The present invention relates to high frequency switches for use in attenuation stages of switchable attenuators, in the following also called, step attenuators, and accordingly switchable attenuators.
Due to the rise of operating frequencies in communications electronics, the requirements on measurement equipment have been constantly rising in recent years. More specifically, there is a need to constantly increase the frequency of measuring signals. A central component in measuring electronics are switchable attenuators (step attenuators). For example, U.S. Pat. No. 7,489,179 B2 describes a step attenuator for high frequencies. The achievable maximum frequency there though is still limited. Also, the step attenuator shown there requires a large physical footprint.
Accordingly, there is a need for a switch, an attenuation stage and a switchable attenuator allowing for very high frequencies and at the same time only requiring a small spatial volume without incurring great construction costs.
Embodiments of the present invention advantageously address the foregoing requirements and needs, as well as others, by providing a switch, an attenuation stage and a switchable attenuator allowing for very high frequencies and at the same time only requiring a small spatial volume without incurring great construction costs.
In accordance with example embodiments of the present invention, a switch is provided. The switch comprises a first strip conductor and a second strip conductor, arranged orthogonally in a first plane. The switch further comprises a first switching conductor, having an orthogonally angled shape in the first plane. The switch further comprises a switching actuator, which is mechanically connected to the first switching conductor and adapted to move vertically relative to the first plane to a first position and to a second position.
According to a further embodiment of the switch, the switching actuator is configured so that in the first position, the first strip conductor is in contact with the first switching conductor and the second strip conductor is in contact with the first switching conductor. The switching actuator is further configured so that in the second position, the first strip conductor and the second strip conductor are not in contact with the first switching conductor. It is thereby possible to achieve a good high frequency behavior while only requiring a small spatial volume of the switch.
According to a further embodiment of the switch, the first strip conductor and the second strip conductor are at least partially enclosed by an electrically conducting strip conductor channel connected to ground. The first strip conductor and the second strip conductor are then separated from the strip conductor channel by an electrically non-conductive gap in the first plane. An especially small spatial volume of the switch can thereby be achieved.
By way of example, the first strip conductor and/or the second strip conductor have a thickness of 0.1-0.5 mm, or more specifically 0.25 mm. By way of further example, first strip conductor and/or the second strip conductor have a width of 0.25-2.0 mm, or more specifically 0.5 mm. By way of further example, the gap has a width of 0.1-0.5 mm, or more specifically 0.25 mm. An especially small spatial volume of the switch can thereby be achieved.
According to a further embodiment of the switch, the first strip conductor and/or the second strip conductor are held in place by axially symmetric non-conductive support elements within the strip conductor channel. It can thereby be assured that the strip conductors have a defined position and are not short-circuited.
According to a further embodiment of the switch, the switching actuator is configured so that, in the second position, the first switching conductor is in contact with a ground plane. This achieves a defined voltage of the first switching conductor during the open-state of the switch. Thereby, resonances of the first switching conductor can be prevented.
According to a further embodiment of the switch, the switch further comprises a third strip conductor, arranged orthogonally to the first strip conductor and opposite to the second strip conductor relative to the first strip conductor in the first plane. The switch further comprises a second switching conductor, having an orthogonally angled shape relative to the first plane. The switching actuator is mechanically also connected to the second switching conductor. The switching actuator is configured so that, in the first position, the first strip conductor and the third strip conductor are not in contact with the second switching conductor, and in the second position, the first strip conductor is in contact with the second switching conductor and the third strip conductor is in contact with the second switching conductor. In this construction, the switch is thereby configured to alternatingly connect the first strip conductor to the second strip conductor by use of the first switching conductor and connecting the first strip conductor to the third strip conductor by use of the second switching conductor.
According to a further embodiment of the switch, the first strip conductor and/or the second strip conductor and/or the third strip conductor are at least partially enclosed by an electrically conducting strip conductor channel connected to ground. The first strip conductor and/or the second strip conductor and/or the third strip conductor are separated from the strip conductor channel by an electrically non-conductive gap in the first plane. An especially small physical volume of the switch can thereby be achieved.
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, or more specifically 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 0.25-2.0 mm, or more specifically 0.5 mm. By way of further example, the gap has a width of 0.1-0.5 mm, or more specifically 0.25 mm. An especially small spatial volume of the switch can thereby be achieved.
According to a further embodiment of the switch, 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. It can thereby be assured that the strip conductors have a defined position and are not short-circuited.
According to a further embodiment of the switch, the switching actuator is configured so that in the first position the second switching conductor is in contact with a ground plane. This achieves a defined voltage of the first switching conductor during the open-state of the switch. Thereby, resonances of the first switching conductor can be prevented.
In accordance with further example embodiments of the present invention, an attenuation stage is provided. The attenuation stage comprises at least two switches according to the foregoing example switch embodiments of the present invention. The second strip conductor of a first switch of the at least two switches is connected to a first terminal of an electrical element. The second strip conductor of a second switch of the at least two switches is connected to a second terminal of the electrical element. The third strip conductor of the first switch is connected with a third strip conductor of the second switch. The first strip conductor of the first switch forms an input terminal of the attenuation stage. The first strip conductor of the second switch forms an output terminal of the attenuation stage. A very small physical footprint of the attenuation stage can thereby be achieved.
According to a further embodiment of the attenuation stage, the electrical element is a resistor formed in thin film technology. An especially small physical footprint of the resulting attenuation stage is thereby achieved.
According to a further embodiment of the attenuation stage, the at least two switches are switches according to specific implementation forms of the first aspect. In this case, the electrical element is disposed on an electrically non-conductive ceramic substrate, such as a silicon-nitride-substrate. By way of example, the ceramic substrate is soldered or pressure welded or glued onto the strip conductor channel. Additionally or alternatively, the electrical element is thermally connected to the strip conductor channel. It is thereby possible to further reduce the physical size of the attenuation stage.
In accordance with further example embodiments of the present invention, a switched attenuator (step attenuator) is provided. The step attenuator comprises an attenuation stage according to the second aspect of the invention. An input terminal of the attenuation stage forms an input terminal of the step attenuator. The output terminal of the attenuation stage forms an output terminal of the step attenuator. It is thereby possible to achieve a small footprint step attenuator which, can achieve very high operating frequencies.
In accordance with further example embodiments of the present invention, a step attenuator is provided. The step attenuator comprises a plurality of attenuation stages according to the foregoing example attenuation stage embodiments of the present invention. The input terminal of a first attenuation stage of the plurality of attenuation stages forms an input terminal of the step attenuator. Further attenuation stages of the plurality of attenuation stages are serially connected so that for each attenuation stage of the further attenuation stages, the output terminal of a preceding attenuation stage is connected to an input terminal of a succeeding attenuation stage. The output terminal of a final attenuation stage of the plurality of attenuation stages forms an output terminal of the step attenuator. A very flexible step attenuator can thereby be achieved.
Still other aspects, features, and advantages of the present invention are readily apparent from the following detailed description, simply by illustrating a number of particular embodiments and implementations, including the best mode contemplated for carrying out the present invention. The present invention is also capable of other and different embodiments, and its several details can be modified in various obvious respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawing and description are to be regarded as illustrative in nature, and not as restrictive.
Embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference numerals refer to similar elements, and in which:
Approaches for a switch, an attenuation stage and a switchable attenuator allowing for very high frequencies and at the same time only requiring a small spatial volume without incurring great construction costs, 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 to
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.
Further details of the individual elements will be given in the further figures.
The strip conductors 31, 32 are held in place by axially symmetric non-conductive support elements 33.
The strip conductor channel 35 has a conductive surface. By way of example, the strip conductor channel 35 is machined into the baseplate 3, which is formed from solid metal. Since the support elements 33 hold the strip conductors 31, 32 with a gap towards the strip conductor channel 35, there is no conductive connection between the strip conductors 31, 32 and the strip conductor channel 35. Also, there is no conductive connection between the electrical elements 34 and the strip conductor channel. Further, the components are configured to exhibit good thermal coupling between the electrical elements 34 and the strip conductor channel and therefore the baseplate 3, which achieves dissipation of the signal power.
A first strip conductor 36 forms an input of the switch. The first strip conductor 36 can be connected to the strip conductor 32, which connects the electrical element 34 and alternatively to the strip conductor 31, which forms the through connection as explained earlier.
The switch comprises an upper connecting rod 45, connected to a first switching conductor 46 and a lower connecting rod 21, connected to a second switching conductor 26. The connecting rods 45, 21 are connected to one of the actuators 6a-6d and 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 conductor 46 is not in contact with the first strip conductor 36 and the second strip conductor 32. The switching conductor 46 instead is contact with a ground plane, for example the upper housing or the high frequency sealing sheet 22 arranged between the upper housing and the baseplate 3. At the same time, the switching conductors 26 is in contact with the first strip conductor 36 and the third strip conductor 31. The further switch switches in a similar manner. This means that either the second strip conductor 32 or the third strip conductor 31 is connected with the input and output of the respective attenuation stage.
By way of example, the switching conductors 26, 46 are orthogonally shaped in the plane of the strip conductors, and the first strip conductor 36 is arranged orthogonally relative to the second strip conductor 32 and the third strip conductor 31. 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.
In the present switching position, the switching conductor 46 is in contact with the first strip conductor 36 and the second strip conductor 32. At the same time, the switching conductor 26 is in contact with the ground plane formed by the high frequency seal 22. In the other switching position, the switching conductor 26 is in contact with the first strip conductor 36 and the third strip conductor 31. At this time, the switching conductor 46 is in contact with the ground formed by the high frequency seal 41.
The switching conductor 46 is connected to the connecting rod 45. The switching conductor 46 in this picture is not in contact with the first strip conductor 36 and the second strip conductor 32. Instead, the switching conductor 26 is in contact with the first strip conductor 36 and the third strip conductor 31. This is though not easily visible in this picture.
Further, that the baseplate 3 has a strip conductor channel wall 37 arranged at the bend of the perpendicular shaped switching conductor 46, separating the switching conductor 46 from the third strip conductor 31. For example an RF coupling of a signal between the third strip conductor and the switching conductor 46 is thereby prevented. A similar strip conductor channel wall 38 is arranged between the second strip conductor 32 and the switching conductor 26. This can readily be seen in
Moreover, the switching conductor 26, 46 can optionally comprise a flattened corner 261 in order to enhance the high frequency behavior.
Furthermore, optionally, the switching conductor 26, 46 can comprise slits 263 in its respective distal ends. These slits are useful for increasing the elasticity of the respective tips of the switching conductor 26, 46, thereby decreasing accuracy requirements regarding the exact positioning of the strip conductors 31, 32, 36.
The first high frequency connector 5a comprises a first inner conductor 52 integrally formed with a first strip conductor 36. The second high frequency connector 321 comprises an inner conductor 320, integrally formed with a second strip conductor 32. The third high frequency connector 311 comprises a third inner conductor 310 integrally formed with a third strip conductor 31.
By way of example, the first strip conductor 36 is arranged orthogonally relative to the second strip conductor 32 in the first plane. Within the same first plane, the first strip conductor 36 is arranged orthogonally to the third strip conductor 31.
By way of further example, the inner conductors 52, 320, 310 of the high frequency connectors 5a, 321, 311 are each arranged in line with the respectively integrally formed strip conductor 36, 32, 31. Therefore, also the high frequency connectors 5a, 321, 311 are arranged in a similar configuration to the respective strip conductor 36, 32, 31. This means that the first high frequency connector 5a is arranged orthogonally to the second high frequency connector 321. Also the first high frequency connector 5a is arranged orthogonally to the third high frequency connector 311.
According to a further embodiment, the switch 100 further comprises a first switching conductor 26 connected to a connecting rod 21 and a second switching conductor 46 connected to a connecting rod 45. The connecting rods 21, 45 are connected to a non-depicted switching actuator, which moves the connecting rods 21, 45 simultaneously and thereby also moves the switching conductors 26, 46 simultaneously. The switching actuator is configured to move the switching conductors 26, 46 between a first position and a second position. In the first position, the first switching conductor 26 is in contact with the first strip conductor 36 and the second strip conductor 32, while the second switching conductor 46 is not in contact with any of the strip conductors 36, 32, 31 but instead to a ground plane. In the second position, the second switching conductor 46 is in contact with the first strip conductor 36 and the third strip conductor 31, while the first switching conductor 26 is not in contact with any of the strip conductors 36, 32, 31 but instead to a ground plane.
This means that the first switching conductor 26 in
The actuator 6a comprises a ridge 68 and is held in place by a securing spring 67, which locks in the ridge 68 and holds the actuator in its place in the respective hole of the upper housing, lower housing and baseplate.
Moreover, the actuator 6a comprises an actuator-element 63a, 63b, which is moved up and down by the actuator 6a between a first position and a second position. The actuator-element 63a is connected to an elastic element 61a on the top side of the actuator 6a and to a second elastic element 61b on the bottom side of the actuator 6a. The actuator-element 63a moves a first side of the elastic elements 61a, 61b, which corresponds to the central part of the respective elastic elements 61a, 61b. In this example, the elastic elements 61a, 61b are diaphragm springs. They comprise a number of slits 62a, 62b, by which the elastic characteristic of the diaphragm springs can be tuned.
Connected to a second side of the elastic elements 61a, 61b are shafts 64a, 64b, which are connected to the connecting rods 21, 45, which in turn are connected to the switching conductors 26, 46. The shafts 64a, 64b are moreover connected to springs 66a, 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 conductors 26, 46 away from each other.
The shafts 64a, 64b are moreover supplied with loops 65a, 65b, which are used for preventing the shafts 64a, 64b from rotating.
The actuator 6a is provided with shafts 64a, 64b, connecting rods 21, 45 and switching conductors 26, 46 on a left side and on a right side and therefore are symmetrical. They are adapted to move the switches simultaneously, as also depicted in
The actuator 6a is supplied with a switching current through a cable 61.
Arranged within the housing 69 and fixed to the housing is a permanent magnet 67. Moreover an electromagnet 70 is arranged fixed to the housing 69. The core 68 along with the actuator element 63a, 63b is therefore movable relative to the permanent magnet 67 and the electromagnet 70.
The permanent magnet 67 makes sure, that there is always a magnetic force pulling the actuator-element 63a, 63b either towards a first switching position or a second switching position. This means that the core 68 is either in contact with an upper side of the housing 69 or a lower side of the housing 69. 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 electromagnet 70, the magnetic force of the permanent magnet 67 is overpowered, thereby allowing a switching between the two stable states.
In
The invention is not limited to the examples. The invention discussed above can be applied to many different types of switches, attenuation stages and step attenuators. Further, the type of actuator is not to be understood as limiting. The characteristics of the example embodiments can be used in any combination.
Although the present invention and its advantages have been described in detail, it should be understood, that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not for limitation. Numerous changes to the disclosed embodiments can be made in accordance with the disclosure herein without departing from the spirit or scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described embodiments. Rather, the scope of the invention should be defined in accordance with the following claims and their equivalents.
Although the invention has been illustrated and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application.
This application claims the benefit of the earlier filing date under 35 U.S.C. § 119(e) from U.S. Provisional Application Ser. No. 62/424,260 (filed 2016 Nov. 18), which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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62424260 | Nov 2016 | US |