Electromagnetically actuated microelectromechanical switch

Patent metadata

Field	Value
Publication number	US-10825628-B2
Application number	US-201715652181-A
Country	US
Kind code	B2
Filing date	Jul 17, 2017
Priority date	Jul 17, 2017
Publication date	Nov 3, 2020
Grant date	Nov 3, 2020

Abstract

An microelectromechanical switch uses electrostatic attraction to draw a beam toward a contact and electromagnetic repulsion to disengage and repel the beam from the contact. The electrostatic attraction is generated by a gate electrode. The electromagnetic repulsion is generated between the beam and a magnetic coil positioned on the same side of the beam as the contact. The magnetic coil produces a magnetic field, which induces a current in the beam that repels the magnetic coil. The gate electrode and the magnetic coil may be co-planar or in different planes. A circuit may also operate a coil-shaped structure act as the gate electrode and the magnetic coil, depending on the configuration.

First claim

What is claimed is:

1. A microelectromechanical systems (MEMS) switch, comprising:
a cantilevered beam connected to an anchor and spaced from an underlying substrate, the beam extending away from the anchor at least in a first direction;
a gate electrode disposed on the substrate and underlying the beam; and
a coil underlying the beam and having a center being offset, along the first direction, relative to the anchor, wherein the coil surrounds the gate electrode.

2. The MEMS switch of claim 1 , further comprising a first source configured to drive the coil to produce a magnetic field and a second source configured to drive the gate electrode.

3. The MEMS switch of claim 1 , wherein the coil is formed of a conducting material with conductivity greater than 10,000 S/m.

4. A microelectromechanical systems (MEMS) switch, comprising:
a cantilevered beam connected to an anchor and spaced from an underlying substrate, the beam extending away from the anchor at least in a first direction;
a gate electrode disposed on the substrate and underlying the beam; and
a coil underlying the beam and having a center being offset, along the first direction, relative to the anchor, wherein the coil is next to the gate electrode on the substrate.

5. The MEMS switch of claim 4 , further comprising a first source configured to drive the coil to produce a magnetic field and a second source configured to drive the gate electrode.

6. The MEMS switch of claim 4 , wherein the coil is formed of a conducting material with conductivity greater than 10,000 S/m.

7. A microelectromechanical systems (MEMS) switch, comprising:
a cantilevered beam connected to an anchor and spaced from an underlying substrate, the beam extending away from the anchor at least in a first direction;
a gate electrode disposed on the substrate and underlying the beam; and
a coil underlying the beam and having a center being offset, along the first direction, relative to the anchor, wherein the coil is a multi-layer coil including conductive traces positioned at multiple levels of the substrate.

8. The MEMS switch of claim 7 , further comprising a first source configured to drive the coil to produce a magnetic field and a second source configured to drive the gate electrode.

9. The MEMS switch of claim 7 , wherein the coil is formed of a conducting material with conductivity greater than 10,000 S/m.

10. A method of controlling a MEMS switch, comprising:
electrostatically attracting a microfabricated, cantilevered beam toward an underlying electrical contact using a gate electrode underlying the microfabricated, cantilevered beam; and
magnetically repulsing the microfabricated, cantilevered beam from the underlying electrical contact by inducing a current in the beam by generating a first magnetic field with a coil positioned under the beam.

11. The method of claim 10 , further comprising alternately driving the coil and the gate electrode.

12. The method of claim 10 , further comprising conductively coupling a radio frequency signal to the microfabricated, cantilevered beam.

13. The method of claim 10 , wherein using the gate electrode and generating the first magnetic field with the coil comprise using a same coil-shaped structure electrically coupled in different configurations.

14. The method of claim 13 , wherein generating a first magnetic field with the coil comprises discharging a capacitor through the coil.

15. The method of claim 14 , further comprising charging the capacitor while using the gate electrode.

16. A microelectromechanical systems (MEMS) switch, comprising:
a substrate;
a beam mounted to the substrate by an anchor, the beam extending away from the anchor at least in a first direction;
a gate electrode disposed on the substrate and underlying the beam; and
a coil disposed on the substrate and underlying the beam, the coil having a center being offset, along the first direction, relative to the anchor, wherein the coil surrounds the gate electrode.

17. The MEMS switch of claim 15 , further comprising a first source configured to drive the coil to produce a magnetic field and a second source configured to drive the gate electrode.

18. The MEMS switch of claim 15 , wherein the coil is formed of a conducting material with conductivity greater than 10,000 S/m.

19. A microelectromechanical systems (MEMS) switch, comprising:
a substrate;
a beam mounted to the substrate by an anchor, the beam extending away from the anchor at least in a first direction;
a gate electrode disposed on the substrate and underlying the beam; and
a coil disposed on the substrate and underlying the beam, the coil having a center being offset, along the first direction, relative to the anchor, wherein the coil is next to the gate electrode on the substrate.

20. A microelectromechanical systems (MEMS) switch, comprising:
a substrate;
a beam mounted to the substrate by an anchor, the beam extending away from the anchor at least in a first direction;
a gate electrode disposed on the substrate and underlying the beam; and
a coil disposed on the substrate and underlying the beam, the coil having a center being offset, along the first direction, relative to the anchor, wherein the coil is a multi-layer coil including conductive traces positioned at multiple levels of the substrate.

Assignees

• Analog Devices Global Unlimited Co

Inventors

• Lee Check F
• Brennan Philip James

Classifications

• H01H59/0009 Primary

  making use of micromechanics · CPC title

• H01H1/0036

  Switches making use of microelectromechanical systems [MEMS] (for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009) · CPC title

• H01H50/005 Primary

  using micromechanics · CPC title

• B81B3/0054

  For holding or placing an element in a given position · CPC title

• H01H2001/0052

  Special contact materials used for MEMS · CPC title