System and method for detecting gas using the configurable dynamic range of a sensor

Abstract

The techniques described herein provide a sensing system and method that offers configurable sensitivity and an extended dynamic range for gas measurement. The system and method apply dielectric excitation to a sensing material at two or more excitation frequencies via a sensing electrode. The linearity of the electrical signal is modified by changing the operating parameters of the gas sensing element of the sensor.

Description

Technical Field

[0001] Statement Regarding Research and Development Funded by the Federal Government This invention was made with government support under Contract No. W15QKN-18-9-1004 awarded by ACC-NJ to the CWMD Consortium. The government has certain rights in this invention.

Background Art

[0002] Combustible gases are used in a variety of applications from cooking and heating to being used as fuel for engines. Combustible gases can include hydrogen and simple or small hydrocarbon molecules up to long-chain hydrocarbon molecules. In various situations, it can be useful to be able to detect the presence of such combustible gases, from trace levels (parts per billion (ppb) levels) to higher levels, both inside and outside the combustion reaction zone, to ensure the proper operation of valuable items. As an example, monitoring such combustible gases can be useful to ensure that the levels of such gases do not exceed the lower explosive limit (LEL) in ambient air. Additionally, as an example, monitoring such combustible gases can also be useful when the LEL is exceeded in ambient air in hydrogen combustion and other industrial uses.

[0003] Gas sensors can be based on a variety of sensing materials including metal oxide semiconductor (MOS) materials, dielectric polymers, conductive polymers, nanotubes, metal organic frameworks, graphene, supramolecular compounds, two-dimensional (2D) transition metal carbides and nitrides (MXene), and others. Often, such gas sensors can exhibit saturation of their responses at high concentrations, leading to incorrect readings.

[0004] Conventional sensors, such as optical sensors, metal oxide semiconductor (MOS) sensors, electrochemical sensors, catalytic perister sensors, and thermal conductivity sensors, have very narrow gas detection ranges, typically two to three orders of magnitude. This narrow detection range is due to the nature of the interaction mechanism between the sensing material and the surrounding environment. For example, MOS sensors, which involve resistance measurement of MOS materials, can have greater commercial success compared to other types of sensors due to their wide range of applications for gas alarms in residential and industrial facilities. Readout of MOS materials is conventionally performed by measuring the change in resistance of the MOS material as a function of gas concentration. Such a relationship follows a well-known power law, and the sensor response saturates at high gas concentrations. [Overview of the project]

[0005] Certain embodiments corresponding to the scope of the disclosed subject matter are summarized below. These embodiments are not intended to limit the scope of the invention, but rather to provide only a brief overview of certain disclosed embodiments. In fact, the invention may encompass a variety of forms that may be similar to or different from the embodiments described below.

[0006] With the above in mind, this embodiment relates to a gas sensor system and method for analyzing at least one gas response signal when a MOS sensing material is dielectrically excited, wherein one or more variables in the environment being monitored are determined and taken into consideration. Specifically, in one embodiment, the gas sensor system may include a gas sensing element as described, one or more controllers (collectively, a “control circuit unit”), and an excitation / detection system. One or more controllers may provide one or more control signals for monitoring at least one component in the analyte gas. The excitation / detection system may be operably coupled to the gas sensing element and controller(s). The excitation / detection system may perform one or more actions based on one or more control signals. The action may include providing a plurality of stimulus signals to the gas sensing element, the excitation / detection system being configured to provide each of the plurality of stimulus signals to the gas sensing element, receiving a sensor response from the gas sensing element in response to the provision of the plurality of stimulus signals, and determining one or more gas concentration values ​​based on analyzing the sensor response to the plurality of stimulus signals. According to such an embodiment, each sensor response is associated with a specific stimulus signal.

[0007] In another embodiment, a method is provided in which the operation of the gas sensor system is carried out by a control circuit unit comprising one or more controllers of the gas sensor system. In this method, one or more control signals are provided by one or more controllers of the gas sensor system to generate a plurality of stimulus signals to the gas sensing element of the gas sensor system. Sensor responses from the gas sensing element are received by the controllers in response to the provision of each of the plurality of stimulus signals. The concentration values ​​of one or more gases are determined based on the analysis of the sensor responses to each of the plurality of stimulus signals.

[0008] In another embodiment, a computer-readable medium is described, which includes computer-executable instructions, which, when executed, cause a processor associated with the gas sensor system to perform an operation. The operation may include providing one or more control signals to the excitation circuit of the gas sensor system to generate a plurality of stimulus signals to the gas sensing element of the gas sensor system, receiving a sensor response from the gas sensing element in response to the provision of the plurality of stimulus signals, and determining one or more gas concentration values ​​based on the analysis of the sensor response. [Brief explanation of the drawing]

[0009] These and other features, aspects, and advantages of the present invention will be better understood by reading the following detailed description with reference to the accompanying drawings. In the accompanying drawings, similar reference numerals throughout the drawings represent similar parts.

[0010] [Figure 1] This figure shows one embodiment of a gas sensor system and a non-limiting example of sensor design according to one embodiment. [Figure 2] This figure shows an exemplary position of a wearable gas sensor system or a gas sensor system mounted on an unmanned vehicle, according to one embodiment. [Figure 3] A flowchart of one embodiment of a method for detecting a target analyte gas is shown. [Figure 4A] This figure shows plots of the real and imaginary parts of the impedance spectrum of a MOS sensing element, as well as the approximate location of the operating frequency range 1, for obtaining a substantially linear response to relatively low gas concentrations, achieved by monitoring the sensor response under a first operating voltage and a first operating temperature and measuring the sensor response using a first tuning capacitor of a first capacitance at a first frequency. [Figure 4B]This figure shows plots of the real and imaginary parts of the impedance spectrum of a MOS sensing element, as well as the approximate location of the operating frequency range 2, for obtaining a substantially linear response to relatively high gas concentrations, achieved by monitoring the sensor response under a second operating voltage and a second operating temperature and measuring the sensor response using a second tuned capacitor of second capacitance at a second frequency, according to one embodiment. [Figure 5] This figure shows a schematic plot of the optimal values ​​of operating parameter 1 and operating parameter 2 for obtaining the response of the gas sensing element to the maximum dynamic range of different analyte gases A, B, and C, according to one embodiment. [Figure 6] This figure shows a plot of the imaginary part of the impedance of a sensing element as a function of test time over a specific first frequency range, a first operating temperature, and a first concentration range of the analyte of interest in a first tuning capacitor, according to one embodiment. [Figure 7] This figure shows a plot of the imaginary part of the impedance of a sensing element as a function of test time over a specific first frequency range, a second operating temperature, and a second concentration range of the analyte of interest in a second tuning capacitor, according to one embodiment. [Modes for carrying out the invention]

[0011] This specification uses examples as part of the invention, including the best mode, and enables those skilled in the art to practice the invention, including the fabrication and use of any device or system and the implementation of any incorporated method. The patentable scope of the invention is defined by the claims and may include other embodiments that a person skilled in the art could conceive. Such other examples are intended to be within the claims if they have structural elements that are not different from the language of the claims, or if they include equivalent structural elements that are substantially different from the language of the claims.

[0012] One or more embodiments of the subject matter described herein provide a sensing system and method that provides configurable sensitivity and an extended dynamic range for gas measurement. The system and method apply dielectric excitation to a sensing material at two or more excitation frequencies via a sensing electrode.

[0013] In some embodiments, excitation or dielectric excitation of a sensor (e.g., a sensor utilizing a metal oxide semiconductor (MOS) sensing material) refers to alternating current (AC) excitation of the sensor (e.g., the MOS sensing material) at the shoulder of its dielectric relaxation region. Dielectric excitation or AC excitation of a sensor can be performed when the sensing material is a MOS material, dielectric polymer material, conductive polymer material, nanotube material, nanowire material, nanoparticle material, metal-organic structural material, graphene material, supramolecular compound material, MXene material, and other materials.

[0014] Linearity of the sensor response across different ranges of gas concentration is achieved by selecting one or more of the following when measuring the impedance of the sensor's gas sensing element: the operating frequency, the operating voltage of the heating element (collectively referred to as the energy delivery element), and the value of the tuning capacitor. As discussed herein, each sensor response is associated with a specific stimulus signal. The gas sensor implementation described herein can have a dynamic range encompassing a detection limit (LOD) of 5 ppb to 50 volume%, representing an eight-order-of-magnitude hydrogen gas concentration.

[0015] At least one technical effect of the various embodiments described herein is the ability to configure and reconfigure the sensitivity and dynamic range of a gas sensor used to obtain measurements of one or more gases. As discussed herein, such gas sensors can be based on a variety of sensing materials. Dielectric excitation may be applied to the sensing material at multiple excitation frequencies. Based on the concentration of the analyte gas to be detected, the system changes (e.g., dynamically) the impedance of the gas sensing element of the sensor based on the dielectric excitation frequency as well as the temperature and voltage of the heating element or energy delivery element. Changing the dielectric excitation frequency of the gas sensing element changes the linearity of the sensor's impedance response, thereby controlling the sensor's sensitivity to different concentrations of the analyte of interest. The impedance of the gas sensing element at at least one measurement frequency can be changed by adding a tuning capacitor to the gas sensing element circuit. Changing the dielectric excitation frequency as well as the temperature and voltage of the heating element expands the range of gas concentrations to be measured by eight orders of magnitude, from 5 ppb to 50 volume%. Another technical benefit of such extended dynamic range measurements (e.g., a wide range of gas concentrations over which the sensor provides accurate readings) is the ability to measure a wide range of concentrations with a single sensor or single gas sensing element, as opposed to having or using different sensors for different concentration ranges. Generally, techniques using dielectric excitation expand the dynamic range of gas detection, improve the stability of the sensor baseline, and significantly reduce or even eliminate the effects of humidity and ambient temperature. Unlike broadband impedance spectroscopy, dielectric excitation techniques utilize a specific frequency range by tracing the forward (high-frequency or low-frequency) shoulders of the spectral peaks obtained from their dielectric relaxation measurements when semiconductor metal oxide materials (n-type or p-type, respectively) are exposed to various gas concentrations. Other sensing materials can also be utilized with their measurements based on dielectric or AC excitation.

[0016] As described above, the method using dielectric excitation expands the dynamic range of gas detection. In particular, the present invention demonstrates that the selection of the appropriate operating frequency when measuring the impedance of the gas sensing element of the sensor, the value of the tuning capacitor, and the operating voltage of the heating element achieves an eight-digit expansion of the dynamic range of the detection of flammable gases.

[0017] According to an embodiment of the present invention, the sensing element can operate at two or more different temperatures in combination with two or more values of the tuning capacitor in order to achieve a desired wide dynamic range for the measurement of gas concentration. The temperature variation represents one of several types of energy, such as thermal energy, which can be varied in order to achieve a desired wide dynamic range for the measurement of gas concentration. The temperature variation can be in the range of -50°C to +1000°C, including the ranges of +20°C to +800°C and +25°C to +700°C.

[0018] In addition to the temperature variation, other types of energy that can be applied can be accompanied by radiant and mechanical (or acoustic) types of energy.

[0019] In one embodiment, the radiant energy can be varied to achieve a desired wide dynamic range for the measurement of gas concentration. The radiant energy can use variations in wavelength and / or variations in the intensity of the radiant energy. The variation in the wavelength of the radiant energy can be within the range from ultraviolet light to visible light and infrared light. The variation in the intensity of the radiant energy can be in the range of 0.00001 mW / cm 2 ~10000 mW / cm 2 including the ranges of 0.0001 mW / cm 2 ~900 mW / cm 2 and 0.001 mW / cm 2 ~1000 mW / cm 2 and can be in the range of 0.00001 mW / cm

[0020] In one embodiment, mechanical (or acoustic) energy can be varied to achieve a desired wide dynamic range for gas concentration measurement. The mechanical (or acoustic) energy can utilize a variation in the frequency of the mechanical (or acoustic) energy. The variation in the frequency of the mechanical (or acoustic) energy can be in the range of 1 kHz to 10 GHz, including the ranges of 10 kHz to 5 GHz and 20 kHz to 4 GHz.

[0021] To achieve a desired wide dynamic range for gas concentration measurement, different individual types of energy can be applied in combination with two or more values of a tuning capacitor.

[0022] To achieve a desired wide dynamic range for gas concentration measurement, different types of energy can be combined and applied in combination with two or more values of a tuning capacitor. In one embodiment, thermal energy can be applied in combination with radiant energy. In another embodiment, thermal energy can be applied in combination with mechanical (or acoustic) energy. In another embodiment, mechanical (or acoustic) energy can be applied in combination with radiant energy. In another embodiment, thermal energy can be applied in combination with radiant energy and mechanical (or acoustic) energy.

[0023] In one or more embodiments of the subject matter of the disclosure described herein, the sensing material is a MOS sensing material. Conventional resistance measurements of MOS sensing materials may suffer from a nonlinear response as a function of gas concentration, because the resistance response follows a power law, which involves saturation of the sensor response at high or elevated concentration values. For example, such a power law response is known to be observed when using MOS sensing materials. As a result, high gas concentrations saturate the sensor response, leading to an underestimation of the gas concentration. The gas sensor systems and methods described herein provide improved sensitivity of the sensor to high or elevated concentration values ​​of the analyte of interest. These sensing systems and methods provide low-cost sensing methods and systems with improved sensitivity and an extended dynamic range of gas concentrations, such as an eight-order-of-magnitude dynamic range of gas concentrations from 5 ppb to 50 volume%, compared to conventional sensing techniques. Relevant features of multivariable sensing as described herein include the linearity of the observed response, the ability to detect relatively low gas concentrations, and the ability to detect relatively high gas concentrations.

[0024] With the foregoing in mind, Figure 1 illustrates one embodiment of the gas sensor system 100. The gas sensor system 100 inspects the fluid in contact with the gas sensor 114. The fluid may be a gas, liquid, gas-liquid mixture, particles, or particulate matter containing one or more analyte gases. For example, in one implementation, the fluid may be ambient air indoors or outdoors. Another example of the fluid is air in an industrial site, residential site, military site, battlefield, construction site, urban site, or any other known site. Furthermore, another example of the fluid may be transformer oil, or any insulating fluid for electrical equipment installed and / or positioned below, above, near, or any other location. In another embodiment, the fluid may be a gas or fuel, such as hydrocarbon fuel or hydrogen fuel. An example of the fluid is natural gas supplied for consumption to a powered system (e.g., a vehicle or stationary generator set). Another example of a fluid is hydrogen gas supplied for consumption to powered systems (e.g., road vehicles, aircraft engines, or stationary generator sets). Other examples of such fluids may include, but are not limited to, gasoline, diesel fuel, jet fuel or kerosene, biofuels, petroleum diesel-biodiesel fuel blends, natural gas (liquid or compressed), and fuel oil. Another example of a fluid is ambient air, indoors or outdoors. Another example of a fluid is air in industrial, residential, military, construction, urban, and / or any other known site. Another example of a fluid is ambient air containing relatively low concentrations of hydrocarbons and / or other contaminants. Another example of a fluid is at least one gas dissolved in industrial liquids such as transformer oil, bioprocess media, fermentation media, and wastewater. Another example of a fluid is at least one gas dissolved in consumer liquids such as milk, non-alcoholic beverages, alcoholic beverages, and cosmetics. Another example of a fluid is at least one gas dissolved in bodily fluids such as blood, sweat, tears, saliva, and urine.

[0025] The gas sensor system 100, as shown in Figure 1, may include a fluid reservoir 112 for holding fluid and a gas sensor 114 at least partially disposed within, on, or inside the fluid reservoir 112. Alternatively, the sensor 114 may be configured in a fluid flow path outside the fluid reservoir 112, such as being coupled to an in-line connector that fluid-communicates with the fluid reservoir 112 defining the flow path. The gas sensor 114 may be a sensor having at least two or more output units substantially independent of each other. The fluid reservoir 112 may be in the form of a container with a controlled volume, or in the form of an open area such as an indoor facility (e.g., a room, hall, house, school, hospital, confined space, etc.), or in the form of an outdoor facility (e.g., a city, battlefield, stadium, gas production site, coast, forest, etc.). In one embodiment, the sensor 114 can provide continuous, periodic, or intermittent monitoring of the fluid in the reservoir or flow path. In one or more embodiments, the sensor 114 may be an impedance gas sensor, an electromagnetic sensor, a photonic sensor, an electronic sensor, a hybrid sensor, or another type of sensor. Optionally, the gas sensor 114 may be a sensor array.

[0026] Sensor 114 can detect the characteristics or properties of a fluid through its resonant or non-resonant impedance spectral response. One or more inductor-capacitor-resistor (LCR) resonant circuits can measure the resonant impedance spectral response of the sensor. If the circuit does not contain an inductor, the non-resonant impedance spectral response is measured. The resonant or non-resonant impedance spectrum of sensor 114 in close proximity to the fluid varies based on the composition and / or components and / or temperature of the sample. The measured resonant or non-resonant impedance values ​​Z' (which may be the real part of the impedance, Zre) and Z'' (which may be the imaginary part of the impedance, Zim) reflect the sensor 114's response to the fluid.

[0027] Suitable sensors may include single-use or multi-use sensors. A suitable multi-use sensor may be a reusable sensor that can be used for the lifetime of the system in which it may be incorporated. In one embodiment, the sensor may be a single-use sensor that can be used for all or part of a reaction or process.

[0028] Data from sensor 114 can be acquired via data acquisition circuit 116, which can be associated with sensor 114 or with a control system such as a controller or workstation 122 including a data processing circuit, where additional processing and analysis can be performed. The controller or workstation 122 may include one or more wireless or wired components and may communicate with other components of system 100. Preferred communication models include wireless or wired. At least one preferred wireless model includes radio frequency devices such as radio frequency identification (RFID) wireless communication. Other wireless communication modalities may be used based on application-specific parameters. Non-limiting examples include Bluetooth, Wi-Fi, 3G, 4G, 5G, and others. For example, if there may be electromagnetic field (EMF) interference, certain modalities may function while others do not. In one embodiment, data acquisition circuit 116 may optionally be located within or integrated with sensor 114. In other embodiments, the data acquisition circuit 116 may be provided within or as part of the workstation 122, as shown in Figure 1. Furthermore, the workstation 122 can be replaced or integrated with a process-wide control system to which the sensor 114 and its data acquisition circuit 116 may be connected to a control system for the generation or combustion process. Non-limiting examples of the workstation 122 are stationary or mobile networked or non-networked devices.

[0029] The data acquisition circuit 116 may be in the form of a sensor reader that can be configured to communicate wirelessly or via a wire with the fluid reservoir 112 and / or the workstation 122. For example, the sensor reader may be a battery-powered device and / or may be powered using energy available from the main control system or by extracting energy (light, vibration, heat, or electromagnetic energy) from an ambient source.

[0030] Additionally, the data acquisition circuit 116 may receive data from one or more gas sensors 114 (e.g., multiple sensors positioned at different locations within or around the fluid reservoir). The data can be stored in short-term and / or long-term memory storage devices, such as archive communication systems, which may be located within or remotely from the system, and / or can be reconstructed and displayed for the operator, such as at an operator workstation. The gas sensors 114 can be positioned on or within the oil fluid reservoir, associated piping components, connectors, flow-through components, and any other relevant process components. The data acquisition circuit 116 may include one or more processors or dedicated circuits configured or programmed to analyze the data received from the gas sensors 114. For example, one or more processors may be one or more computer processors, controllers (e.g., microcontrollers), or other logic-based devices that perform operations based on one or more instruction sets (e.g., software). The instructions on which one or more processors operate may be stored in tangible, non-temporary, computer-readable storage media, such as memory devices. Memory devices may include hard drives, flash drives, RAM, ROM, EEPROM, and / or similar. Alternatively, one or more instruction sets that direct the operation of one or more processors may be hardwired to the logic of one or more processors, such as by hardwired logic formed and / or stored in the hardware of one or more processors. Alternatively, the data acquisition circuit 116 may be implemented as one or more application-specific integrated circuits (ASICs).

[0031] In addition to displaying data, the operator workstation 122 can control the aforementioned operations and functions of system 100. The operator workstation 122 may include one or more processor-based components, such as a general-purpose or application-specific computer 124 or a similar processor-based system. In addition to the processor-based components, the computer may include various memory and / or storage components, including magnetic and optical mass storage devices, and internal memory such as RAM chips. The memory and / or storage components can be used to store programs and routines for carrying out the technologies described herein, which can be executed by the operator workstation 122 or associated components of system 100. Alternatively, the programs and routines may be stored in computer-accessible storage devices and / or memory that are remote from the operator workstation 122 but accessible by network and / or communication interfaces located on computer 124. Computer 124 may also have various input / output (I / O) interfaces and various network or communication interfaces. Various I / O interfaces can enable communication with user interface devices such as the display 126, keyboard 128, electronic mouse 130, and printer 132, which can be used to view and input configuration information and / or to operate the imaging system. Other devices not shown, such as touchpads, heads-up displays, microphones, and similar devices, may be useful for the interface. Various network and communication interfaces can enable connectivity to both local and wide-area intranets, as well as storage networks and the internet. Various I / O and communication interfaces can utilize wires, lines, or appropriate wireless interfaces as needed or desired.

[0032] In one or more embodiments, the sensor 114 may be a wearable device attached to an object such as a human or animal, or mounted on an unmanned vehicle, as illustrated in Figure 2. Specifically, Figure 2 illustrates a non-limiting example of the location of a gas detection system for detecting flammable gases or any other gas or vapor of any purpose using a single sensor 114 having a wide dynamic range. Figure 2 represents various locations where the wearable sensor 114 may be attached. For example, the wearable sensor 114 may be attached directly to the body of an object. Alternatively, the wearable sensor 114 may be detachably coupled or integrated to an article worn by the object. For example, as illustrated in Figure 2, the wearable sensor 114 may be attached to military or industrial headgear, the sleeve of a shirt, or the front of a shirt, jacket, or vest. Additionally, the wearable sensor 114 may be attached to the hand or wrist, either directly to the body or integrated into a glove, as depicted in Figure 2. Alternatively, the wearable sensor 114 may be detachably coupled or integrated with an unworn, transportable object, such as an unmanned vehicle, on the ground or in the air, or on another vehicle. In this way, the wearable sensor 114 can be coupled or integrated with any alternative object or device that may be transportable, such as the sensor 114 being moved between different locations, or being stationary or substantially stationary. Although not shown in Figure 2, the wearable sensor may also be detachably coupled or integrated with eyeglasses, trousers, safety vests, safety protective clothing, hats, hearing devices, or any other wearable device or clothing. In the embodiment illustrated in Figure 2, the subject is a human subject, but the subject may be a mammalian subject, a plant subject, a robotic subject, etc.

[0033] An electric field can be applied to the sensing material 308 of the sensor 114 via the electrode 310. The distance between the electrodes, the geometry of the electrodes, and / or the periodic voltage applied to the electrodes can define the magnitude of the electric field applied to the sensor 114 (e.g., to the sensing material or film). The electrode 310 may be in direct contact with the sensing material 308, as shown in Figure 1. For example, the sensor 114 may be a combination of a circuit associated with a sensing region, and / or the sensing region may be coated with the sensing material 308. The sensing material 308 may be a semiconductor material or a metal oxide material, i.e., a MOS material. The sensing material 308 may be any sensing material.

[0034] Suitable comb-type electrode structures for probing fluid samples include 2-electrode and 4-electrode structures. Suitable materials for electrodes include platinum, gold, precious metals, and others. Suitable materials for dielectric substrates may include silicon dioxide, silicon nitride, alumina, ceramics, and others. Suitable examples of sensing materials or sensing films include metal oxide materials, composite materials, semiconductor materials, n-type semiconductor materials, p-type semiconductor materials, nanocomposite materials, inorganic materials, organic materials, polymer materials, compounded materials, nanotube materials, nanowire materials, nanoparticle materials, metal-organic structural materials, graphene materials, supramolecular compound materials, MXene materials, and any known sensing materials. Suitable electrodes can be formed using metal etching, screen printing, inkjet printing, and mask-based metal deposition techniques. The thickness of electrodes fabricated on a substrate may range from about 10 nanometers to about 1000 micrometers. The materials, substrates, sensing layers, and electrode formation methods for comb-type electrode structures can be selected at least partially based on application-specific parameters.

[0035] Returning to Figure 1, this figure illustrates one embodiment of the gas sensor 114. Sensor 114 may represent another version of the sensor or sensing system described herein. Sensor 114 includes a gas sensing element 340 having a dielectric substrate 302 such as a dielectric material, a sensing film or sensing material 308 bonded to the dielectric substrate 302, and an electrode 310. The sensing material 308 may be exposed to at least one analyte gas. In one or more embodiments of the subject matter described herein, the sensing material 308 utilizes a metal oxide semiconductor sensing film. The sensing material 308 may include one or more materials deposited on the dielectric substrate 302 to perform a function that predictably and reproducibly influences the impedance sensor response when interacting with the environment. For example, a metal oxide such as SnO2 may be deposited as the sensing material 308. The sensing material 308 is exposed to, in contact with, or indirectly in contact with a fluid containing at least one analyte gas. One or more heating elements 304, such as high-resistivity elements, are coupled to different sides of the dielectric substrate 302 with respect to the sensing material 308. The heating elements 304 (collectively referred to as energy delivery elements) receive current from a power supply 306 for the heating elements (collectively referred to as the energy source for the energy delivery elements), which conducts heater current or voltage to the heating elements 304, heating or delivering energy to the dielectric substrate 302, or to the sensing film or sensing material 308 coupled to the other side of the dielectric substrate 302, representing hardware circuitry. The energy source can generate any combination of energy of the type of heat, radiation, or acoustics. The heating elements 304 may also be controlled by a control circuit, or more specifically, a power supply controller 312, which selects the appropriate power of the current received by the heating elements 304 to achieve an operating temperature (collectively referred to as the operating energy level) and an operating voltage (collectively referred to as the selected energy level) based on pre-selected operating parameters. In the illustrated example, the heating element 304 is located on the opposite side of the dielectric substrate 302 from the sensing material 308. Alternatively, the sensing material 308 and the heating element 304 may be coupled to the same side of the dielectric substrate 302.

[0036] In the illustrated embodiments shown in Figures 3 and 4, the sensing electrode 310 is coupled to and / or disposed within the sensing material 308 and connected to the dielectric substrate 302. The sensing electrode 310 is a conductor conductively coupled to the impedance detector 320. The impedance detector 320 operates at two or more operating frequencies in the shoulder region of the dielectric relaxation area of ​​the impedance spectrum of the sensing material 308. In the illustrated embodiments, the sensing electrode 310 is conductively coupled to the impedance detector 320 directly and independently. Optionally, the sensing electrode 310 may be conductively coupled to the impedance detector 320 directly or indirectly. The impedance detector 320 can be communicatively coupled to a control circuit section including an operating frequency range controller 321 to provide two or more measurement frequencies, where the first measurement frequency is lower than the second measurement frequency. The operating frequency range controller 321 may have one or more processors or circuits, which may include one or more microprocessors, field-programmable gate arrays, and / or integrated circuits.

[0037] In one or more embodiments, the sensing electrode 310 may be coated with a sensing material that reacts with one or more analyte gases of interest. The controller 321 of the operating frequency range may select a first frequency for dielectric excitation of the sensing material and instruct the impedance detector 320 to perform a measurement at the first frequency of the impedance response of the sensing material. The controller 321 of the operating frequency range may then select a second frequency for dielectric excitation of the sensing material and instruct the impedance detector 320 to perform a measurement at the second frequency of the impedance response of the sensing material. The phrase “dielectric excitation of the sensing material” may be used synonymously with the phrase “AC excitation of the sensing material in its shoulder of the dielectric relaxation spectrum.”

[0038] In one or more embodiments, the operating frequency range of the dielectric excitation measurement may be tuned by one or more tuning capacitors 314 in the electrical circuit of the sensor 114, which is in parallel with the gas sensing element 340 and the impedance detector 320. For example, the impedance detector 320 can receive from the sensing electrode 310 an electrical signal representing a measured response signal or response of the gas sensing element 340 when it is dielectric excited during exposure of the sensing material 308 to a fluid sample at the operating temperature. In an alternative embodiment, the impedance detector 320 may be referred to as a detector system utilizing an AC excitation source. The impedance detector 320 examines the electrical impedance of the gas sensing element 340 to determine the presence and / or amount (e.g., concentration) of one or more analyte gases in the environment to which the sensing material 308 is exposed, as described herein. In this way, the operating frequency range controller 321 can provide scanning capability for measuring sensor impedance responses at multiple discrete frequencies. Additionally, the operating frequency range controller 321 can provide capability for measuring sensor impedance responses across a frequency range.

[0039] The control circuit section may also include a gas sensor system controller 316 that can be operably coupled with a controller 321 for the operating frequency range and a power supply controller 312. The gas sensor system controller 316 includes one or more processors, including one or more microprocessors, field-programmable gate arrays, and / or integrated circuits. The gas sensor system controller 316 selects and controls one or more tuning capacitors 314 to extend the measurement range of the gas concentration.

[0040] Figure 3 illustrates a flowchart of one embodiment of method 700 for detecting one or more target analyte gases. Method 700 can represent operations performed by the gas sensor system 100 and gas detection element 340 described herein, or optionally, operations performed by another detection system and / or another gas sensor. For example, method 700 can represent operations performed by system 100 and / or gas detection element 340 under the direction of one or more software applications, or optionally, algorithms useful for describing such software applications.

[0041] In 702, context inputs are applied to select expected application scenarios for the gas sensor 114 with an extended dynamic range. Non-limiting examples of context inputs may include the intended sensor use as a particular wearable device or permanent installation. Context inputs may also include expected gas concentrations in a particular environment, or concentrations of analyte gases that the operator may need to detect to ensure the environment is safe to occupy. Other context inputs may include the geographical area of ​​sensor use, location based on Global Positioning System coordinates, location of a particular region or city, elevation at a particular location, etc. Other context inputs may include the type of sensing material being used or the type of analyte gas expected to be measured. In 705, a first set of operating parameters is further selected based on the context inputs. The first set of operating parameters includes a selected operating voltage for the heating element 304, two or more frequencies for dielectric excitation, and selected capacitances for one or more capacitors. Depending on the analyte gas to be detected, the type of sensor, the sensing material, and the expected concentration level of the analyte gas, the number of operating parameters may range from 1 to N, where N may be 2 to 4 in one implementation configuration. The operating parameters may include a first operating voltage and a set of two or more frequencies for the impedance detector 320, which measures the imaginary part Z'' of the sensor impedance at the high-frequency or low-frequency shoulder of the dielectric relaxation spectrum using a tuning capacitor 314 having a selected capacitance.

[0042] For example, to measure a relatively low concentration of gas, the operating parameters may include a first sensor operating voltage to achieve a first operating temperature of the heating element 304 and a measurement of the imaginary part Z'' of the sensor impedance at the high-frequency or low-frequency shoulder of the dielectric relaxation spectrum of the MOS material via the impedance detector 320, and one or more tuning capacitors 314 are set to one or more first capacitances based on a first set of two or more frequencies. To measure a relatively high concentration of gas, the operating parameters may include a second sensor operating voltage to achieve a second operating temperature and a measurement of the imaginary part Z'' of the sensor impedance at the high-frequency or low-frequency shoulder of the dielectric relaxation spectrum of the MOS material via the impedance detector 320, and one or more tuning capacitors 314 are set to one or more second capacitances based on a second set of two or more frequencies. Generally, the first operating voltage and temperature are higher than the second operating voltage and temperature. That is, the first operating voltage and temperature associated with the detection of a relatively low concentration of gas may be greater than the second operating voltage and temperature associated with the detection of a relatively high concentration of gas. Generally, one or more first capacitances are smaller than the second tuning capacitance. That is, the capacitance associated with detecting relatively low concentrations of gas may be lower than the capacitance associated with detecting relatively high concentrations of gas. Therefore, in embodiments having two or more tuning capacitors, the first tuning capacitor may be smaller than the second tuning capacitor. Similarly, generally, a first set of two or more frequencies may be lower than a second set of two or more frequencies. That is, two or more frequencies associated with detecting relatively low concentrations of gas will be lower than two or more frequencies associated with detecting relatively high concentrations of gas. In another embodiment, the first set of two or more frequencies may be the same as or similar to a second set of two or more frequencies. Measurements of relatively low and relatively high concentrations of gas can be performed using the same impedance detector 320 operating at two or more operating frequencies in the shoulder of the dielectric relaxation region of the impedance spectrum of the MOS sensing material.To extend the range of detectable gas concentrations by eight orders of magnitude, from 5 ppb to 50 volume%, the above manipulation of the variables can be repeated for operating parameters 1 to N. Figure 5 shows how the manipulation of multiple (two) variables can result in the optimal position of response 210 for the best dynamic range for different analyte gases and various gas sensing elements (e.g., A, B, and C). The first operating voltage and temperature can be lower than the second operating voltage and temperature.

[0043] In 707, 711, and 712, the gas sensor 114 is operated under pre-selected operating parameters and presented to the measurement environment. Specifically, in 711, the heating element 304 heats the sensing material 308 based on pre-selected excitation parameters (i.e., dielectric excitation frequency and temperature). In 712, the sensing electrode 310 applies a first dielectric excitation to the sensing material 308 of the gas sensing element 340 based on a pre-selected operating voltage to detect and acquire one or more electrical signals representing the sensor 114's response to the dielectric excitation. In this step, one or more tuning capacitors 314 are also applied to the electrical circuit of the gas sensor 114. In one or more embodiments, the first dielectric excitation may be performed on or applied to the sensing material 308 at a first dielectric excitation frequency. In one embodiment, the electrode 310 may be subjected to dielectric excitation at a single excitation frequency of approximately 400 kHz, but dielectric excitation may be applied at different excitation frequencies such as 10 kHz, 100 kHz, 1 MHz, 10 MHz or 100 MHz, or any other frequency. The sensing material 308 may be exposed to hydrogen, methane, ethane, propane, butane, propene, butene, ethylene, acetylene, isobutylene, or any alternative analyte gas (one or more) in a range of concentrations.

[0044] Which tuning capacitor 314 is selected, or how one or more tuning capacitors 314 are tuned, may depend on the selected operating frequency parameter. For example, to detect lower concentrations of gas, the gas sensor 114 can use one or more tuning capacitors 314 of a first capacitance. Alternatively, to detect higher concentrations, the gas sensor 114 can use one or more tuning capacitors 314 of a second capacitance. For example, in 704, the response of the gas sensor 114 is measured under a pre-selected frequency of dielectric excitation, which includes a measurement of the imaginary part Z'' of the sensor impedance in the high-frequency shoulder of the dielectric relaxation spectrum, and the tuning capacitor 314 is selected based on the first pre-selected frequency. The response of the gas sensor 114 can be represented by an electrical signal, which can represent the electrical impedance or impedance response of the gas sensing element 340 during exposure of the sensing material 308 to the first dielectric excitation over a concentration range of one or more analytes of interest. The response data is acquired via the data acquisition circuit 116. In 713, the response of the gas sensor 114 at pre-selected operating parameters is compared with corresponding values ​​in a lookup table via the acquisition circuit 116. Then, in 714 and 715, the data acquisition circuit 116 reports the detected concentration of the measured gas over a given time and / or over time, which can be displayed via the operator workstation 122.

[0045] The method 700 and the corresponding gas sensor 114 disclosed herein can be used to detect analyte gas concentrations of at least eight orders of magnitude, whereas conventional sensors typically have a range of two to three orders of magnitude and rarely extend to gas concentrations of four to six orders of magnitude. For example, to obtain a desired substantially linear response for relatively low analyte gas concentrations, monitoring of the sensor response is selected to be carried out using appropriate operating parameters.

[0046] To obtain the desired substantially linear response to relatively high gas concentrations, the monitoring of the sensor response is selected to be performed under appropriate operating parameters of the same sensor, summarized as "second operating parameters." Depending on the detected flammable, toxic, harmful, or polluting gas, the type of sensor, and the selected operating parameters that constitute the operating parameters, the number of such operating parameters can range from 1 to N, and in one implementation configuration, N can be 2 to 4.

[0047] Measurements of relatively low and relatively high gas concentrations can be performed using the same impedance detector 320 operating at two or more operating frequencies in the shoulder of the dielectric relaxation region of the impedance spectrum of the MOS sensing material. In the measurement of relatively low gas concentrations, the first operating parameter includes a measurement of the imaginary part Z'' of the sensor impedance in the high-frequency shoulder of the dielectric relaxation spectrum of the MOS material using a first operating voltage of the first tuning capacitor and heating element 304 at a first measurement frequency. In the measurement of relatively high gas concentrations, the second operating parameter includes a measurement of the imaginary part Z'' of the sensor impedance in the high-frequency shoulder of the dielectric relaxation spectrum of the MOS material using a second operating voltage of the second tuning capacitor and heating element 304 at a second measurement frequency.

[0048] Therefore, the method provides a first measurement range for gas concentration, with a combination of a first value of the tuning capacitor 314 and a first value of the operating voltage of the heating element 304. The method further provides a second measurement range for gas concentration (i.e., an extended dynamic range of gas concentration measurement), with a combination of a second value of the tuning capacitor 314 and a second value of the operating voltage of the heating element 304. The method may further involve the measurement of flammable, toxic, harmful, or polluting gases. The method may further involve measurements at the high-frequency shoulder or low-frequency shoulder of the dielectric relaxation spectrum of the sensing material. The method may further involve measurements using metal oxide semiconductor materials, dielectric polymer materials, conductive polymer materials, nanotube materials, nanowire materials, nanoparticle materials, metal-organic structural materials, graphene materials, supramolecular compound materials, MXene materials, and other materials. Another sensing material may be a two-dimensional carbon allotrope such as a semiconductor diamine. Yet another sensing material may be a graphlarene, which is an atomically thin material made of linked fullerene subunits.

[0049] For example, the excitation parameters for detecting relatively low gas concentrations (i.e., first operating parameters including a first operating frequency, a first operating temperature, and a first tuning capacitor) are different from (e.g., greater than or less than) the excitation parameters or second operating parameters for detecting relatively high gas concentrations (i.e., an Nth operating voltage and an Nth temperature). The capacitance of the first tuning capacitor is less than the capacitance of the sensor's second tuning capacitor. The first operating temperature is greater than the sensor's second operating temperature. The first measurement frequency is lower than the sensor's second measurement frequency.

[0050] In one embodiment, information from readings of a gas sensor 114 having a wide dynamic range for measuring gas concentration can be implemented for informational purposes via an alarm. That is, the gas sensor can be communicably coupled to an alarm to provide alerts such as visual, acoustic, and / or tactile, or any other known alerts. Alarms can be generated or issued on a gas sensor system 100 having a gas sensor 114. Alarms can be transmitted to a central station or to another gas sensor system 100 having a similar or different gas sensor 114. Alarms can be in the form of quantitative information, such as the concentration of the detected gas. For example, an alarm coupled to a gas sensor 114 can provide an alert when the detected gas concentration exceeds a threshold. Alarms can be in the form of qualitative and / or semi-quantitative information, such as the bottled level of the detected gas, for example, three bottles such as yellow, orange, and red levels of the alarm.

[0051] In another embodiment, information from readings of a gas sensor 114 having a wide dynamic range for measuring gas concentration can be implemented for decision-making purposes. Decision-making purposes may include actions such as activating an emergency response, initiating a specific action, or decontaminating an object having a gas sensor system 100 having the gas sensor 114. Decision-making purposes may include actions such as optimizing logistical steps after gaining knowledge of the detected gas concentration. Decision-making purposes may include actions such as minimizing logistical steps after gaining knowledge of the detected gas concentration.

[0052] Figure 4A illustrates plots of the real and imaginary parts of the impedance spectrum of a MOS sensing element that identifies a first operating frequency in a first operating state. Specifically, a substantially linear response to relatively low gas concentrations is achieved by monitoring the sensor response under its operating voltage and a first temperature and measuring the sensor impedance Z'' using a first tuning capacitor at a first measurement frequency.

[0053] Figure 4B illustrates plots of the real and imaginary parts of the impedance spectrum of a MOS sensing element that identifies a second operating frequency in a second operating state. Specifically, a substantially linear response to relatively high gas concentrations is achieved by monitoring the sensor response under its operating voltage and second temperature and measuring the sensor impedance Z'' using a second tuning capacitor at a second measurement frequency.

[0054] Analyte gases may include a wide range of materials and / or chemicals with varying hazard indices. Materials with a "high" hazard index may include, for example, ammonia, arsine, boron trichloride, boron trifluoride, carbon disulfide, chlorine, diborane, ethylene oxide, fluorine, formaldehyde, hydrogen bromide, hydrogen chloride, hydrogen cyanide, hydrogen fluoride, hydrogen sulfide, nitric acid, fumes, phosgene, phosphorus trichloride, sulfur dioxide, sulfuric acid, and tungsten hexafluoride.

[0055] Materials with a “moderate” hazard index may include, for example, acetone cyanohydrin, acrolein, acrylonitrile, allyl alcohol, allylamine, allyl chlorocarbonate, boron tribromide, carbon monoxide, carbonyl sulfide, chloroacetone, chloroacetonitrile, chlorosulfonic acid, diketene, 1,2-dimethylhydrazine, ethylene dibromide, hydrogen selenide, methanesulfonyl chloride, methyl bromide, methyl chloroformate, methylchlorosilane, methylhydrazine, methyl isocyanate, methyl mercaptan, nitrogen dioxide, phosphine, phosphorus oxychloride, phosphorus pentafluoride, selenium hexafluoride, silicon tetrafluoride, stivin, sulfur trioxide, sulfuryl chloride, sulfuryl fluoride, tellurium hexafluoride, n-octyl mercaptan, titanium tetrachloride, trichloroacetyl chloride, and trifluoroacetyl chloride.

[0056] Materials with a "low" hazard index include, for example, allyl isothiocyanate, arsenic trichloride, bromine, bromine chloride, bromine pentafluoride, bromine trifluoride, carbonyl fluoride, chlorine pentafluoride, chlorine trifluoride, chloroacetaldehyde, chloroacetyl chloride, crotonaldehyde, cyanogen chloride, dimethyl sulfate, diphenylmethane-4,40-diisocyanate, ethyl chloroformate, ethyl chlorothioformate, ethyl phosphonate dichloride, ethyl phosphonate dichloride, ethyleneimine, and hexachlorocyclopenta The analyte gas may include dienes, hydrogen iodide, iron pentacarbonyl, isobutyl chloroformate, isopropyl chloroformate, isopropyl isocyanate, n-butyl chloroformate, n-butyl isocyanate, nitric oxide, n-propyl chloroformate, parathion, perchloromethyl mercaptan, sec-butyl chloroformate, tert-butyl isocyanate, tetraethyl lead, tetraethyl pyrophosphate, tetramethyl lead, toluene 2,4-diisocyanate, and toluene 2,6-diisocyanate. The analyte gas may also include a range of indoor environmental agents such as acetaldehyde, formaldehyde, 1,3-butadiene, benzene, chloroform, methylene chloride, 1,4-dichlorobenzene, perchloroethylene, trichloroethylene, naphthalene, and polycyclic aromatic compounds, as well as outdoor environmental agents such as ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide. Furthermore, the analyte gas may include industrial chemicals such as flammable materials and hazardous materials for confined spaces.

[0057] Experiments were conducted using the disclosed method to demonstrate that the disclosed gas sensor 114 has a dynamic range from a detection limit of 5 ppb to 50 volume%, representing an eight-order-of-magnitude gas concentration. In these experiments, hydrogen gas was selected as the analyte gas, as an example. A low-power consumption gas sensing element was used. The gas sensing element had a structure consisting of an integrated heater formed on a silicon substrate using microelectromechanical systems (MEMS) technology and a MOS material layer formed on the sensing chip, as a surface-mount ceramic package. The gas sensing element required a heater power consumption of less than 100 mW. The actual heater power consumption was 15 mW. Hydrogen was presented to the gas sensing element from two gas tanks. A gas mixing system was used to dilute the concentration of hydrogen in the gas tanks to the desired concentration. One gas tank contained 20 ppm of hydrogen in the air. A 20 ppm hydrogen flow from this gas tank was diluted with air to obtain concentrations of 0.77 ppm, 1.5 ppm, 2.3 ppm, and 3.1 ppm presented to the sensor. Another gas tank contained 100 vol% hydrogen. A 100 vol% hydrogen flow from that gas tank was diluted with air to obtain concentrations of 12.5 vol%, 25.0 vol%, 37.5 vol%, and 50 vol% presented to the same sensor. Dielectric excitation of the sensing MOS element was achieved using an integrated circuit impedance analyzer such as ADuCM355 (Analog Devices, Norwood, MA 02062-9106, USA). Real and imaginary impedance measurements were performed with a step size of 10 kHz over a frequency range from 10 kHz to 200 kHz. The scan time between these frequencies was 0.5 seconds. While the sensor was exposed to hydrogen at concentrations of 0.77 ppm, 1.5 ppm, 2.3 ppm, and 3.1 ppm (i.e., relatively low gas concentrations), the gas sensing element operated at 2.4 volts and had a capacitance of 560 pF as part of its electrical circuit connected in parallel with the gas sensing element. Z” measurements were performed at 10 kHz.While the sensor was exposed to 12.5 vol%, 25.0 vol%, 37.5 vol%, and 50 vol% hydrogen (i.e., relatively high gas concentrations), the gas sensing element operated at 0.9 volts and had a 5200 pF capacitor as part of the sensor's electrical circuit. Z” measurements were performed at 200 kHz.

[0058] Figure 6 illustrates the ultrafast response speed of the sensor 114 of this disclosure when detecting a wide dynamic range of relatively low concentrations of hydrogen gas in a first operating state associated with the detection of low concentrations of hydrogen gas. Hydrogen gas detection was performed at sub-ppm and low ppm levels. The sensor's response to hydrogen at 0.77 ppm, 1.5 ppm, 2.3 ppm, and 3.1 ppm was measured when data acquisition was one data point per 0.5 seconds. The detection limit of the sensor was 5 ppb. The baseline area highlighted with a square and the sensor response at the minimum test hydrogen gas concentration of 0.77 ppm were used to calculate the detection limit. The sensor response speed was 1 to 2 data points for different concentrations of hydrogen. The response speed of the hydrogen sensor was approximately 1 second, meeting the requirements of hydrogen safety and other applications. Such a rapid response speed of the hydrogen sensor represents a substantial improvement over conventional hydrogen gas sensor technology.

[0059] Figure 7 illustrates the ultrafast response speed of the sensor 114 of this disclosure when detecting a wide dynamic range of relatively high concentrations of hydrogen gas in a second operating state associated with the detection of high concentrations of hydrogen gas. Hydrogen gas detection was performed up to 50 vol%, which is 12.5 times higher than the lower explosive limit (LEL) of hydrogen in air (4 vol%). Sensor data acquisition was performed every 0.5 seconds. One or two data points were required to achieve the sensor response to hydrogen at these high concentrations.

[0060] The results presented herein demonstrate that the sensors of this disclosure can detect hydrogen at single-digit ppb levels. To calculate the detection limit for hydrogen, the signal intensity of the sensor noise and the sensor response to hydrogen were measured. The detection limit is the minimum detectable concentration at a given signal-to-noise ratio (e.g., SNR=3). The detection limit (LOD) at SNR=3 was calculated using the formula LOD=[3×(baseline region noise)×(0.77 ppm H2)] / [sensor response to 0.77 ppm H2]. The sensors disclosed herein have a detection limit of 5 ppb. The gas sensor systems and methods disclosed herein enable the detection of hydrogen over a wide range of hydrogen gas concentrations from ppb to volume percentage levels. As described herein, the sensors of this disclosure are designed to detect hydrogen at high volume percentage levels in air, including levels above the lower explosive limit (LEL) of hydrogen in air (4 volume%). Such high concentrations of hydrogen cannot be reliably detected by conventional sensors such as catalytic perister sensors, MOS sensors, and electrochemical sensors. As shown herein, the sensor of this disclosure detects hydrogen at up to 50 volume%, which is 12.5 times higher than LEL. Thus, the hydrogen sensor has a dynamic range ranging from a detection limit of 5 ppb to 50 volume%, which is an eight-order-of-magnitude hydrogen gas concentration. This unexpected performance over such a wide measurement range is a significant milestone for the concept of gas detection, as conventional sensors typically have a range of two to three orders of magnitude and rarely extend to gas concentrations of four to six orders of magnitude.

[0061] Where used herein, elements or steps listed in the singular and followed by the word "a" or "an" should be understood not to exclude multiple such elements or steps unless such exclusion is expressly stated. Furthermore, references to "one embodiment" of the subject matter of the invention described herein are not intended to be construed as excluding the existence of additional embodiments that also incorporate the listed features. Moreover, unless expressly stated to the contrary, embodiments that "comprising," "including," or "having" (or similar terms) an element or multiple elements having a particular characteristic may include additional such elements that do not have the particular characteristic.

[0062] As used herein, terms such as “system” or “controller” may include hardware and / or software that operate to perform one or more functions. For example, a system or controller may include a computer processor or other logic-based device that performs operations based on instructions stored in a tangible, non-temporary, computer-readable storage medium such as computer memory. Alternatively, a system or controller may include a hardwired device that performs operations based on the device’s hardwired logic. The systems and controllers shown in the figures may represent hardware that operates based on software or hardwired instructions, software that instructs the hardware to perform operations, or a combination thereof.

[0063] It should be understood that the subject matter described herein is not limited in its application to the details of configuration and arrangement of elements described herein or illustrated in the drawings herein. Other embodiments of the subject matter described herein are possible and can be implemented or carried out in various ways. Furthermore, it should be understood that the expressions and terms used herein are for illustrative purposes only and should not be considered limiting. The use of “including,” “comprising,” or “having” and their variations herein means encompassing the items listed thereafter and their equivalents, as well as additional items.

[0064] It should be understood that the above description is intended to be illustrative and not limiting. For example, the embodiments (and / or aspects thereof) described above may be used in combination with one another. In addition, many modifications can be made to adapt the teachings of the subject matter described herein to specific circumstances or materials without departing from their scope. The dimensions, material types and coatings described herein are intended to define parameters of the subject matter disclosed, but they are not limiting and are illustrative embodiments. Many other embodiments will be apparent to those skilled in the art upon consideration of the above description. Thus, the scope of the subject matter of the invention should be determined by reference to the appended claims, along with the entire scope of equivalents to which such claims are granted. In the appended claims, the terms “including” and “in which” are used as plain English synonyms for the terms “comprising” and “wherein,” respectively. Furthermore, in the following claims, terms such as “first,” “second,” and “third” are used merely as labels and are not intended to impose numerical requirements on their subjects. Furthermore, unless such limitation of claims explicitly uses the phrase “means for” followed by a description of a function without further structure, and until such limitation of claims is used, it is not intended to be written in means-plus-function form and to be interpreted under 35 U.S. SC § 112(f).

[0065] This specification uses examples to disclose several embodiments of the subject matter of the invention and to enable a person skilled in the art to carry out embodiments of the subject matter of the invention, including fabricating and using any device or system, and carrying out any incorporated method. The patentable scope of the subject matter of the invention is defined by the claims and may include other examples that a person skilled in the art may conceive. Such other examples are intended to be within the claims if they have structural elements that are not different from the language of the claims, or if they include equivalent structural elements that are not substantially different from the language of the claims.

Claims

1. A gas sensor system that provides an extended dynamic range for measuring gas concentration, It is a gas sensor, A gas detection element comprising at least two electrodes, a dielectric substrate, and a detection material coupled to the at least two electrodes and configured to be exposed to the analyte gas, At least one heating element coupled to the sensing material and the dielectric substrate, configured to heat the gas sensing element to an operating temperature based on a selected operating voltage, At least one impedance detector configured to operate at two or more frequencies, Located within the electrical circuit of the gas sensor system, and comprising one or more tuning capacitors in parallel with the gas detection element, A gas sensor equipped with, Control circuit section, Controlling the power supply of the at least one heating element, wherein the power supply is configured to select an operating voltage for heating the at least one heating element to an operating temperature based on the selected operating voltage. Adjusting the two or more frequencies of the at least one impedance detector such that the AC excitation of the gas sensing element is provided at the two or more frequencies, Selecting one or more tuning capacitors based at least partially on the selected operating voltage, A control circuit unit is configured to perform the following: A gas sensor system equipped with the following features.

2. Data acquisition circuit section, When the gas detection element is AC-excited, one or more response signals are received from the gas detection element. The gas sensor system according to claim 1, further comprising a data acquisition circuit configured to determine the concentration of the analyte gas in the environment at a given time or over time by comparing one or more response signals with values ​​stored in a lookup table.

3. The gas sensor system according to claim 1, wherein the sensing material is a metal oxide semiconductor material, a dielectric polymer, a conductive polymer, a nanotube material, a metal-organic structural material, graphene, a supramolecular compound material, a two-dimensional transition metal carbide, and a nitride material.

4. The gas sensor system according to claim 2, wherein the gas sensor is configured to detect a first range of gas concentration by measuring one or more response signals when the gas sensing element is dielectrically excited at a first value of the one or more tuning capacitors and a first value of the selected operating voltage.

5. The gas sensor system according to claim 2, wherein the gas sensor is configured to detect a second range of gas concentration by measuring one or more response signals when the gas sensing element is dielectrically excited at a second value of one or more tuning capacitors and a second value of the selected operating voltage.

6. The gas sensor system according to claim 1, wherein the two or more operating frequencies of the impedance detector are located at the shoulder of the dielectric relaxation region of the impedance spectrum of the detection material.

7. The gas sensor system according to claim 1, wherein the gas sensor is a wearable device that is attached by an operator.

8. The gas sensor system according to claim 1, wherein the gas sensor has a response speed of up to 1 second.

9. The gas sensor system according to claim 1, wherein the gas sensor is communicably coupled to an alarm configured to provide an alert in response to the gas sensor detecting a gas concentration exceeding a threshold.

10. The gas sensor system according to claim 9, wherein the gas sensor is configured to implement a decision-making objective in response to the concentration of the gas exceeding the threshold.

11. The gas sensor system according to claim 10, wherein the decision-making objective includes activating an emergency response, activating a specific process, decontaminating the object having the gas sensor, optimizing a logistical step after the knowledge regarding the detected concentration of the gas, or minimizing a logistical step after the knowledge regarding the detected concentration of the gas.

12. A method for operating a gas sensor system that provides an extended dynamic range for measuring gas concentration, Applying contextual inputs to select application scenarios with an extended dynamic range for gas concentration measurement, The operation parameters of the gas sensor system are selected in advance, Exposure of a gas sensor's gas detection element to an environment containing an analyte gas, wherein the gas detection element comprises at least two electrodes, a dielectric substrate, and a detection material coupled to the substrate and configured to be exposed to the analyte gas. The sensing material is heated to the pre-selected operating temperature via a heating element, A tuning capacitor is provided in parallel with the aforementioned gas detection element, The process involves measuring one or more impedance outputs of the gas detection element via an impedance detector in the aforementioned pre-selected operating parameters, The process involves comparing the one or more impedance outputs of the pre-selected operating parameters with the corresponding values ​​stored in the lookup table. Based on the aforementioned lookup table, the measured gas concentration over a given time or period is determined, Displaying the determined concentration of the gas measured at a given time or the determined concentration of the gas measured over time via an output device, Methods that include...

13. The method according to claim 12, comprising providing linearity of the sensor response over different ranges of gas concentrations through the selection of the pre-selected operating parameters, wherein the pre-selected operating parameters include an operating frequency, an operating voltage, and a tuning capacitor value when measuring the one or more impedance outputs.

14. The method according to claim 12, wherein the pre-selected operating parameters include an operating frequency, an operating voltage, and a tuning capacitor value when measuring one or more impedance outputs.

15. The method according to claim 12, wherein the pre-selected operating parameters correspond to detecting a first range of gas concentrations up to 5 ppb.

16. The method according to claim 12, wherein the pre-selected operating parameters correspond to detecting a second range of gas concentrations up to 50 volume percent.

17. A gas sensor that provides an extended dynamic range for measuring gas concentration, A gas detection element comprising at least two electrodes, a dielectric substrate, and a detection material coupled to the substrate and configured to be exposed to the analyte gas, At least one heating element coupled to the dielectric substrate and configured to heat the gas sensing element to an operating temperature based on a selected operating voltage, At least one impedance detector configured to operate at two or more operating frequencies, Located within the electrical circuit of the gas sensor, and comprising one or more tuning capacitors in parallel with the gas detection element, Control circuit section, A controller for the power supply of the at least one heating element, configured to select the operating voltage for heating the at least one heating element to reach the operating temperature, A controller for the at least one impedance detector, configured to adjust the two or more frequencies of the at least one impedance detector, wherein the AC excitation of the gas sensing element is provided at the two or more frequencies; A controller for the one or more tuning capacitors, configured to select the one or more tuning capacitors based at least partially on the selected operating voltage, A control circuit section comprising, A gas sensor equipped with the following features.

18. The gas sensor according to claim 16, wherein the detection material includes a metal oxide semiconductor material.

19. The aforementioned gas sensor A first range of gas concentrations corresponding to the first value of one or more tuning capacitors, the first value of the selected operating voltage, and the first value of the selected operating frequency, A second range of gas concentrations corresponding to the second value of one or more tuning capacitors, the second value of the selected operating voltage, and the second value of the selected operating frequency, The gas sensor according to claim 16, configured to detect [something].

20. The gas sensor according to claim 18, wherein the gas sensor is configured to detect a first range and a second range of the gas concentration via at least one impedance detector operating at two or more operating frequencies, the at least one impedance detector detects one or more dielectric excitation responses of the gas sensing element, the two or more frequencies are located at the shoulders of the dielectric relaxation region of the impedance spectrum of the metal oxide semiconductor sensing material, and provides gas concentrations of at least eight orders of magnitude of the dynamic range of the gas sensor.

21. The gas sensor according to claim 19, wherein the gas sensor is configured to detect a first range of gas concentration and a second range of gas concentration via a processor configured to receive one or more dielectric excitation responses detected by the gas sensing element and compare the responses with values ​​stored in a lookup table.

22. The gas sensor according to claim 16, wherein the detection material includes a semiconductor material.

23. The gas sensor according to claim 16, wherein the gas sensor is a wearable device that is attached by an operator.

24. A gas sensor system that provides an extended dynamic range for measuring gas concentration, It is a gas sensor, A gas detection element comprising at least two electrodes, a dielectric substrate, and a detection material coupled to the at least two electrodes and configured to be exposed to the analyte gas, At least one energy delivery element coupled to the sensing material and configured to deliver energy to the gas sensing element up to an operating energy level based on a selected energy level, At least one impedance detector configured to operate at two or more frequencies, Located within the electrical circuit of the gas sensor system, and comprising one or more tuning capacitors in parallel with the gas detection element, A gas sensor equipped with, Control circuit section, Controlling the energy source of the at least one energy delivery element, wherein the energy source is configured to select an energy level to control the at least one energy source element to reach the operating energy level based on the selected operating energy level. Adjusting the two or more frequencies of the at least one impedance detector such that the AC excitation of the gas sensing element is provided at the two or more frequencies, Selecting one or more tuning capacitors based at least partially on the selected operating energy level, A control circuit unit is configured to perform the following: A gas sensor system equipped with the following features.

25. The gas sensor system according to claim 23, wherein the energy source generates at least one or a combination of energy of the types of heat, radiation, or acoustics.

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