow capacitance change range and long response times.
Innovation Solution
A phase shifter based on micro-electro-mechanical systems (MEMS) with a substrate, transmission lines, and phase control elements comprising a transmission line extension portion and a membrane bridge that moves in response to voltage differences, allowing for significant capacitance change and reduced dielectric loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional phase shifters use ferrite materials or PIN diodes, then phase control is achieved, but the device complexity and fabricating cost increase
Solution Approach 1:
The patent replaces conventional electronic phase control mechanisms (ferrite materials, PIN diodes, FETs) with a MEMS-based mechanical system. The phase shifter uses a movable conductive plate that can be positioned at different locations between capacitor plates through electrostatic actuation, substituting electronic control with mechanical displacement to achieve phase modulation with simpler fabrication processes
Solution Approach 2:
The invention changes the capacitance parameter by physically moving the conductive plate to different positions between the capacitor plates. This positional parameter change directly modifies the capacitance value, enabling phase control through geometric configuration rather than through complex electronic circuitry
2Reliability
If liquid crystal phase shifters are used, then phase adjustment is possible, but the response time increases and capacitance change range narrows
Solution Approach 1:
The patent replaces liquid crystal-based phase control with a MEMS mechanical system featuring a movable conductive plate. This substitution eliminates the slow molecular reorientation process of liquid crystals and replaces it with rapid electrostatic actuation of a conductive plate, achieving significantly faster response times while maintaining phase adjustment capability
Solution Approach 2:
The invention introduces dynamic movement of the conductive plate between different positions using electrostatic forces. The plate can be rapidly positioned at different locations to dynamically adjust capacitance and phase, providing fast response times compared to static or slowly changing liquid crystal configurations
3Reliability
If conventional phase shifters are implemented, then phase control is achieved, but the volume increases
Solution Approach 1:
The patent employs a compact nested structure where the movable conductive plate is positioned within the space between the capacitor plates. This nested configuration allows the phase control element to be integrated within the existing capacitor structure, minimizing additional volume requirements while maintaining full phase control functionality
Solution Approach 2:
The invention utilizes the third dimension by moving the conductive plate in the vertical direction between the capacitor plates. This dimensional approach allows phase control to be achieved through spatial positioning rather than through planar circuit expansions, significantly reducing the overall device footprint
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 MEMS phase shifter offers enhanced capacitance change range, shorter response time, and lower dielectric loss, expanding its application scope and reducing antenna losses compared to liquid crystal phase shifters.
Implementation Method 1
the membrane bridge is configured to move in response to the first and second transmission lines being applied with different voltages
Implementation Method 2
change a distance of the portion of the membrane bridge from the transmission line extension portion
Data Source
AI summary
The present disclosure provides a phase shifter, a method for fabricating the same, and an antenna. The phase shifter includes a substrate, first and second transmission lines spaced apart from each other on the substrate, and at least one phase control element on the substrate. Each phase control element includes a membrane bridge and a transmission line extension which is on the substrate, between the first and second transmission lines, and electrically coupled to the first transmission line; the membrane bridge is on a side of the transmission line extension distal to the substrate, opposite to and spaced apart from the transmission line extension, and electrically coupled to the second transmission line. The membrane bridge is configured to move a portion of the membrane bridge in response to the first and second transmission lines being applied with different voltages, to change a distance from the transmission line extension.