Abstract
A waveguide in the form of a wave duct for transmitting microwave signals includes at least one non-conducting body arranged in and/or on the wave duct, and by at least one MHD pump, by which an electrically conductive liquid medium can be admitted to fill the at least one body and/or to exert a force on at least one wall of the wave duct.
Claims
1. A waveguide for transmitting microwave signals, the waveguide including at least one non-conducting body arranged in and/or on the waveguide, and including at least one MHD pump, by which an electrically conductive liquid medium can be admitted to fill the at least one body and/or to exert a force on at least one wall of the waveguide.
2. The waveguide as recited in claim 1, wherein the at least one body is partially or completely filled with liquid metal.
3. The waveguide as recited in claim 1, wherein the waveguide is a wave duct.
4. The waveguide as recited in claim 3, wherein the at least one body is arranged in the wave duct to form a plane of reflection.
5. The waveguide as recited in claim 4, wherein shiftable, non-conducting bodies are arranged in the wave duct.
6. The waveguide as recited in claim 3, wherein the at least one body is arranged on at least one wave duct wall.
7. The waveguide as recited in claim 6, wherein at least one slot arranged on the wave duct can be closed and opened by the at least one body to influence decoupling from the wave duct.
8. The waveguide as recited in claim 3, wherein the MHD pump and a volume filled with the electrically conductive liquid medium are arranged on the wave duct wall such that, by actuating the MHD pump, a pressure element exerts a pressure on the wave duct wall.
9. The waveguide as recited in claim 1, wherein the waveguide is made of a metal or a metallized plastics material.
10. The waveguide as recited in claim 1, wherein the waveguide has a rectangular or polygonal or round or oval, cross-sectional shape.
11. The waveguide as recited in claim 1, wherein the electrically conductive liquid is a liquid metal.
12. The waveguide as recited in claim 11, wherein the liquid metal is a eutectic alloy of gallium, indium, and tin.
13. The waveguide as recited in claim 1, wherein the waveguide is configured to act as an antenna.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Exemplary embodiments of the present invention are shown in the figures and are explained in greater detail in the following description.
[0019] FIG. 1 schematically shows a wave duct according to an example embodiment of the present invention for transmitting microwave signals.
[0020] FIG. 2 is a simplified schematic view of the wave duct shown in FIG. 1 for explaining the SP2T function (double-throw switch).
[0021] FIG. 3A shows the attenuation of all the gates among one another (S parameters).
[0022] FIG. 3B schematically shows the active path between ports 2 and 3, with the EM field depicted in FIG. 3A.
[0023] FIG. 4 schematically shows another specific example embodiment of the wave duct according to the present invention in the form of a filter/phase modifier.
[0024] FIG. 5 shows the transmission behavior from port 3 to port 2 of the wave duct shown in FIG. 4.
[0025] FIG. 6 schematically shows a further specific example embodiment of a wave duct according to the present invention comprising three capillaries/bodies for producing a variable phase modifier or final phase control element.
[0026] FIG. 7 schematically shows a specific example embodiment of the present invention in which a pressure is exerted on a wave duct wall.
[0027] FIG. 8 schematically shows the phase variation over the frequency.
[0028] FIG. 9 shows another specific example embodiment of the present invention in which the pressure is exerted on a microstrip.
[0029] FIG. 10 shows a wave duct comprising slot-shaped openings, according to an example embodiment of the present invention.
[0030] FIG. 11 shows the wave duct shown in FIG. 10 and schematically shows an assembly configured to close and open the slots by way of an electrically conductive liquid medium with the aid of an MHD pump.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
[0031] A waveguide designed as a wave duct 50 for transmitting microwave signals, shown in FIG. 1, is designed as a wave duct T-piece comprising three ports 1, 2, 3, by way of example. An MHD pump 100, which acts as a waveguide/wave duct switch, is arranged at the junction of the T-piece. In further specific embodiments, gang switches can also be designed, in particular for channel multiplexing or a polarization switch in the antenna system. In a conventional manner, this MHD pump 100 comprises two permanent magnets 110 as well as two electrodes 120. A substantially U-shaped body 130, of which the U-legs designed as channels 131, 132 project into the wave duct 50, is arranged between the permanent magnets 110. The body 130 is made of a non-conducting material, for example plastics material. The wave duct 50 itself consists of metal or a metallized plastics material; it is implemented in the form of a metallized plastics injection molding, for example. The wave propagation in the wave duct 50 from the port 3 to the port 1 is shown schematically with the aid of arrows 60. If the body 131 shown on the left in FIG. 1 is not filled with an electrically conductive liquid medium, in particular liquid metal, while the body 132 shown on the right in FIG. 1 is filled with an electrically conductive liquid medium, in particular liquid metal, the waves 60 are deflected in the wave duct as shown in FIG. 1 with the aid of the arrows 60, i.e., from the port 3 to the port 1. By actuating the MHD pump, the liquid can be transferred from the right-hand body, in the form of the U-leg 132, into the left-hand body, in the form of the U-leg 131, by pumping, and a different wave propagation is produced in the wave duct in this way. FIG. 2 schematically shows this arrangement with the MHD pump omitted; in this case, the left-hand body, i.e., the left-hand U-leg 131, is filled with liquid metal, while the right-hand body, i.e., the right-hand U-leg 132, is empty.
[0032] FIG. 3B shows the active path between the ports 2 and 3 of the wave duct. The attenuation is schematically shown in FIG. 3A. Since this arrangement is reciprocal, S21=S12, S31=S13, and S23=S32. The frequency in the range of 70 to 80 GHz is shown on the x axis. The attenuations are shown on the y axis, on which the attenuation S32/23 is 0 dB, while the attenuation S12/21 is >100 dB.
[0033] By shifting the two U-legs away from the junction, filters or phase modifiers can be implemented, as shown schematically in FIG. 4. In FIG. 4, the two U-legs 131, 132 are not right at the junction at which the body 52 discharges into the body 51, but instead are a predefinable length away from this discharge point. This predefinable length can be λ/4, for example, resulting in destructive interference. In FIG. 4, the leg 131 is again filled with liquid metal, while the leg 132 is not filled. By way of shiftable short-circuit planes of this kind, a very sharp filter function can be produced, as in FIG. 5, which shows the transmission behavior from port 3 to port 2. The transmission behavior is shown over a frequency range from 75 to 81 GHz. As can be seen in this figure, at 76.2 GHz there is a sharp peak, i.e., a stop band.
[0034] Yet another configuration of a wave duct according to the present invention for transmitting microwave signals, as shown in FIG. 6, provides three capillaries 181, 182, 183, which can be filled with liquid metal by the MHD pump, in a rectangular wave duct 180. An arrangement of this kind produces a variable phase modifier. In this case, the MHD pump functions as a final phase control element.
[0035] In another specific embodiment (not shown), a body, which can be filled with liquid metal, is arranged in parallel with the wave duct. By filling this body, the cross section of the wave duct, and therefore the emission behavior of the waveguide, is changed.
[0036] The MHD pump or the MHD actuator can also be actuated such that a pressure or a force is exerted on the wall of the wave duct; if this wall is deformable, this results in the wave duct being deformed. Deformation of this kind which causes a change in the cross section of the wave duct results in a change in the transmission behavior of the wave duct. In this case, the MHD actuator or the MHD pump can apply a force or a pressure to a wall of the wave duct or a wave duct antenna in order to thus bring about a change in the cross section of the wave duct or a desired structure of the wave duct.
[0037] One exemplary embodiment of this is shown in section in FIG. 7. On one of its walls, a rectangular wave duct 710 comprises a pipe 720, which is filled with an electrically conductive liquid medium 730 and is blanked off at the end by an electrically non-conducting hemisphere 740. This hemisphere presses on the wall 712 of the wave duct 710 facing the pipe 720. Depending on the exertion of the pressure exerted by this MHD pump (not shown), the wall 712 is deformed. This results in a phase shift in the transmission behavior owing to the hemisphere 740 being impressed by the MHD pump, as indicated on the basis of the S parameters shown in FIG. 8, which represent the phases in degrees over the frequency.
[0038] Another specific embodiment is shown in FIG. 9, which shows a microstrip 910 on which a pipe 920 is arranged again, which is filled with an electrically conductive liquid medium 930 and is blanked off at its end facing the microstrip 910 by an electrically non-conducting hemisphere 940. In this case, too, the hemisphere 940 is pressed against the microstrip 910 by pressure being applied by the MHD pump.
[0039] According to a specific embodiment shown in FIGS. 10 and 11, the decoupling from the waveguide is influenced, in particular by covering and re-opening openings, e.g., decoupling slots. With the MHD pump omitted, FIG. 10 schematically shows a wave duct 1010, which comprises rectangular slots 1020. As shown schematically in FIG. 11, these slots can be closed and opened by an electrically conductive liquid medium 1030, which is shown in FIG. 11 without the surrounding guides made of an electrical insulator and without reservoirs and cavities, the electrically conductive liquid metal being actuated by gate electrodes 1040 and permanent magnets or coil packages 1050. This results in a multi-channel, independently actuable configuration of which the emission behavior is adjustable.
