Mems-tuned high power, high efficiency, wide bandwidth power amplifier

• US 20040100341A1
• Filed: 11/22/2002
• Published: 05/27/2004
• Est. Priority Date: 11/22/2002
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Streeter, Robert D., Luetzelschwab, Roland C., McMillan, Lee A.
• Granted Patent: US 6,992,543 B2
• Time in Patent Office: Days
• US Class Current: 333/32
• CPC Class Codes: H03F 1/56 Modifications of input or output impedances, not otherwise provided for
• CPC Class Codes: H03F 2200/391 the output circuit of an amplifying stage comprising an LC-network
• CPC Class Codes: H03F 2200/421 Multiple switches coupled in the output circuit of an amplifier are controlled by a circuit
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/541 Transformer coupled at the output of an amplifier
• CPC Class Codes: H03F 3/191 Tuned amplifiers H03F3/193, H03F3/195 take precedence
• CPC Class Codes: H03H 7/38 Impedance-matching networks

Abstract

A circuit for matching the impedance of an output load to an active device includes a transformer including a first winding having a terminal for coupling to the output of the active device and a second winding electromagnetically coupled to the first winding, and a plurality of taps, each of the plurality of taps having a first end coupled to a position on the second winding corresponding to a ratio of the second winding to first winding differing from other ones of the plurality of taps, and a second end. The matching circuit further includes a plurality of MEMS switches each having a control input for receiving a corresponding control signal, a first terminal coupled to the second end of a corresponding one of the plurality of taps, and a switched output selectively coupled to a matching junction in response to the corresponding control signal.

Claims

1. A circuit for matching the impedance of an output load to an active device comprising:

a transformer comprising;

a first winding having a terminal for coupling to the output of the active device;

a second winding electromagnetically coupled to the first winding; and

a plurality of taps, each of the plurality of taps having a first end, coupled to a position disposed on the second winding corresponding to a ratio of the second winding to first winding differing from other ones of the plurality of taps, and a second end; and

a plurality of MEMS switches each having a control input for receiving a corresponding control signal, a first terminal coupled to the second end of a corresponding one of the plurality of taps, and a switched output selectively coupled to a matching junction in response to the corresponding control signal.

2. The circuit of claim 1 wherein the transformer comprises a MEMS transformer.

3. The circuit of claim 2 wherein the MEMS transformer and the plurality of MEMS switches are provided in a monolithic substrate.

4. The circuit of claim 1 wherein the transformer comprises a transmission line transformer.

5. The circuit of claim 1 wherein the transformer comprises a plurality of transformers each having a primary winding and a secondary winding and wherein each of the primary windings is connected in series and each of the secondary windings is connected in series.

6. The circuit of claim 1 wherein the transformer comprises a plurality of transformers each having a primary winding and a secondary winding and wherein each of the primary windings is connected in parallel and each of the secondary windings is connected in series.

7. The circuit of claim 1 further comprising a MEMS controllable reactive network coupled to the matching junction.

8. The circuit of claim 7 wherein the MEMS controllable reactive network comprises at least one of:

a PI network;

a TEE network;

an L network;

a Lattice network; and

a PI-TEE-PI-TEE network.

9. The circuit of claim 7 wherein the MEMS controllable reactive network comprises:

a first plurality of MEMS selectable shunt capacitors coupled to the matching junction;

a plurality of MEMS selectable series inductors coupled in series and having a first end coupled to the matching junction and a second end for coupling to a load terminal; and

a second plurality of MEMS selectable shunt capacitors coupled to the second end of the plurality of MEMS selectable series inductors.

10. The circuit of claim 7 wherein the MEMS controllable reactive network comprises a plurality of binary networks of MEMS selectable reactive devices.

11. The circuit of claim 1 wherein the at least one MEMS switch comprises a plurality of MEMS switches arranged in a redundant series/shunt configuration.

12. The circuit of claim 1 wherein the output load comprises a broadband antenna.

13. The circuit of claim 1 wherein the output load comprises an input of a transistor and wherein the circuit transforms the transistor'"'"'s input impedance to a predetermined impedance.

14. The circuit of claim 13 wherein the transistor is at least one of:

a bipolar junction transistor;

a silicon metal oxide semiconductor field effect transistor;

a laterally diffused metal oxide semiconductor field effect transistor;

a gallium arsenide metal semiconductor field effect transistor;

a silicon carbide MESFET; and

a field effect transistor.

15. The circuit of claim 13 wherein the predetermined impedance is approximately fifty ohms.

16. An amplifier comprising:

an active device having an input for receiving an RF signal and an output;

a transformer having a first winding coupled to the output of the active device, and a second winding having a transformer output;

at least one tap having a first end coupled to the secondary winding and a second end; and

at least one MEMS switch having a control input for receiving a control signal, a switch input coupled to the second end of the at least one tap, and a switched output selectively coupled to the transformer output in response to the control signal.

17. An amplifier comprising:

an active device having an input for receiving an RF signal and an output;

a transformer having a first winding coupled to the active device output, and a second winding providing a transformer output;

a plurality of transformer taps each having a first end coupled to the second winding and each corresponding to a different ratio of the second winding to first winding; and

a plurality of MEMS switches each coupled between a corresponding one of the plurality of transformer taps and a matching junction, and each of the plurality of MEMS switches having a control input for receiving a corresponding control signal for changing the impedance of the transformer in response to the control signal.

18. The amplifier of claim 17 further comprising:

a MEMS controllable reactive network coupled to the matching junction comprising;

a first plurality of MEMS selectable shunt capacitors coupled to the transformer output;

a plurality of MEMS selectable series inductors coupled in series and having a first end coupled to the transformer output and a second end for coupling to a load; and

a second plurality of MEMS selectable shunt capacitors coupled to the second end of the plurality of MEMS selectable series inductors.

19. The amplifier of claim 18 wherein the active device and the MEMS controllable reactive network are provided in a monolithic substrate.

20. The amplifier of claim 18 wherein the MEMS controllable reactive network comprises a plurality of binary networks of MEMS selectable reactive devices

21. The amplifier of claim 17 wherein the transformer and MEMS switches are provided in a monolithic substrate.

22. The amplifier of claim 17 further wherein the active device comprises at least one of:

a single ended transistor;

two single-ended transistors; and

a push-pull transistor configuration.

23. The amplifier of claim 17 wherein the amplifier class of operation is one of class A to class F.