PHASE SHIFT BASED IMPROVED REFERENCE INPUT FREQUENCY SIGNAL INJECTION INTO A COUPLED VOLTAGE CONTROLLED OSCILLATOR (VCO) ARRAY DURING LOCAL OSCILLATOR (LO) SIGNAL GENERATION TO REDUCE A PHASE-STEERING REQUIREMENT DURING BEAMFORMING

• US 20140266891A1
• Filed: 03/17/2014
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Original Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Inventors: Schiller, Christopher T., Kennedy, Jonathan
• Granted Patent: US 9,780,449 B2
• Time in Patent Office: Days
• US Class Current: 342/367
• CPC Class Codes: H01Q 3/30 varying the relative phase between the radiating elements of an array H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence
• CPC Class Codes: H01Q 3/42 using frequency-mixing H01Q3/2676 takes precedence
• CPC Class Codes: H03B 27/00 Generation of oscillations providing a plurality of outputs of the same frequency but differing in phase, other than merely two anti-phase outputs

Abstract

A method includes injecting a reference input signal into each Voltage Controlled Oscillator (VCO) of a number of VCOs forming a coupled VCO array to reduce a level of injection energy required therefor. The reference input signal is configured to control operating frequency of the coupled VCO array. The method also includes utilizing a phase shift circuit: between individual VCOs of the coupled VCO array and/or in a path of injection of the reference input signal into one or more VCO(s) of the individual VCOs, and mixing outputs of the number of VCOs 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. Further, the method includes reducing a phase-steering requirement of the coupled VCO array during the beamforming based on the utilization of the phase shift circuit.

Claims

1. A method comprising:

injecting a reference input signal into each Voltage Controlled Oscillator (VCO) of a plurality of VCOs forming a coupled VCO array to reduce a level of injection energy required therefor compared to injecting the reference input signal at an end of the coupled VCO array, the reference input signal being configured to control operating frequency of the coupled VCO array;

utilizing a phase shift circuit at least one of;

between individual VCOs of the coupled VCO array and in a path of injection of the reference input signal into at least one VCO of the individual VCOs;

mixing outputs of 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; and

reducing a phase-steering requirement of the coupled VCO array during the beamforming based on the utilization of the phase shift circuit.

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

3. The method of claim 2, comprising:

coupling a VCO of the coupled VCO array to another VCO thereof through a bidirectional coupling circuit; and

coupling the phase shift circuit in series with the bidirectional coupling circuit between the VCO and the another VCO.

4. 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.

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

6. The method of claim 1, comprising providing a phase inverter circuit as the phase shift circuit.

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 plurality of VCOs forming a coupled VCO array, each VCO of the plurality of VCOs being configured to have a reference input signal injected therein to reduce a level of injection energy required therefor compared to injecting the reference input signal at an end of the coupled VCO array, and the reference input signal being configured to control operating frequency of the coupled VCO array;

a phase shift circuit utilized at least one of;

between individual VCOs of the coupled VCO array and in a path of injection of the reference input signal into at least one VCO of the individual VCOs;

an antenna array comprising a plurality of antenna elements; and

a plurality of mixers, each of which is configured to mix an output of the each VCO of the plurality of VCOs forming 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,

wherein the utilization of the phase shift circuit is configured to reduce a phase-steering requirement of the coupled VCO array during the beamforming.

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

10. The beamforming system of claim 9, wherein:

a VCO of the coupled VCO array is configured to be coupled to another VCO thereof through a bidirectional coupling circuit, and

the phase shift circuit is configured to be coupled in series with the bidirectional coupling circuit between the VCO and the another VCO.

11. 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.

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

13. The beamforming system of claim 8, wherein the phase shift circuit is a phase inverter circuit.

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 plurality of VCOs forming a coupled VCO array, each VCO of the plurality of VCOs being configured to have a reference input signal injected therein to reduce a level of injection energy required therefor compared to injecting the reference input signal at an end of the coupled VCO array, and the reference input signal being configured to control operating frequency of the coupled VCO array;

a phase shift circuit utilized at least one of;

between individual VCOs of the coupled VCO array and in a path of injection of the reference input signal into at least one VCO of the individual VCOs;

an antenna array comprising a plurality of antenna elements; and

a plurality of mixers, each of which is configured to mix an output of the each VCO of the plurality of VCOs forming 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, the utilization of the phase shift circuit being configured to reduce a phase-steering requirement of the coupled VCO array during the beamforming; 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 two or more VCOs of the coupled VCO array of the beamforming system are injection locked to each other.

17. The wireless communication system of claim 16, wherein:

a VCO of the coupled VCO array of the beamforming system is configured to be coupled to another VCO thereof through a bidirectional coupling circuit, and

the phase shift circuit is configured to be coupled in series with the bidirectional coupling circuit between the VCO and the another VCO.

18. 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.

19. The wireless communication system of claim 15, wherein the phase shift circuit of the beamforming system is a phase inverter circuit.

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.