Electromagnetically actuated microelectromechanical switch
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.
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.