MEMS Phase Shifter Film Bridge Layout With Fewer Bias Lines
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Solution Overview
Problem
MEMS phase shifters face challenges with a large number of bias lines and pins due to each metal film bridge needing a separate bias line, and the long bridges are prone to collapse during manufacturing, reducing yield rates.
Innovation Solution
A phase shifter design with a substrate, signal line, and phase shifting units where the metal film bridges span between adjacent signal line segments, reducing the distance and number of bias lines needed, and using a bias signal transmitted through the signal line and ground lines to change the capacitance and achieve phase shifting, thereby minimizing the risk of bridge collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each metal film bridge is connected to a separate bias line, then the phase shifting function is achieved, but the number of bias lines and pins increases significantly
Solution Approach 1:
Multiple phase shifting units share common bias lines and reference electrodes. The invention combines multiple independent bias lines into shared bias lines that serve multiple film bridges simultaneously, while using common reference electrodes to establish the bias potential, thereby reducing the total number of bias lines and pins required
Solution Approach 2:
The reference electrodes serve multiple functions: they act as common reference potentials for multiple phase shifting units, provide return paths for bias currents, and establish the electrical reference for the entire array. This multi-functionality reduces the need for separate dedicated structures for each function
2Reliability
If long metal film bridges are used to span between reference electrodes, then the phase shifting range is achieved, but the bridges are prone to collapse during manufacturing
Solution Approach 1:
The phase shifting function is divided into multiple discrete phase shifting units, each with its own film bridge spanning between adjacent signal line segments. This segmentation allows each bridge to be short and stable while collectively achieving the required total phase shifting range through multiple units working in parallel
Solution Approach 2:
The invention transitions from a single long bridge spanning in one dimension between distant reference electrodes to multiple short bridges arranged in an array, where the phase shifting capability is achieved through the collective effect of multiple units rather than a single extended structure
3Adaptability or versatility
If multiple separate bias lines are used for each phase shifting unit, then individual control is achieved, but the manufacturing complexity and yield rate are reduced
Solution Approach 1:
Multiple phase shifting units share common bias lines and reference electrodes, merging multiple independent control paths into shared infrastructure. This reduces the number of manufacturing steps, reduces pin count, and improves yield rate while maintaining the ability to individually control each unit through selective activation
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 design reduces the number of bias lines and the distance metal film bridges need to span, preventing collapse and improving yield rates by allowing for efficient phase shifting with fewer transmission paths and simpler manufacturing.
Implementation Method 1
changes a capacitance between the metal film bridge and the signal line
Implementation Method 2
a bias signal...to move the metal film bridge
Data Source
AI summary
A phase shifter includes a substrate, a transmission line on the substrate and extending in a first direction, and first and second reference electrodes respectively on both sides of an extension direction of the transmission line. The transmission line includes signal line segments, any adjacent two of which have a gap therebetween to define a connection region. The phase shifter further includes at least one phase shifting unit each including: a film bridge extending in the first direction, a connection electrode extending in a second direction, and an interlayer insulating layer on a side of the connection electrode distal to the substrate. Both ends of the connection electrode are respectively connected with the first and second reference electrodes, and an orthogonal projection of the connection electrode on the substrate is in the connection region. Both ends of the film bridge are respectively connected with adjacent two signal line segments.