Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
  • G01R27/28—Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N22/00—Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
  • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
  • G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
  • G01R27/2617—Measuring dielectric properties, e.g. constants
  • G01R27/2635—Sample holders, electrodes or excitation arrangements, e.g. sensors or measuring cells
  • G01R27/2647—Sample holders, electrodes or excitation arrangements, e.g. sensors or measuring cells of coaxial or concentric type, e.g. with the sample in a coaxial line

Definitions

• the present invention relates to a sensor and a method for determining a dielectric property of a medium. Furthermore, the invention relates to a sensor arrangement with such a sensor and an analysis device.
• Transmission measurement reflection measurement or resonance measurement.
• dielectric properties are determined based on the transmission of signals through a medium or a conductor.
• spur dielectric properties are determined based on the reflection of signals at or by means of the Me ⁇ diums.
• the resonance measurement is based on the Determined ⁇ development of the resonance characteristics, that is, the vibration characteristics of the medium, which in turn can be used to determine the dielectric properties.
• the results of these measurements can be used to determine the dielectric properties of the medium, in particular the complex dielectric constant. These properties can provide information about various other properties of the medium. These include, for example, the concentration of glucose, alcohol or salt in a medium.
• the determination of the dielectric constant may be desired in various areas, such as in medicine or in industrial plants, for example in the context of process instrumentation. Here it is desirable already to detect small changes in concentration, which requires a high measurement accuracy.
• an object of the present invention is to improve the determination of dielectric properties of a medium with regard to the measurement accuracy.
• a sensor for detecting a dielectric property of a medium includes a substrate having at least one via and a waveguide disposed planar with respect to an upper surface of the substrate.
• the Wellenlei ⁇ ter is connected via the at least one via with an analysis device. Is further adapted to the wave conductors to receive an input signal from the analysis ⁇ apparatus and outputting an output signal to the Analy ⁇ sevoriques, wherein characteristics of the input signal and the output signal upon contact of the waveguide with a medium indicative of the dielectric property of the medium are.
• the proposed sensor transmission and reflection measurements can be made. Its planar structure improves the measurement accuracy of the dielectric property of the medium. Furthermore, compact measuring units can be realized, whereby the sensor can be used in a variety of technical fields. Since the sensor can have small dimensions, it can also be used on the go.
• the sensor can be used for example in the medical field as a mobile device, which can also perform measurements directly on a person, the medium could correspond to the skin. Therefore, a sampling can be omitted.
• the sensor can be used in various industrial installations, either as a fixed or as a mobile device. Here, the sensor can also if brought directly into contact with the medium, where ⁇ can be omitted by a sampling.
• a waveguide is arranged planar with respect to a substrate.
• a printed circuit board can play, be used.
• the substrate may consist of or comprise a dielectric material.
• the waveguide may be any type of waveguide that may be planar with respect to the top surface of the substrate. "Planar in respect to the top upper surface of the substrate ⁇ " may mean at or planar with the upper surface of the substrate in this context planar. Preferably, it is a planar waveguide.
• planar is meant an arrangement of the waveguide in which the upper surface of the sensor array is planar or flat.
• the waveguide can be connected via vias to an analysis device.
• Vias in this context refer to openings that extend from the top surface of the substrate to the opposite side of the substrate through the substrate.
• the analyzer may be any device capable of sending an input signal to the waveguide, receiving an output signal therefrom, and determining a dielectric property of the medium based on characteristics of these two signals. The determination can be carried out, for example, based on a comparison of the phase and / or amplitude of the input signal and the username and password, as these material-dependent, that is, depending on the medium, change.
• a signal which is sent through the waveguide, he ⁇ witnesses to the waveguide a stray field.
• This (electromag- netic) stray field penetrates the medium. In this case, for example, change the phase and / or amplitude of the input and output signals. These changes can be used to determine the dielectric property (s) of the medium.
• the input signal is generated by the analyzer. If the measurement to be performed is a
• the input signal is fed to ei ⁇ nem end of the waveguide in the waveguide and received at the other end of the waveguide as an output signal as ⁇ of the analyzer.
• the input signal is fed to the waveguide at one end.
• the signal exits the waveguide in the medium and is at least partially reflected by this and fed back in the waves ⁇ conductor. This feedback signal is in turn received by the analyzer as an output signal.
• the analysis device can be, for example, a network analyzer.
• a network analyzer can be a vector network analyzer (VNA). This can be used to measure scattering parameters of electrical DUTs. Scattering parameters denote the reflection and transmission properties of the measurement objects.
• VNA vector network analyzer
• the term "measurement object” refers to a medium. The medium may assume a solid, liquid or gaseous state, which may include, but is not limited to, a liquid or gas.
• the waveguide is planarly disposed on the top surface of the substrate. According to this embodiment, the waveguide is a
• planar waveguide disposed on the upper surface of the substrate.
• planar means that the waveguide is flat and forms a flat surface with the substrate.
• the waveguide is a stripline.
• a stripline may be a microstrip line, a coplanar line or a slotline. Others too
• Strip lines typically consist of one or more thin conductive strips deposited on a dielectric (eg, a substrate).
• the substrate has at least two plated-through holes
• the waveguide is on the input terminal, at least two plated-through holes with an inlet and connectable to an output terminal of Analysevor ⁇ direction.
• the waveguide can be connected to the analysis device with its two ends.
• the analysis device may be a 2-port analysis device. This arrangement is used for transmission measurement, in which an input signal is fed by the analysis device into one end of the waveguide and an output ⁇ signal is received at the other end of the waveguide. As soon as the waveguide is in contact with the medium to be examined, that is to say it is "loaded", the egg changes. characteristics of the output signal compared to mattersssig ⁇ nal.
• the so-called scatter parameters can be determined. These S-parameters are measured as a function of frequency and indicate values of reflection and transmission. From these can by means of suitable processes, the dielectric properties of the medium, such as the dielectric constant, determines the ⁇ .
• the dielectric properties of the medium such as the dielectric constant.
• one end of the waveguide is arranged planar with the substrate.
• the waveguide is arranged so that only one end of the waveguide is disposed on the upper surface of the substrate and the waveguide extends through the via.
• the end of the Wellenlei ⁇ ters on the upper surface of the substrate is disposed planar with the substrate.
• the waveguide is formed as an open conductor.
• An open conductor that is, a conductor which is coupled to the analyzer with only one end, whereas the other end is without electrical connection, is used for reflection measurement as described above.
• a signal which is fed into the waveguide emerges from the waveguide at the open end. Through the medium to be examined, the signal is at least partially fed back into the waveguide. Based on this feedback, S parameters can also be determined.
• the network analyzer can be designed as a one-port in this case.
• the substrate comprises a dielectric material.
• the substrate may be a printed circuit board, which consists of a ⁇ lectric material.
• a protective layer is disposed over the upper surface of the substrate. Such a protective layer can serve to protect against contamination or even moisture through the medium.
• Protective layer may be, for example, a film.
• Parylene C or silicone can be used as Mate ⁇ rial for the protective layer. These materials can be used over a high temperature range. Other materials can also be used. Preferably, these should not affect the high frequency characteristics of the waveguide.
• the protective layer can be very thin, beispielswei ⁇ se few micrometers thick, being, for example, in the loading range of 5 to 10 micrometers, which also contributes to not be influence the high-frequency characteristics of the waveguide ⁇ .
• the substrate has a lower substrate layer and an upper substrate layer.
• Both substrate layers can be made of the same material.
• the analysis ⁇ device can be integrated.
• a mass ⁇ layer is disposed between the upper substrate layer and the bottom substrate layer.
• the mass layer separates the upper from the lower substrate ⁇ layer.
• the ground layer may consist of a metal or have a metallization.
• the waveguide is connected via a coaxial transition to a further waveguide on the lower substrate layer.
• a coaxial transition refers to a broadband transition, that is, a connection between the waveguide and another waveguide or other conductor. This means that the waveguide can be connected to the analysis device via broadband transitions. Broadband transitions offer the transmission of a wide frequency range.
• Coaxial transitions are used for this purpose. These junctions are provided by means of a coaxial conductor having an inner conductor and concentrically arranged around this another conductor. This additional conductor can consist of several individual conductors.
• This arrangement provides a broadband (through the coaxial junction) and multilayer (through the plurality of waveguides) junctions.
• a sensor arrangement for determining a dielectric property of a medium is proposed.
• the sensor arrangement comprises the above-explained sensor and an analysis device which is connected to the sensor. In a development, the analysis device is integrated in the substrate of the sensor.
• the analyzer may be integrated directly into the substrate.
• the waveguide is in this case on one side of the sensor assembly and the analyzer on the opposite side of the sensor assembly. In this way, on the one hand, a compact sensor arrangement can be achieved. On the other hand, it is possible to bring only the side of the sensor arrangement which has the waveguide in contact with the medium, so that the analysis device is protected.
• the analysis device is a network analyzer.
• VNA network analyzer
• the network analyzer may send a signal (traveling wave) into the waveguide that is in contact with the device under test, ie the medium.
• the frequency, amplitude and phase of the signal are known.
• the medium reflects a portion of that signal (step back ⁇ de shaft at the entrance), which part is the starting signal at the reflection measurement.
• the remaining, that is not reflected, signal passes into the waveguide in the medium, where it is changed (for example attenuated, amplified or phase-shifted) and is received again at the output of the waveguide as a transmitted signal (return wave at the output) of the network analyzer.
• the differences between the input signal and the output signal are used, as described above, to determine the dielectric properties of the medium.
• a method for determining a property of a medium dielektri- will be seen by a sensor beat pre ⁇ .
• the sensor includes a substrate which has at least one plated-through hole, and a waveguide, which is planar arranged with respect to an upper surface of the sub ⁇ strats, wherein the waveguide through which a via hole with an analysis device is at least connected.
• the method includes, as a first step, receiving an input signal from the analysis device. In a further step an output signal is outputted to the analysis device, wherein characteristics of the input signal and the output signal upon contact of the waves are ⁇ conductor with a medium indicative of the dielectric egg ⁇ genschaft of the medium.
• FIG. 1 shows a schematic view of an embodiment of a sensor for determining a dielectric property of a medium
• FIG. 2 shows a schematic view of a first exemplary embodiment of a sensor arrangement for determining a dielectric property of a medium
• Figure 3 is a schematic view of a second execution ⁇ example of a sensor arrangement for determining a dielectric property of a medium.
• Figure 4 is a schematic view of a third execution ⁇ example of a sensor arrangement for determining a dielectric property of a medium.
• Figure 5 is a schematic plan view of an exemplary embodiment of a Koaxialschreibgangs for a sensor of Figure 1 or for a sensor arrangement according to one of the figures 2 to 4..;
• Fig. 6 is a schematic side view of an exemplary embodiment of a Koaxialschreibgangs for a sensor of Figure 1 or for a sensor arrangement according to one of the figures 2 to 4.
• Fig. 7 is a schematic plan view of an exemplary embodiment of a Koaxialübergangs for a sensor according to Fig. 1 or for a sensor arrangement according to one of the figures 2 or 3;
• FIG. 8 is a schematic flow diagram of an example of a method for determining a dielectric
• FIG. 1 shows an exemplary embodiment of a sensor 10 for determining a dielectric property of a medium.
• the sensor 10 has a substrate 11, wherein a waveguide 12 is arranged planar with respect to the substrate 11 on an upper surface of the substrate 11.
• Planar with respect to the substrate 11 may be both planar on the upper surface of the substrate 11 and planar with the substrate 11. This will be explained in more detail in the following figures. Although protrudes in Fig. 1, the waveguide 12 by way of illustration on the substrate 11, the upper surface of the substrate 11 together with the Wellenlei ⁇ ter 12 is substantially planar.
• the waveguide can be connected to an analysis device 20, for example a network analyzer.
• the vectorial network analyzer (VNA) 20 sends a signal to the waveguide 12, couples a signal into the waveguide 12, and receives a signal from the waveguide 12. Based on these signals, the VNA 20 can determine a dielectric property of a medium. which is brought into contact with the sensor 10. With the sensor 10, a reflection measurement is feasible.
• the sensor 10 in the sensor arrangement 200 has two substrate layers, an upper substrate ⁇ layer 201 and a lower substrate layer 202.
• the wave ⁇ conductor 12 is in contact with a medium 205, beispielswei se se ⁇ a liquid in a container 206, brought.
• the container 206 can be chosen so large that it has no influence on the measurement.
• the waveguide 12 is connected via multi-layer broadband transitions 203, 204 with the VNA 20.
• the sensor 10 can be inexpensively manufactured on commercially available substrates such as printed circuit boards.
• the VNA 20 may be integrated in the lower substrate layer 202 as shown in FIG. Alternatively, the VNA 20 may be located externally. An integral structure, however, offers a particularly compact sensor arrangement.
• the VNA 20 for the measurement of discrete frequencies may be a two-port network analyzer with two ports 305, 306.
• a high measurement accuracy is desirable, which can be achieved by the embodiments of the sensor and the sensor arrangement described herein.
• the gates 305, 306 are via connections 307, such as cables, through the
• a protective layer 304 where ⁇ play, a film may be placed over the sensor 10 in order to increase the robustness of the sensor 10.
• This protective layer ⁇ 304 protects the sensor 10 from contamination or liquid penetration. As a result, the penetration of the substrate 11 with liquid can be prevented.
• a ground layer 303 is arranged in this embodiment. Through this, a connection from the upper substrate layer 301 to ground is possible without the Making connections through the lower substrate layer 302. This also leads to a simplified and compact sensor arrangement 300.
• the waveguide 12 is arranged planar with the upper surface of the upper substrate layer 301. One end of the waveguide 12 thus terminates with the upper surface. Via a coaxial transition 401, the waveguide 12 is connected to a gate 402 of the VNA 20, which in this case is a one-port Net analyzer.
• Another waveguide (not shown here), for example a microstrip line, may be located on the underside of the lower substrate layer 302. This is transferred through the coaxial transition 401 in an open conductor.
• Fig. 5 shows such a coaxial junction 500. This can be used to connect two waveguides with each other or a waveguide 12 to the VNA 20.
• a center conductor 501 provides a via from the upper substrate layer 301 to the lower substrate layer. Having a thickness r ⁇ (inside radius) of the central conductor of egg ⁇ ner insulating layer 502 is surrounded. A second insulation layer 503 ⁇ surrounds this. In turn, a third insulating layer 505 surrounds the second insulating layer 503.
• the isolators ⁇ tion layers 502, 503, 505 are arranged concentrically around the central conductor five hundred and first In the third insulation layer 505, vias 504 are provided which provide connection to the ground layer.
• the vias 504 extend only to the ground layer 303.
• a first waveguide 500 is disposed on the upper substrate layer 301 and a second waveguide 500 is disposed on the lower substrate layer 302.
• the two waveguides 500 are connected together via the conductor 501 of the centra ⁇ len Koaxialübergangs.
• the central conductor 501 is penetrated by the ground layer 303 an insulation layer 601 or recess electrically ge ⁇ separates.
• FIG. 7 shows a coaxial transition 700 for such a sensor.
• the two coaxial transitions 500 shown are connected by the microstrip line 701, or other waveguide.
• the coupling length l k of the coaxial ⁇ transitions, that is, the length of the microstrip line can, depending on the measurement frequencies and the medium to be examined 205 are selected in order to achieve an optimal waveguide.
• the choice of radii r ⁇ and r a can influence the sensitivity of the measurements.
• FIG. 8 shows a schematic flow chart of a method 800 for determining a dielectric property of a medium 205.
• a waveguide 12 of a sensor 10 receives an input signal from an analysis
• the waveguide 12 outputs an output signal to the analysis device 20. If the waveguide is in contact with a medium 205 12, characteristics of the input signal and the output ⁇ signal indicative of the dielectric property of the Medi ⁇ around 205. This can be further determined as described above and used.
• the sensor described herein and the corresponding sensor arrangement are inexpensive to manufacture compared to known sensors. The sensors can be used in different measuring environments and easily integrated.
• the sensitivity of the measurements can be adjusted by appropriate choice of the radii r ⁇ and r a of the coaxial ⁇ transitions. Furthermore, the planar construction makes it possible to realize a compact measuring device since the sensor and the analysis device can form a single unit. To- additionally larger measuring ranges and accuracies improved Messge ⁇ be made possible.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Biochemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Electromagnetism (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Measurement Of Resistance Or Impedance (AREA)
• Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
• Waveguides (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)

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• 2013
  • 2013-03-15 DE DE102013204586.7A patent/DE102013204586A1/de not_active Withdrawn
• 2014
  • 2014-03-13 JP JP2015562141A patent/JP6305444B2/ja not_active Expired - Fee Related
  • 2014-03-13 EP EP14711197.5A patent/EP2951564A1/de not_active Withdrawn
  • 2014-03-13 CN CN201480015953.3A patent/CN105026919B/zh not_active Expired - Fee Related
  • 2014-03-13 US US14/777,270 patent/US10317444B2/en not_active Expired - Fee Related
  • 2014-03-13 WO PCT/EP2014/054919 patent/WO2014140151A1/de active Application Filing

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