Antenna arrangements for measurement of angle of arrival

1. A method for determining an angle of arrival of a beam received at an antenna array, the antenna array having at least two antenna elements, the method comprising:

receiving a first signal at an antenna element A, and receiving a second signal at an antenna element B;

producing, via a first network, a first output signal E based on a first combination of the first and second signals and producing, via the first network, a second output signal F based on a second combination of the first and second signals;

determining a difference of first output signal E and second output signal F to produce a first difference signal (DIFF AB);

receiving a third signal at an antenna element C, and receiving a fourth signal at an antenna element D;

producing, via a second network, a third output signal G based on a first combination of the third and fourth signals and producing, via the second network, a fourth output signal H based on a second combination of the third and fourth signals;

determining a difference of third output signal G and fourth output signal H to produce a second difference signal (DIFF CD); and

determining a first directional angle of arrival of the beam from a first set of candidate angles of arrival based at least in part on the first difference signal (DIFF AB) and the second difference signal (DIFF CD).

2. The method of claim 1 , further comprising:

producing, via a third network, a fifth output signal J based on a first combination of the first and third signals and producing, via the third network, a sixth output signal K based on a second combination of the first and the third signals;

determining a difference of fifth output signal J and sixth output signal K to produce a third difference signal (DIFF AC);

producing, via a fourth network, a seventh output signal L based on a first combination of the second and fourth signals and producing, via the fourth network, an eighth output signal M based on a second combination of the second and fourth signals;

determining a difference of seventh output signal L and eighth output signal M to produce a second difference signal (DIFF BD); and

determining a second directional angle of arrival of the beam from a second set of candidate angles of arrival based at least in part on the first difference signal (DIFF AC) and the second difference signal (DIFF BD).

3. The method of claim 2 , wherein antenna elements A and B are at different distances from a reference plane and antenna elements C and D are at different distances from the reference plane.

4. The method of claim 2 , wherein a separation of the antennas elements A and B is a first distance and a separation of the antenna elements C and D is a second distance different from the first distance.

5. The method of claim 2 , wherein the antenna elements C and D are at an obtuse angle with respect to the antenna elements A and B.

6. The method of claim 2 , wherein the first directional angle of arrival is a horizontal angle of arrival and the second directional angle of arrival is a vertical angle of arrival.

7. The method of claim 1 , wherein the first network includes two 90 degree splitters and two zero degree combiners, each zero degree combiner configured to receive inputs from both 90 degree splitters.

8. The method of claim 1 , wherein a candidate angle of arrival is determined based on one of formulas and values in a look up table.

9. A receiver for determining an angle of arrival of a beam received at an antenna array of the receiver, the antenna array having at least two antenna elements, the receiver comprising:

an antenna element A configured to receive a first signal, an antenna element B configured to receive a second signal, an antenna element C configured to receive a third signal and an antenna element D configured to receive a fourth signal;

a first network configured to produce a first output signal E based on a first combination of the first and second signals and configured to produce a second output signal F based on a second combination of the first and second signals;

a second network configured to produce a third output signal G based on a first combination of the third and fourth signals and configured to produce a fourth output signal H based on a second combination of the third and fourth signals; and

a processor configured to:

determine a difference of the first output signal E and the second output signal F to produce a first difference signal (DIFF AB);

determine a difference of the third output signal G and the fourth output signal H to produce a second difference signal (DIFF CD); and

determine a first directional angle of arrival of the beam from a first set of candidate angles of arrival based at least in part on the first difference signal (DIFF AB) and the second difference signal (DIFF CD).

10. The receiver of claim 9 , further comprising:

a third network configured to produce a fifth output signal J based on a first combination of the first and third signals and configured to produce a sixth output signal K based on a second combination of the first and third signals;

a fourth network configured to produce a seventh output signal L based on a first combination of the second and fourth signals and configured to produce an eighth output signal M based on a second combination of the second and fourth signals; and

wherein the processor is further configured to:

determine a difference of fifth output signal J and sixth output signal K to produce a third difference signal (DIFF AC);

determine a difference of seventh output signal L and eighth output signal M to produce a second difference signal (DIFF BD); and

determine a second directional angle of arrival of the beam from a second set of candidate angles of arrival based at least in part on the first difference signal (DIFF AC) and the second difference signal (DIFF BD).

11. The receiver of claim 10 , wherein the antenna elements A and B are at different distances from a reference plane and the antenna elements C and D are at different distances from the reference plane.

12. The receiver of claim 10 , wherein a separation of the antennas elements A and B is a first distance and a separation of the antenna elements C and D is a second distance different from the first distance.

13. The receiver of claim 10 , wherein the antenna elements A and B are at an obtuse angle with respect to the antenna elements C and D.

14. The receiver of claim 10 , wherein the first directional angle of arrival is a horizontal angle of arrival and the second directional angle of arrival is a vertical angle of arrival.

15. The receiver of claim 9 , wherein the first network includes two 90 degree splitters and two zero degree combiners, each zero degree combiner configured to receive inputs from both 90 degree splitters.

16. The receiver of claim 9 , wherein a candidate angle of arrival is determined based on one of formulas and values in a look up table.

17. A method in a receiver configured to determine an angle of arrival of a beam, the method comprising:

receiving a first signal at an antenna element A, receiving a second signal at an antenna element B, receiving a third signal at an antenna element C, and receiving a fourth signal at an antenna element D;

producing, via a first network, a first output signal E based on a first combination of the first and second signals and producing, via the first network, a second output signal F based on a second combination of the first and second signals, the first network having first and second 90 degree splitters and first and second combiners, the first and second splitters and first and second combiners configured to receive the first and second signals at input ports of the first and second splitters, respectively, and to produce the first output signal E and the second output signal F at different output ports of the first and second combiners;

producing, via a second network, a third output signal G based on a first combination of the third and fourth signals and producing, via the second network, a fourth output signal H based on a second combination of the third and fourth signals, the second network having third and fourth 90 degree splitters and third and fourth combiners, the third and fourth splitters and third and fourth combiners configured to receive the third and fourth signals at input ports of the third and fourth splitters, respectively, and to produce the third output signal G and the fourth output signal H at different output ports of the third and fourth combiners;

determining a difference of first output signal E and second output signal F to produce a first difference signal (DIFF AB);

determining a difference of third output signal G and fourth output signal H to produce a second difference signal (DIFF CD); and

determining a first directional angle of arrival of the beam from a set of candidate angles of arrival based at least in part on the first difference signal (DIFF AB) and the second difference signal (DIFF CD).

18. The method of claim 17 , wherein the antenna elements A, B, C and D are patch antenna elements positioned at different distances away from a ground plane.

19. The method of claim 18 , further comprising determining the first difference signal DIFF AB by computing a ratio of the first output signal E to the second output signal F.

20. The method of claim 19 , further comprising determining the second difference signal DIFF CD by computing a ratio of the third output signal G to the fourth output signal H.