ANTENNA ARRANGEMENT FOR A FILL-LEVEL MEASURING DEVICE

• US 20160138957A1
• Filed: 06/04/2014
• Published: 05/19/2016
• Est. Priority Date: 07/03/2013
• Status: Active Grant

• Current Assignee: Endress+Hauser SE+Co. KG (Endress+Hauser AG)
• Original Assignee: Endress + Hauser GmbH + Company KG (Endress+Hauser AG)
• Inventors: Blodt, Thomas
• Granted Patent: US 10,224,597 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01F 23/284 Electromagnetic waves
• CPC Class Codes: H01Q 1/225 used in level-measurement devices, e.g. for level gauge measurement
• CPC Class Codes: H01Q 1/42 Housings not intimately mechanically associated with radiating elements, e.g. radome
• CPC Class Codes: H01Q 13/02 Waveguide horns
• CPC Class Codes: H01Q 15/08 formed of solid dielectric material
• CPC Class Codes: H01Q 19/062 for focusing

Abstract

Antenna arrangement for a fill-level measuring device for ascertaining and monitoring a fill level of a medium in a container by means of a microwave, travel-time measurement method, comprising a horn antenna having a horn shaped component (2) for focusing microwaves and a microwave transmissive, process isolating element (13), which is provided in the region of the exit opening (5) of the horn shaped component (2) facing the medium and which isolates the interior of the horn shaped component (2) from the interior of the container, wherein there is provided for additional focusing of the microwaves a lengthening component (15), which lengthens the horn shaped component (2) in the radiated direction (3) of the microwaves, wherein the process isolating element (13) is embodied and arranged in such a manner that it isolates the horn shaped component (2) and the lengthening component (15) galvanically from one another.

Claims

1. Antenna arrangement for a fill-level measuring device for ascertaining and monitoring a fill level of a medium in a container by means of a microwave, travel-time measurement method, comprising a horn antenna having a horn shaped component (2) for focusing microwaves and a microwave transmissive, process isolating element (13), which is provided in the region of the exit opening (5) of the horn shaped component (2) facing the medium and which isolates the interior of the horn shaped component (2) from the interior of the container, wherein there is provided for additional focusing of the microwaves a lengthening component (15), which lengthens the horn shaped component (2) in the radiated direction (3) of the microwaves, characterized in that the process isolating element (13) is embodied and arranged in such a manner that it isolates the horn shaped component (2) and the lengthening component (15) galvanically from one another.

2. Antenna arrangement as claimed in claim 1, wherein the horn antenna is at least partially arranged in a housing (23), wherein the lengthening component (15) has at least one securement component (22), and wherein the lengthening component (15) is secured to the housing (23) by means of the at least one securement component (22).

3. Antenna arrangement as claimed in claim 1, wherein the process isolating element (13) is essentially embodied disc shaped and dimensioned in the radial direction larger than the exit opening (5) of the horn shaped component (2).

4. Antenna arrangement as claimed in claim 1, wherein the process isolating element (13) is secured to the housing (23) in an edge region.

5. Antenna arrangement as claimed in claim 1, wherein there is associated with the at least one securement component (22) at least one electrically conducting, hollow cylinder, which surrounds the process isolating element (13) in the radial direction, so that microwaves, which escape in the radial direction from the edge region of the process isolating element (13), are reflected back approximately loss-freely.

6. Antenna arrangement as claimed in claim 1, wherein there is associated with the at least one securement component (22) at least one annular cavity resonator (29a,b), which surrounds the process isolating element (13) in the radial direction, and is so dimensioned that microwaves, which escape in the radial direction from the edge region of the process isolating element (13), are reflected back approximately loss-freely.

7. Antenna arrangement as claimed in claim 5, wherein the hollow cylinder or the cavity resonator (29a,b) is embodied in such a way that microwaves, which escape from the edge region of the process isolating element (13), after an integer multiple of the half wavelength, are reflected back on an inner wall of the hollow cylinder or of the cavity resonator (29a,b).

8. Antenna arrangement as claimed in claim 1, wherein the lengthening component (15) is embodied horn shaped in such a way that the lengthening component (15) aligns with the horn shaped component (2).

9. Antenna arrangement as claimed in claim 1, wherein the lengthening component (15) is embodied horn shaped and has an aperture angle, which corresponds approximately to an aperture angle of the horn shaped component (2), and the lengthening component (15) includes an entrance opening (14), which is less or greater than the exit opening (5) of the horn shaped component (2).

10. Antenna arrangement as claimed in claim 1, wherein the lengthening component (15) is embodied in the form of a hollow cylinder, wherein the lengthening component (15) has an entrance opening (7), whose diameter is less than the diameter of the lengthening component (15), wherein the lengthening component (15) is secured in the edge region of the entrance opening (7) to the edge region of the process element (13), so that the lengthening component (15) has a step in the radiated direction.

11. Antenna arrangement as claimed in claim 10, wherein the lengthening component (15) is dimensioned in such a way that a TM11 mode is produced with an annular region (25), in which the field strength is minimum, and wherein the annular region (25) has a diameter, which corresponds approximately to the diameter of the process isolating element (13).

12. Antenna arrangement as claimed in claim 10, wherein the lengthening component (15) has a length (27) of at least 8 times, preferably at least 16 times, the wavelength of the microwaves.

13. Antenna arrangement as claimed in claim 10, wherein the lengthening component (15) has a diameter (26) of at most three times the diameter of the process isolating element (13) and at least three times the diameter of the exit opening (5) of the horn shaped component (2).

14. Antenna arrangement as claimed in claim 10, wherein an exit opening (8) of the lengthening component (15) is embodied horn shaped for additional focusing of the microwaves or it has the shape of an exponential funnel (28).

15. Antenna arrangement as claimed in claim 1, wherein the process isolating element (13) includes a dielectric lens (18) for more extensive focusing of the microwaves.

16. Fill-level measuring device for ascertaining and monitoring a fill level of a medium in a container by means of a microwave, travel-time measurement method, comprising a measurement transmitter and an antenna arrangement (1) as claimed in claim 1.