Use of Micro-Structured Plate for Controlling Capacitance of Mechanical Capacitor Switches

• US 20120279845A1
• Filed: 04/11/2012
• Published: 11/08/2012
• Est. Priority Date: 04/11/2011
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Bachman, Mark, Li, Guann-Pyng, Zhang, Yang, Wang, Minfeng, Chang, Ruisheng, Kim, Sungjun
• Granted Patent: US 9,641,174 B2
• Time in Patent Office: Days
• US Class Current: 200/600
• CPC Class Codes: H03K 17/975 using a capacitive movable element

Abstract

Micro capacitive switches and methods of manufacturing micro capacitive switches at variable nominal capacitance value using micro-structures on the contact plates of the same dimension. In a preferred embodiment, a separately manufactured contact plate can be mounted to a movable magnet in order to be actuated to “on” and “off” state of the capacitive switch. Depending on the contact plate'"'"'s surface condition, variable contact capacitance at “on” state can be precisely specified by geometrical properties of the micro-structures on the surface, such as the density, size and depth.

Claims

1. A capacitance switch comprising

a first plate,

a second plate, and

a plurality of micro-structures extending from the first plate, the plurality of micro-structures having a dielectric coating deposited thereon for a capacitive contact with the second plate during an “

on”

state.

2. The capacitance switch of claim 1 wherein the dielectric is silicon nitride.

3. The capacitance switch of claim 1 wherein the plurality of micro-structures include one of posts and micro-wells.

4. The capacitance switch of claim 3 wherein the plurality of micro-structures have a rectangular shape.

5. The capacitance switch of claim 3 wherein plurality of micro-structures have a circular shape.

6. The capacitance switch of claim 3 wherein plurality of micro-structures have a octagonal shape.

7. The capacitance switch of claim 1 wherein a capacitive value of the capacitance contact is a function of a contact area between the plurality of micro-structures and the second plate.

8. The capacitance switch of claim 1 wherein a capacitive value of the capacitance contact is a function of the height of a micro-structure of the plurality of micro-structures.

9. The capacitance switch of claim 1 wherein a capacitive value of the capacitance contact is a function of a periodic pattern of the plurality of micro-structure.

10. A micro-structure circuit comprising

a top plate including a magnet,

a plurality of micro-posts with dielectric material coupled to the top plate, and

a pair of parallel bottom plates,

wherein radio frequency power is transmitted between the top and bottom plates through the plurality of micro-posts when in an “

on”

state, wherein the plurality of micro-posts capacitively couple the top and bottom plates in the “

on”

state.

11. The micro-structure circuit of claim 10 wherein the dielectric is silicon nitride.

12. The micro-structure circuit of claim 10 wherein the plurality of micro-posts comprise micro-wells.

13. The micro-structure circuit of claim 10 wherein the plurality of micro-posts have a rectangular shape.

14. The micro-structure circuit of claim 10 wherein plurality of micro-posts have a circular shape.

15. The micro-structure circuit of claim 10 wherein plurality of micro-posts have a octagonal shape.

16. The micro-structure circuit of claim 10 wherein the capacitive coupling has a value that is a function of a contact area between the plurality of micro-posts and the second plate.

17. The micro-structure circuit of claim 10 wherein the capacitive coupling has a value that is a function of the height of a micro-post of the plurality of micro-posts.

18. The micro-structure circuit of claim 10 wherein the capacitive coupling has a value that is a function of a periodic pattern of the plurality of micro-post.