EP4181313B1 - High frequency adapter for connecting a radio frequency antenna to an antenna connector - Google Patents

Description

Field of invention

The invention relates to a high-frequency adapter for connecting a high-frequency antenna to an antenna plug. The invention further relates to a use of the high-frequency adapter and a method for producing a high-frequency adapter.

background

In high-frequency technology, especially in radar technology, electromagnetic energy, for example from a high-frequency generator, is conducted to a high-frequency antenna, for example a horn antenna, in order to be able to emit and/or receive high-frequency waves. This can be achieved using a high-frequency adapter. In at least some cases, the high-frequency waves are conducted from the antenna to the adapter via a waveguide. For example, in this way, moisture can get into the high-frequency adapter and lead to a disruption in the function of the adapter, e.g. to a short circuit of conductive parts.

The publication CN 103 268 971 A relates to a device for connecting a coaxial cable to a circular waveguide.

The publication JP H02 128 503 A relates to a coaxial intermediate piece between an outer conductor connected to a waveguide and an antenna section.

The publication DE 31 27 693 A1 16 relates to a transition element between a waveguide and a microstrip line.

Summary

It is the object of the invention to reduce the penetration of moisture into fault-prone parts of a high-frequency adapter. This task is carried out by the subject of the independent patent claims solved. Further developments of the invention result from the subclaims and the following description.

• ein Impedanz-Anpassungselement, das innerhalb des Hohlleiters angeordnet ist und das zu einer Impedanz-Anpassung an die Hochfrequenzantenne eingerichtet ist;
• einen leitfähigen Innenleiter, der elektrisch und mechanisch mit dem Impedanz-Anpassungselement verbunden ist, wobei der Innenleiter elektrisch direkt oder indirekt mit dem Antennenstecker verbunden ist;
• ein einen leitfähigen (insbesondere hohlzylindrischen) Mantel, der an den Hohlleiter anschließt; und
• ein elektrisch isolierendes hohlzylindrisches Abstandselement, das zwischen dem Mantel und dem Innenleiter angeordnet ist und so den Innenleiter von dem Mantel isoliert und den Hohlleiter fluiddicht abschließt.

One aspect relates to a high-frequency adapter (adapter for short) for connecting a high-frequency antenna to an antenna plug. The high-frequency adapter has: a (in particular hollow cylindrical) waveguide, which is set up to transmit high-frequency waves from and to the high-frequency antenna;

• an impedance matching element, which is arranged within the waveguide and which is set up to match the impedance to the high-frequency antenna;
• a conductive inner conductor electrically and mechanically connected to the impedance matching element, the inner conductor being electrically connected directly or indirectly to the antenna connector;
• a a conductive (in particular hollow cylindrical) jacket that connects to the waveguide; and
• an electrically insulating hollow cylindrical spacer element which is arranged between the jacket and the inner conductor and thus isolates the inner conductor from the jacket and seals the waveguide in a fluid-tight manner.

The high-frequency adapter can be set up in particular to transmit high-frequency waves in a range of radar waves. At least some specifics of the adapter can, for example, be set up for a part of the radar frequency range, e.g. for the so-called K-band, which extends over a frequency range of 18 to 27 GHz.

At least some of these specifics can also be adaptable to other frequency ranges of the radar frequency range - for example through minor modifications. The adapter can be connected on one side, for example, to a horn antenna and/or another high-frequency antenna. The adapter can be connected on another side, for example to an antenna connector in the form of a coaxial connector. The high-frequency waves can be transmitted or forwarded to the antenna using a waveguide, which can have a hollow cylindrical shape. The antenna can be arranged in an environment that can contain moisture in at least some cases.

In at least some cases, the high-frequency waves are conducted from the antenna to the adapter via a waveguide. For at least some frequency ranges, an impedance matching element can be arranged within the waveguide, which is set up to match the impedance to the high-frequency antenna. The impedances at the two ends of the adapter can differ from each other: In the coaxial area, for example, the impedance can be around 50 - 75 ohms, and in the area of the waveguide, the impedance can be in the range of around 700 ohms, for example. For lower-frequency radar bands, e.g. for the K-band, the impedance matching element can, for example, be designed in a step-shaped manner and significantly narrower than an inner diameter of the waveguide. The impedance matching element designed in this way is sometimes referred to as a fin. The impedance matching element can have a different shape for other frequency ranges. In order to realize the adaptation and/or radiation, the impedance matching element can have electrical contact with the outer conductor of the coaxial system at at least one point in the area of the transition between the coaxial and waveguide system and on the base surface of the fin.

The impedance matching element is electrically and mechanically connected to a conductive inner conductor. The inner conductor can be electrically connectable directly or indirectly to the antenna plug. In the case of a direct connection, the inner conductor can be guided to the end of the adapter that is opposite the antenna connection, so that in this case the antenna plug can be plugged onto this end of the inner conductor. In the case of an indirect connection, at least one further conductive component can be arranged on the inner conductor. The inner conductor extends along a central axis of the waveguide.

The high-frequency adapter also has a conductive hollow cylindrical jacket that connects to the waveguide. The jacket can connect seamlessly and/or tightly to the waveguide. The jacket can have a different material than the waveguide; For example, the jacket can have or consist of stainless steel, the waveguide can have or consist of copper. Both the waveguide and the jacket can advantageously be conductive in order to ensure electrical shielding and/or contribute to a defined impedance of the adapter. The jacket can be arranged parallel to the central axis of the waveguide.

The high-frequency adapter also has an electrically insulating hollow cylindrical spacer element which is arranged between the jacket and the inner conductor, and which thus isolates the inner conductor from the jacket and seals the waveguide in a fluid-tight manner.

In a variation, the waveguide and/or the jacket can have a rectangular, in particular square, shape. The rectangular shape can affect the outer contour and/or the inner walls. The inner and/or outer corners can be rounded.

With this design, in particular due to the spacer element, the high-frequency adapter not only has a defined impedance in the area of the coaxial system, but is also robust against diffused and then condensing moisture because the spacer element reduces or even prevents moisture from penetrating into fault-prone parts of a high-frequency adapter can prevent, and in particular can prevent a short circuit between the jacket and the inner conductor. A possible condensation point can therefore be moved to an area that is less sensitive to high-frequency waves. In addition, the spacer element can simplify the assembly of the high-frequency adapter, e.g. serve as an insertion aid during assembly and thereby contribute to preventing incorrect assembly. Furthermore, the adapter has proven to be particularly robust in experiments, especially with regard to vibrations, and has increased longevity, for example due to the additional support of the inner conductor of the coaxial system.

A first inside diameter of the jacket is smaller than a second inside diameter of the waveguide, so that a step is formed in the area of the connection between the waveguide and the jacket. In addition, the spacer element is at least partially arranged in the waveguide and forms a collar in the waveguide. This can lead to better mechanical cohesion of the adapter as well contribute to a better seal against diffused moisture. In addition, this collar can prevent condensate from accumulating in the cavity.

In some embodiments, the spacer element has or consists of materials such as polytetrafluoroethylene, PTFE, polyetheretherketone, PEEK, polyethylene, PE, or polyvinylidene fluoride, PVDF, which are suitable for HF technology. These materials not only have dielectric properties, but also a certain toughness and elasticity, so that the spacer element nestles particularly tightly between the adjacent components of the adapter and in this way fills the technically necessary gap between the fin and the coaxial feed. The hole for the inner conductor also creates a guide for assembly in production, to which the relatively low friction - also during assembly - can contribute. In addition, at least some of the usable materials can be temperature-resistant and/or hydrophobic.

In one embodiment, the spacer element can be realized as a plastic turned part. PTFE, for example, can be used as a plastic. This type of production allows the spacer element to be manufactured particularly precisely.

In some embodiments, the radio frequency adapter further comprises a process isolation disposed within the jacket and through which a conductive element is passed that is electrically connected to the inner conductor. The process separation can be designed, for example, as a glass feedthrough. It should be noted that - thanks to the spacer element - moisture can no longer condense on the process separation, in particular because the spacer element creates a seal against the waveguide and other parts of the adapter.

In one embodiment, the conductive element is designed in one piece with the inner conductor. This can contribute to particularly simple production. This embodiment can be implemented with and without process separation.

In one embodiment, the conductive element has a similar coefficient of expansion as the process separation. As a result, the conductive element remains advantageously arranged in the process separation in a robust and long-term manner, even in the event of large fluctuations in temperature.

In some embodiments, the process separation comprises glass and/or ceramic, and/or the conductive element comprises a nickel alloy, or these elements may be made of these materials.

In one embodiment, the conductive element is set up for direct connection to the antenna plug. The conductive element can be designed to be particularly robust and/or have a particularly conductive and/or corrosion-resistant coating at the connection points, such as gold.

• anordnen eines elektrisch isolierenden hohlzylindrischen Abstandselements in einem leitfähigen hohlzylindrischen Mantel; und
• einfügen eines leitfähigen Innenleiters in das Abstandselement; und
• anschließen eines Hohlleiters mit einem Impedanz-Anpassungselement, das innerhalb des Hohlleiters angeordnet ist, beispielsweise durch Einpressen in eine vorhandene Bohrung in dem Impedanz-Anpassungselement.

One aspect relates to a method for producing a high-frequency adapter, with the steps:

• arranging an electrically insulating hollow cylindrical spacer element in a conductive hollow cylindrical jacket; and
• inserting a conductive inner conductor into the spacer element; and
• connecting a waveguide with an impedance matching element which is arranged within the waveguide, for example by pressing into an existing hole in the impedance matching element.

The spacer element can serve particularly advantageously as an insertion aid during assembly and thereby contribute to preventing incorrect assembly.

In some embodiments, the method includes the further step:
arranging a process separation in the jacket, wherein a conductive element is guided through the process separation and is set up for an electrical connection to the inner conductor.

One aspect relates to the use of a high-frequency adapter as described above and/or below for connecting a high-frequency antenna to an antenna plug. The high-frequency adapter can be particularly suitable for level measurement, topology determination and/or limit level determination, because it can be used, for example, to implement a feedthrough between an antenna in a container and a high-frequency generator outside the container. Due to the robust design of the high-frequency adapter, the container can also be a process tank, for example, which is designed in particular for high temperatures and/or pressures. In addition, embodiments with process separation can further increase the robustness of the high-frequency adapter.

For further clarification, the invention is described using the embodiments shown in the figures. These embodiments are only to be understood as an example and not as a limitation.

Short description of the characters

Fig. 1

schematisch einen Hochfrequenzadapter gemäß dem Stand der Technik in einem Längsschnitt;

Fig. 2

schematisch einen Hochfrequenzadapter gemäß einer Ausführungsform in einem Längsschnitt;

Fig. 3

schematisch einen Hochfrequenzadapter gemäß einer Ausführungsform in einem weiteren Längsschnitt;

Fig. 4

schematisch einen Hochfrequenzadapter gemäß einer Ausführungsform in einer perspektivischen Außenansicht;

Fig. 5

schematisch einen Hochfrequenzadapter gemäß einer weiteren Ausführungsform in einem Längsschnitt;

Fig. 6

ein Flussdiagramm mit einem Verfahren gemäß einer Ausführungsform.

This shows:

Fig. 1

schematically a high-frequency adapter according to the prior art in a longitudinal section;

Fig. 2

schematically a high-frequency adapter according to one embodiment in a longitudinal section;

Fig. 3

schematically a high-frequency adapter according to one embodiment in a further longitudinal section;

Fig. 4

schematically a high-frequency adapter according to one embodiment in a perspective external view;

Fig. 5

schematically a high-frequency adapter according to a further embodiment in a longitudinal section;

Fig. 6

a flowchart with a method according to an embodiment.

Detailed Description of Embodiments

Fig. 1 shows schematically a high-frequency adapter 12 according to the prior art in a longitudinal section. The high-frequency adapter 12 has a hollow cylindrical waveguide 20, which is set up to transmit high-frequency waves from and to a high-frequency antenna 80 (not shown). A conductive jacket 50 adjoins the waveguide 20. A conductive inner conductor 40 is arranged at least partially within the jacket 50 and is electrically and mechanically connected to an impedance matching element 30. The inner conductor 40 is separated from the jacket 50 by a cavity 18. The cavity 18 can be designed as a rotationally symmetrical cavity, for example in the case of a round high-frequency adapter; For other shapes of the high-frequency adapter - e.g. rectangular, hexagonal, etc. - adapted accordingly or also cylindrical. In at least some cases, moisture can penetrate into the cavity 18. This can significantly worsen the functionality of the high-frequency adapter, even causing the adapter to fail.

Fig. 2 schematically shows a high-frequency adapter 10 according to one embodiment in a longitudinal section. The high-frequency adapter 10 is set up to connect a high-frequency antenna 80 (left side, not shown) with an antenna plug 90 (right side, not shown). The high-frequency adapter 10 has a hollow cylindrical waveguide 20, which is set up to transmit high-frequency waves from and to the high-frequency antenna 80 - which is arranged to the left of the waveguide 20. A step-shaped impedance matching element 30 is arranged within the waveguide 20 and is set up to match the impedance to the high-frequency antenna 80. The high-frequency adapter 10 also has a conductive inner conductor 40, which is electrically and mechanically connected to the impedance matching element 30, the inner conductor 40 being connected electrically indirectly - namely via a conductive element 45 - to the antenna plug 90. A conductive hollow cylindrical jacket 50 adjoins the waveguide 20. The joint between the waveguide 20 and the jacket 50 can be tight, but in at least some cases it can also be faulty and / or due to long-term Loads allow moisture to penetrate. In at least some embodiments, the joint can be dispensed with. The high-frequency adapter 10 also has an electrically insulating hollow cylindrical spacer element 60, which is arranged between the jacket 50 and the inner conductor 40 and thus isolates the inner conductor 40 from the jacket 50 and seals the waveguide 20 in a fluid-tight manner. In at least some embodiments that do not fall within the scope of the claims, the spacer 60 may also not be designed to be fluid-tight. The spacer element 60 can be designed so that it "occupies" the space where condensate could form and in this way can displace the condensate or reduce or prevent the formation of condensate. In this way, a malfunction of the high-frequency adapter 10 can advantageously be avoided even in the event of moisture penetration. The high-frequency adapter 10 also has a process separation 70 to further increase the robustness of the high-frequency adapter. The conductive element 45 is guided through the process separation 70. The conductive element 45 is electrically connected to the inner conductor 40 on one side. On the other hand, the conductive element 45 is set up for a connection to an antenna plug 90 (right side, not shown), via the end protruding from the process separation 70 and from a casing 55 on the right.

Fig. 3 shows schematically a high-frequency adapter 10 according to one embodiment in a further longitudinal section. The same reference numbers as in Fig. 2 same or similar elements. This shows Fig. 3 It is particularly clear how the spacer element 60 isolates the inner conductor 40 from the jacket 50 and - with the cooperation of a collar 62 - also creates a seal against the wall 50. In this exemplary embodiment, the conductive element 45 is realized with pointed ends in order to further simplify assembly.

Fig. 4 schematically shows a high-frequency adapter 10 according to one embodiment in a perspective external view. The same reference numbers as in Fig. 2 same or similar elements. In particular, the design of the impedance matching element 30 becomes clear, which in this exemplary embodiment is designed to be step-shaped and significantly narrower than an inner diameter of the waveguide. This way designed impedance matching element 30 is sometimes referred to as a fin. This design can be particularly suitable for lower-frequency radar bands, for example for the K-band. For other frequency ranges, the impedance matching element - and/or other components of the high-frequency adapter 10 - can be designed at least slightly differently.

Fig. 5 shows schematically a high-frequency adapter 10 according to a further embodiment in a longitudinal section. The same reference numbers as in Fig. 2 same or similar elements. This embodiment does not have a process separation 70. Furthermore, the conductive element 45 is designed in one piece with the inner conductor (40), so that an antenna plug 90 (right, not shown) is electrically connected directly to the antenna plug 90. Furthermore, it is clear that a first inner diameter 52 of the jacket 50 (such as in Fig. 2 ) is smaller than a second inner diameter 22 of the waveguide 20, so that a step 25 is formed in the area of the connection between the waveguide and the jacket.

Fig. 6 shows a flowchart 100 with a manufacturing process for a high-frequency adapter 10 (see e.g Fig. 2 to Fig. 5 ) according to one embodiment. In an optional step 102, a process separation 70 is arranged in the jacket 50, with a conductive element 45 being guided through the process separation 70, which is set up for an electrical connection to the inner conductor 40. In a step 104, an electrically insulating spacer element 60 is arranged in a conductive jacket 50. In a step 106, a conductive inner conductor 40 is inserted into the spacer element 60. In a step 108, a waveguide 20 is connected, with an impedance matching element 30 which is arranged within the waveguide 20.

List of reference symbols

10

High frequency adapter

12

High frequency adapter

15

Central axis

18

cavity

20

Waveguide

22

Inner diameter of the waveguide

25

Level

30

Impedance matching element

40

Interior conductor

45

conductive element

50

Coat

52

Inside diameter of the jacket

55

Sheathing

60

Spacer element

62

Collar of the spacer element

70

Process separation

80

antenna

90

Antenna connector

100

flow chart

102 - 108

steps

Claims (10)

1. A radio frequency adapter (10) for connecting a radio frequency antenna (80) to an antenna connector (90), the radio frequency adapter (10) comprising:

   a waveguide (20) which is arranged to transmit radio frequency waves from and to the radio frequency antenna (80);

   an impedance matching element (30), which is arranged within the waveguide (20) and which is configured for impedance matching to the radio frequency antenna (80);

   a conductive inner conductor (40) which is electrically and mechanically connected to the impedance matching element (30), wherein the inner conductor (40) can be electrically connected directly or indirectly to the antenna connector (90), wherein the inner conductor (40) extends along a central axis (15) of the waveguide (20);

   a conductive sheath (50) adjacent to the waveguide (20); and

   an electrically insulating spacer element (60), which is arranged between the sheath (50) and the inner conductor (40) and thus insulates the inner conductor (40) from the sheath (50) and seals the waveguide (20) in a fluid-tight manner,

   wherein a first internal diameter of the sheath (50) is smaller than a second internal diameter of the waveguide (20), so that a step is formed in the region of the connection between the waveguide (20) and the sheath (50), and

   wherein the spacer element (60) is arranged at least partially in the waveguide (20) and

   characterized in that

   the spacer element (60) forms a collar (62) in the waveguide (20).
2. The radio frequency adapter (10) according to claim 1,
   wherein the spacer element (60) comprises or consists of polytetrafluoroethylene, PTFE, polyether ether ketone, PEEK, polyethylene, PE, or polyvinylidene fluoride, PVDF.
3. The radio frequency adapter (10) according to any one of the preceding claims, further comprising:

   a conductive element (45); and

   a process isolator (70) arranged inside the sheath (50) and passing through the conductive element (45), which is electrically connected to the inner conductor (40).
4. The radio frequency adapter (10) according to claim 3,
   wherein the conductive element (45) is made in one piece with the inner conductor (40).
5. The radio frequency adapter (10) according to claim 3 or 4,
   wherein the conductive element (45) has a coefficient of expansion similar to that of the process separation (70).
6. The radio frequency adapter (10) according to any one of claims 4 or 5, wherein the process separation (70) comprises or consists of glass and/or ceramic, and/or the conductive element (45) comprises or consists of a nickel alloy.
7. The radio frequency adapter (10) according to any one of claims 3 to 6, wherein the conductive element (45) is arranged for a direct connection to the antenna connector (90).
8. A method of manufacturing a radio frequency adapter (10), comprising the steps of:

   arranging an electrically insulating hollow cylindrical spacer element (60) in a conductive hollow cylindrical sheath (50);

   inserting a conductive inner conductor (40) into the spacer element (60);

   connecting a waveguide (20) with an impedance matching element (30) arranged inside the waveguide (20), wherein the inner conductor (40) extends along a central axis (15) of the waveguide (20),

   wherein a first internal diameter of the sheath (50) is smaller than a second internal diameter of the waveguide (20), so that a step is formed in the region of the connection between the waveguide (20) and the sheath (50), and

   wherein the spacer element (60) is arranged at least partially in the waveguide (20), and

   characterized in that

   the spacer element (60) forms a collar (62) in the waveguide (20).
9. Method according to claim 8, with the further step:
   arranging a process separation (70) in the sheath (50), wherein a conductive element (45) is guided through the process separation (70), which is configured for an electrical connection to the inner conductor (40).
10. Use of a radio frequency adapter (10) according to any one of claims 1 to 7 for connecting a radio frequency antenna (80) to an antenna connector (90).

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