Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras
Method of Varying Resonant Frequency in Capacitance Type Radio Frequency (RF) Micro-electro-mechanical System (MEMS) Switches
Categories for this Invention
Technology: RF MEMS Switch;
Industry & Application: RF MEMS Switch, Electronic System & Design Manufacturing;
Market: The global RF MEMS Switch market is projected to grow at a CAGR of 11.1% during 2024-2030.
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Problem Statement
- In the conventional RF MEMS switches, said switch is suspended above the bottom electrode and the movable membrane (beam) is anchored on the ground planes, bridging them across the signal line.
- One of the issue disclosed that the interface at the contact of the beam & the bottom electrode is not always perfect which can reduce the down-state capacitance from the expected value. Due to this, it increases the value of resonant frequency.
- Hence, there is a need to address the issues.
- Present invention provides the solution of the problem arising in RF MEMS switches related to variation in resonant frequency.
Technology
- Present invention describes a method for varying the resonant frequency (fo) in a capacitance type radio frequency (RF) Micro-Electro-Mechanical Sysytem (MEMS) switch.
- Further, the present invention explains also about a capacitance type radio frequency Micro electric mechanical system. (Refer Fig.2)
- The claimed method comprising following few steps illustrated in the smart chart:
- Further the process is illustrated using a graph showing the variation of a down state capacitance with a length of the floating Matel (LFM).
- Furthermore, the claimed invention deals with a capacitance type RF MEMS which is depicted in Fig. 2.
- Said RF MEMS comprising a substrate, a lower electrode formed on said substrate; a dielectric layer formed on said lower electrode; a floating metal encapsulated on said dielectric layer; a beam connected to a ground.
- Further, the length of the floating metal is varied to vary said resonant frequency by computing a down-state capacitance (Cd) between said beam & said floating metal.
Key Features / Value Proposition
Technical Perspective:
- The RF MEMS capacitive switches can be used to make tunability easier to achieve any frequency of operation.
- The lengths of the floating metal chosen for simulation may be 140μm, 180μm & 240μm irrespective of each beam. (Refer Fig.2)
- Accordingly, with the variation in the length of the floating metal, the resonant frequency is shifting, (Exemplary, the f0 changes a range from  8.223GHz to 7.226GHz respectively for different lengths of floating metal aforementioned)
- Claimed invention can be for multi- frequency applications with single set of beams. (wherein the beam is among said plurality of beam either in down state and as well as up-state.)
- The isolation at resonance is >30dB in magnitude which is appreciable for claimed RF MEMS capacitive switch.
- The insertion loss is <1dB in magnitude until 25GHz for which said MF switch is configured. (Refer Fig)
Industry Perspective:
- Claimed invention is advantageous for multi-frequency applications with single set of beams.
- Further claimed system can be used in coplanar waveguide (CPW) signal transmission & in CPW to toggle the state of a transmission line.
- Moreover, facilitates efficient solutions in cost-effective manner.
Questions about this Technology?
Contact For Licensing
sm-marketing@imail.iitm.ac.in
ipoffice2@iitm.ac.in
Research Lab
Prof. Amitava Das Gupta
Prof. Deleep R Nair
Department of Electrical Engineering
Intellectual Property
IITM IDF Ref. 1338
IN Patent No: 525767
Technology Readiness Level
TRL-4
Proof of Concept ready, tested in lab.