WO2014174494A2

WO2014174494A2 - Flanges for connection between corrugated wave-guiding modules

Info

Publication number: WO2014174494A2
Application number: PCT/IB2014/061013
Authority: WO
Inventors: Alessandro Macor; Emile De Rijk; Dylan FIVAT
Original assignee: Swissto12 Sa
Priority date: 2013-04-26
Filing date: 2014-04-25
Publication date: 2014-10-30
Also published as: WO2014174494A3

Abstract

A system for connecting corrugated wave-guiding modules comprising an asexual, auto aligning, flange (1) with a corrugated structure and screws and/or dowels (4) to prevent the structure to fall outside the flange's inner guiding shape (6).

Description

FLANGES FOR CONNECTION BETWEEN CORRUGATED WAVE-GUIDING

MODULES

REFERENCE TO RELATED APPLICATION

The present application claims priority to European patent application N°13165666.2 filed in the name of SWISStol2 SA, the content of which is incorporated by reference in its entirety in the present application.

TECHNICAL FIELD OF THE INVENTION

The terahertz region from 0.3 to 10 THz in the electromagnetic spectrum (1mm to 0.03 mm wavelength in free space) is a frontier area for research in physics, chemistry, biology, material science and medicine.

Source of high quality radiation in this area have been scarce, but this gap has recently begun to be filled by a wide range of new technologies. Terahertz radiation is now available in both continuous wave (CW] and pulsed form. New sources has led to new science in many areas, as scientists begin to become aware of the opportunities for research progress in their fields using THz signals.

THz radiation lies above the frequency range of traditional electronics, but below the range of optical and infrared generators. The fact that the THz frequency range lies in the transition region between photonics and electronics has led to unprecedented creativity in source and transmission components development.

The barriers to perform experiments using THz radiation are enormous because one needs not only a THz source, but also an appropriate understanding of many experimental details on the transmitting/receiving chain. Further research in quasi-optic waveguides is critical.

BACKGROUND OF THE INVENTION:

Hollow metallic corrugated wave-guiding components such as waveguides or horns antennas are an effective technological choice when building low loss transmission lines propagating electromagnetic signals at Sub-Terahertz and Terahertz.

Due to low absorption, low dispersion, efficient coupling, and wave confinement, hollow corrugated components apt for THz signals are crucial in the signal transmission and in particular for the assembly of circular, rectangular, or any suitable shape waveguides, down or up-tapers, horn antennas, cavities, mode converters and overall to transmit signals with high frequency up to the THz region for applications in:

- Physics applications, such as fundamental studies of nanostructures and Quantum coherence and control experiments, as transmission lines for plasma additional heating techniques in plasma reactors based on magnetic confinement (e.g. Tokamaks, Stellarators] - Chemistry studies on gas phase spectra and dynamics, membranes, Langumir-Blodget (LB) films, self-assembled monolayers (SAMs), phonon modes of inorganic and organic crystal, electron spin resonance (ESR), Dynamic Nuclear Polarization enhanced Nuclear Magnetic Resonance (DNP- NMR), high resolution Electron Paramagnetic Resonance (EPR), high resolution FerroMagnetic Resonance (FMR)

Medical THz imaging or spectroscopy where endoscopic techniques are required for environments that are otherwise difficult to access

- Terahertz sensing and imaging for security applications such as for explosive detection.

Typical corrugation parameters are the period "p", width "w" and depth "d", which are related to the wavelength λ of the propagating signal. In the example of hollow circular corrugated waveguides, a typical section of these waveguides is illustrated in figure 1, the period has to be less than λ/2 (e.g. to transmit more than 1 THz, period has to be less than λ/2 =0.15 mm), the width should be as wide as possible, and the depth (on the order of λ/2). The choice of these parameters can be used to tune the bandwidth of the waveguides.

The so-called HE11 mode propagates through corrugated modules, which has the effect of having very low losses in transmission. Power losses reach the order of 0.05dB per 100m (about 0.01% per meter) for the waveguide's nominal frequency, and goes up to 0.5dB per 100m (about 0.12% per meter) when the waveguide operates ten times above its designed frequency.

In WO 2012/076995, the content of which is incorporated in its entirety in the present application by reference, it is proposed to overcome the limits of conventional machining when building corrugated wave-guiding components. This is achieved by stacking series of rings in a guiding pipe where the rings' outer shape corresponds to the inner shape of the hollow guiding rod for aligning the rings in the rod, and hence aligning the rings with respect to each other. This means, for example, that rings have a continuous or a discrete number of contact points on their outer shape corresponding with the inner shape of the hollow guiding rod. The inner and outer shape may thus be different as long as contact points are provided for proper alignment. The rings' outer shape preferably remains unchanged along the structure while the inner hollow shape of rings may assume every appearance and design suitable for the desired effect. In particular ring's thickness and inner diameter D is alternatively varied to create corrugation with suited features.

One important issue that has to be addressed during the set-up of the transmission line is the connection between the different corrugated wave- guiding modules.

In WO 2012/076995 a possible solution has been introduced. Document WO 2012/076994, the content of which is incorporated by reference in its entirety in the present application, discloses a passive component for the transmission and manipulation of electromagnetic signals having frequencies from 30 GHz to 100 THz, wherein said component comprises a corrugated or smooth wall unit alone or an assembly of at least one corrugated or smooth wall unit in a hollow guiding rod, wherein the external shape of said unites) is adapted to the internal shape of the hollow guiding rod, and wherein said units or the entire assembly is metal plated to form the component. Specifically, the invention described in this prior art proposes to manufacture the waveguides from one or a plurality of passive components formed by pilling up successive layers of material to be used as such or possibly stacked together in a hollow guiding rod. Depending on the material used for the passive components, a metal plating may be necessary to 10 maintain the necessary surface reflection properties. In the case of sub-units piled up in a hollow guiding rod, the outer edge of the sub-units could be shaped with indentations or other equivalent means in order to reduce friction against the internal wall of the hollow guiding rod while still providing aligning properties.

DESCRIPTION OF THE INVENTION

It is an aim of the present invention to improve the connection means for sub- THz and THz wave-guiding modules, especially in so called transmission lines.

It is a further aim of the present invention to provide a connection means that is simple to use and allows for a proper alignment of the rings at module interfaces with no further adjustment.

In one embodiment, the invention concerns a connection system for connecting corrugated wave-guiding modules, wherein flanges comprise a corrugated structure and screws and/or dowels to prevent corrugated structure to fall outside the flange's inner guiding shape (6), wherein said flange is asexual and auto-aligning.

In one embodiment the flange preferably has an inner hollow shape that guides and aligns the corrugated elements during the assembly phase. The inner hollow shape of the flange and the outer shape of the corrugated structure may have continuous contact or a discrete number of contact points.

In one embodiment of the system, connected flanges may be attached together by external means.

In one embodiment the connection external means may comprise threaded collars combined with a threaded ring.

In one embodiment the system may be used with a bent structure in corrugated wave-guiding structures. In one embodiment the structure may comprises at least an insert, said insert being placed in the corrugated structure of the flange or of a transmission line for transmitting the waves.

In one embodiment, the insert may be a mirror, a sample holder or a sample itself.

In one embodiment the system may be used as a gas chamber, said flange comprising at least a gas inlet/outlet.

In one embodiment the system may comprise a modified corrugated structure with an interruption corresponding to said inlet/outlet.

In one embodiment the corrugated structure may be formed by a stack of rings or by a corrugated module/unit. The rings may have different inner sizes to form the corrugated structure as disclosed in WO 2012/076995. The corrugated units may be as described in WO 2012/076994 for example.

One embodiment of the present invention concerns a device comprising a system as described herein.

The device may be a corrugated waveguide, corrugated cavity, corrugated frequency filter, corrugated mode converter or corrugated horn antenna.

In one embodiment the connection system and the guiding tube are attached to each other, or are integral with each other.

One embodiment^' of the present invention concerns a method of connecting waveguides, such as corrugated waveguide, corrugated cavity, corrugated frequency filter, corrugated mode converter or corrugated horn antenna using at least a system as defined herein.

A further embodiment of the present invention concerns a method for irradiating an insert, wherein said insert is in the corrugated structure of the flange and/or in the guiding tube containing a corrugated structure.

The method may enable the propagation of a HEll electromagnetic mode, for irradiating an insert, wherein said insert is put across the signal propagation direction in the corrugated wave-guiding structures.

In the method, the insert maybe a mirror, or a sample or a sample holder carrying a sample.

In an embodiment, the invention concerns a transmission line comprising a, but not limited to, corrugated structure formed by a stack of rings or by a corrugated module, wherein said transmission line comprises an insert in said structure for irradiating said insert put across the signal propagation direction. The transmission line may be used for propagating an HEll electromagnetic mode.

In an embodiment of the transmission line, the insert may be a mirror, a sample holder carrying a sample or a sample itself.

In an embodiment of the line, the sample may be a dielectric or a biological sample or a sample of any material.

In one embodiment, the invention concerns a system or a device as defined herein in combination with a transmission line as described herein.

The present innovative technical solution proposes a flange allowing fast link and auto-aligning capabilities without introducing discontinuities in the corrugation profile between sub-THz and THz wave-guiding modules or units, the modules being possibly manufactured by stacking rings or by any other equivalent method for example as disclosed in WO 2012/076994.

Figure 1 illustrates in cut view typical corrugations used in the field of the invention;

Figure 2 illustrates perspective, front and side schematic views of an embodiment of the invention;

Figure 3 illustrates exploded and mounted schematic perspective views of an embodiment of the invention;

Figure 4 illustrates schematical side, cut and- perspective views of an embodiment between two flanges subject of the invention;

Figure 5 illustrates exploded, front and side cut schematic views of a partial embodiment of a variant of the invention;

Figure 6 illustrates schematic side, cut and perspective views of an embodiment of the invention;

Figure 7 illustrates perspective exploded, mounted schematic and cut views of an embodiment of the invention;

Figure 8 illustrates exploded and mounted schematic perspective views of an embodiment of the invention;

Figure 9 illustrates exploded and mounted schematic perspective views of an embodiment of the invention;

Figure 10 illustrates a cut view of an embodiment of the invention; Figure 11 illustrate another embodiment of the present invention. Contrary to the flange proposed in WO 2012/076995, the present flange 1, schematically illustrated in figure 2 (a possible variant, 29, is presented in fig 5, and another embodiment in figure 11] is asexual and allows the fast connection/disconnection and auto-aligning capabilities between two flanges integrating the design proposed by the invention.

The proposed flange also prevents rings, 5, from falling out of the flange's inner guiding shape 6, in the event the wave-guiding modules are manufactured by using stacked rings. This feature is allowed by the use of screws and/or dowels, 4. This feature may also be advantageously used if the corrugations are made in another way than by stacking rings in the flange, for example with barrels or modules/units as in WO 2012/076994.

A core idea may be summarized as follows:

The present invention proposes an asexual, auto-aligning, flange 1 hosting a corrugated section obtained either with stacked rings 5 or with corrugated barrels especially shaped for the purpose. The flange includes screws and/or dowels 4 to prevent rings to fall outside the flange's inner guiding shape 6.

The flanges preferably have an inner shape 6 that is used to guide and align rings 5 and/or corrugated barrels during the assembly phase. The hollow shape 6 of the flange having continuous or discrete number of contact points with the outer shape of the inserted rings 5 and/or the corrugated modules to ensure a proper alignment.

Figures from 3 to 11 represents several embodiments of the invention.

In the proposed embodiment of figure 3, the flanges 1 are screwed onto the straight guiding tubes 8 and are used to block the stacked rings 7 [or corrugated module) into the tubes 8 in the case stacked rings 7 are the solution of choice. Alternatively the flanges 1 may be glued, soldered, shrink-fitted, interference fitted, brazed, diffusion bonded, welded and/or fixed with screws to the corrugated waveguide sections 8. Any other equivalent method may be used, for example the flanges 1 may be integral with the guiding tube 8 and made from one piece of material.

The connection between two flanges 1 is achieved by compressing two proposed flanges 1 put face-to-face as illustrated in figure 4. The aim of the compression is to achieve proper contact and pressure between the two adjacent last rings or corrugated barrels of each flange. The flanges 1 are rotated with respect to each other by a defined angle. As an example, in the embodiment represented in the figures 3 and 4, this angle is 60 degrees.

The flange 1 have slots/grooves 2 used to host and align corresponding ridges 3 on the other flange to be connected with when both flanges are put face-to-face such as illustrated in the figure 4. Of course, depending on the construction and the shape of the face of the flange, other angles or geometries may be envisaged as exemplified in figures 5 or 11 where different embodiments are shown. In the embodiment represented in figure 5, the flanges 1 need to be rotated with respect to each other by 45 degrees to be connected face-to-face as in figure 11.

In a preferred embodiment screws and/or dowels 4 with flat heads block the rings 5 and/or corrugated module inserted in the flange 1. These screws and/or dowels 4, respectively the rings and/or the corrugated module 5, having a shape that allows the screws heads not to mechanically interfere with the rings and/or the corrugated module of the opposite flange when the flanges are put face-to- face.

Moreover as schematized in figure 5, the flange's inner shape 6, not only acts as a stopper for rings 5, and/or corrugated barrel but also it allows to compress the rings 5 and/or corrugated barrels stacked in the flange to compress the rings 7 and/or corrugated barrels stacked in the guiding tube 8 having inner shape 31 when the flange is mounted on the tube 8.

In order to compress the two flanges one against the other, one possible embodiment may use two threaded collars 9 screwed to a threaded ring 10 surrounding the two connected flanges as represented in figure 6. The ring 10 may be independent or form one piece with a collar 9.

The principle of the invention may also be employed for bends as illustrated in figure 7 representing one exemplary embodiment. Such bends, very often known as miter-bends, are commonly used for corrugated waveguides in the microwave regime.

Two straight waveguide segments 8 having at least one of the flanges according to the present invention 1 may be assembled to form an angle along the signal propagation path defined by the corrugation/ring 5 axes. This angle being 90 degrees in the figure 7. Of course other angles are possible and this is only an illustration of a possible embodiment.

For this purpose an ad hoc miter-bend 13 is needed. This miter-bend, known in the prior art, includes a flat mirror 14 or for particular purposes an ad hoc shaped mirror to eventually correct signal phase distortions. The mirror is used to bounce the signal that passes trough the waveguide segments connected to the bend from one waveguide aperture to the other.

With same mechanical principles detailed above for the flanges 1 assembled to the waveguide segments 8, a special flange 11 is proposed in order to perform a perfect and fast connection to bends. This flange 11 hosts rings 5 and/or corrugated barrels blocked by screws and/or dowels 4 in order to ensure a perfect suited alignment and corrugation continuity between waveguide segments and bends as described herein. The special flange 11 is embedded in the bend structure 13. The compression is guaranteed by screwing a threaded collar 9 on a threaded bend appendix 12 as represented in the preferred embodiment.

In other possible embodiments, permanent magnets 15 such as Neodymium based magnets and ferromagnetic elements 16 embedded in slots 2 and ridges 3, as illustrated in figure 8, may be employed to join the flanges face-to-face and guarantee the necessary compression.

In another use (see figure 8), the proposed flange can be used to host one or a plurality of inserts 17. The insert 17 being held in between rings 5 and/or corrugated barrels.

This is the case of mirrors represented by metalized dielectric sheets and/or polished metal sheet fitting the inner shape of the flange 6, for example, when corrugated waveguides 8 are used as the chamber of a resonant cavity. In such case, two mirrors 17, placed at the apertures of a corrugated waveguide section, are used to limit the resonant region where the THz signal bounces back and forward.

Another possible flange's embodiment is represented by the inclusion of an insert 17 used as a sample holder and/or as a sample itself. This possible embodiment is useful to measure dielectric proprieties of materials such as, but not limited to, dielectrics and biological samples or other solid, liquid and/or gaseous materials, irradiated with electromagnetic signals and so put across the signal propagation direction in the corrugated wave-guiding modules. In fact, the characterization of a sample can be performed in a straight transmission line irradiating the insert 17 and collecting the reflected signal and/or the transmitted signal at the transmission line extremities.

The sample holder 17 may have any suitable shape and comprise means to hold samples in solid, liquid and/or gaseous states. The sample holder may be used to hold any suitable sample.

This principle is of course is not limited to using the flange 1 and the insert 17 may be placed across the signal propagation direction in a transmission line propagating an HE11 electromagnetic mode such as but not limited to the guiding tube 8 which comprises a corrugated structure. Accordingly, for example, the sample with or without an insert may be placed in corrugated structure as disclosed in WO 2012/076995 and WO 2012/0769954 cited above or other suitable equivalent structures for propagating the waves.

Another preferred flange's embodiment is represented by the simultaneous use of corrugated waveguide sections 8 possibly realized by stacking rings 7 along with special flanges 24 and/or 25 able to be linked, possibly, via a threaded access 27 to the inner region of the corrugated waveguide, to a gas inlet 19. Due to flange's design including grooves 26 that can host joints, possibly O-rings 20, 20, sealed wave-guiding modules can be created. This embodiment is illustrated in figure 9. This embodiment can be used as a gas chamber for, but not limited to, gas spectroscopy and gas detection techniques involving the interaction between THz signals and gasses at study.

The gas inlet 19 is to be used alternatively to introduce the gas at study in the gas chamber realized in the waveguide inner volume and/or to purge the gas chamber.

Threaded collars 9 along with a threaded ring 21 adapted to the use of O-rings 20 is then used to fasten the special flange 25 one against each other or against a flange 24 comprising an adapted design 26 to host the O-ring 20 but not having the access 27 to the inner region of the corrugated waveguide.

To create the access to the inner region of the waveguide to purge and/or to fill the waveguide possibly with gasses, a series of rings 5 needs to be modified creating in correspondence of access 27 a discontinuity in the corrugation profile. To do so, modified rings 23 are possibly proposed to be stacked in the flange 25; the interruption of the ring profile being in correspondence with the access/hole 27 of the flange 25 as schematized in figure 10.

Figure 11 illustrates another embodiment of a flange 1 according to the present invention. Here, the screws 4 are mounted in ridges 3 that have a cylindrical shape which is intended to enter corresponding slots 2 when two flanges are connected in accordance with the principle of the present invention. In this embodiment, plates 30 are used to compress the stacked rings 5 or the module used to form the corrugations. This embodiment is used as the one of figure 5, with a 45° rotation between two flanges connected together, the ridges 3 penetrating in the slots 2. Also, it is possible to use the threaded collars 9 and rings 10 as disclosed in relation to figure 6 to attach two flanges 1 together. Of course, the elements of this embodiment may be used in other embodiments disclosed in the present application and the flange 1 may be attached by any suitable method to the tube 8 as disclosed herein or made integral with said tube 8.

The present description provides exemplary embodiments and is not intended to limit the scope, applicability, or configuration of the claims. Rather, the present description will provide those skilled in the art with an enabling description for implementing the described embodiments, it being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the appended claims.

In addition, the examples and values given above are only for illustrative purposes and should not be construed in a limiting manner. Different embodiments of the invention as described herein may be combined together according to circumstances. Moreover, other embodiments and applications may be envisaged for example by using equivalent means. In addition, the flange according to the invention may have different outer shapes, for example as illustrated (cylindrical) or square, rectangular, oval etc. Also two connected flanges may have the same outer shape or a different one. The choice may depend on the construction or circumstances.

The parts of the invention may be made in any suitable materials, for example metals, alloys and/or metalized supports. For example, such materials may include all metals such as, but not limited to, aluminum, stainless steel, titanium, copper or brass. Other non conducting materials may be used such as, but not limited to, various plastics or polymers like PEEK, vespel, Kel-F, epoxy plastics, glass fibers, polyester, Plexiglas, PTFE or any other ceramic or composite materials.

Claims

1. A connection system for connecting corrugated wave-guiding modules, wherein said flange (1) comprises a corrugated structure and screws and/or dowels (4) to prevent corrugated structure (5) to fall outside the flange's inner guiding shape (6), wherein said flange is asexual and auto-aligning.

2. The system of claim 1, wherein said flange (1] preferably has an inner hollow shape (6) that guides and aligns the corrugated structure during the assembly phase, wherein the inner hollow shape (6) of the flange and the outer shape of the corrugated structure have continuous contact or a discrete number of contact points.

3. The system as defined in one of the preceding claims, wherein connected flanges (1) are attached together by external means.

4. The system of claim 3, wherein said external means comprise threaded collars (9) combined with a threaded ring (10).

5. The system as defined in one of the preceding claims, wherein it is used with a bent structure (13) in corrugated wave-guiding structures.

6. The system as defined in one of the preceding claims, wherein it comprises at least an insert (17), said insert being put across the signal propagation direction in a wave-guiding structure (5; 8).

7. The system as defined in the preceding claims, wherein said insert is a mirror, a sample holder carrying a sample or a sample itself and wherein said sample is a dielectric or a biological sample or a sample of another solid, liquid and/or gaseous material.

8. The system as defined in one of the preceding claims, wherein it is used as a gas chamber, said flange comprising at least a gas inlet/outlet (19).

9. The system of the preceding claim, wherein it comprises a modified corrugated structure with an interruption corresponding to said inlet/outlet.

10. The system as defined in one of the preceding claims, wherein the corrugated structure is formed by a stack of rings (5) or by a corrugated module.

11. The system as defined in one of the preceding claims, wherein the connection system and the guiding tube are attached to each other, or are integral with each other.

12. A device comprising at least a system as defined in one of the preceding claims.

13. The device of the preceding claim, wherein said system is a corrugated waveguide, corrugated cavity, corrugated frequency filter, corrugated mode converter or corrugated horn antenna.

14. A method of connecting waveguides, such as corrugated waveguide, corrugated cavity, corrugated frequency filter, corrugated mode converter or corrugated horn antenna using at least a system as defined in one of claims 1 to 11 or a device as defined in one of claims 12 or 13.

15. A method using a system such as defined in one of claims 1 to 11 or a device as defined in one of claims 12 or 13 enabling the propagation of a HE11 electromagnetic mode, for irradiating an insert, wherein said insert is put across the signal propagation direction in the corrugated wave-guiding structures.

16. The method as defined in the preceding claim, wherein said insert is a mirror, or a sample or a sample holder carrying a sample.

17. A transmission line for propagating an HE11 electromagnetic mode such as but not limited to corrugated structure formed by a stack of rings (5) or by a corrugated module, wherein said transmission line comprises an insert in said structure for irradiating said insert put across the signal propagation direction.

18. The line as defined in claim 17, wherein said insert is a mirror, a sample holder carrying a sample or a sample itself.

19. The line as defined in claim 18, wherein said sample is dielectric or a biological sample or a sample of another solid, liquid and/or gaseous material.

20. The system as defined in one of the preceding claims 1 to 11, or a device as defined in one of claims 12 to 13, in combination with a line as defined in one of claims 17 to 19.