Integrated tunable high efficiency power amplifier

• US 6,232,841 B1
• Filed: 07/01/1999
• Issued: 05/15/2001
• Est. Priority Date: 07/01/1999
• Status: Expired due to Term

• Current Assignee: OL Security LLC (Intellectual Ventures LLC)
• Original Assignee: Rockwell Science Center LLC
• Inventors: Mehrotra, Deepak, Pehlke, David R., Yao, Jun J., Bartlett, James L., Tham, J. L. Julian, Marcy, 5th, Henry O., Seabury, Charles W., Pedrotti, Kenneth D., Chang, Mau Chung F.
• Primary Examiner(s): Lee, Benny
• Assistant Examiner(s): Nguyen, Patricia T.
• Application Number:
  US09/346,097
• Time in Patent Office: 684 Days
• Field of Search: 330/302, 330/303, 330/305, 330/306
• US Class Current: 330/305
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: H03F 3/2176 Class E amplifiers

Abstract

Power amplifiers having reactive networks (such as classes C, C-E, E and F) employ tunable reactive devices in their reactive networks, with the reactive devices respective reactance values capable of being adjusted by means of respective control signals. The tunable reactive devices are made from micro-electromechanical (MEM) devices capable of being integrated with the control circuitry needed to produce the control signals and other amplifier components on a common substrate. The reactive components have high Q values across their adjustment range, enabling the amplifier to produce an output with a low harmonic content over a wide range of input signal frequencies, and a frequency agile, high quality output. The invention can be realized on a number of foundry technologies.

Claims

1. A tunable high efficiency power amplifier, comprising:

an active device connected to receive an RF input signal at a control input and having a current circuit which is switched between conductive and non-conductive states in accordance with said RF input signal, and

a network of reactive devices connected to said current circuit, said active device and said network forming a power amplifier arranged to amplify said RF input signal over a range of input signal frequencies determined by the values of said reactive devices, said reactive devices comprising;

at least one inductance, and

at least one capacitance,

at least one of said at least one inductance and at least one of said at least one capacitance being tunable reactive devices, each of which comprises at least one micro-electromechanical (MEM) device that operates in response to a respective control signal and that varies its respective tunable reactive device'"'"'s reactance value in accordance with said control signal such that said range of input signal frequencies over which said amplifier is operational is varied in accordance with said control signals, thereby enabling said amplifier to operate efficiently over a wider range of input frequencies.

2. The tunable amplifier of claim 1, wherein said active device and said network of reactive devices are integrated together on a common substrate.

3. The tunable amplifier of claim 1, wherein each of said tunable reactive devices has a high Q value over its full range of reactance values.

4. The tunable amplifier of claim 1, wherein said tunable reactive devices each comprise:

at least two fixed value reactive components, and

at least one MEM switch that opens and closes in response to said control signal, said at least one switch and said fixed value components interconnected to form a network having an input and an output such that the reactance value between said input and output varies in accordance with the state of said at least one switch.

5. The tunable amplifier of claim 4, wherein each of said fixed value reactive components has a high Q value such that a high Q reactive network is presented to said active device regardless of the network'"'"'s reactance value set by the state of said at least one switch.

6. The tunable amplifier of claim 1, wherein said at least one tunable reactive device is a tunable capacitor comprising a MEM device having first and second terminals and arranged to continuously vary the capacitance value between said first and second terminals in accordance with the value of said control signal.

7. The tunable amplifier of claim 6, wherein said tunable capacitor has a high Q value such that a high Q reactive network is presented to said active device across the range of capacitance values obtainable with said control signal.

9. The tunable amplifier of claim 1, further comprising a control circuit arranged to provide said control signals to respective MEM devices and thereby establish the reactance values of each of said tunable reactive devices.

10. The tunable amplifier of claim 9, wherein said active device, said network of reactive devices and said control circuit are integrated together on a common substrate.

11. The tunable amplifier of claim 9, wherein said control circuit automatically provides said control signals in response to a command signal.

8. A tunable high efficiency power amplifier, comprising:

an active device connected to receive an RF input signal at a control input and having a current circuit which is switched between conductive and non-conductive states in accordance with said RF input signal,

a network of reactive devices connected to said current circuit, said active device and said network forming a power amplifier arranged to amplify said RF input signal over a range of input signal frequencies determined by the values of said reactive devices, said reactive devices comprising;

at least one inductance, and

at least one capacitance,

at least one of said at least one capacitances being a tunable capacitor comprising at least one micro-electromechanical (MEM) device having first and second terminals, said tunable capacitor arranged to continuously vary the capacitance value between said first and second terminals in accordance with the value of a control signal such that said range of input signal frequencies over which said amplifier is operational is varied in accordance with said control signal, thereby enabling said amplifier to operate efficiently over a wider range of input frequencies, and

a control circuit arranged to provide said control signal to said tunable capacitor and thereby establish its capacitance, said control circuit including a digital-to-analog (D/A) converter which produces said control signal in response to a digital command signal.

12. A tunable class E power amplifier, comprising:

an active device connected to receive an RF input signal at a control input and having a current circuit which is switched between conductive and non-conductive states in accordance with said RF input signal,

a bias inductor connected to said current circuit,

a network of reactive devices connected to said current circuit, said active device, said bias inductor and said network of reactive devices forming a class E power amplifier arranged to amplify said Rf input signal over a range of input signal frequencies determined by the values of said reactive devices, said reactive devices comprising;

a shunt capacitor,

a series inductor, and

a series capacitor,

at least two of said shunt capacitor, said series inductor and said series capacitor being tunable reactive devices, each of which comprises at least one micro-electromechanical (MEM) device that operates in response to a respective control signal and that varies its respective tunable reactive device'"'"'s reactance value in accordance with said control signal such that said range of input signal frequencies over which said amplifier is operational is varied in accordance with said control signals, thereby enabling said amplifier to operate efficiently over a wider range of input frequencies, and

a control circuit arranged to provide said control signals to each of said at least two MEM devices and thereby establish the reactance value of each MEM device'"'"'s respective tunable reactive device.

13. The tunable class E power amplifier of claim 12, wherein said active device, said bias inductor, said network of reactive devices and said control circuit are integrated together on a common substrate.

14. The tunable class E power amplifier of claim 12, wherein each of said shunt capacitor, said series inductor, and said series capacitor are said tunable reactive devices.

15. The tunable class E power amplifier of claim 12, wherein said control circuit automatically provides said control signals in response to a command signal.

16. A tunable class C power amplifier, comprising:

an active device connected to receive an RF input signal at a control input and having a current circuit which is switched between conductive and non-conductive states in accordance with said RF input signal,

a bias inductor connected to said control input of said active device,

a blocking capacitor connected to said current circuit,

a network of reactive devices connected to said current circuit, said active device, said bias inductor, said blocking capacitor and said network of reactive devices forming a class C power amplifier arranged to amplify said RF input signal over a range of input signal frequencies determined by the values of said reactive devices, said reactive devices arranged in a parallel tuned circuit which is connected to said current circuit and comprising;

a capacitor, and

an inductor,

at least one of said capacitor and said inductor connected in said parallel tuned circuit being a tunable reactive device comprising at least one micro-electromechanical (MEM) device that operates in response to a respective control signal and that varies its respective tunable reactive device'"'"'s reactance value in accordance with said control signal such that said range of input signal frequencies over which said amplifier is operational is varied in accordance with said control signal, thereby enabling said amplifier to operate efficiently over a wider range of input frequencies, and

a control circuit arranged to provide said control signals to each of said at least one MEM device and thereby establish the reactance value of each MEM device'"'"'s respective tunable reactive device.

17. The tunable class C power amplifier of claim 16, wherein said active device, said bias inductor, said blocking capacitor, said network of reactive devices and said control circuit are integrated together on a common substrate.

18. The tunable class C power amplifier of claim 16, wherein each of said capacitor and said inductor connected in said parallel tuned circuit are said tunable reactive devices.

19. The tunable class C power amplifier of claim 16, wherein said control circuit automatically provides said control signals in response to a command signal.

20. The tunable class C power amplifier of claim 16, wherein said bias inductor is a tunable reactive device comprising at least one micro-electromechanical (MEM) device that operates in response to a control signal and that varies said bias inductor'"'"'s inductance value in accordance with said control signal.

21. A tunable class C-E power amplifier, comprising:

an active device connected to receive an RF input signal at a control input and having a current circuit which is switched between conductive and non-conductive states in accordance with said RF input signal,

a bias inductor connected to said current circuit,

a network of reactive devices connected to said current circuit, said active device, said bias inductor and said network of reactive devices forming a class C-E power amplifier arranged to amplify said Rf input signal over a range of input signal frequencies determined by the values of said reactive devices, said reactive devices comprising;

a shunt capacitor,

a series inductor, and

a series capacitor,

at least two of said shunt capacitor, said series inductor and said series capacitor being tunable reactive devices, each of which comprises at least one micro-electromechanical (MEM) device that operates in response to a respective control signal and that varies its respective tunable reactive device'"'"'s reactance value in accordance with said control signal such that said range of input signal frequencies over which said amplifier is operational is varied in accordance with said control signals, thereby enabling said amplifier to operate efficiently over a wider range of input frequencies, and

a control circuit arranged to provide said control signals to each of said at least one MEM devices and thereby establish the reactance value of each MEM device'"'"'s respective tunable reactive device.

22. The tunable class C-E power amplifier of claim 21, wherein said active device, said bias inductor, said network of reactive devices and said control circuit are integrated together on a common substrate.

23. The tunable class C-E power amplifier of claim 21, wherein each of said shunt capacitor, said series inductor, and said series capacitor are said tunable reactive devices.

24. A tunable class F power amplifier, comprising:

an active device connected to receive an RF input signal at a control input and having a current circuit which is switched between conductive and non-conductive states in accordance with said RF input signal,

a bias inductor connected to said current circuit,

a capacitor connected in series with said current circuit,

a network of reactive devices connected to said current circuit, said active device, said bias inductor, said capacitor and said network of reactive devices forming a class F power amplifier arranged to amplify said RF input signal over a range of input signal frequencies determined by the values of said reactive devices and to produce said amplified RF input signal at an output, said reactive devices arranged in one or more parallel tuned circuits connected to said output, each of said parallel tuned circuits comprising;

a capacitor, and

an inductor,

said capacitor and said inductor connected in said parallel tuned circuit being tunable reactive devices, each of which comprises at least one micro-electromechanical (MEM) device that operates in response to a respective control signal and that varies its respective tunable reactive device'"'"'s reactance value in accordance with said control signal such that said range of input signal frequencies over which said amplifier is operational is.

25. The tunable class F power amplifier of claim 24 wherein said active device, said bias inductor, said capacitor, said network of reactive devices and said control circuit are integrated together on a common substrate.

26. The tunable class E power amplifier of claim 24, wherein each of said capacitors and said inductors connected in said parallel tuned circuits are said tunable reactive devices.