Millimeter wave antennas having dual patch resonating elements

1. A millimeter wave antenna, comprising:

a ground plane;

first and second conductive patches separated from the ground plane by a height and distributed symmetrically about an axis; and

an antenna feed having a first feed terminal formed at a conductive trace, coupled to the first and second conductive patches, and configured to convey antenna signals for both the first and second conductive patches, and a second feed terminal coupled to the ground plane, wherein the ground plane is interposed between the conductive trace and the first conductive patch, the ground plane has an opening, the first feed terminal is directly coupled to the first conductive patch using a first conductive structure that extends through the opening, and the first feed terminal is directly coupled to the second conductive patch using a second conductive structure that extends through the opening.

2. The millimeter wave antenna defined in claim 1 , wherein first conductive patch is configured to convey a first antenna current and the second conductive patch is configured to convey a second antenna current that is 180 degrees out of phase with respect to the first antenna current.

3. The millimeter wave antenna defined in claim 1 , further comprising:

a transmission line having a positive signal conductor coupled to the first feed terminal and a ground conductor that includes a portion of the ground plane.

4. The millimeter wave antenna defined in claim 3 , wherein the first conductive structure is coupled to a first point at a first end of the first conductive patch, the second conductive structure is coupled to a second point at a first end of the second conductive patch, the first conductive patch has a second end that is separated from the first end of the first conductive patch by a given distance, and the second conductive patch has a second end that is separated from the first end of the second conductive patch by the given distance.

5. The millimeter wave antenna defined in claim 4 , wherein the first end of the first conductive patch is interposed between the first end of the second conductive patch and the second end of the first conductive patch.

6. The millimeter wave antenna defined in claim 5 , wherein the first conductive patch has third and fourth sides that extend between the first and second ends of the first conductive patch and that are separated by the given distance, and the second conductive patch has third and fourth sides that extend between the first and second ends of the second conductive patch and that are separated by the given distance.

7. The millimeter wave antenna defined in claim 5 , further comprising:

first impedance matching notches in the first conductive patch that are configured to match an impedance of the first conductive patch with an impedance of the first conductive structure; and

second impedance matching notches in the second conductive patch that are configured to match an impedance of the second conductive patch with an impedance of the second conductive structure.

8. The millimeter wave antenna defined in claim 5 , further comprising:

a third conductive structure that shorts the second end of the first conductive patch to the ground plane; and

a fourth conductive structure that shorts the second end of the second conductive patch to the ground plane.

9. The millimeter wave antenna defined in claim 5 , further comprising:

a first parasitic antenna resonating element, wherein the first conductive patch is interposed between the first parasitic antenna resonating element and the ground plane; and

a second parasitic antenna resonating element, wherein the second conductive patch is interposed between the second parasitic antenna resonating element and the ground plane.

10. The millimeter wave antenna defined in claim 1 , comprising:

a stacked dielectric substrate having a first layer, a second layer, and a third layer, the second layer being interposed between the first and third layers, metal traces on the second layer forming the ground plane, and metal traces on the third layer forming the first and second conductive patches, wherein the first conductive structure extends through the second and third layers, and the second conductive structure extends through the second and third layers.

11. The millimeter wave antenna defined in claim 10 , wherein the first conductive patch has opposing first and second sides, the second conductive patch has opposing first and second sides, the first conductive structure is coupled to a first point at the first side of the first conductive patch, the second conductive structure is coupled to a second point at the first side of the second conductive patch, and the first side of the first conductive patch is interposed between the second side of the first conductive patch and the first side of the second conductive patch.

12. The millimeter wave antenna defined in claim 11 , further comprising:

a third conductive structure coupled between the second side of the first conductive patch and the ground plane; and

a fourth conductive structure coupled between the second side of the second conductive patch and the ground plane.

13. The millimeter wave antenna defined in claim 10 , wherein the stacked dielectric substrate has a fourth layer, the third layer is interposed between the second and the fourth layers, and the millimeter wave antenna further comprises:

metal traces on the fourth layer that form a first parasitic antenna resonating element for the first conductive patch and a second parasitic antenna resonating element for the second conductive patch.

14. The millimeter wave antenna defined in claim 1 , wherein the first conductive patch has a length and a width, the second conductive patch has the length and the width, the first conductive patch has a first side closest to the second conductive patch, the second conductive patch has a second side closest to the first conductive patch, the first feed terminal is coupled to the first conductive patch at the first side of the first conductive patch and coupled to the second conductive patch at the second side of the second conductive patch.

15. The millimeter wave antenna defined in claim 1 , wherein the first conductive patch has first and second opposing edges, the first edge being interposed between the second edge and the second conductive patch, and the second conductive patch has third and fourth opposing edges, the third edge being interposed between the fourth edge and the first conductive patch, the first conductive structure directly coupling the first feed terminal to the first edge, and the second conductive structure directly coupling the second feed terminal to the third edge.

16. An electronic device, comprising:

a ground plane for an antenna;

first and second conductive patches for the antenna that are separated from the ground plane by a height and distributed symmetrically about an axis; and

an antenna feed for the antenna having a first feed terminal formed at a conductive trace, coupled to the first and second conductive patches, and configured to convey antenna signals for both the first and second conductive patches, and a second feed terminal coupled to the ground plane, wherein the ground plane is interposed between the conductive trace and the first conductive patch, the ground plane has an opening, the first feed terminal is directly coupled to the first conductive patch using a first conductive structure that extends through the opening, and the first feed terminal is directly coupled to the second conductive patch using a second conductive structure that extends through the opening.