Adaptively tunable antennas and method of operation therefore

• US 20070200766A1
• Filed: 01/16/2007
• Published: 08/30/2007
• Est. Priority Date: 01/14/2006
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Research in Motion RF Inc (Blackberry Limited)
• Inventors: McKinzie, William, Mendolia, Greg, Manssen, Keith
• Granted Patent: US 8,325,097 B2
• Time in Patent Office: Days
• US Class Current: 343/700.MS
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence
• CPC Class Codes: H01Q 9/0442 with particular tuning means

Abstract

An embodiment of the present invention is an apparatus, comprising a tunable antenna including a variable reactance network connected to the antenna a closed loop control system adapted to sense the RF voltage across the variable reactance network and adjust the reactance of the network to maximize the RF voltage. The variable reactance network may comprise a parallel capacitance or a series capacitance. Further, the variable reactance networks may be connected to the antenna, which may be a patch antenna, a monopole antenna, or a slot antenna.

Claims

1. An apparatus, comprising:

a tunable antenna including a variable reactance network connected to said antenna; and

a closed loop control system adapted to sense the RF voltage across said variable reactance network and adjust the reactance of said network to maximize the RF voltage.

2. The apparatus of claim 1, wherein said variable reactance network comprises a parallel capacitance.

3. The apparatus of claim 1, wherein a variable reactance network comprises a series capacitance.

4. The apparatus of claim 1, wherein a multiplicity of variable reactance networks are connected to said antenna.

5. The apparatus of claim 1, wherein said antenna comprises a patch antenna, a monopole antenna, or a slot antenna.

6. The apparatus of claim 1, wherein said control loop control system uses an algorithm implemented on a digital processor to maximize the RF voltage.

7. The apparatus of claim 6, further comprising using the digital processor in a baseband processor in a mobile phone.

8. The apparatus of claim 1, further comprising a directional coupler used at the input port of the tunable antenna to monitor input return loss.

9. The apparatus of claim 8, further comprising a dual input voltage detector to monitor forward and reverse power levels allowing the return loss to be calculated by a controller.

10. The apparatus of claim 9 wherein said controller sends signals to the a driver circuit which transforms control signal into a bias voltage or current for said variable reactance elements said variable reactive to minimize the input return loss at an RF_in port.

11. A method, comprising:

improving the efficiency of an antenna system by sensing the RF voltage present on a variable reactance network within said antenna system;

controlling the bias signal presented to said variable reactance network; and

maximizing the RF voltage present on the variable reactance network.

12. The method of claim 11, wherein the antenna comprises a patch antenna, a monopole antenna, or a slot antenna.

13. The method of claim 11, further comprising using an algorithm implemented on a digital processor to maximize the RF voltage.

14. The method of claim 13, further comprising using the digital processor in a baseband processor in a mobile phone.

15. An adaptively tuned antenna, comprising

a variable reactance network connected to said antenna;

an RF detector to sense the voltage on the antenna;

a controller that monitors said RF voltage and supplies control signals to a driver circuit; and

wherein said driver circuit converts said control signals to bias signals for said variable reactance network.

16. The adaptively tuned antenna of claim 15 wherein said variable reactance network comprises a parallel capacitance.

17. The antenna of claim 15 wherein said variable reactance network comprises a series capacitance.

18. The antenna of claim 15 wherein a multiplicity of variable reactance networks are connected to the antenna.

19. A machine-accessible medium that provides instructions, which when accessed, cause a machine to perform operations comprising:

improving the efficiency of an antenna system by sensing the RF voltage present on a variable reactance network within said antenna system;

controlling the bias signal presented to said variable reactance network; and

maximizing the RF voltage present on the variable reactance network.

20. The machine-accessible medium of claim 19, wherein the antenna comprises a patch antenna, a monopole antenna, or a slot antenna.

21. The machine-accessible medium of claim 19, further comprising said instructions causing said machine to perform operations further comprising controlling an algorithm implemented on a digital processor to maximize the RF voltage is.

22. The machine-accessible medium of claim 21, further comprising said instructions causing said machine to perform operations further comprising using the digital processor in a baseband processor in a mobile phone.

23. A method, comprising:

improving the radiated harmonic distortion of a transmitting antenna system by sensing the RF voltage present on a variable reactance network within said antenna system;

controlling the bias signal presented to said variable reactance network; and

maximizing the RF voltage present on the variable reactance network.

24. A method, comprising:

improving the DC power consumption of a transceiver system by sensing the RF voltage present on a variable reactance network within the transceiver'"'"'s antenna system;

controlling the bias signal presented to said variable reactance network; and

maximizing the RF voltage present on the variable reactance network.