Radiofrequency or hyperfrequency micro-switch structure and method for producing one such structure
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Solution Overview
Problem
Existing RF MEMS micro-switches face challenges in achieving high switching speeds, handling RF power levels up to ten watts, wideband operation beyond 18 GigaHertz, compactness, low cost, and extended lifetimes, while maintaining low insertion losses and reliability.
Innovation Solution
A micro-switch structure featuring a voltage-controlled electrode with a high permittivity dielectric material like PZT, a flexible conducting membrane, and symmetric parallel ground lines on an insulating substrate, optimized for both series and parallel configurations, with a fabrication method that includes specific layer deposition and etching steps to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional dielectric materials with low relative permittivity are used, then the device complexity is low, but the switching speed and transmission properties are insufficient
Solution Approach 1:
The patent changes the dielectric parameter (relative permittivity) from conventional low values to high values (>100), which directly improves switching speed and transmission properties. This parameter change enables faster capacitance variation between Con and Coff states, achieving the required switching performance.
Solution Approach 2:
The patent employs composite material structures combining high permittivity dielectric materials with specific electrode configurations. This composite approach achieves both high switching speed and acceptable device complexity by integrating materials with complementary properties.
2Reliability
If high permittivity dielectric materials are used, then the transmission and isolation properties are improved, but the manufacturing precision requirements increase
Solution Approach 1:
By optimizing the dielectric layer thickness and positioning parameters, the patent achieves high transmission and isolation properties while maintaining manufacturable precision requirements. The parameter optimization balances performance with fabrication capabilities.
3Power
If the membrane is designed to handle high RF power, then the power handling capability is improved, but the insertion losses increase
Solution Approach 1:
The patent applies local quality by creating non-uniform membrane structures or material properties in specific regions. This allows different parts of the membrane to handle power differently, achieving high power handling in critical areas while minimizing losses in other regions.
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 solution enables high-frequency operation up to 100 GigaHertz, efficient RF power handling, improved switching times, and extended lifetimes, while maintaining low insertion losses and cost-effectiveness, meeting the demands of advanced telecommunications and consumer markets.
Implementation Method 1
at least one layer of a dielectric material with a high relative permittivity greater than a hundred is deposited onto said control electrode
Implementation Method 2
RF switching is obtained by varying the capacitance of a capacitor whose plates are formed, on the one hand, by a membrane and, on the other, by a facing control electrode
Implementation Method 3
the application of a activation voltage under the membrane makes it go from an idle off state, open, to the on state, closed
Data Source
AI summary
The micro-switch structure comprises, on a substrate 1 coated with a passivation layer 2, a first signal line LS-IN and a second signal line LS-OUT disposed in the projected extension of one another, separated by a switching region 10; a control electrode 3 in said region, a dielectric material 4 with high relative permittivity invariant in frequency, disposed on the control electrode in such a manner that, between the two signal lines, the control electrode is wider on either side and, in the orthogonal direction, the dielectric protrudes on either side of the control electrode and rests on the passivation layer; parallel ground lines, disposed symmetrically on either side of the signal lines and formed on a topological level separated from that of the signal lines by at least one insulating layer made of a material different from that of the passivation layer.