Coplanar Waveguide MEMS Switch Anchor for High-Frequency Isolation
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Solution Overview
Problem
Existing MEMS switches with coplanar waveguides face challenges in maintaining high isolation and low insertion loss, particularly at higher frequencies, due to parasitic capacitance and surface current distribution.
Innovation Solution
Incorporating a dovetail-shaped aperture in the anchor of the MEMS switch to reduce parasitic capacitance and optimize surface current flow, thereby improving isolation while minimizing insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional anchor design is used in the MEMS switch, then the structure is simple, but parasitic capacitance increases and isolation deteriorates at higher frequencies
Solution Approach 1:
The anchor is divided into multiple segments separated by apertures, creating a segmented structure that reduces parasitic capacitance between the anchor and the beam while maintaining mechanical support functionality
Solution Approach 2:
The anchor structure is modified locally by adding apertures in specific regions to reduce parasitic capacitance, while other regions maintain solid structure for mechanical support, creating non-uniform local properties throughout the anchor
2Reliability
If the anchor structure is modified to reduce parasitic capacitance, then isolation improves, but manufacturing complexity increases
Solution Approach 1:
The anchor is segmented into multiple parts with apertures between them, which can be fabricated using standard MEMS processing techniques such as selective etching, making the complex structure manufacturable with existing technology
Solution Approach 2:
The apertures are positioned asymmetrically in the anchor structure to optimize the balance between parasitic capacitance reduction and mechanical strength, allowing effective isolation improvement while maintaining manufacturability
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 aperture design enhances isolation by 1 dB or more at frequencies up to 40 GHz with a negligible increase in insertion loss, ensuring high performance in radio frequency applications.
Implementation Method 1
Existing MEMS switches with coplanar waveguides face challenges in maintaining high isolation and low insertion loss, particularly at higher frequencies, due to parasitic capacitance and surface current distribution
Implementation Method 2
The beam is configured to responsive to assertion of a control signal at a gate of the MEMS switches, contact the anchor to establish a current path between the input terminal and the output terminal
Implementation Method 3
The beam is also configured to responsive to deassertion of the control signal at the gate, disconnect from the anchor to galvanically isolate the input terminal from the output terminal
Data Source
AI summary
A microelectromechanical system (MEMS) switch implemented with a coplanar waveguide. The MEMS switch includes an input terminal, an output terminal. The MEMS switch includes a beam extending between the input terminal and the output terminal. The beam includes a first edge and a second edge coupled to a gate of the MEMS switch. The beam includes a third edge proximate the input terminal. The first edge includes a first set of finger contacts proximate a first corner of the beam and a second set of finger contacts proximate a second corner of the beam. The beam includes a fourth edge proximate the output terminal, the fourth edge opposing the third edge. The MEMS switch has a first anchor coupled to the input terminal. The first anchor includes a first segment extending from a region proximate the input terminal to a region overlying the first set of finger contacts.