U.S. patent application number 13/934329 was filed with the patent office on 2014-01-09 for gas-tight waveguide coupling, high-frequency module, fill-level radar and use.
The applicant listed for this patent is VEGA Grieshaber KG. Invention is credited to Daniel Schultheiss, Christian WEINZIERLE.
Application Number | 20140007674 13/934329 |
Document ID | / |
Family ID | 49877503 |
Filed Date | 2014-01-09 |
United States Patent
Application |
20140007674 |
Kind Code |
A1 |
WEINZIERLE; Christian ; et
al. |
January 9, 2014 |
GAS-TIGHT WAVEGUIDE COUPLING, HIGH-FREQUENCY MODULE, FILL-LEVEL
RADAR AND USE
Abstract
A gas-tight waveguide coupling is for coupling an
electromagnetic transmission signal from a high-frequency module
into a waveguide. The waveguide coupling includes a planar
radiator, which is arranged on a carrier and is used for emitting
the transmission signal. The waveguide coupling further includes a
dielectric sealing element, which seals off the waveguide in a
gas-tight manner. In this way, explosion protection can be
provided.
Inventors: |
WEINZIERLE; Christian;
(Wolfach, DE) ; Schultheiss; Daniel; (Hornberg,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VEGA Grieshaber KG |
Wolfach |
|
DE |
|
|
Family ID: |
49877503 |
Appl. No.: |
13/934329 |
Filed: |
July 3, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61668154 |
Jul 5, 2012 |
|
|
|
61668161 |
Jul 5, 2012 |
|
|
|
Current U.S.
Class: |
73/290V ;
333/24R |
Current CPC
Class: |
G01F 23/284 20130101;
H01Q 13/02 20130101; H01P 5/107 20130101; H01P 5/024 20130101; H01P
5/08 20130101 |
Class at
Publication: |
73/290.V ;
333/24.R |
International
Class: |
G01F 23/284 20060101
G01F023/284; H01P 5/08 20060101 H01P005/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 4, 2012 |
EP |
12 175 004.6 |
Jul 4, 2012 |
EP |
12 175 007.9 |
Claims
1. A gas-tight waveguide coupling for coupling an electromagnetic
signal from a high-frequency module into a waveguide, comprising: a
planar radiator element arranged on a carrier, the element
configured to emit the signal; a waveguide configured to transmit
the emitted signal; and a dielectric sealing element sealing off
the waveguide in a gas-tight manner.
2. The waveguide coupling according to claim 1, wherein the
dielectric sealing element is made from a circuit board.
3. The waveguide coupling according to claim 1, wherein the
dielectric sealing element is one of a cylindrical and a
rectangular plastics material part.
4. The waveguide coupling according to claim 1, wherein the
waveguide includes an internal, peripheral web on which the
dielectric sealing element is laid.
5. The waveguide coupling according to claim 1, wherein the
waveguide includes an external, peripheral web on which the carrier
is laid.
6. The waveguide coupling according to claim 1, wherein the
dielectric sealing element includes a stepped surface.
7. The waveguide coupling according to claim 1, wherein a region of
the sealing element in which the sealing element is connected to
the waveguide in the gas-tight manner includes a metal coating so
as to form a gas-tight soldered or adhesive connection to the
waveguide.
8. The waveguide coupling according to claim 1, wherein the
waveguide is configured for transmitting the emitted signal from a
volume defined by a start region of the waveguide along a volume
defined by a main region of the waveguide; wherein the planar
radiator element is one of (a) arranged in the start region and (b)
arranged immediately upstream from the start region; and wherein an
internal diameter of the start region in a transition region to the
main region is the same as an internal diameter of the main region,
and becomes larger towards the planar radiator element.
9. The waveguide coupling according to claim 8, wherein the
dielectric sealing element is arranged in the start region.
10. The waveguide coupling according to claim 8, wherein a diameter
of the planar radiator element is greater than the internal
diameter of the main region.
11. The waveguide coupling according to claim 1, further
comprising: a housing connected in a gas-tight manner to the
carrier.
12. The waveguide coupling according to claim 11, wherein the
waveguide is integrated into the housing and wherein the housing
and the waveguide are formed in one piece.
13. A high-frequency module for generating a measurement signal for
a fill-level measurement device, comprising: a waveguide coupling
according to claim 1.
14. A fill-level radar, comprising: a high-frequency module
according to claim 13.
15. Use of a waveguide coupling according to claim 1 in a field
device (700).
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of the filing date of EP
Patent Applications Serial Nos. 12 175 004.6 and 12 175 007.9, both
filed on 4 Jul. 2012 and U.S. Provisional Patent Application Ser.
Nos. 61/668,154 and 61/668,161, both filed on 5 Jul. 2012. The
disclosure of the above applications is hereby incorporated by
reference.
FIELD OF INVENTION
[0002] The present invention relates to fill-level measurement. In
particular, the invention relates to a gas-tight waveguide coupling
for coupling an electromagnetic signal from a high-frequency module
into a waveguide, to a high-frequency module comprising a gas-tight
waveguide coupling, to a fill-level radar comprising a
high-frequency module and to the use of a gas-tight waveguide
coupling in a field device.
BACKGROUND INFORMATION
[0003] Field devices, in particular field devices which are used
together with sensors to measure fill levels or boundary positions,
are often based on delay measurements. In delay measurements, the
signal delays of radar signals or guided microwave pulses are
determined. The desired measurement value is subsequently
determined from these signal delays.
[0004] The signals are of a particular frequency and duration. The
radar signals and the microwave signals can be allocated to the
high-frequency technology (HF technology) range. As signals which
are in the high-frequency range, signals in the frequency range up
to 2 GHz are generally used as guided microwave signals, and
signals in the range of 5 GHz to 79 GHz and above are used as radar
signals.
[0005] For safety reasons, it may be necessary for the electronics
of the field device to be separated from the measurement
environment (for example the inside of a container filled with a
filling medium) in an explosion-protected manner. The separation
consists for example of a gas-tight seal. This can prevent
explosive substances or gas mixtures from reaching the electronics
of the field device from the container interior and igniting
there.
[0006] EP 2 093 846 A1 discloses a gas-tight guide feed-through for
a field device, which can provide explosion protection of this
type. The guide feed-through is coaxial in form and is used for
example in a frequency range of between 5 and 28 GHz.
SUMMARY OF THE INVENTION
[0007] The present invention relates to a field device, having
explosion protection, which is suitable for transmission
frequencies of over 60 GHz.
[0008] In accordance with a first aspect of the invention, a
gas-tight waveguide coupling (also referred to as a waveguide
connection) for coupling an electromagnetic signal from a
high-frequency module into a waveguide is provided. In this
context, the electromagnetic signal is generated by the
high-frequency module, emitted by a planar radiator element of the
waveguide coupling, which is arranged on a carrier, and
subsequently transmitted by the waveguide.
[0009] The waveguide coupling comprises a dielectric sealing
element (111), which seals off the waveguide (104, 105) in a
gas-tight manner.
[0010] The main region of the waveguide is for example cylindrical
in form. However, it may also be a rectangular waveguide. For
example, the waveguide is of a constant internal diameter along the
main region.
[0011] The electromagnetic signal which is emitted by the planar
radiator element may also be referred to as a transmission signal.
The planar radiator element may also further be configured so as to
receive the reception signal, which is the reflected transmission
signal (in the case of a delay-based fill-level measurement device)
which has been reflected inter alia on the filling material
surface. The planar radiator element may also be in the form of an
array of a plurality of radiator elements.
[0012] The carrier is for example a circuit board.
[0013] The waveguide, which is configured so as to transmit the
emitted signals, can be connected to the carrier in a gas-tight
manner. The waveguide coupling further comprises a dielectric
sealing element, which seals the waveguide in a gas-tight manner in
the interior thereof. In other words, this sealing element
separates a front region of the waveguide, which is located in the
region of the planar radiator element, from a rear region of the
waveguide, which is located in the region of the probe end (or of
the waveguide), that is to say in the direction of the measurement
environment.
[0014] In accordance with a further embodiment of the invention,
the dielectric sealing element is made, for example milled, from a
circuit board.
[0015] In accordance with a further embodiment of the invention,
the dielectric sealing element is a cylindrical plastics material
part.
[0016] In accordance with a further embodiment of the invention,
the dielectric sealing element is a conical, pyramidal,
double-cone-shaped or double-pyramid-shaped plastics material part,
which further comprises a cylindrical region in which the sealing
element is connected to the waveguide in a gas-tight manner.
[0017] In accordance with a further embodiment of the invention,
the dielectric sealing element comprises a stepped surface.
[0018] In accordance with a further embodiment of the invention,
the region of the sealing element in which the sealing element is
connected to the waveguide in a gas-tight manner comprises a metal
coating, so as to form a gas-tight soldered or adhesive connection
to the waveguide. In the case of an adhesive connection to the
waveguide, the metal coating may still be provided (but does not
have to be). In particular, the adhesive itself may be
metallic.
[0019] In accordance with a further embodiment of the invention,
the dielectric sealing element comprises a secondary radiator,
which is attached to the sealing element or integrated into the
sealing element and which receives the signal emitted from the
planar radiator element and emits it again. The secondary radiator
may also receive the reflected reception signal and emit it in the
direction of the planar radiator element.
[0020] In accordance with a further embodiment of the invention,
the planar radiator element is arranged in or immediately upstream
from the start region of the waveguide, in such a way that the
emitted signal is initially located in the start region of the
waveguide and migrates in the direction of the main region of the
waveguide.
[0021] What is essential in this embodiment is that the start
region of the waveguide widens towards the planar radiator element.
In other words, in the transition region to the main region of the
waveguide (that is to say at the point where the start region and
main region meet), the internal diameter of the start region of the
waveguide is exactly the same as the internal diameter of the main
region, whilst the internal diameter of the start region becomes
larger towards the planar radiator element.
[0022] This means that the planar radiator element can have a
relatively large radiator surface and thus a relatively large
diameter. As a result, the quality of the signal can be
improved.
[0023] In the following, the terms "start region" and "main region"
of the waveguide are to be defined again. The start region of the
waveguide is located at the end of the waveguide in the region of
which the planar radiator element is located. This start region is
widened towards the planar radiator element and thus tapers in the
direction of the main region of the waveguide. In other words, the
internal diameter of the start region becomes continuously or
incrementally (discontinuously) smaller in the direction of the
main region. The minimum diameter of the start region is located at
the interface between the start region and the main region. At this
point, the internal diameters of the start region and the main
region are equal.
[0024] The main region of the waveguide is for example of a
constant internal diameter and extends from the interface between
the start region and the main region to the other end of the
waveguide.
[0025] For example, the main region is of a round or rectangular
internal cross-section.
[0026] The (transmission) signal, which is emitted by the planar
radiator element, migrates in the radiation direction of the planar
radiator element through the internal volume responsible for the
signal transportation, defined by the start region, and into the
main region of the waveguide, and subsequently continues towards
the waveguide end or waveguide output.
[0027] In accordance with one embodiment of the invention, the main
region of the waveguide is arranged at a distance from the planar
radiator element in the radiation direction of the signal. In other
words, the signal initially covers a particular distance inside the
start region of the waveguide before entering the main region of
the waveguide.
[0028] In accordance with a further embodiment of the invention,
the inside of the start region of the waveguide follows a conical
progression. In other words, the internal volume defined by the
start region of the waveguide is funnel-shaped.
[0029] In accordance with a further embodiment of the invention,
the inside of the start region follows a hyperbolic
progression.
[0030] In accordance with a further embodiment of the invention,
the inside of the start region follows a stepped progression.
[0031] In accordance with a further embodiment of the invention,
the internal diameter of the planar radiator element is greater
than the internal diameter of the cylindrical main region of the
waveguide.
[0032] In accordance with a further embodiment of the invention,
the diameter of the planar radiator element is less than half, or
even a third, of the maximum internal diameter of the start region
of the waveguide.
[0033] In accordance with a further embodiment of the invention,
the waveguide connection has a relative bandwidth of more than 5%,
for example even more than 8%, at the frequency of the signal of 79
GHz.
[0034] In accordance with a further embodiment of the invention,
the planar radiator element is a rectangular, round, elliptical or
triangular patch element, which is supplied by a microstrip
line.
[0035] In accordance with a further embodiment of the invention,
the waveguide comprises an internal, peripheral web on which the
dielectric sealing element is laid.
[0036] In accordance with a further embodiment of the invention,
the waveguide comprises an external, peripheral web on which the
carrier is laid.
[0037] In accordance with a further embodiment of the invention,
the dielectric sealing element is arranged in the start region of
the waveguide.
[0038] In accordance with a further aspect of the invention, a
high-frequency module for generating a measurement signal for a
field device, for example a fill-level measurement device, is
provided, the high-frequency module comprising a waveguide coupling
as disclosed above and in the following.
[0039] In accordance with a further aspect of the invention, a
fill-level radar comprising a high-frequency module as disclosed
above and in the following is provided.
[0040] In accordance with a further aspect of the invention, the
use of a waveguide coupling as disclosed above and in the following
in a field device is provided. The field device is for example a
fill-level measurement device which takes delay measurements so as
to determine the fill level therefrom. The signals used for this
purpose may be electromagnetic signals, such as microwave or radar
signals. In particular, these signals may be pulsed. However,
continuous signals may also be used.
[0041] A first central idea of the invention is that the waveguide
of a field device comprises an explosion protection, in that the
start region thereof (that is to say the region where the
transmission signal is coupled in) is sealed off in a gas-tight
manner from the measurement environment. This is achieved in that
it is connected in a gas-tight manner to the carrier material of
the planar radiator element (signal source), on the one hand, and
comprises a sealing part (sealing element) which is glued or
soldered into the interior region thereof, on the other hand.
[0042] A further aspect of the invention is that the transition
from the planar radiator element to the waveguide is widened
towards the planar radiator element, for example conically,
incrementally or hyperbolically.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] FIG. 1 is a cross-sectional drawing of a waveguide coupling
in accordance with one embodiment of the present invention.
[0044] FIG. 2 is a cross-sectional view of a waveguide coupling in
accordance with a further embodiment of the invention.
[0045] FIG. 3 is a cross-sectional view of a waveguide coupling in
accordance with a further embodiment of the invention.
[0046] FIG. 4 is a cross-sectional view of a waveguide coupling in
accordance with a further embodiment of the invention.
[0047] FIG. 5 shows a dielectric sealing element in accordance with
one embodiment of the invention.
[0048] FIG. 6 shows a dielectric sealing element in accordance with
a further embodiment of the invention.
[0049] FIG. 7 shows a fill-level measurement device in accordance
with one embodiment of the invention.
[0050] FIG. 8 shows four examples of planar radiator elements,
which can be used in a waveguide coupling in accordance with
embodiments of the invention.
[0051] FIG. 9 is a cross-sectional view of a waveguide coupling in
accordance with one embodiment of the invention.
[0052] FIG. 10 shows a waveguide coupling in accordance with one
embodiment of the invention.
[0053] FIG. 11 shows the inside of a housing and the carrier of a
waveguide coupling in accordance with one embodiment of the
invention.
[0054] FIG. 12 shows the inside of the housing of FIG. 11 and a
dielectric sealing element in accordance with one embodiment of the
invention.
DETAILED DESCRIPTION
[0055] The drawings are schematic and not to scale. If like
reference numerals are used in different drawings, they may denote
like or similar elements. However, like or similar elements may
also be denoted by different reference numerals.
[0056] FIG. 1 is a cross-sectional view of a waveguide coupling 100
in accordance with one embodiment of the invention. At this point,
it should be noted that the waveguide couplings shown in the
drawings are connected, by way of example, to the high-frequency
module. However, the high-frequency module may also be part of the
device 100, referred to here and in the following as a waveguide
coupling. In this case, the device 100 could also be referred to as
a high-frequency module comprising a waveguide coupling.
[0057] In particular, the waveguide coupling may be part of the
measuring probe. Alternatively, it comprises an interface in the
region of reference numeral 105, to which the continuing waveguide
of the measurement probe can be connected.
[0058] The waveguide coupling 100 comprises a housing 114 suitable
for high frequencies. This HF housing 114 comprises the waveguide
104, 105. In other words, the waveguide 104, 105 is integrated into
the HF housing.
[0059] Further, the housing may comprise side walls 106, 107 and a
rear wall 108, not least for reasons of stability, but also for
reasons of better sealing. The waveguide 104, 105 leads through the
rear wall 108 in the direction of the planar radiator element 102,
which is arranged on the underside of the carrier 101, that is to
say in the inside of the HF housing. On the upper side of the
carrier 101, there is a metal coating which can serve as an earth
plane.
[0060] The HF housing 114 may for example be made rotationally
symmetrical or rectangular. In the case of the rotationally
symmetrical configuration, two concentrically arranged,
rotationally symmetrical regions 106, 107 and 104, 105 are thus
provided.
[0061] The inner rotationally symmetrical region 104, 105 consists
of the start region 104 of the waveguide and the main region 105 of
the waveguide.
[0062] The two regions define a waveguide which is responsible for
transmitting the signals.
[0063] In the embodiment of FIG. 1, the interior of the start
region 104 is of a stepped shape (in this case with two steps;
however, there may also be more steps). The stepped inner surface
113 of the outer region 104 widens in the direction of the planar
radiator element 102 and tapers in the direction of the main region
105 of the waveguide. At the upper end of the main region 105 of
the waveguide, at the point where the main region meets the start
region, there is a sealing element 111, which consists for example
of dielectric material and is metal-coated (see reference numeral
112) at the point where it touches the inner wall of the waveguide
105.
[0064] In the embodiment of FIG. 1, this sealing element 111 is in
the form of a double cone, comprising a cylindrical region between
the two cones. The external surface of this cylindrical region is
metal-coated, in such a way that the sealing element can be
soldered or welded onto the inner wall of the main region 105 of
the waveguide.
[0065] The sealing element 111 may also be glued on.
[0066] There may be a cavity 109, 110 between the inner ring, which
is formed by the waveguide 104, 105, and the outer ring 106, 107 of
the housing.
[0067] The waveguide coupling 100 may be used as a waveguide
connection. In other words, a waveguide may be connected to the
lower region 105.
[0068] The waveguide connection 100 can be made gas-tight and can
be configured for use together with a microwave module involving
strip conductor technology in the frequency range of approximately
79 GHz. In particular, the waveguide connection is integrated into
the HF housing 114.
[0069] The carrier 101, which may be a circuit board, is connected
in a gas-tight manner to the HF housing 114. For example, the HF
housing is glued to the carrier.
[0070] In this way, the internal cavities 109, 104, 110 can be
sealed off from the environment in a gas-tight manner.
[0071] The sealing element disclosed above and in the following may
be a plastics material part, a ceramics part or a glass part. This
sealing element is glued or soldered into the main region of the
waveguide.
[0072] The transition from the signal-generating electronics to the
waveguide is provided by a microstrip line and a patch antenna
connected thereto, which forms the planar radiator element.
[0073] The widening of the waveguide towards the planar structure
is conical, hyperbolic or stepped. In particular, the waveguide and
the HF housing may be formed in a single piece.
[0074] This results in a simple and cost-effective mechanical
construction comprising few individual parts. The arrangement has
good high-frequency properties, with a low throughput attenuation
and a high reflection attenuation.
[0075] In the following, the microstrip-to-waveguide transition
will be disclosed by way of example.
[0076] A planar structure in the form of a planar radiator element
102 (for example a patch antenna) is attached to the circuit board,
and primarily emits orthogonally to the carrier plate 101. The
waveguide 104, 105, which is dimensioned in accordance with the
frequency range to be transmitted, is placed above this planar
structure. This waveguide is widened sufficiently towards the
circuit board that the waveguide walls are at a sufficient distance
from the planar structure for the influence on the transmission
signal from the walls to be reduced.
[0077] Other couplings into a waveguide require a high .di-elect
cons..sub.r of the circuit board material, in such a way that the
planar structure can be made small enough so as not to be disrupted
by the waveguide walls. However, a high .di-elect cons..sub.r can
result in a reduced relative bandwidth of the arrangement, which
may be for example between 1% and 3%. This can be a drawback for a
broadband radar system. "Relative bandwidth" is understood to mean
the ratio of the bandwidth to the central frequency of the
transmission signal.
[0078] As a result of the widening of the waveguide towards the
planar element, a circuit board substrate having a low .di-elect
cons..sub.r can be used, meaning that the relative bandwidth can be
raised to approximately 8%. In this case, .di-elect cons..sub.r is
for example between 1.8 and 3.5.
[0079] The planar element 102 may for example be a rectangular
patch element 1021, a round patch element 1022, an elliptical patch
element 1023 or a triangular patch element 1024 (see FIG. 8).
[0080] The patch element can be supplied by the supply line or
lines 801, 802 (microstrip lines) directly, via an adapter network
or indirectly (via an electromagnetic coupling). An example of
indirect supply is shown on the left of FIG. 8.
[0081] The widening of the waveguide towards the planar element may
be conical, incremental or hyperbolic.
[0082] FIG. 2 shows an example of hyperbolic widening, FIG. 3 shows
an example of an initially conical widening, followed by a
cylindrical region 121, the end of which is glued to the carrier
plate 101, and FIG. 4 shows an example of a completely cylindrical
widening 120.
[0083] FIG. 2 further shows that the diameter 125 of the radiator
element 102 is much less than the maximum diameter 124 of the start
region 104 of the waveguide. By contrast, the minimum internal
diameter 123 of the start region of the waveguide corresponds to
the internal diameter of the main region of the waveguide.
[0084] This applies to all of the embodiments.
[0085] In the following, the aspect of the gas-tight separation
(explosion protection) is disclosed in greater detail:
[0086] An HF module (or an electronic circuit in general) is
separated from the environment in a gas-tight manner for reasons of
explosion protection. A gas-tight separation may for example be
provided by encapsulating the electronics. However, in the
high-frequency field, and especially in microwave technology,
encapsulation has a major influence on the HF properties of the
circuit. For this reason, the HF housing 114 is glued tightly to
the carrier plate (for example a circuit board) in such a way that
there is air above the carrier plate 101. This assembly is then in
turn encapsulated. The HF signal is passed to the outside, for
example in the direction of the filling material, by means of a
gas-tight coupling through the housing and the encapsulation.
[0087] In particular in a frequency range of 60 GHz and above, a
gas-tight passage in a waveguide may be used. This passage is
achieved in that a dielectric sealing element 111 is glued into the
waveguide or initially metal-coated in part and subsequently
soldered in.
[0088] In this context, the dielectric 111 may take on a number of
forms. For example, it may be in the form of a planar disc of
circuit board material, which comprises a metal-coated edge rest
for the soldered connection to the waveguide. This is shown for
example in FIG. 4.
[0089] For this purpose, a round disc may be manufactured from a
circuit board substrate (for example HF substrates made of PTFE or
PTFE/ceramic mixtures, such as Rogers RT Duroid 5880, Rogers RO
3003 etc.). These discs thus comprise for example a metal-coated
edge which can be produced in the normal circuit board process.
[0090] Optionally, a secondary radiator can be applied to the disc
in the form of slits or metal-coated structures during the circuit
board manufacturing process.
[0091] The disc can be incorporated into either the cylindrical
part or the widened part of the waveguide.
[0092] At this point, it should be noted that in general the
sealing element 111 need not necessarily be arranged in the main
region 105, but may also be arranged in the widened region 104,
even though this is not shown in the drawings.
[0093] The dielectric sealing element may also be in the form of a
cylindrical plastics material part comprising a metal coating on
the periphery for the soldered connection to the waveguide (cf.
FIG. 6), and in particular it may be attached in the cylindrical
part (main region) of the waveguide in this case.
[0094] The sealing element may also be in the form of a
double-cone-shaped plastics material part comprising a cylindrical
neck and a metal coating on the periphery for the soldered
connection to the waveguide and may be configured for arrangement
in the cylindrical part (cf. FIGS. 1 and 2).
[0095] The sealing element may also be in the form of a stepped
cylindrical plastics material part comprising metal coating on the
periphery for the soldered connection to the waveguide (cf. FIG.
3).
[0096] FIG. 2 shows the configuration of the sealing element as a
double cylinder (similarly to FIG. 1), but with the intermediate
region between the two cylinders being of a greater diameter than
the cylinder base (by contrast with FIG. 1, in which the diameters
are equal).
[0097] FIG. 5 and FIG. 6 show two examples of a dielectric sealing
element 111. In the case of FIG. 5, the dielectric sealing element
comprises an annular metal coating 112 on the upper side and/or
underside thereof. A coating 112 of this type can also be seen for
example in FIGS. 2 and 4.
[0098] In the embodiment of FIG. 6, the sealing element 111
comprises a peripheral coating 112 on the peripheral face thereof,
as is also provided in the embodiments of FIGS. 1 and 3.
[0099] The sealing elements 111 may further comprise a secondary
radiator 121, which is located on the upper side (as in FIG. 6)
and/or on the underside or in the interior of the sealing element
111. The secondary radiator serves to be supplied by the planar
radiator element 102. This takes place in that the planar radiator
element 102 emits the signal, which is supplied to the secondary
radiator, which thereupon emits a corresponding signal into the
main region of the waveguide 104.
[0100] FIG. 7 shows a fill-level measurement device 700, which
comprises a high-frequency module 701. The high-frequency module
701 generates the transmission signal, which is subsequently
supplied to the waveguide 104, 105.
[0101] FIG. 9 is a cross-sectional view of a waveguide coupling 100
in accordance with one embodiment of the invention. In this
embodiment, the sealing element 111 is positioned in the widened
start region 104 of the waveguide 104, 105. Furthermore, the
sealing element 111 can also be arranged in the start region 104 in
the embodiments of FIGS. 1 to 4.
[0102] The sealing element is for example a separator plate made of
circuit board material. The sealing element may be of a thickness
of at least 0.5 mm and may be made of Rogers RO 5880 circuit board
material.
[0103] The separator plate may be rectangular or square in form.
This is expedient in particular if the start region 104 of the
waveguide is also of a rectangular or square cross-section.
Alternatively, the sealing element 111 may also be of a round
cross-section, for example if the cross-section of the start region
104 is also round (circular).
[0104] The cross-section of the main region 105 of the waveguide
may also be round. This can be seen for example in FIGS. 10 and
12.
[0105] The distance between the sealing element 111 and the carrier
101 comprising the planar radiator element (not shown in FIG. 9) is
for example 0.2 to 0.3 mm, but may also be more or less. The
thickness of the sealing element is for example approximately 0.5
mm.
[0106] The carrier 101, which is formed as a circuit board, can be
glued and/or soldered onto the housing 114. Soldered connections
may for example be provided at the regions 1030, 1031, 1032 and
1033 shown in black.
[0107] The soldered connections may also be used for electrical
contact between the housing and the carrier 101.
[0108] As can be seen in FIG. 9, the diameter or the maximum edge
length of the sealing element 111 is greater than the internal
diameter of the main region 105 of the waveguide. The diameter or
the maximum edge length of the radiator element corresponds
approximately for example to the internal diameter of the main
region 105 of the waveguide.
[0109] As can also be seen from FIG. 10, the housing 114 is of a
substantially rectangular construction. To increase the stability,
the housing may comprise a thickening 1001 around the waveguide.
The waveguide may also similarly have a thickening 1002, which may
be provided with a thread (cf. FIG. 10), at the point where said
waveguide exits the housing or the housing thickening.
[0110] Subsequently, the waveguide 105 continues at a reduced
external diameter 1003. By contrast, the internal diameter of the
main region of the waveguide is constant.
[0111] Where the starting region 104 of the waveguide transitions
into the main region 105 of the waveguide, the waveguide comprises
an internal, peripheral web 1004, on which the dielectric sealing
element 111 is laid. Further, an external, peripheral web 1005 is
provided which is arranged at the end of the waveguide, that is to
say at the start of the start region 104 of the waveguide, and is
placed on the carrier 101. Between these two webs 1004 and 1005
there is a depression 1011, where the sealing element 111 can be
soldered and/or glued to the housing.
[0112] Webs 1005, 1006, 1007 on which the carrier 101 is laid are
also provided alongside the other soldered or glued regions 1030,
1031, 1032, 1033.
[0113] The housing may further comprise tabs or pins 1008, 1009
which are passed through corresponding holes in the carrier 101 so
as to position the carrier.
[0114] FIG. 10 is a perspective view of a waveguide coupling 100 in
accordance with one embodiment of the invention. By contrast with
the embodiment of FIG. 9, in this case an external thread is
provided in the region 1002 of the waveguide, so as to screw the
waveguide coupling into a container flange. Otherwise, the two
embodiments are identical.
[0115] The external thread can also be used so as to screw on a
connection waveguide which continues, that is to say is attached
to, the main region 105 of the waveguide of the coupling.
[0116] It can be seen from FIG. 10 that the thickening 1001 is
largely circular.
[0117] FIG. 11 shows the inside of the housing 114 and the
underside of the carrier 101, that is to say the side facing the
inside of the housing.
[0118] In particular the planar radiator element 1021, which in
this embodiment is rectangular in form, is arranged on the carrier.
The longer longitudinal side of the planar radiator element 1021 is
of an edge length which substantially corresponds to the internal
diameter of the main region of the waveguide.
[0119] It can be seen in particular from FIG. 11 that the external,
peripheral web 1005 is square in form.
[0120] FIG. 12 is a further drawing of the housing of FIG. 11 and
of a sealing element 111. It can be seen from FIG. 12 that the
internal, peripheral web 1004 is circular in form and is arranged
concentric with the external web 1005. The sealing element 111 is
square in form and is adapted to the size of the external web 1005,
in such a way that it can be placed on the lower, internal
peripheral web 1004.
[0121] At this point, it should be noted that the external,
peripheral web 1005 need not be continuous, but may comprise an
interruption through which the supply line 801 (cf. FIG. 11) to the
planar radiator element is passed.
[0122] For completeness, it should be noted that "comprising" and
"having" do not exclude the possibility of other elements or steps,
and "an" or "a" does not exclude the possibility of a plurality. It
should further be noted that features or steps which have been
disclosed with reference to one of the above embodiments may also
be used in combination with other features or steps of other
above-disclosed embodiments. Reference numerals in the claims
should not be treated as limiting.
* * * * *