Variable dielectric constant antenna having split ground electrode
A multi-layer antenna having radiation layer including radiating elements; transmission layer including delay lines for coupling the RF signal to the radiating elements; control layer comprising variable dielectric constant (VDC) plate; RF coupling layer including arrangements for coupling RF signal to each of the delay lines; ground layer functioning as ground for the RF signal. The ground layer may also function as ground for the VDC control signal. The ground plane may comprise a plurality of conductive ground patches, each conductive ground patch separated from a neighboring conductive ground patch by a distance that appears as a break for a square wave signal of up to 400 Hz, but appears as a short for the RF signal. It is beneficial to make the separation not larger than a tenth of the wavelength of the RF signal.
1. An antenna comprising:
an insulating substrate;
a plurality of conductive patches provided on top surface of the insulating substrate;
a variable dielectric constant (VDC) plate;
a plurality of conductive delay lines provided over the VDC plate, each of the delay lines coupling RF signal to one of the plurality of conductive patches;
a ground plane provided below the VDC plate, the ground plane comprising at least one DC break sized to form a short for ground path of the RF signal.
2. The antenna of claim 1 , wherein the VDC plate defines a plurality of VDC pixels, the antenna further comprising at least one activation electrode corresponding to each of the plurality of VDC pixels.
3. The antenna of claim 1 , wherein each of the plurality of delay line comprises activation signal input configured for receiving activation signal from a controller.
4. The antenna of claim 1 , wherein the activation signal comprises a square wave signal.
5. The antenna of claim 1 , wherein the ground plane comprises a plurality of elongated DC breaks dividing the ground plane to a plurality of ground strips.
6. The antenna of claim 1 , wherein the width of the DC break is not more than λ/10 with respect to the wavelength of the RF signal.
7. The antenna of claim 1 , wherein the ground plane further comprises a plurality of apertures, each aperture being aligned below one of the conductive delay lines.
8. The antenna of claim 1 , wherein the ground plane comprises a plurality of DC breaks, each traversing the entire ground plane, thus dividing the ground plane into a plurality of physically separated ground patches.
9. The antenna of claim 1 , wherein each radiating patch comprises a conductive stub, each conductive stub being coupled to activation signal line of a controller.
10. The antenna of claim 1 , wherein each conductive delay line being coupled to activation signal line of a controller.
11. The antenna of claim 8 , further comprising a controller, the controller comprising a plurality of common signal outputs, each common signal output being coupled to one of the ground patches.
12. The antenna of claim 1 , wherein the variable dielectric constant layer comprises an upper binder layer, a bottom binder layer, and a variable dielectric constant material sandwiched between the upper binder layer and the bottom binder layer, and a plurality of spacers dispersed between the upper binder layer and the bottom binder layer.
13. The antenna of claim 1 , wherein the ground plane comprises a plurality of DC breaks, each traversing the entire ground plane, thus dividing the ground plane into a plurality of elongated rows, each row being aligned below a row of conductive delay lines.
14. The antenna of claim 13 , wherein each of the elongated rows is independently coupled to a common signal output of a controller.
15. A multi-layer antenna comprising:
a radiating layer comprising a plurality of radiating patch provided on a top surface of the insulating spacer and arranged in an array of row and columns;
a transmission layer comprising a plurality of delay lines arranged in an array of row and columns, each delay line being coupled to a corresponding on of the radiating patches;
a control layer comprising a variable dielectric constant (VDC) plate;
an RF coupling arrangement for coupling RF signal to each of the radiating patches; and,
a ground layer comprising a plurality of conductive ground patches, each conductive ground patch separated from a neighboring conductive ground patch by a distance not larger than a tenth of the wavelength of the RF signal.
16. The antenna of claim 15 , wherein each of the conductive ground patches is aligned below a row of the delay lines.
17. The antenna of claim 15 , wherein each of the conductive ground patches is aligned below a single one of the delay lines.
18. The antenna of claim 15 , wherein each of the conductive ground patches is separately coupled to a common signal output of a controller.
19. The antenna of claim 15 , wherein all of the conductive ground patches cooperatively form a common ground for the RF signal.
20. The antenna of claim 15 , wherein each of the conductive ground patches comprises at least one aperture aligned below one of the conductive delay lines.