Electronically-controlled monolithic array antenna
View Patent ↗An electronically controlled monolithic array antenna includes a transmission line through which an electromagnetic signal may be propagated, and a metal antenna element defining an evanescent coupling edge located so as to permit evanescent coupling of the signal between the transmission line and the antenna element. The antenna element includes a conductive ground plate; an array of conductive edge elements defining the coupling edge, each of the edge elements being electrically connected to a control signal source, and each of the edge elements being electrically isolated from the ground plate by an insulative isolation gap; and a plurality of switches, each of which is selectively operable in response to the control signal to electrically connect selected edge elements to the ground plate across the insulative isolation gap so as to provide a selectively variable electromagnetic coupling geometry of the coupling edge.
1. An electronically controlled monolithic array antenna, comprising:
a transmission line through which an electromagnetic signal may be propagated; and a metal antenna element defining an evanescent coupling edge located so as to permit evanescent coupling of the signal between the transmission line and the antenna element;
wherein the antenna element comprises:
a conductive ground plate;
an array of conductive edge elements defining the coupling edge, each of the edge elements being configured for electrical connection to a control signal source, each of the edge elements being electrically isolated from the ground plate; and
a plurality of switches, each of which is selectively operable in response to the control signal to electrically connect selected edge elements to the ground plate so as to provide a selectively variable electromagnetic coupling geometry of the coupling edge.
2. The antenna of claim 1 , wherein the control signal is generated in accordance with a computer program.
3. The antenna of claim 1 , wherein the transmission line is selected from the group consisting of at least one of a dielectric waveguide, a slot line, a coplanar line, a rib waveguide, a groove waveguide, and an imaging waveguide.
4. The antenna of claim 1 , wherein the switches are selected from the group consisting of at least one of PIN diodes, bipolar transistors, MOSFETs, HBTs, MEMS switches, piezoelectric switches, photoconductive switches, capacitive switches, lumped IC switches, ferro-electric switches, electromagnetic switches, gas plasma switches, and semiconductor plasma switches.
5. The antenna of claim 1 , wherein the ground plate and the edge elements are formed on a substrate.
6. The antenna of claim 5 , wherein the substrate is made of a material selected from the group consisting of at least one of a dielectric material and a semiconductor material.
7. The antenna of claim 6 , wherein the substrate is a dielectric material selected from the group consisting of at least one of quartz, sapphire, ceramic, plastic, and a polymeric composite.
8. The antenna of claim 6 , wherein the substrate is a semiconductor material selected from the group consisting of at least one of silicon, gallium arsenide, gallium phosphide, germanium, gallium nitride, indium phosphide, gallium aluminum arsenide, and SOI.
9. The antenna of claim 1 , wherein each of the edge elements is electrically isolated from the ground plate by an insulative isolation gap, and wherein each of the switches is selectively operable to electrically connect the selected edge elements to the ground plate across the isolation gap.
10. The antenna of claim 9 , wherein the electromagnetic signal has an effective wavelength λ in the isolation gap, and wherein the isolation gap has a length that has a predefined relationship with λ.
11. The antenna of claim 10 , wherein the isolation gap has a length of approximately λ/4.
12. The antenna of claim 10 , wherein each of the isolation gaps includes a main portion across which one of the switches is operable, and a branch portion having a length of approximately λ/4.
13. The antenna of claim 5 , wherein the substrate has first and second surfaces, and wherein the ground plate comprises a first ground plate element on the first surface and a second ground plate element on the second surface.
14. An electronically controlled monolithic array antenna, comprising:
a substrate having a front edge:
a dielectric transmission line through which an electromagnetic signal may be propagated, the transmission line being located substantially parallel to the front edge of the substrate;
an array of conductive edge elements provided along the front edge of the substrate, the edge elements defining an evanescent coupling edge located so as to permit evanescent coupling of the signal between the transmission line and the edge elements;
a control signal source electrically coupled to each of the edge elements;
a ground plate located on the substrate so as to be electrically isolated from each of the edge elements; and
a plurality of switches provided between the edge elements and the ground plate, each of the switches being selectively operable in response to the control signal to electrically connect selected edge elements to the ground plate so as to provide a selectively variable electromagnetic coupling geometry for the coupling edge.
15. The antenna of claim 14 , wherein the ground plate comprises a plurality of ground plate elements, each of which is electrically isolated from any adjacent edge elements by an insulative isolation gap, and wherein each of the switches is selectively operable to electrically connect selected edge elements to the ground plate across the isolation gap.
16. The antenna of claim 14 , wherein the control signal is generated in accordance with a computer program.
17. The antenna of claim 14 , wherein the transmission line is selected from the group consisting of at least one of a dielectric waveguide, a slot line, a coplanar line, a rib waveguide, a groove waveguide, and an imaging waveguide.
18. The antenna of claim 14 , wherein the switches are selected from the group consisting of at least one of PIN diodes, bipolar transistors, MOSFETs, HBTs, MEMS switches, piezoelectric switches, photoconductive switches, capacitive switches, lumped IC switches, ferro-electric switches, electromagnetic switches, gas plasma switches, and semiconductor plasma switches.
19. The antenna of claim 14 , wherein the ground plate and the edge elements are formed on a substrate.
20. The antenna of claim 19 , wherein the substrate is made of a material selected from the group consisting of at least one of a dielectric material and a semiconductor material.
21. The antenna of claim 20 , wherein the substrate is a dielectric material selected from the group consisting of at least one of quartz, sapphire, ceramic, plastic, and a polymeric composite.
22. The antenna of claim 20 , wherein the substrate is a semiconductor material selected from the group consisting of at least one of silicon, gallium arsenide, gallium phosphide, germanium, gallium nitride, indium phosphide, gallium aluminum arsenide, and SOI.
23. The antenna of claim 14 , wherein the electromagnetic signal has an effective wavelength λ in the isolation gap, and wherein the isolation gap has a length that has a predefined relationship with λ.
24. The antenna of claim 23 , wherein the isolation gap has a length of approximately λ/4.
25. The antenna of claim 23 , wherein each of the isolation gaps includes a main portion across which one of the switches is operable, and a branch portion having a length of approximately λ/4.
26. The antenna of claim 19 , wherein the substrate has first and second surfaces, and wherein the ground plate comprises a first ground plate element on the first surface and a second ground plate element on the second surface.