Wide band cross point switch using MEMS technology

• US 7,034,373 B2
• Filed: 12/03/2004
• Issued: 04/25/2006
• Est. Priority Date: 05/09/2002
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Lee, Jar J., Allison, Robert C.
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): Nguyen, Dao H.
• Application Number:
  US11/003,031
• Publication Number:
  US 20050139941A1
• Time in Patent Office: 508 Days
• Field of Search: 257/415, 257/678
• US Class Current: 257/415
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 67/22 Switches without multi-position wipers
• CPC Class Codes: H01L 2224/48095 Kinked
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49109 outside the semiconductor or solid-state body
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/15192 Resurf arrangement of the internal vias
• CPC Class Codes: H01L 2924/30111 matching
• CPC Class Codes: H01P 1/127 Strip line switches

Abstract

A multilayer switching assembly for switching high frequency signals has MEMS structures on a ceramic substrate having a top surface 500, a bottom surface and a plurality of insulating layers (510,512,514). The insulating layers are separated by at least a first conductor 502 and a second conductor 504. The first conductor 502 is connected to a ground potential. The second conductor 504 is separated from the first conductor 502 by one of the insulating layers. The second conductor presents a specific impedance (50 ohms) with respect to the first conductor to high frequency signals traveling on the second conductor.

64 MEMS structures (e.g. 540,708,716,718, 720) are mounted on the top surface. Each MEMS has an input, an output, and a control. The input connected to the second conductor. The output is connected to a coplanar waveguide (508) placed on the top surface (500). The control is connected to the bottom surface.

The input to each MEMS is electrically separated from the output and from the control by a third conductor (534,550,532,530) connected to the first (grounded) conductor (502). The third conductor traverses one or more of the insulating layers thereby acting as a shield and precluding the high frequency signals presented to the input from propagating to the output and to the control. The 64 MEMS are arranged in a square 8 by 8 matrix, as well as their controls. High frequency inputs and outputs to be switched by the MEMS are placed on the periphery of the substrate to further enhance the separation of signals. Terminating resistors (50 ohms) are also placed near the periphery.

Claims

1. A switching assembly for switching any of 8 incoming high frequency signals to any of 8 outputs comprising:

64 MEMS structures, each of said 64 MEMS structures having a first terminal, a second terminal, a third terminal and a fourth terminal, a first control terminal and a second control terminal;

a multilayer substrate having a square periphery, said square periphery having four equal sides, a top surface, a bottom surface and a plurality of insulating layers, said insulating layers separated by a first conductor and a second conductor, said first conductor connected to a ground potential, said second conductor separated from said first conductor by one of said insulating layers, said second conductor presenting a specific impedance with respect to said first conductor to said high frequency signals traveling on said second conductor;

said 64 MEMS structures mounted on said top surface forming a first 8 by 8 array, said array having 8 inputs and 8 outputs, said 8 inputs and said 8 outputs disposed on the periphery of said substrate;

each of said 64 second terminals and said 64 third terminals connected to a coplanar waveguide (CPW), said 64 CPWs formed on said top surface;

each of said 64 first terminals and said 64 fourth terminals connected to a descender, said 64 descenders connected to said 64 second conductors;

each of said 64 first control terminals forming a second 8 by 8 array;

each of said 64 second control terminals forming a third 8 by 8 array.

2. An assembly as claimed in claim 1 wherein said first insulating layer and said second insulating layer are a ceramic material.

3. An assembly as claimed in claim 1 wherein each of said descenders and each of said CPWs presents a characteristic impedance to said high frequency signals.

4. An assembly as claimed in claim 3 wherein said characteristic impedance is 50 ohms.

5. An assembly as claimed in claim 1 wherein said high frequency signals have wavelengths between 0.01 millimeters and 100 millimeters.

6. An assembly as claimed in claim 1 wherein said high frequency input signals are transmitted using package pins located outside said first array, said second array and said third array, along said periphery of said multilayer substrate.

7. An assembly as claimed in claim 1 wherein said high frequency output signals are transmitted using package pins located outside said first array, said second array and said third array.

8. An assembly as claimed in claim 1 wherein the 64 members of said first array are equidistantly spaced.

9. An assembly as claimed in claim 1 wherein the 64 members of said second array are equidistantly spaced.

10. An assembly as claimed in claim 1 wherein the 64 members of said third array are equidistantly spaced.

11. An assembly as claimed in claim 1 wherein 16 resistors matching said characteristic impedance are provided on said multilayer substrate.

12. An assembly as claimed in claim 11 wherein of said 16 resistors, 12 are located outside said first array, said second array and said third array.

13. An assembly as claimed in claim 12 wherein of said 12 resistors located outside said first array, said second array and said third array are along three sides of said four sides of said substrate.