Extending beamforming capability of a coupled voltage controlled oscillator (VCO) array during local oscillator (LO) signal generation through fine control of a tunable frequency of a tank circuit of a VCO thereof

• US 9,184,498 B2
• Filed: 03/17/2014
• Issued: 11/10/2015
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Original Assignee: Gigpeak, Inc. (Renesas Electronics Corporation)
• Inventors: Schiller, Christopher T.
• Primary Examiner(s): Vuong, Quochien B
• Application Number:
  US14/217,238
• Publication Number:
  US 20140273817A1
• Time in Patent Office: 603 Days
• Field of Search: 455/209, 455/255, 455/258, 455/262, 455/265, 455/273, 455/276.1, 455/561, 455/562.1, 342/368, 342/371, 342/372, 342/374
• US Class Current: 1/1
• CPC Class Codes: H01Q 3/40 with phasing matrix

Abstract

A method includes implementing a coupled Voltage Controlled Oscillator (VCO) array with a number of VCOs, and arranging a number of switched capacitor elements in a geometric proportion in a tank circuit of each VCO to provide for finesse in control of a tunable frequency of the tank circuit. The method also includes utilizing a voltage control input of a varactor element of the tank circuit solely for achieving phase separation between the each VCO and another VCO of the coupled VCO array based on the provision of finesse in the control of the tunable frequency of the tank circuit, and mixing Local Oscillator (LO) signals generated through the number of VCOs of the coupled VCO array with signals from antenna elements of an antenna array to introduce differential phase shifts in signal paths coupled to the antenna elements during performing beamforming with the antenna array.

Claims

1. A method comprising:

implementing a coupled Voltage Controlled Oscillator (VCO) array with a plurality of VCOs;

implementing a plurality of switched capacitor elements in a tank circuit of each VCO of the coupled VCO array;

arranging switched capacitor elements of the plurality of switched capacitor elements in a geometric proportion to provide for finesse in control of a tunable frequency of the tank circuit;

utilizing a voltage control input of a varactor element of the tank circuit solely for achieving phase separation between the each VCO and another VCO of the coupled VCO array based on the provision of finesse in the control of the tunable frequency of the tank circuit; and

mixing Local Oscillator (LO) signals generated through the plurality of VCOs of the coupled VCO array with signals from antenna elements of an antenna array to introduce differential phase shifts in signal paths coupled to the antenna elements during performing beamforming with the antenna array.

2. The method of claim 1, comprising calibrating out, based on the provision of the plurality of switched capacitor elements in the tank circuit of the each VCO of the coupled VCO array, a variation in an uncalibrated oscillation frequency of the coupled VCO array due to at least one of:

a manufacturing process, a power supply voltage and a temperature influence on a value of at least one circuit element of the tank circuit.

3. The method of claim 1, further comprising injection locking two or more VCOs of the coupled VCO array to each other.

4. The method of claim 1, further comprising coupling a VCO of the coupled VCO array to another VCO thereof through a bidirectional coupling circuit.

5. The method of claim 1, comprising providing one of:

a one-dimensional, a two-dimensional and a three-dimensional VCO array as the coupled VCO array.

6. The method of claim 1, further comprising combining outputs of the mixing at a combiner circuit as part of the beamforming.

7. The method of claim 1, further comprising extrapolating a length of the coupled VCO array based on a requirement of the beamforming.

8. A beamforming system comprising:

a coupled VCO array comprising a plurality of VCOs coupled to one another, each VCO of the plurality of VCOs comprising a tank circuit in which a plurality of switched capacitor elements is implemented, the plurality of switched capacitor elements being arranged in a geometric proportion to provide for finesse in control of a tunable frequency of the tank circuit, and a voltage control input of a varactor element of the tank circuit being configured to be utilized solely for achieving phase separation between the each VCO and another VCO of the coupled VCO array based on the provision of finesse in the control of the tunable frequency of the tank circuit;

an antenna array comprising a plurality of antenna elements; and

a plurality of mixers, each of which is configured to mix an LO signal generated through the each VCO of the coupled VCO array with a signal from an antenna element of the antenna array to introduce differential phase shifts in signal paths coupled to the antenna elements during performing beamforming with the antenna array.

9. The beamforming system of claim 8, wherein, based on the provision of the plurality of switched capacitor elements in the tank circuit of the each VCO of the coupled VCO array, a variation in an uncalibrated oscillation frequency of the coupled VCO array due to at least one of:

a manufacturing process, a power supply voltage and a temperature influence on a value of at least one circuit element of the tank circuit is configured to be calibrated out.

10. The beamforming system of claim 8, wherein two or more VCOs of the coupled VCO array are configured to be injection locked to each other.

11. The beamforming system of claim 8, further comprising a plurality of bidirectional coupling circuits, each of which is configured to couple a VCO of the coupled VCO array to another VCO thereof.

12. The beamforming system of claim 8, wherein the coupled VCO array is one of:

a one-dimensional, a two-dimensional and a three-dimensional VCO array.

13. The beamforming system of claim 8, further comprising a combiner circuit to combine outputs of the plurality of mixers as part of the beamforming.

14. The beamforming system of claim 8, wherein a length of the coupled VCO array is configured to be extrapolated based on a requirement of the beamforming.

15. A wireless communication system comprising:

a beamforming system comprising;

a coupled VCO array comprising a plurality of VCOs coupled to one another, each VCO of the plurality of VCOs comprising a tank circuit in which a plurality of switched capacitor elements is implemented, the plurality of switched capacitor elements being arranged in a geometric proportion to provide for finesse in control of a tunable frequency of the tank circuit, and a voltage control input of a varactor element of the tank circuit being configured to be utilized solely for achieving phase separation between the each VCO and another VCO of the coupled VCO array based on the provision of finesse in the control of the tunable frequency of the tank circuit;

an antenna array comprising a plurality of antenna elements; and

a plurality of mixers, each of which is configured to mix an LO signal generated through the each VCO of the coupled VCO array with a signal from an antenna element of the antenna array to introduce differential phase shifts in signal paths coupled to the antenna elements during performing beamforming with the antenna array; and

a receiver channel configured to receive a combined output of the plurality of mixers of the beamforming system.

16. The wireless communication system of claim 15, wherein, based on the provision of the plurality of switched capacitor elements in the tank circuit of the each VCO of the coupled VCO array of the beamforming system, a variation in an uncalibrated oscillation frequency of the coupled VCO array due to at least one of:

a manufacturing process, a power supply voltage and a temperature influence on a value of at least one circuit element of the tank circuit is configured to be calibrated out.

17. The wireless communication system of claim 15, wherein two or more VCOs of the coupled VCO array of the beamforming system are configured to be injection locked to each other.

18. The wireless communication system of claim 15, wherein the beamforming system further comprises a plurality of bidirectional coupling circuits, each of which is configured to couple a VCO of the coupled VCO array to another VCO thereof.

19. The wireless communication system of claim 15, wherein the coupled VCO array of the beamforming system is one of:

a one-dimensional, a two-dimensional and a three-dimensional VCO array.

20. The wireless communication system of claim 15, wherein a length of the coupled VCO array of the beamforming system is configured to be extrapolated based on a requirement of the beamforming.