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A slot antenna for receiving and/or transmitting a RF signal at a desired one of a plurality of different frequencies. The slot antenna includes at least one conductive sheet having a slot defined therein, the slot being longer than it is wide and having at least one end which is open. A plurality o

A slot antenna for receiving and/or transmitting a RF signal at a desired one of a plurality of different frequencies. The slot antenna includes at least one conductive sheet having a slot defined therein, the slot being longer than it is wide and having at least one end which is open. A plurality of switch members are mounted along said slot close to the open end thereof, each of said plurality of switch members acting, when closed, to couple the at least one conductive sheet on one side of said slot to the at least one conductive sheet on a second side thereof. A feed point is provided for adjacent said slot. The plurality of switch members are closable in a controlled manner to change a desired resonance frequency at which the slot antenna receives and/or transmits the RF signal.

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1. A slot antenna for receiving and/or transmitting a RF signal at a desired one of a plurality of different frequencies, the slot antenna comprising:(a) at least one conductive sheet having a slot defined therein, the slot being longer than it is wide, the slot having a first end which is electrica

1. A slot antenna for receiving and/or transmitting a RF signal at a desired one of a plurality of different frequencies, the slot antenna comprising:(a) at least one conductive sheet having a slot defined therein, the slot being longer than it is wide, the slot having a first end which is electrically closed and a second end which is open; (b) a plurality of switch members mounted along said slot closer to the second end than to the first end thereof, each of said plurality of switch members acting, when closed, to couple the at least one conductive sheet on one side of said slot to the at least one conductive sheet on a second side thereof; (c) a feed point for coupling an RF signal to and/or from the at least one conductive sheet, the feed point being disposed adjacent said slot at a location which is nearer to said first end than it is to a closer or closest one of said plurality of switch members; and (d) the plurality of switch members be closable in a controlled manner to change a desired resonance frequency at which the slot antenna receives and/or transmits the RF signal. 2. The slot antenna of claim 1 wherein said plurality of switch members are disposed along said slot closer to one end of the slot than to another end thereof.3. The slot antenna of claim 2 wherein said plurality of switch members are disposed along said slot closer to the second end of the slot than the first end thereof.4. The slot antenna of claim 1 wherein the electrically closed end of the slot is formed by a portion of said at least one conductive sheet which physically closes said slot.5. The slot antenna of claim 1 wherein the electrically closed end of the slot is formed by a controllable switch connected across said slot, which controllable switch, when in its closed position, connects said one side of the conductive sheet with the other side thereof at said first end.6. The slot antenna of claim 5 wherein the controllable switch is one of a plurality of controllable switches arranged along said slot adjacent the first end thereof, said controllable switches being separately closable to change the location of said first end along said slot and thereby affect the impedance of the feed point.7. The slot antenna of claim 1 wherein the slot has an L-shaped configuration having first and second orthogonally-disposed sections, the feed point being disposed adjacent a point where the two orthogonally-disposed sections meet, the first section having an end which is electrically closed when a controllable switch associated with the second section is closed and the second section having an end which is electrically closed when a controllable switch associated with the first section is closed, the first end of the slot moving between the controllable switch associated with the second section and the controllable switch associated with the first section in response to closures of the controllable switches associated with the first and second sections.8. The slot antenna of claim 1 further including a cavity arranged adjacent said slot in said at least one conductive sheet.9. The slot antenna of claim 1 wherein said plurality of switch members are mounted on a one or more dielectric carriers, said one or more dielectric carriers being mounted over said slot so that said plurality of switch members are thereby mounted along said slot.10. A cavity backed slot antenna for receiving and/or transmitting a RF signal at least at a desired one of a plurality of different frequencies, the slot antenna comprising:(a) at least one conductive sheet having a first slot defined therein, the first slot being longer than it is wide, the first slot having at least one open end which is electrically closable by MEMS switch devices bridging the first slot, the slot having a cavity disposed behind it, the cavity being defined by (i) said at least one conductive sheet having the first slot defined therein, (ii) another conductive sheet spaced from said at least one conductive sheet having the first slot defined therein and (iii) sidewalls coupling said at least one conductive sheet having the first slot defined therein to said another conductive sheet, at least one of said sidewalls being disposed adjacent said at least one open end of said first slot, the at least one of said sidewalls having a gap therein which aligns with said at least one open end of said first slot; (b) the MEMS switch devices including a first plurality of switch members mounted along the first slot, each of said first plurality of switch members acting, when closed, to couple at least one conductive sheet on one side of said first slot to the at least one conductive sheet on a second side thereof, (c) a feed point for coupling an RF signal to and/or from the at least one conductive sheet, the feed point being disposed adjacent said first slot; and (d) the plurality of switch members be closable in a controlled manner to change the resonance frequency at which the slot antenna receives and/or transmits the RF signal. 11. The slot antenna of claim 10 wherein said first plurality of switch members are disposed along said first slot closer to a peripheral edge of said cavity than to said feed point.12. The slot antenna of claim 11 wherein said first slot has two open ends which terminate at the peripheral edge of said cavity and further including a second plurality of switch members disposed along said slot closer a second open end of the slot than to said feed point.13. The slot antenna of claim 12 further including a second slot having two open ends which terminate at the peripheral edge of said cavity, the second slot intersecting the first slot at a position which is at a midpoint of each of said first and second slots, the second slot having first and second pluralities of MEMS switch members arranged along said second slot closer to the open ends thereof than to said feed point.14. The slot antenna of claim 10 wherein the slot has an electrically closed end remote from the open end thereof.15. The slot antenna of claim 14 wherein the electrically closed end of the slot is formed by a portion of said at least one conductive sheet.16. A method of making a slot antenna comprising:(a) forming a longitudinal slot in an electrically conductive member, the longitudinal slot meeting at least one edge of the electrically conductive member to thereby define an open end of said slot, the slot having another end remote from said open end; and (b) disposing a series of MEMS switches along said slot and nearer its open end that its remote end, the MEMS switches coupling one side of the slot to an opposite side thereof when closed. 17. The method of claim 16 wherein the other end of the slot also meets an edge of the electrically conductive member to thereby define a second open end of said slot and further including the step of disposing a second series of MEMS switches along said slot and nearer its second open end than its first mentioned open end, the second series of MEMS switches coupling one side of the slot to an opposite side thereof when closed.18. The method of claim 16 wherein the slot has parallel side walls.19. The method of claim 18 wherein the remote end of the slot is electrically closed by said electrically conductive member.20. The method of claim 18 wherein the remote end of the slot is electrically closed by slot end adjusting switches, the slot end adjusting switches being disposed closer to a feed point of the antenna than are said series of MEMS switches.21. The method of claim 16 wherein the remote end of the slot is electrically closed by said electrically conductive member.22. The method of claim 16 wherein the remote end of the slot is electrically closed by slot end adjusting switches, the slot end adjusting switches being disposed closer to a feed point of the antenna than are said series of MEMS switches.23. A method of making a slot antenna capable of operating at a plurality of operating frequencies, the method comprising:(a) forming a longitudinal slot in an electrically conductive member; and (b) disposing a plurality of MEMS switches along said longitudinal slot, the plurality of MEMS switches coupling one side of the slot to an opposite side thereof when closed, the longitudinal slot having at least one end which is electrically closed by at least a selected one of said plurality of MEMS switches to operate at a selected one of said plurality of operating frequencies, the electrically conductive member providing an electrically conductive route in parallel with said at least a selected one of a plurality of MEMS switches which is at least one-quarter of a wavelength long at said selected one of said plurality of operating frequencies. 24. The method of claim 23 further including:(c) forming a second longitudinal slot in the electrically conductive member, the second longitudinal slot being disposed at a right angle to the first mentioned longitudinal slot; and (d) disposing a second plurality of MEMS switches along said second longitudinal slot, the second plurality of MEMS switches coupling one side of the second slot to an opposite side thereof when closed, the second longitudinal slot having at least one end which is electrically closed by at least a selected one of said second plurality of MEMS switches to operate at a second selected one of said plurality of operating frequencies, the electrically conductive member providing a second electrically conductive route in parallel with said at least a selected one of said second plurality of MEMS switches which is at least one-quarter of a wavelength long at said second selected one of said plurality of operating frequencies. 25. The method of claim 24 wherein the second longitudinal slot intersects the first mentioned longitudinal slot.26. The method of claim 24 wherein the first mentioned route and the second route are each infinitely long.27. A slot antenna capable of operating at a plurality of operating frequencies, the slot antenna comprising:(a) an electrically conductive member having a longitudinal slot defined therein; and (b) a plurality of MEMS switches disposed along said longitudinal slot, the plurality of MEMS switches coupling one side of the slot to an opposite side thereof when closed, the longitudinal slot having at least one end which is electrically closed by at least a selected one of said plurality of MEMS switches to operate at a selected one of said plurality of operating frequencies, the electrically conductive member providing an electrically conductive route in parallel with said at least a selected one of a plurality of MEMS switches which is at least one-quarter of a wavelength long at said selected one of said plurality of operating frequencies. 28. The slot antenna of claim 27 further including:(c) a second longitudinal slot in the electrically conductive member, the second longitudinal slot being disposed at a right angle to the first mentioned longitudinal slot; and (d) a second plurality of MEMS switches disposed along said second longitudinal slot, the second plurality of MEMS switches coupling one side of the second slot to an opposite side thereof when closed, the second longitudinal slot having at least one end which is electrically closed by at least a selected one of said second plurality of MEMS switches to operate at a second selected one of said plurality of operating frequencies, the electrically conductive member providing a second electrically conductive route in parallel with said at least a selected one of said second plurality of MEMS switches which second route is at least one-quarter of a wavelength long at said second selected one of said plurality of operating frequencies. 29. The slot antenna of claim 28 wherein the second longitudinal slot intersects the first mentioned longitudinal slot.30. A method of making a slot antenna comprising:(a) forming a longitudinal slot in an electrically conductive member, the longitudinal slot meeting at least one edge of the electrically conductive member to thereby define an open end of said slot, the slot having another end remote from said open end; and (b) disposing a series of MEMS switches along said slot and nearer its open end that its remote end, the MEMS switches coupling one side of the slot to an opposite side thereof when closed and thereby defining an active region of the slot between the closed end thereof and a closed one of the MEMS switches, the active region acting as an antenna to support radiation and/or reception of electromagnetic waves by said slot. 31. The method of claim 30 wherein the slot has straight side walls which are disposed parallel to one another.32. The method of claim 30 wherein the remote end of the slot is electrically closed by said electrically conductive member.