1. A radiating source for transmitting and receiving at different frequencies, intended to be installed on board a satellite to define a radiation pattern in a terrestrial zone, said source being intended to be disposed in or near the focal plane of a reflector associated with other sources corresponding to other terrestrial zones, the source including a plurality of radiating apertures, each of which has an efficiency at least equal to 70%, and feed means for feeding each radiating aperture, the radiating apertures and their feed means being such that the energy radiated by all of the radiating apertures is practically limited to the corresponding reflector, at least for transmission.
2. A source according to claim 1, wherein the radiating apertures are fed differently for transmission and for reception.
3. A source according to claim 1, wherein the feed means for each radiating aperture are such that the radiation pattern is substantially the same for transmission and for reception.
4. A source according to claim 1, including a central radiating aperture and peripheral radiating apertures.
5. A source according to claim 4, wherein the peripheral radiating apertures are regularly distributed around the axis of the central radiating aperture.
6. A source according to claim 4, wherein the feed to the central radiating aperture is such that said radiating aperture produces the most radiation.
7. A source according to claim 6, wherein the feed means for the peripheral radiating apertures are such that the radiation produced by each of said peripheral radiating apertures is of practically the same intensity and less than the intensity of the radiation produced by the central radiating aperture.
8. A source according to claim 1, wherein the radiation to be transmitted by the source has linear polarization in a particular direction and the feed means are such that each radiating aperture transmits radiation polarized in said particular direction, which is oriented relative to the set of radiating apertures in such a manner as to maximize the uniformity of the radiation in three dimensions.
9. A source according to claim 8, wherein the polarization direction is chosen so that a straight line segment in that direction passing through the center of the exit plane of the source passes through a minimum number of radiating apertures.
10. A source according to claim 1, wherein the radiating apertures and the feed means are such that the intensity of the transmitted radiation at the periphery of the reflector is approximately 9 dB below the intensity of the transmitted radiation in the central part of the associated reflector.
11. A source according to claim 1, wherein the Ka band is used for transmission and for reception.
12. A source according to claim 11, wherein the transmit frequency is of the order of 20 GHz and the receive frequency is of the order of 30 GHz.
13. A source according to claim 1, wherein the distance between the axes of two adjoining radiating apertures is of the same order as the wavelength of the transmit radiation.
14. A telecommunications system in which calls are relayed by antennas on board a satellite, in particular a geosynchronous satellite, including an antenna with radiating sources each of which is a radiating source according to claim 1.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of fabricating a microelectromechanical systems (MEMS) device, comprising:
forming an electrode layer over a substrate;
depositing a sacrificial layer over the electrode layer;
forming a plurality of support structures, said support structures extending through the sacrificial layer, wherein at least some of said plurality of support structures comprise edge support structures;
depositing a mechanical layer over the plurality of support structures;
patterning the mechanical layer to form strips, wherein said strips are separated by gaps, and wherein said gaps are located over a central portion of each of said edge support structures; and
after forming the plurality of support structures, etching a portion of each of said edge support structures underlying the gaps, thereby forming isolated edge support structures.
2. The method of claim 1, wherein etching a portion of each of said edge support structures underlying the gaps comprises etching a central portion of each of said edge support structures to form two isolated edge support structures.
3. The method of claim 1, wherein patterning the mechanical layer to form strips comprises using a mask, and wherein etching a portion of each of said edge support structures comprises using the same mask.
4. The method of claim 1, wherein the patterned mechanical layer is used as a hard mask during the etching of a portion of each of said edge support structures.
5. The method of claim 1, additionally comprising removing said sacrificial material.
6. The method of claim 1, wherein forming a plurality of support structures comprises:
patterning the layer of sacrificial material to form apertures;
depositing a layer of support structure material over the patterned sacrificial layer and into the apertures; and
patterning the layer of support structure material to form support structures.
7. The method of claim 6, wherein patterning the layer of sacrificial material to form apertures comprises patterning the layer of sacrificial material to form tapered apertures.
8. The method of claim 6, additionally comprising depositing a reflective layer over the sacrificial layer prior to patterning the sacrificial layer.
9. The method of claim 6, additionally comprising depositing a reflective layer over the sacrificial layer after patterning the sacrificial layer.
10. The method of claim 9, wherein etching a portion of each of said edge support structures comprises using a plasma etch.
11. The method of claim 9, wherein patterning the layer of support structure material to form support structures comprises using a plasma etch or wet etch.
12. The method of claim 6, wherein patterning the layer of support structure material to form support structures comprises removing portions of the support structure layer located away from the apertures, thereby forming support structures having wing portions which extend horizontally along the sacrificial layer near the apertures.
13. The method of claim 1, wherein the electrode layer comprises indium tin oxide.
14. The method of claim 1, wherein the sacrificial layer comprises molybdenum, silicon, tungsten, or tantalum.
15. The method of claim 1, wherein the support structures comprise a material selected from the group of: SiO2 and SiNx.
16. The method of claim 1, wherein the mechanical layer comprises a material selected from the group of: nickel and aluminum.
17. The method of claim 16, wherein the mechanical layer is used as a hard mask during the etching of the portions of the edge support structures.
18. The method of claim 1, additionally comprising depositing a partially reflective layer over the substrate.
19. The method of claim 18, wherein the partially reflective layer is deposited over the electrode layer.
20. The method of claim 18, wherein the partially reflective layer comprises chromium.
21. The method of claim 1, additionally comprising depositing a dielectric layer over the electrode layer.
22. The method of claim 21, wherein the dielectric layer comprises a material selected from the group of: SiO2 and SiNx.
23. The method of claim 1, additionally comprising depositing a reflective layer over the sacrificial layer.
24. The method of claim 23, wherein the reflective layer comprises a material selected from the group of: aluminum, silver, gold, copper, palladium, platinum, and rhodium.
25. The method of claim 23, additionally comprising etching the reflective layer to remove the portions of the reflective layer located under the gaps in the mechanical layer.
26. A microelectromechanical systems device fabricated by the method of claim 1.