Beam-steering antenna
According to an embodiment, an antenna includes a conductive antenna element, a voltage-bias conductor, and a polarization-compensation conductor. The conductive antenna element is configured to radiate a first signal having a first polarization, and the voltage-bias conductor is coupled to a side of the antenna element and is configured to radiate a second signal having a second polarization that is different from the first polarization. And the polarization-compensating conductor is coupled to an opposite side of the antenna element and is configured to radiate third a signal having a third polarization that is approximately the same as the second polarization and that destructively interferes with the second signal. Such an antenna can be configured to reduce cross-polarization of the signals that its antenna elements radiate.
1. An antenna, comprising:
a conductive antenna element;
a ground conductor;
a conductive DC-voltage-bias via coupled to the antenna element; and
a conductive, resonant signal-bypass stub disposed below the conductive antenna element and configured to couple an RF signal from the DC-voltage-bias via to the ground conductor.
2. The antenna of claim 1 , further comprising:
a transmission medium disposed below the antenna element; and
wherein the resonant signal-bypass stub is disposed within the transmission medium.
3. The antenna of claim 1 , further comprising:
a transmission medium disposed below the antenna element and configured to carry a transmit reference signal to the antenna element; and
wherein the resonant signal-bypass stub is disposed within the transmission medium.
4. The antenna of claim 1 , further comprising:
a transmission medium disposed below the antenna element and configured to carry a receive reference signal from the antenna element; and
wherein the resonant signal-bypass stub is disposed within the transmission medium.
5. The antenna of claim 1 , wherein the resonant signal-bypass stub is configured to form, along with an insulator region below the ground conductor, a resonant circuit.
6. The antenna of claim 1 , wherein the resonant signal-bypass stub is radially tapered and has a circular-arc end.
7. The antenna of claim 1 , further comprising:
a second conductive signal-bypass stub disposed below the conductive, resonant signal-bypass stub;
wherein each of the resonant signal-bypass stub and the second conductive signal-bypass stubs are tapered inward toward the conductive DC-voltage-bias via.
8. The antenna of claim 1 , further comprising:
a second conductive signal-bypass stub disposed above the conductive, resonant signal-bypass stub;
wherein each of the resonant signal-bypass stub and the second conductive signal-bypass stubs are tapered inward toward the conductive DC-voltage-bias via.
9. The antenna of claim 1 , further comprising:
a waveguide disposed below the antenna element; and
wherein the resonant signal-bypass stub is disposed within the waveguide.
10. An antenna, comprising:
a conductive antenna element;
a first conductive region disposed below the conductive antenna element;
an iris disposed in the first conductive region;
a first conductive signal-bypass stub disposed below the first conductive region;
a second conductive signal-bypass stub disposed below the first signal-bypass stub;
a second conductive region disposed below the second signal-bypass stub; and
a conductive voltage-bias via coupled to the antenna element and to the first and second signal-bypass stubs and disposed outside of the iris.
11. The antenna of claim 10 wherein each of the first and second signal-bypass stubs is tapered inward toward the voltage-bias via.
12. The antenna of claim 10 wherein the first and second signal-bypass stubs are approximately aligned with one another.
13. The antenna of claim 10 , further comprising:
a first insulator region disposed between the antenna element and the first conductive region and having a first thickness;
a second insulator region disposed between the first conductive region and the first signal-bypass stub and having a second thickness that is significantly less than the first thickness;
a third insulator region disposed between the first and second signal-bypass stubs and having a third thickness that is significantly greater than the second thickness; and
a fourth insulator region disposed between the second signal-bypass stub and the second conductive region and having a fourth thickness that is significantly less than the first and third thicknesses.
14. The antenna of claim 10 , further comprising:
a first insulator region disposed between the antenna element and the first conductive region and having a first thickness;
a second insulator region disposed between the first conductive region and the first signal-bypass stub and having a second thickness that is significantly less than the first thickness;
a third insulator region disposed between the first and second signal-bypass stubs and having a third thickness that is approximately the same as the first thickness; and
a fourth insulator region disposed between the second signal-bypass stub and the second conductive region and having a fourth thickness that is approximately the same as the second thickness.
15. An antenna, comprising:
a conductive antenna element;
a first conductive region disposed below the conductive antenna element;
an iris disposed in the first conductive region;
a first conductive signal-bypass stub disposed below the first conductive region;
a second conductive signal-bypass stub disposed below the first signal-bypass stub;
a second conductive region disposed below the second signal-bypass stub;
a conductive voltage-bias via coupled to the antenna element and to the first and second signal-bypass stubs;
a third conductive signal-bypass stub disposed below the first conductive region at approximately a same level as the first signal-bypass stub;
a fourth conductive signal-bypass stub disposed below the third conductive signal-bypass stub and approximately at a same level as the second signal-bypass stub;
wherein the voltage-bias via is coupled to a first side of the antenna element; and
a conductive polarization-compensation via coupled to a second side of the antenna element and to the third and fourth signal-bypass stubs, the second side of the antenna element being opposite to the first side of the antenna element.