Switch for switching between different high frequency signals

A high frequency switch is provided. The high frequency switch comprises a first high frequency connector, comprising a first inner conductor, integrally formed with a first strip conductor. Moreover, the high frequency switch comprises a second strip conductor arranged orthogonally in a first plane relative to the first strip conductor, a third strip conductor, arranged orthogonally in the first plane relative to the first strip conductor, a first switching conductor, having an orthogonally angled shape relative to the first plane, a second switching conductor, having an orthogonally angled shape relative to the first plane. A switching actuator is mechanically connected to the first switching conductor and to the second switching conductor adapted to move vertically relative to the first plane, to a first position and to a second position.

FIELD

The present invention relates to a switch for high frequency signals, such as signals of frequencies over 85 GHz.

BACKGROUND

In recent years, in communications electronics, a shift towards increasingly high frequencies has been ongoing. In order to perform measurements in these frequency ranges, the requirements regarding hardware are continually increasing in complexity and cost. More specifically, this shift to higher frequencies has generated needs for enhanced frequency behavior, while commercial aspects increasingly require low costs and decreasing physical footprints. For example, U.S. Pat. No. 7,489,179 B2 shows a step attenuator comprising high frequency switches. The technology described in this patent, however, does not allow for sufficiently high frequencies.

Accordingly, there is a need for a switch configured to switch between different high frequency signals or signal destinations, and that is capable of handling very high frequencies, and at the same time only requiring a low cost of construction and having a small physical footprint.

SOME EXAMPLE EMBODIMENTS

Embodiments of the present invention advantageously address the foregoing requirements and needs, as well as others, by providing a switch configured to switch between different high frequency signals or signal destinations, and that is capable of handling very high frequencies, and at the same time only requiring a low cost of construction and having a small physical footprint.

In accordance with example embodiments of the present invention, a high frequency switch is provided. The high frequency switch comprises a first high frequency connector, comprising a first inner conductor, integrally formed with a first strip conductor. The high frequency switch further comprises a second strip conductor arranged orthogonally in a first plane relative to the first strip conductor, and a third strip conductor arranged orthogonally in the first plane relative to the first strip conductor. The high frequency switch further comprises a first switching conductor having an orthogonally angled shape relative to the first plane, and a second switching conductor having an orthogonally angled shape relative to the first plane.

According to a further embodiment, the high frequency switch further comprises a switching actuator, mechanically connected to the first switching conductor and to the second switching conductor, which is configured to move vertically relative to the first plane between a first position and a second position. It is thereby possible to switch signals between the three strip conductors in a high frequency behavior, and with a small physical footprint and at a low cost of manufacture.

According to a first such embodiment, the switching actuator, the first switching conductor and the second switching conductor are configured so that in the first position, the first strip conductor is in contact with the first switching conductor, the second strip conductor is in contact with the first switching conductor, and the second switching conductor is not in contact with the first strip conductor, the second strip conductor and the third strip conductor. Thereby, a high isolation of the non-switched strip conductor is achieved.

According to a second such embodiment, the switching actuator, the first switching conductor and the second switching conductor are configured so that in the second position, the first strip conductor is in contact with the second switching conductor, the second strip conductor is in contact with the second switching conductor and the first switching conductor is not in contact with the first strip conductor, the second strip conductor and the third strip conductor. Thereby, a high isolation of the non-switched strip conductor is also achieved.

According to a third such embodiment, the high frequency connector comprises a first port-support, holding the first inner conductor and the first strip conductor. A very simple construction of the first high frequency connector is thereby achieved.

According to a fourth such embodiment, the switch additionally comprises a second high frequency connector, comprising a second inner conductor, integrally formed with the second strip conductor, and a third high frequency connector, comprising a third inner conductor, integrally formed with the third strip conductor. A switching between signals on the three high frequency connectors is thereby possible, which allows for a very simple to construct switch with three coaxial ports.

According to a further embodiment, the first high frequency connector comprises a first port support, holding the first inner conductor and the first strip conductor. Additionally or alternatively, the second high frequency connector comprises a second port support, holding the inner conductor and the second strip conductor. Additionally or alternatively, the third high frequency connector comprises a third port support, holding the third inner conductor and the third strip conductor. A further simplified to construct switch can thereby be achieved.

According to a further embodiment, the second high frequency connector and the third high frequency connector are each orthogonally arranged relative to the first high frequency connector in the first plane. This allows for a very high isolation between the switched and the non-switched strip conductor, since the electromagnetic fields are also arranged orthogonally.

By way of example, the first strip conductor and/or the second strip conductor and/or the third strip conductor have a thickness of 0.1-0.5 mm, and more specifically can have a thickness of 0.25 mm. By way of further example, the first strip conductor and/or the second strip conductor and/or the third strip conductor have a width of 0.25 mm-2.0 mm, and more specifically can have a width of 0.5 mm. This allows for a very small physical footprint of the resulting switch, while still functionally achieving extremely high frequencies.

According to a further embodiment, the high frequency switch comprises a housing in a sandwich construction, which further facilitates simplicity in the construction of the switch.

According to a further embodiment, the high frequency switch comprises a high frequency baseplate, comprising a strip conductor channel, connected to ground. The strip conductor channel at least partially encloses the first strip conductor, the second strip conductor and the third strip conductor. The first strip conductor, the second strip conductor and the third strip conductor are separated from the strip conductor channel by an electrically non-conductive gap in the first plane. The electromagnetic field thereby exists between the edge of the respective strip conductor and the electrically conductive inner surface of the strip conductor channel. This allows for further decreases in the physical footprint of the resulting switch.

By way of example, the gap has a width of 0.1 mm-0.5 mm, and more specifically may have a gap width of 0.25 mm, which facilitates a very small construction of the switch.

According to a further embodiment, the high frequency baseplate comprises a first high frequency wall blocking the strip conductor channel between the second strip conductor and the second switching conductor. Alternatively or additionally, the high frequency baseplate comprises a second high frequency wall, blocking the strip conductor channel between the third strip conductor and the first switching conductor. By use of these high frequency walls, it is possible to further increase the isolation between the two strip conductor branches formed by the second strip conductor and the third strip conductor.

According to a further embodiment, the first strip conductor and/or the second strip conductor and/or the third strip conductor are held in place by axially symmetric non-conductive support elements, within the strip conductor channel. This allows for a very high precision positioning of the strip conductors and thereby allows a very beneficial high frequency behavior of the switch.

According to a further embodiment, the high frequency switch comprises a lower housing and an upper housing. The lower and the upper housing cover the high frequency baseplate and the strip conductor channel, are electrically conductive, and are electrically isolated from the first strip conductor, the second strip conductor, and the third strip conductor. This allows for very beneficial high frequency behavior.

According to a further embodiment, the switching actuator, the first switching conductor and the second switching conductor are configured so that in the first position, the second switching conductor is in contact to the upper housing and so that in the second position, the first switching conductor is in contact to the lower housing. Thereby, contact to a ground plane is achieved. This allows for defined voltage conditions and thereby prevents resonances of the non-switching switching conductor.

DETAILED DESCRIPTION

Approaches for a switch configured to switch between different high frequency signals or signal destinations, and that is capable of handling very high frequencies, and at the same time only requiring a low cost of construction and having a small physical footprint, are described. It is apparent, however, that the invention may be practiced without these specific details or with an equivalent arrangement. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the invention.

First, the general construction of a multi-stage step attenuator is described with reference toFIGS. 1-5. Second, with reference toFIGS. 6-8, details of the conductors within the step attenuator are shown. With reference toFIG. 9, the construction of an electrical element within the step attenuator is described. With reference toFIG. 10, an example input port of an example step attenuator is described. With reference toFIGS. 11-17, different embodiments of a high frequency switch in accordance with example embodiments of the present invention are described. With reference toFIGS. 18-19, the construction and function of a switching actuator in accordance with example embodiments of the present invention are described. In the following description, similar entities and reference numbers in different figures have been partially omitted.

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. However, the following embodiments of the present invention may be variously modified and the range of the present invention is not limited by the following embodiments.

FIG. 1shows a first example step attenuator1. The step attenuator1includes an input port5aand an output port5b. The step attenuator1further comprises a lower housing2, a baseplate3and an upper housing4. The lower housing2and the upper housing4sandwich the baseplate3. Moreover, the step attenuator1comprises a number of attenuation stages, which are not separately depicted here. The attenuation stages are arranged between the input port5aand the output port5b. Each attenuation stage has an actuator6a,6b,6c,6d. With each of the actuators6a-6d, it is possible to switch an electrical element, for example a resistor into the signal path between the input port5aand the output port5b.

FIG. 2shows an expanded view of the step attenuator1ofFIG. 1. It can clearly be seen here that the input port5ais held in place by bolts8a, which screw into the upper housing4and the lower housing2. Also, the output port5bis held in place by bolts8b, which also screw into the upper housing4and the lower housing2. The upper housing4, the baseplate3and the lower housing2are moreover held together by bolts7.

Further details of the individual elements will be given in the further figures.

FIG. 3shows a detailed view of an example upper housing4and surrounding components of the step attenuator1ofFIG. 1. The upper housing4comprises a number of holes47a,47b,47c,47d, which are configured for passing an actuator6a-6dthrough. Moreover, the upper housing4comprises additional holes48a,48b,48c,48dfor passing through connecting rods45, which are attached to switching conductors46on their lower side and shafts43on their upper side. Between the respective shaft43and the upper housing4, additionally a respective spring44is arranged, holding the connecting rod45and the attached shaft43under tension. Below the upper housing4, a high frequency sealing sheet41is arranged. Bolts42keep the upper housing4, the sealing sheet41and the baseplate3aligned.

FIG. 4shows an expanded view of an example baseplate3of the step attenuator1ofFIG. 1. The baseplate3comprises a strip conductor channel35, which connects the input port side and the output port side of the baseplate3. For each of the attenuation stages of the step attenuator1, the strip conductor channel35forms two paths, one path for a through connection and one path for a connection with an electrical element34. Within the strip conductor channel35strip conductors31and32are arranged. The strip conductor31forms the respective through connection in each of the attenuation stages. The strip conductor32connects the electrical element34of the respective stage. Within each of the attenuation stages, switches on an input side and on an output side, switch either the strip conductor31or the strip conductor32into the signal path between the input port and the output port.

The strip conductors31,32are held in place by axially symmetric non-conductive support elements33.

The strip conductor channel35has a conductive surface. By way of example, the strip conductor channel35is machined into the baseplate3, which is formed from solid metal. Since the support elements33hold the strip conductors31,32with a gap towards the strip conductor channel35, there is no conductive connection between the strip conductors31,32and the strip conductor channel35. Also, there is no conductive connection between the electrical elements34and the strip conductor channel. Further, the components are configured to exhibit a good thermal coupling between the electrical elements34and the strip conductor channel, and therefore the baseplate3, which achieves dissipation of the signal power.

FIG. 5shows an expanded view of an example lower housing2of the step attenuator1ofFIG. 1. Also here, a high frequency sealing sheet22is arranged between the lower housing2and the baseplate3. Bolts23hold the lower housing2, the high frequency sealing sheet22and the baseplate3aligned. The lower housing2comprises a number of holes27a,27b,27cand27dfor passing an actuator6a-6dthrough. Moreover, the lower housing2as well as the high frequency sealing sheet22comprise additional holes28a,28b,28cand28dfor passing connecting rods21through. The connecting rods21are attached to switching conductor26on the upper side and to shafts25on the lower side. Between the lower housing and the respective shaft25, for each connecting rod21, a spring24is arranged, holding the shafts and the connecting rods at tension relative to the lower housing2.

FIG. 6shows a further expanded view of the example baseplate3ofFIG. 5. Here, the strip conductors31and32are shown in an expanded view relative to the baseplate3. It can clearly be seen that the strip conductor31forms a through connection between a left side and a right side of the baseplate3, while the strip conductor32forms a connection between the left side and the right side of the baseplate3through the electrical element34. Also, the support elements33can easily be seen here. Moreover, this figure clearly shows the strip conductor channel35, which is machined into the baseplate3.

FIG. 7shows a detailed view of two example switches of the step attenuator1ofFIG. 1, without the surrounding baseplate3and housing2,4. Since the two switches are constructed identically, only the left switch is provided with reference signs.

A first strip conductor36forms an input of the switch. The first strip conductor36can be connected to the strip conductor32, which connects the electrical element34and alternatively to the strip conductor31, which forms the through connection as explained earlier.

The switch comprises an upper connecting rod45, connected to a first switching conductor46and a lower connecting rod21, connected to a second switching conductor26. The connecting rods45,21are connected to one of the actuators6a-6dand are moved simultaneously.

The switches can be positioned in a first position and in a second position. In the first position shown here, the switching conductor46is not in contact with the first strip conductor36and the second strip conductor32. The switching conductor46instead is contact with a ground plane, for example the upper housing or the high frequency sealing sheet22arranged between the upper housing and the baseplate3. At the same time, the switching conductors26is in contact to the first strip conductor36and the third strip conductor31. The further switch switches in a similar manner. This means that either the second strip conductor32or the third strip conductor31is connected with the input and output of the respective attenuation stage.

By way of example, the switching conductors26,46are orthogonally shaped in the plane of the strip conductors, and the first strip conductor36is arranged orthogonally relative to the second strip conductor32and the third strip conductor31. This achieves an advantageous high frequency behavior, since a high frequency coupling to the presently non-switched path is effectively prevented due to the orthogonal nature of the electromagnetic field.

FIG. 8shows a top-down view of one example attenuation stage of the step attenuator1ofFIG. 1. Here the first strip conductor36, the switching conductor26and the strip conductors31,32are shown. Also the electrical element34and the support elements33can readily be seen. Moreover, the strip conductor channel35is also depicted here.

FIG. 9shows a detailed view of an example electrical element34of the step attenuator1ofFIG. 1. The electrical element34is arranged on a substrate341, such as a ceramic substrate. For example a silicon-nitride-substrate can be used. This is advantageous, because such a substrate has a high temperature conductivity, which facilitates dissipation of a high signal power away from the electrical element34. By way of example, in order to thermally connect the substrate341to the surrounding, it is soldered or pressure welded or glued, directly onto the surface of the baseplate3within the strip conductor channel35. Since the substrate341itself is non-conductive, this does not constitute a short-circuit between the electrical element and the strip conductor channel35.

FIG. 10shows an example input port5aand a connected attenuation stage of the step attenuator1ofFIG. 1. The input port5acomprises an outer conductor51and an inner conductor52and forms a coaxial port. The inner conductor52is held in place by a conductor support53. The inner conductor52is formed as one piece with the first strip conductor36. This allows for a very simple construction and very beneficial high frequency behavior. As already described earlier, the first strip conductor can be switched to connect to the second strip conductor32or the third strip conductor31. The already earlier described elements, although depicted here, are not described again.

FIG. 11shows a side-view of an example input port of a first example high frequency switch in accordance with example embodiments of the present invention. As is evident here, the inner conductor52is formed as one piece with the first strip conductor36. Further, here the position of the switching conductor46and26and the high frequency sealing sheets41,22can clearly be seen.

In the present switching position, the switching conductor46is in contact with the first strip conductor36and the second strip conductor32. At the same time, the switching conductor26is in contact to the ground plane formed by the high frequency seal22. In the other switching position, the switching conductor26is in contact with the first strip conductor36and the third strip conductor31. At this time, the switching conductor46is in contact to the ground formed by the high frequency seal41.

FIG. 12shows a three dimensional view of the baseplate3surrounding the switching conductors46,26of a second example high frequency switch in accordance with example embodiments of the present invention. The baseplate3has a strip conductor channel35machined into its surface. The first strip conductor36, the second strip conductor32and the third strip conductor31are each arranged within this strip conductor channel35separated from the strip conductor channel by a gap. By way of example, the gap has a width of 0.1-0.5 mm, and more specifically the gap may have a width of 0.25 mm. By way of further example, the strip conductors31,32,36have a width of 0.25-2.0 mm, and more specifically may have a width of 0.5 mm. By way of further example, the strip conductors31,32and36have a thickness of 0.1-0.5 mm, and more specifically may have a thickness of 0.25 mm.

The switching conductor46is connected to the connecting rod45. The switching conductor46in this picture is not in contact with the first strip conductor36and the second strip conductor32. Instead, the switching conductor26is in contact with the first strip conductor36and the third strip conductor31. This is though not easily visible in this picture.

Further, the baseplate3has a strip conductor channel wall37arranged at the bend of the perpendicular shaped switching conductor46, separating the switching conductor46from the third strip conductor31. For example, an RF coupling of a signal between the third strip conductor and the switching conductor46is thereby prevented. A similar strip conductor channel wall38is arranged between the second strip conductor32and the switching conductor26. This can readily be seen inFIG. 13.

FIG. 13shows a cut-open view corresponding to the view ofFIG. 12. Here, the two switching conductors46,26can readily be seen. Also, the two high frequency channel walls37,38are easily recognizable.

FIG. 14shows a detailed view of the switching conductors26,46. Each of the switching conductors26,46comprises holes262near the bend of its perpendicular shape. These holes262are used for connecting the connecting rod21,45. By way of example, this may be achieved by injection molding the connecting rod21,45, for example from a plastic material, wherein the material of the connecting rod21,45flows through the holes262and surrounds the switching conductor26,46, thereby connecting and holding the switching conductor26,46by the connecting rod21,45.

Moreover, the switching conductor26,46can optionally comprise a flattened corner261in order to enhance the high frequency behavior.

Furthermore, optionally, the switching conductor26,46can comprise slits263in its respective distal ends. These slits are useful for increasing the elasticity of the respective tips of the switching conductor26,46, thereby decreasing accuracy requirements regarding the exact positioning of the strip conductors31,32,36.

FIG. 15shows a detailed view of the switching conductor26,46in connection to the connecting rod21,45.

FIG. 16shows an example application of a switch100of an example high frequency switch in accordance with example embodiments of the present invention. Here, the switch100is used as a selector switch, configured to switch between different high frequency connectors5a,311,321. The switch100comprises a first high frequency connector5a, a second high frequency connector321and a third high frequency connector311.

The first high frequency connector5acomprises a first inner conductor52integrally formed with a first strip conductor36. The second high frequency connector321comprises an inner conductor320, integrally formed with a second strip conductor32. The third high frequency connector311comprises a third inner conductor310integrally formed with a third strip conductor31.

By way of example, the first strip conductor36is arranged orthogonally relative to the second strip conductor32in the first plane. Within the same first plane, the first strip conductor36is arranged orthogonally to the third strip conductor31.

By way of further example, the inner conductors52,320,310of the high frequency connectors5a,321,311are each arranged in line with the respectively integrally formed strip conductor36,32,31. Therefore, also the high frequency connectors5a,321,311are arranged in a similar configuration to the respective strip conductor36,32,31. This means that the first high frequency connector5ais arranged orthogonally to the second high frequency connector321. Also the first high frequency connector5ais arranged orthogonally to the third high frequency connector311.

According to a further embodiment, the switch100further comprises a first switching conductor26connected to a connecting rod21and a second switching conductor46connected to a connecting rod45. The connecting rods21,45are connected to a non-depicted switching actuator, which moves the connecting rods21,45simultaneously and thereby also moves the switching conductors26,46simultaneously. The switching actuator is configured to move the switching conductors26,46between a first position and a second position. In the first position, the first switching conductor26is in contact to the first strip conductor36and the second strip conductor32, while the second switching conductor46is not in contact to any of the strip conductors36,32,31but instead to a ground plane. In the second position, the second switching conductor46is in contact to the first strip conductor36and the third strip conductor31, while the first switching conductor26is not in contact to any of the strip conductors36,32,31but instead to a ground plane.

This means that the first switching conductor26inFIG. 16is lowered onto the first strip conductor36and the second strip conductor32in the first position, while the second switching conductor46is moved downwards away from the strip conductor36,32,31. In the second position, the second switching conductor46is moved upwards towards the lower side of the first switching conductor36and the third switching conductor31, while the first switching conductor26is moved away from the upper side of the switching conductor36,32,31.

FIG. 17shows a view an input of one of the input high frequency connectors5a. The high frequency connectors5a,311,321may be constructed identically. Alternatively, the high frequency connectors5a,311,321may be of different technologies, allowing for a mode transfer of the high frequency signal.

Here, the high frequency connector5acomprises an outer conductor51and an inner conductor52. In this example, the conductors51,52form a coaxial connector. Within the high frequency connector5a, a port support53is arranged, which holds the inner conductor52within the outer conductor51in a non-conductive manner. Since the inner conductor52is integrally formed with the first strip conductor36, the port support53also holds the first strip conductor36in position. On the right side ofFIG. 17, the identical components already depicted inFIG. 16are shown again, but not described in detail, here.

FIG. 18shows a detailed view of a switching actuator6a. The actuators6a-6dare identical to each other.

The actuator6acomprises a ridge68and is held in place by a securing spring67, which locks in the ridge68and holds the actuator in its place in the respective hole of the upper housing, lower housing and baseplate.

Moreover, the actuator6acomprises an actuator-element63a,63b, which is moved up and down by the actuator6abetween a first position and a second position. The actuator-element63ais connected to an elastic element61aon the top side of the actuator6aand to a second elastic element61bon the bottom side of the actuator6a. The actuator-element63amoves a first side of the elastic elements61a,61b, which corresponds to the central part of the respective elastic elements61a,61b. In this example, the elastic elements61a,61bare diaphragm springs. They comprise a number of slits62a,62b, by which the elastic characteristic of the diaphragm springs can be tuned.

Connected to a second side of the elastic elements61a,61bare shafts64a,64b, which are connected to the connecting rods21,45, which in turn are connected to the switching conductors26,46. The shafts64a,64bare moreover connected to springs66a,66b, which on their respective other side are in contact with the outer side of the baseplate, exerting an elastic force, forcing the respectively connected switching conductors26,46away from each other.

The shafts64a,64bare moreover supplied with loops65a,65b, which are used for preventing the shafts64a,64bfrom rotating.

The actuator6ais provided with shafts64a,64b, connecting rods21,45and switching conductors26,46on a left side and on a right side and therefore are symmetrical. They are adapted to move the switches simultaneously, as also depicted inFIG. 7andFIG. 10. Therefore, one actuator6ais used for two switches and therefore for one attenuation stage.

The actuator6ais supplied with a switching current through a cable61.

FIG. 19shows a cut-open view of the actuator6aofFIG. 18. The elements already described alongFIG. 16are not described again here. The actuator6acomprises the before-described actuator-element63a,63b, which is formed in conjunction with a core68. The actuator-element63a,63bmoves together with the core68within a housing69.

Arranged within the housing69and fixed to the housing is a permanent magnet67. Moreover an electromagnet70is arranged fixed to the housing69. The core68along with the actuator element63a,63bis therefore movable relative to the permanent magnet67and the electromagnet70.

The permanent magnet67makes sure, that there is always a magnetic force pulling the actuator-element63a,63beither towards a first switching position or a second switching position. This means that the core68is either in contact with an upper side of the housing69or a lower side of the housing69. The magnetic force is in equilibrium in a central position, but this position is not stable. Therefore, the actuator is bi-stable in the two switching positions. By running a switching current through the electromagnet70, the magnetic force of the permanent magnet67is overpowered, thereby allowing a switching between the two stable states.

InFIG. 19, in addition to the depiction inFIG. 18, the strip conductors are shown.

The invention is not limited to the examples. The invention discussed above can be applied to many different types of switches. Further, the type of actuator is not to be understood as limiting. The characteristics of the example embodiments can be used in any combination.

The examples shown inFIGS. 1-10 and 18-19are to be understood as disclosure regarding the construction of details of the embodiments. Such as, the construction of the strip conductors, the switching conductors, the shafts, the actuators, and the strip conductor channel of the embodiments are explained there. These elements are identical between the examples ofFIGS. 1-10 and 18-19and the embodiments ofFIGS. 11-17.