Measuring device with cylindrical monopole antenna

Abstract

The invention relates to a measuring device, designed as a level measuring device, pressure measuring device, temperature measuring device or flow measuring device for process automation in an industrial or private setting, comprising a sensor unit for detecting level measurement data, pressure measurement data, temperature measurement data or flow measurement data, and a cylindrical monopole antenna for transmitting the measurement data to an external receiver. Batteries and one or more circuit boards are arranged inside the monopole antenna.

Description

[0001]VEGA GRIESHABER KG Our reference: V10916WO / CGS ----------------------------------------------------------------------------------------------------- VEGA Grieshaber KG Hauptstraße 5, 77709 Wolfach, Germany ------------------------------------------------------------------------------------------------------ Measuring device with cylindrical monopole antenna ------------------------------------------------------------------------------------------------------ Reference to related applications The present application claims priority to German patent application No. 102023206601.7, filed on July 12, 2023, which is incorporated in its entirety by reference into the present document. Field of the invention The present invention relates to measuring instrument technology in industrial and private environments.In particular, the present invention relates to a measuring device with a cylindrical monopole antenna, a cylindrical monopole antenna and the use of a cylindrical monopole antenna in a measuring device. Technical background In measuring devices for process automation in industrial or private environments, and in particular in the case of self-contained sensors, the arrangement of the antenna inside the housing often leads to a reduction in the transmission and reception properties, which requires more energy for radio communication. In particular, energy storage devices and their cabling or other circuit boards often prove to be disruptive due to their relatively large dimensions when located close to the antenna and thus impair their radiation behavior. Furthermore, particularly high efficiencies cannot be achieved with SMT chip antennas on the lower mobile radio frequencies if the circuit boards are too small or circular.CGS:CGS Summary Against this background, it is an object of the present disclosure to provide a measuring device which has good transmission properties when transmitting the measurement data to an external receiver. This object is achieved by the features of the independent patent claims. Further developments of the invention emerge from the subclaims and the following description of embodiments. A first aspect of the present disclosure relates to a measuring device which is designed as a level measuring device for process automation in an industrial or private environment. It has a sensor device which is designed to record level measurement data, and a cylindrical monopole antenna which serves to transmit the level measurement data to an external receiver. One or more batteries orA charge storage device and / or a circuit board and / or a radar antenna horn are arranged. The measuring device can be designed as a field device in automation technology. It can have a plastic housing or a metal housing with a housing opening and an electronics unit arranged inside the housing with at least one circuit board. The antenna is designed to transmit and receive electromagnetic waves with at least one predetermined wavelength. The antenna is oriented such that it is designed to transmit electromagnetic waves through the housing or the housing opening and to receive electromagnetic waves to be received from the direction of the housing or the housing opening. This allows a wireless communication connection to be established between the electronics unit and a transmitting / receiving unit arranged outside the housing of the field device by means of the antenna.The term "process automation in industrial environments" can be understood as a branch of technology that includes measures for operating machines and systems without human intervention. One goal of process automation is to automate the interaction of individual components of a plant in the chemical, food, pharmaceutical, petroleum, paper, cement, shipping, or mining industries. A variety of sensors can be used for this purpose, which are specifically adapted to the specific requirements of the process industry, such as mechanical stability, insensitivity to contamination, extreme temperatures, and extreme pressures. Measured values ​​from these sensors are usually transmitted to a control room, where process parameters such as fill level, limit level, flow rate, pressure, or density are monitored, and settings for the entire plant can be changed manually or automatically.A sub-area of ​​process automation in the industrial environment concerns the logistics automation of plants and the logistics automation of supply chains. With the help of distance and angle sensors, processes inside or outside a building, or within a single logistics facility, are automated in the field of logistics automation. Typical applications for logistics automation systems include baggage and freight handling at airports, traffic monitoring (toll systems), retail, parcel distribution, and building security (access control). What the aforementioned examples have in common is that the respective application requires presence detection in combination with precise measurement of the size and location of an object.Sensors based on optical measurement methods using lasers, LEDs, 2D cameras, or 3D cameras that measure distances according to the time-of-flight (ToF) principle can be used for this purpose. Another sub-area of ​​process automation in the industrial environment concerns factory / production automation. Applications for this can be found in a wide variety of sectors, such as automotive manufacturing, food production, the pharmaceutical industry, or packaging in general. The goal of factory automation is to automate the production of goods using machines, production lines, and / or robots, i.e. to allow it to run without human intervention. The sensors used here and the specific requirements with regard to measurement accuracy when detecting the position and size of an object are comparable to those in the previous example of logistics automation.The terms used in the claims should be construed to give them the broadest possible reasonable interpretation consistent with the foregoing description. For example, the use of the article "a" or "the" in introducing an element should not be construed to exclude a plurality of elements. Likewise, the mention of "or" should be construed to include a plurality of elements, so that the mention of "A or B" does not exclude "A and B" unless it is clear from the context or the preceding description that only one of A and B is intended.Furthermore, the phrase "at least one of A, B, and C" should be understood as one or more elements from a group of elements consisting of A, B, and C, and should not be interpreted as requiring at least one of each of the listed elements A, B, and C, regardless of whether A, B, and C are related as categories or in some other way. Furthermore, the reference to "A, B, and / or C" or "at least one of A, B, or C" should be interpreted to include each individual unit of the listed elements, e.g., A, each subset of the listed elements, e.g., A and B, or the entire list of elements A, B, and C. Another aspect of the present disclosure relates to a measuring device configured as a pressure measuring device for process automation in industrial or domestic environments. This also comprises the elements described above (sensor device, cylindrical monopole antenna).A further aspect of the present disclosure relates to a measuring device configured as a temperature measuring device for process automation in industrial or private environments and comprising a sensor arrangement for acquiring temperature measurement data as well as the cylindrical monopole antenna described above. A further aspect of the present disclosure relates to a measuring device configured as a flow measuring device for process automation in industrial or private environments and comprising a sensor device for acquiring flow measurement data as well as the cylindrical monopole antenna described above. The cylindrical monopole antenna is more efficient than known arrangements. By accommodating the battery or other components inside the antenna, any impairment of the radio properties of the antenna due to interference / reflections / shielding is reduced.According to a further embodiment of the present disclosure, the cylindrical monopole antenna tapers conically at its end facing the process and / or at its end facing away from the process. According to a further embodiment of the present disclosure, the measuring device has a radio-frequency circuit board that is arranged outside the cylindrical monopole antenna and is configured to generate the antenna signal to be radiated. According to a further embodiment of the present disclosure, the cylindrical monopole antenna is placed on or attached to the RF circuit board. According to a further embodiment of the present disclosure, the RF circuit board represents the opposite pole of the cylindrical monopole antenna. According to a further embodiment of the present disclosure, the inner diameter of the cylindrical monopole antenna corresponds to the outer diameter of the battery or battery pack.According to a further embodiment of the present disclosure, the measuring device further comprises a contact pin arranged concentrically with the cylindrical monopole antenna, which connects the positive pole of the battery to the RF circuit board. According to a further embodiment of the present disclosure, the measuring device comprises a circuit board arranged in the interior of the cylindrical monopole antenna. It can be provided that the battery rests on this circuit board. According to a further embodiment of the present disclosure, the measuring device comprises a plastic housing in which the cylindrical monopole antenna and the sensor device are arranged. The plastic housing is preferably closed and sealed.A further aspect of the present disclosure relates to a cylindrical monopole antenna, as described above and below, configured to transmit measurement data from a measuring device to an external receiver, wherein a battery and / or one or more circuit boards are arranged in the interior of the cylindrical monopole antenna. A further aspect of the present disclosure relates to the use of a cylindrical monopole antenna, as described above and below, in a measuring device for process automation in an industrial or private environment for transmitting measurement data from the measuring device to an external receiver. Embodiments of the present disclosure are described below with reference to the figures. Where the same reference numerals are used in the following description of the figures, they designate identical or similar elements. The representations in the figures are schematic and not to scale.Brief description of the figures Fig. 1 shows several measuring devices and an external receiver according to one embodiment. Fig. 2 shows a cross-sectional view through a measuring device according to one embodiment. Fig. 3 shows a cross-sectional view through a measuring device according to another embodiment. Fig. 4 shows a front view and a side view of a measuring device according to one embodiment in cross-sectional representation. Fig. 5 shows a plan view of a high-frequency circuit board according to one embodiment. Fig. 6 shows the simulation of the achievable adaptation of a cylindrical monopole antenna of a measuring device according to one embodiment. Detailed description of embodiments Fig. 1 shows several measuring devices 100, 400 and an external receiver 300 in the form of a display and control unit. The external receiver 300 can communicate with the measuring devices 100, 400 via the cloud 500, or directly, and receive measurement data from them.The measuring devices are designed, for example, as a level measuring device 100, flow measuring device 100, pressure measuring device 400 or temperature measuring device 100 and all have a cylindrical monopole antenna 200 and a sensor device 101. In the case of a pressure measuring device, the sensor device 101 is a pressure measuring cell, in the case of a level measuring device, for example, a radar chip with an antenna, in the case of a temperature measuring device, a temperature measuring cell, and in the case of a flow measuring device, a flow measuring cell. The level measuring device can, for example, be designed as a level radar measuring device and emit a radar signal of 80 GHz or above (or below). Fig. 2 shows a cross-sectional view of a measuring device 100, 400 according to one embodiment. The antenna 2 used is a monopole. It is not designed as a wire antenna, but as a cylinder with a sufficient cavity in which components such as, for example,Batteries or their cabling or circuit boards are included. Because the interior is field-free (Faradey cage), the components located there cannot influence the radiated or received field of the antenna. In order for the antenna to achieve maximum efficiency at the mobile radio frequencies used, for example, for NB-IoT, LTE-M, LPWAN, and LoRaWAN, modifications to the classic monopole are necessary. As the diameter of the cylindrical base plate of the monopole increases, the capacitive load causes the antenna to detune, especially in the upper frequency bands. Therefore, the lower part of the antenna is designed as a truncated cone, which can also be used as a parameter to improve matching. A short-circuit connection from the antenna housing to the ground of the RF circuit board 10 is also provided, which, as with the known PIF antennas, provides an additional option for impedance matching.This ground connection also ensures that the negative pole of the battery is routed to the RF circuit board without interference. The positive pole of the battery is routed coaxially inside the RF feed and therefore has no noticeable influence. An important aspect is the integration of components, such as the battery and circuit boards, inside antenna 2 in order to avoid disrupting the antenna's radiation properties and to achieve the highest possible antenna efficiency. In principle, the measuring devices described are self-contained sensors, i.e., battery-operated measuring devices whose recorded values ​​are transmitted to the control center via a radio interface in the desired time sequence. The efficiency of the antenna has a significant influence on battery life, because if the antenna efficiency is too low, significantly more power is required for radio communication. Fig.Figure 2 shows a first embodiment of a measuring device in which the required components are housed in a dust- and watertight plastic housing 1. The batteries and their cabling are advantageously integrated in the cylindrical cavity of the antenna 2, as these are exclusively conductive parts with a corresponding influence on the electromagnetic fields of the antenna. In the embodiment shown, five batteries 4 are combined in a battery holder 5 and connected by cable connectors or otherwise to the circuit board 6 resting on the cone rim. Depending on requirements and available height, additional circuit boards 6' can also be installed inside the cylinder. This also applies to the measuring cells 3 and 3' (not described in detail), which can be located inside and / or outside the antenna 2. The measuring cell 3' can, for example, have a radar antenna horn.The batteries can also be arranged in the measuring cell 3, which is located outside the cylindrical cavity. The monopole antenna 2, which tapers to a conical shape due to the capacitive load, is placed in the center of the RF circuit board 10 and fixed to the RF circuit board by a plastic ring 7 with supports, while simultaneously supported on the housing 1. Fig. 3 shows a minimalist embodiment in which a single battery 4 of size D (monocell) is installed. The diameter of the antenna 2 is advantageously designed so that the battery 4 is supported on the cylindrical wall of the monopole 2. A circuit board 8 located inside the antenna accommodates the positive pole of the battery 4 and conducts the pole, shielded, to the RF circuit board 10 via a contact pin 9. The circuit board 8 can also have simple circuit components such as reverse polarity protection or current limitation, thus reducing malfunctions.All components for radio communication are located on the RF circuit board 10. The RF circuit board 10 also represents the opposite pole of the monopole. The negative pole of the battery is connected to the conductive cover 5 via a spring contact 11, which, for example, is screwed into the thread of the antenna cylinder and thus simultaneously clamps the battery. Other fastening methods are also possible; the electrical contact between the battery 4 and the antenna 2 is important. The antenna 2 is attached to the center of the RF circuit board 10 via a plastic ring with supports, ensuring a constant distance from the housing 1. This results in a circular antenna pattern in the azimuthal direction. On the lower side, the antenna 2 tapers conically towards the RF circuit board 10 to reduce the capacitive load to ground.If the lower diameter of the truncated cone is varied, this can simultaneously improve the matching in the frequency bands used. Fig. 4 shows two more detailed views of the connection between the antenna 2 and the RF circuit board 10. The contact pin 9 from the positive pole 4' of the battery 4 is inserted coaxially through the feed 13 directly into the RF circuit board 10. For insulation from ground, either air is used inside the cylindrical feed 13, or a plastic body 15 is inserted into the cavity of the feed 13. This provides better hold for the contact pin 9 and at the same time hermetically shields the battery 4 inside the antenna against external influences. The signal to be radiated reaches the antenna via two connection pins 14.Below the conical base of antenna 2 is a shorting plate 12, which, similar to known PIF antennas, creates a current path to the ground of the circuit board. The negative pole of the battery is routed to the circuit board via contact pin 16, providing another opportunity to improve antenna matching. To achieve optimal antenna matching for, for example, the lower and upper LTE frequency bands, it has proven advantageous to connect contact pin 16 of shorting plate 12 via a short-circuited line. Fig. 5 shows the connection of the antenna to the circuit board separately. It shows a line 17 that is short-circuited with ground holes 19. The length of this line 17 to contact pin 16 determines the effective impedance with which the antenna is matched.Alternatively, an inductance can be placed between contact pin 16 and ground, and adjustment can be made by varying the inductance value. Opposite is a 50 ohm line 18, along which the high-frequency signals are routed to the antenna. This is done via the two contact pins 14, which are connected to the connecting ring 20. The bore for receiving contact pin 9 can be seen inside the connecting ring 20. If multiple signals are to be routed into the interior of the antenna, this is possible in principle. In this case, an insulating body can be provided that accommodates the connecting pins and is pressed together with them into the cylinder of the feed. Fig. 6 shows a simulation for a sensor as shown in Fig. 2 in a closed PTFE housing with a total diameter of 93 mm and a total length of 150 mm, for which the achievable adaptation was calculated using a field simulator.The result of the simulation is the matching curve shown in Fig. 6, which exhibits a very good S11 value of ≤ -14 dB (VSWR ≤ 1.5) at the band edges. This allows antenna efficiencies of more than 90 percent to be achieved in both bands.

Claims

AMENDED CLAIMS received by the International Bureau on 28 November 2024 (28.11.2024) 1. Measuring device, designed as a level measuring device for process automation in industrial or private environments, comprising: a sensor device (101, 3) designed to detect Fill level measurement data; a cylindrical monopole antenna (2, 200) configured to transmit the fill level measurement data to an external receiver (300); wherein a battery (4) and / or a circuit board (6) and / or a radar antenna horn (3') is arranged in the interior of the cylindrical monopole antenna.

2. Measuring device, configured as a pressure measuring device (400) for process automation in an industrial or private environment, comprising: a sensor device (101, 3) configured to detect Pressure measurement data; a cylindrical monopole antenna (2, 200) configured to transmit the pressure measurement data to an external receiver (300); wherein a battery (4) and / or a circuit board (6) is arranged in the interior of the cylindrical monopole antenna.

3. Measuring device, configured as a temperature measuring device (100) for process automation in an industrial or private environment, comprising: a sensor device (101, 3) configured to detect Temperature measurement data; a cylindrical monopole antenna (2, 200) configured to transmit the temperature measurement data to an external receiver (300); wherein a battery (4) and / or a circuit board (6) is arranged in the interior of the cylindrical monopole antenna.

4. Measuring device, configured as a flow measuring device (100) for process automation in an industrial or private environment, comprising: a sensor device (101, 3) configured to detect flow measurement data; a cylindrical monopole antenna (2, 200) configured to transmit the flow measurement data to an external receiver (300); wherein a battery (4) and / or a circuit board (6) is arranged in the interior of the cylindrical monopole antenna.

5. Measuring device according to one of the preceding claims, wherein the cylindrical monopole antenna (2, 200) tapers conically at its end facing or remote from the process.

6. Measuring device according to one of the preceding claims, further comprising: an RF circuit board (10) which is arranged outside the cylindrical monopole antenna (200) and which is configured to generate the antenna signal to be radiated.

7. Measuring device according to claim 6, wherein the cylindrical monopole antenna (2, 200) is placed on the RF circuit board (10).

8. Measuring device according to claim 6 or 7, wherein the HF circuit board (10) forms the opposite pole of the cylindrical Monopole antenna (200).

9. Measuring device according to one of the preceding claims, wherein a battery (4) is arranged in the interior of the cylindrical monopole antenna; wherein the inner diameter of the cylindrical monopole antenna (2, 200) corresponds to the outer diameter of the battery (4).

10. Measuring device according to one of claims 4 to 7, further comprising: a contact pin (9) arranged concentrically to the cylindrical monopole antenna (2, 200), wherein a battery (4) is arranged in the interior of the cylindrical monopole antenna, wherein the contact pin (9) connects the positive pole of the battery (4) to the RF circuit board (10).

11. Measuring device according to one of the preceding claims, further comprising: a circuit board (6) which is arranged in the interior of the cylindrical monopole antenna (2, 200), wherein a battery (4) is arranged in the interior of the cylindrical monopole antenna and the battery rests on the circuit board (6).

12. Measuring device according to one of the preceding claims, further comprising: a plastic housing (1) in which the cylindrical monopole antenna (2, 200) and the sensor device (101, 3) are arranged.

13. Cylindrical monopole antenna (2, 200), configured to transmit measurement data from a measuring device to an external receiver (300), wherein a battery (4) and / or a printed circuit board (6) and / or a radar antenna horn (3') is arranged in the interior of the cylindrical monopole antenna.

14. Use of a cylindrical monopole antenna (2, 200) according to claim 13 in a measuring device for process automation in an industrial or private environment for transmitting measurement data from the measuring device to an external receiver (300).

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