Patent Description:
In many fields of wireless communication, such as microwave communication, as well as for applications associated with radars and other sensors using microwave technology, waveguides are used for transporting wireless signals, due to the low losses incurred in a waveguide.

When mounting or connecting one waveguide section to another waveguide section, it is important that the two waveguide sections are properly aligned such that mismatch between the two waveguide sections is avoided. For <NUM>, point-to-point and other wireless applications, frequencies are increasing which leads to decreasing waveguide dimensions. Each waveguide interface will then be very sensitive to misalignment between different mechanical interfaces. Today, different types of guiding pins are used, but for waveguides operating at high frequencies such as <NUM> and higher, each interface will introduce a degradation of return loss where fractions of a millimeter in misalignment will cause a problem. With multiple interfaces, the return loss can be seriously degraded even if each individual interface has an acceptable misalignment.

There can also be a gap between two waveguide sections in a waveguide arrangement, and at such gaps the electromagnetic field can partly escape the waveguide arrangement which also affects return loss and transition loss, i.e. both unwanted reflections and losses occur. Counteracting such gaps by means of having high manufacturing tolerances is relatively costly, therefore different types of microwave gaskets are commonly used, for example resilient ring gaskets that comprise a conductive material and RF gaskets where a thin metal plate comprises resilient angled fingers that provide a spring load towards against a surface that should be electrically sealed.

It is, however, desired to obtain improved waveguide interfaces with respect to alignment and leakage via gaps.

<CIT> discloses a waveguide connecting method in which a shim is fabricated to have a cylindrical portion and flange. One end of a cylindrical portion of the shim is inserted into a first waveguide and a second waveguide is urged against the first waveguide.

<CIT> and <CIT> both disclose a connection for waveguides that is inserted into the waveguides.

<CIT> discloses waveguides that are opposed and adjacent to each other and are connected together while being insulated by an electric insulator.

<CIT> discloses a waveguide expansion joint for connecting two circular waveguides operating in the TE01 mode while allowing for waveguide expansion and contraction due to temperature variations. The expansion joint includes first and second rings on the outside surface at one end thereof.

It is an object of the present disclosure to provide a waveguide interface with improved properties regarding alignment and leakage via gaps. It is also an object of the present disclosure to provide associated components and methods.

This object is obtained by means of a waveguide interface comprising a first waveguide aperture, provided in a first waveguide device, a second waveguide aperture, provided in a second waveguide device, and a waveguide connecting tube. The waveguide connecting tube has a longitudinal extension and comprises waveguide walls and a connecting waveguide aperture for transfer of microwave signals. The waveguide connecting tube comprises a first end that is adapted to be at least partly inserted into the first waveguide aperture, and a second end that is adapted to be at least partly inserted into the second waveguide aperture. In this way, the first waveguide aperture and the second waveguide aperture are electrically connected via the waveguide connecting tube.

This means that the waveguide devices can be electrically connected in an efficient manner, minimizing degradation of return loss due to misalignment as well as leakage without having to use RF gaskets.

In addition, the waveguide connecting tube is adapted to run via at least one other component when electrically connecting the first waveguide aperture to the second waveguide aperture, each other component comprising a corresponding component aperture through which the waveguide connecting tube is adapted to run. The other component is a circuit board and/or a cooling plate.

In this way, an accumulated misalignment that is increased for a plurality of components to be connected is eliminated.

According to some aspects, each end of the waveguide connecting tube is chamfered to have corresponding edge chamfers, where the waveguide devices comprise corresponding edge tapers. These edge tapers are adapted to be engaged by the edge chamfers of the waveguide connecting tube and to provide alignment when the waveguide connecting tube is inserted into each waveguide aperture.

In this way, increased alignment and efficient mounting is achieved.

According to some aspects, each edge taper is deformable along the longitudinal extension.

This enables that a secure electrical and mechanical connection between the waveguide connecting tube and the waveguide devices is obtained.

According to some aspects, the waveguide interface comprises an electrically conductive paste applied between each end and walls of the corresponding waveguide aperture.

This provides enhanced electrical connections and reduces possible RF leakage.

This object is also obtained by means of waveguide connecting tubes and methods which are associated with the above advantages.

<FIG> and <FIG> show a first example of a waveguide interface <NUM>, <FIG> showing an exploded side perspective view and <FIG> showing a cut-open side view. The waveguide interface <NUM> comprises a first waveguide aperture <NUM>, provided in a first waveguide device <NUM>, and a second waveguide aperture <NUM>, provided in a second waveguide device <NUM>. The waveguide devices <NUM>, <NUM> are here in the form of waveguide connecting flanges that suitably are connected to other waveguide components via a waveguide connection (not shown). It should be noted that the waveguide devices <NUM>, <NUM> can be of any suitable kind, for example wave guide filters, such as diplexers, waveguide to coax/microstrip/stripline transitions and electronic components with a waveguide interface such as microwave amplifiers. The waveguide devices <NUM>, <NUM> need not be of the same kind.

The waveguide interface <NUM> further comprises a waveguide connecting tube <NUM> having a longitudinal extension L and comprising waveguide walls <NUM> and a connecting waveguide aperture <NUM> for transfer of microwave signals. According to the present disclosure, the waveguide connecting tube <NUM> comprises a first end <NUM> that is adapted to be at least partly inserted into the first waveguide aperture <NUM>, and a second end <NUM> that is adapted to be at least partly inserted into the second waveguide aperture <NUM>, such that the first waveguide aperture <NUM> and the second waveguide aperture <NUM> are electrically connected via the waveguide connecting tube <NUM>.

This means that the waveguide devices <NUM>, <NUM> can be electrically connected in an efficient manner, minimizing degradation of return loss due to misalignment as well as leakage without having to use RF gaskets.

This is even more emphasized in the case when one or more components are positioned between the waveguide devices <NUM>, <NUM>. According to some aspects, the waveguide connecting tube <NUM> is adapted to run via at least one other component <NUM>, <NUM> when electrically connecting the first waveguide aperture <NUM> to the second waveguide aperture <NUM>, each other component <NUM>, <NUM> comprising a corresponding component aperture <NUM>, <NUM> through which the waveguide connecting tube <NUM> is adapted to run.

According to some aspects, the other component is a circuit board <NUM> and/or a cooling plate <NUM>. In the present example, there is a first other component in the form of a circuit board <NUM> and a second other component in the form of a cooling plate <NUM>. The cooling plate <NUM> is suitably a metal plate that is attached to the circuit board <NUM> and is for example adapted to create rigidity and dissipate heat generated by components connected to the circuit board <NUM>.

As clearly shown in <FIG>, the waveguide connecting tube <NUM> alleviates all kinds of misalignments that may occur between the first waveguide devices <NUM>, the circuit board <NUM>, the cooling plate <NUM> and the second waveguide device <NUM>, and in particular between the corresponding apertures <NUM>, <NUM>, <NUM>, <NUM>.

With reference to <FIG> that schematically shows a cut-open side view of a waveguide interface <NUM>' according to a second example, according to some aspects, each end <NUM>', <NUM>' of the waveguide connecting tube <NUM>' is chamfered to have corresponding edge chamfers <NUM>, <NUM>, <NUM>, <NUM>. The waveguide devices <NUM>', <NUM>' comprise corresponding edge tapers <NUM>, <NUM>, <NUM>, <NUM> that are provided along an inner edge of the corresponding waveguide aperture <NUM>, <NUM>. The edge tapers <NUM>, <NUM>, <NUM>, <NUM> are adapted to be engaged by the edge chamfers <NUM>, <NUM><NUM>, <NUM> of the waveguide connecting tube <NUM>' and to provide alignment when the waveguide connecting tube <NUM>' is inserted into each waveguide aperture <NUM>', <NUM>'.

In this way, both alignment and a secure fit is provided between the waveguide devices <NUM>', <NUM>' and the waveguide connecting tube <NUM>' when the waveguide connecting tube <NUM>' is inserted into the waveguide devices <NUM>', <NUM>'.

Here, the wall thickness of the waveguide connecting tube <NUM>' does not affect the waveguide width w that is maintained constant all the way through the waveguide interface <NUM>' since the aperture <NUM>, <NUM> of the other components <NUM>, <NUM> are adapted accordingly.

Having a width that is unaffected by the wall thickness of the waveguide connecting tube <NUM>' can of course be achieved without having edge tapers <NUM>, <NUM>, <NUM>, <NUM> that are adapted to engage edge chamfers <NUM>, <NUM>, <NUM>, <NUM>. For example, in <FIG>, only a straight indent could be provided in the waveguide devices <NUM>', <NUM>' and the other components <NUM>, <NUM>, these indents having dimensions that corresponds to the wall thickness of the waveguide connecting tube <NUM>'.

With reference to <FIG> that schematically shows a cut-open side view of a waveguide interface <NUM>" according to a third example, according to some aspects, there is a waveguide interface <NUM>'' similar to the one described with reference to <FIG>, but where each edge chamfer <NUM>", <NUM>" ,<NUM>'', <NUM>'' is deformable along its longitudinal extension L. The components of the waveguide interface <NUM>'' are the same as in the second example except the waveguide connecting tube <NUM>" that comprises the corresponding edge chamfers <NUM>'', <NUM>", <NUM>", <NUM>" that provide alignment into each waveguide aperture <NUM>', <NUM>'.

When the waveguide connecting tube <NUM>" is inserted into the waveguide devices <NUM>', <NUM>', the edge chamfers <NUM>", <NUM>'', <NUM>'', <NUM>" engage the corresponding edge tapers <NUM>, <NUM>, <NUM>, <NUM> of the waveguide devices <NUM>', <NUM>', and when submitted to pressure, the edge chamfers <NUM>", <NUM>", <NUM>", <NUM>'' are deformed such that a secure electrical and mechanical connection between the waveguide connecting tube <NUM>" and the waveguide devices <NUM>', <NUM>' is obtained. The deformable edge chamfers <NUM>", <NUM>'', <NUM>", <NUM>" can for example be in the form of foldable metal fingers or by pre-folded parts that either are separately formed in sheet metal and attached to the rest of waveguide connecting tube <NUM>" or formed in the same material as the rest of the waveguide connecting tube <NUM>".

According to some aspects, as illustrated only for one edge taper <NUM> and corresponding edge chamfer <NUM> in <FIG>, the waveguide interface comprises an electrically conductive paste <NUM> applied between each end <NUM>', <NUM>' and walls of the corresponding waveguide aperture <NUM>', <NUM>'. The electrically conductive paste <NUM> should normally be applied all along the ends <NUM>, <NUM>', <NUM>"; <NUM>, <NUM>', <NUM>" and walls of the corresponding waveguide aperture <NUM>, <NUM>; <NUM>', <NUM>', for example along all edge tapers <NUM>, <NUM>, <NUM>, <NUM> and corresponding edge chamfers <NUM>, <NUM>, <NUM>, <NUM>, and may be applied for all types of waveguide interfaces. For example, solder paste or any other sort of electrically conductive paste can be used. The electrically conductive paste <NUM> provides enhanced electrical connections and reduces possible RF leakage.

It is to be noted that the drawings are of a schematic character, only illustrating principles and not realistic dimensions and relations between different parts. For example, the circuit board <NUM> is normally larger and thinner, and is provided with a plurality of components and electrical connections in form of metal tracks.

The present disclosure relates to the above waveguide interface <NUM>. With reference to <FIG> and <FIG>, the present disclosure also relates to a waveguide connecting tube <NUM> having a longitudinal extension L and comprising waveguide walls <NUM> and a connecting waveguide aperture <NUM> for transfer of microwave signals. The waveguide connecting tube <NUM> is adapted to electrically connect a first waveguide aperture <NUM>, provided in a first waveguide device <NUM>, to a second waveguide aperture <NUM>, provided in a second waveguide device <NUM>. The waveguide connecting tube <NUM> comprises a first end <NUM> that is adapted to be at least partly inserted into the first waveguide aperture <NUM>, and a second end <NUM> that is adapted to be at least partly inserted into the second waveguide aperture <NUM>, such that the first waveguide aperture <NUM> and the second waveguide aperture <NUM> are electrically connected via the waveguide connecting tube <NUM>.

According to some aspects, the waveguide connecting tube <NUM> is adapted to run via at least one other component <NUM>, <NUM> when electrically connecting the first waveguide aperture <NUM> to the second waveguide aperture <NUM>, each other component <NUM>, <NUM> comprising a corresponding component aperture <NUM>, <NUM> through which the waveguide connecting tube <NUM> is adapted to run.

According to some aspects, the other component is a circuit board <NUM> and/or a cooling plate <NUM>.

According to some aspects, with reference to <FIG> and <FIG>, each end <NUM>', <NUM>'; <NUM>'', <NUM>'' of the waveguide connecting tube <NUM>', <NUM>'' is chamfered to have corresponding edge chamfers <NUM>, <NUM><NUM>, <NUM>; <NUM>", <NUM>", <NUM>", <NUM>" that are adapted to provide alignment into each waveguide aperture <NUM>', <NUM>'.

According to some aspects, with reference to <FIG>, each edge chamfer <NUM>'', <NUM>", <NUM>", <NUM>" is deformable along the longitudinal extension L.

With reference to <FIG>, the present disclosure also relates to a method for assembling a waveguide interface <NUM>, where the method comprises providing S100 a first waveguide device <NUM> with a first waveguide aperture <NUM>, providing S200 a second waveguide device <NUM> with a second waveguide aperture <NUM>, and providing S300 a waveguide connecting tube <NUM> having a first end <NUM> and a second end <NUM>. The method further comprises inserting S600 the first end <NUM> into the first waveguide aperture <NUM>, and inserting S700 the second end <NUM> into the second waveguide aperture <NUM>, such that the first waveguide aperture <NUM> and the second waveguide aperture <NUM> are electrically connected via the waveguide connecting tube <NUM>.

According to some aspects, the method comprises providing S400 edge chamfers <NUM>, <NUM><NUM>, <NUM>; <NUM>", <NUM>", <NUM>", <NUM>" at each end <NUM>', <NUM>'; <NUM>", <NUM>'' of the waveguide connecting tube <NUM>', <NUM>" and providing S500 corresponding edge tapers <NUM>, <NUM>, <NUM>, <NUM> at each waveguide device <NUM>', <NUM>'. The edge chamfers <NUM>, <NUM><NUM>, <NUM>; <NUM>", <NUM>", <NUM>", <NUM>" and edge tapers <NUM>, <NUM>, <NUM>, <NUM> are used for providing alignment by mutual engagement when inserting the waveguide connecting tube <NUM>', <NUM>" into each waveguide aperture <NUM>', <NUM>'.

The present disclosure is not limited to the above, but may vary freely within the scope of the appended claims. For example, there can be less or more than the two other components <NUM>, <NUM> shown.

Claim 1:
A waveguide interface (<NUM>) comprising a first waveguide aperture (<NUM>), provided in a first waveguide device (<NUM>), a second waveguide aperture (<NUM>), provided in a second waveguide device (<NUM>), and a waveguide connecting tube (<NUM>) having a longitudinal extension (L) and comprising waveguide walls (<NUM>) and a connecting waveguide aperture (<NUM>) for transfer of microwave signals, wherein the waveguide connecting tube (<NUM>) comprises a first end (<NUM>) that is adapted to be at least partly inserted into the first waveguide aperture (<NUM>), and a second end (<NUM>) that is adapted to be at least partly inserted into the second waveguide aperture (<NUM>), such that the first waveguide aperture (<NUM>) and the second waveguide aperture (<NUM>) are electrically connected via the waveguide connecting tube (<NUM>),
wherein the waveguide connecting tube (<NUM>) is running via at least one other component (<NUM>, <NUM>) when electrically connecting the first waveguide aperture (<NUM>) to the second waveguide aperture (<NUM>), each other component (<NUM>, <NUM>) comprising a corresponding component aperture (<NUM>, <NUM>) through which the waveguide connecting tube (<NUM>) is adapted to run,
characterized in that the other component is a circuit board (<NUM>) and/or a cooling plate (<NUM>).