A gas sensor utilizing carbon nanotubes (CNTs) is disclosed. The sensor can include a patch antenna, a feed line, and a stub line. The stub line can include a carbon nanotube (CNT) thin-film layer for gas detection. The CNTs can be functionalized to detect one or more analytes with specificity designed to detect, for example, environmental air contaminants, hazardous gases, or explosives. The sensor can provide extremely sensitive gas detection by monitoring the shift in resonant frequency of the sensor circuit resulting from the adsorption of the analyte by the CNT thin-film layer. The sensor can be manufactured using inkjet printing technologies to reduce costs. The integration of an efficient antenna on the same substrate as the sensor enables wireless applications of the sensor without additional components, for wireless standoff chemical sensing applications including, for example, defense, industrial monitoring, environmental sensing, automobile exhaust analysis, and healthcare applications.

A through hole (3) is provided on a supporting substrate (2). A plate-shaped beam (4) extends from an edge of the through hole (3) to a facing edge in such a way as to cover part of the through hole (3) and is provided with a piezoelectric element. A drive electrode (16) vibrates the beam (4) by applying voltage to the piezoelectric element. Detection electrodes (17A, 17B) detect information about the vibration frequency of the beam (4). Substance adsorption films (5A, 5B) change the vibration frequency of the beam (4) by adhesion of a substance. The substance adsorption films (5A, 5B) and the detection electrodes (17A, 17B) are respectively provided at the same position on the front and the back of the beam (4).

A method for fabricating a sensor system includes providing a surface acoustic wave (SAW) tag on a substrate including a detector bank of reflectors at one end to generate a detector SAW responsive to an interrogation signal, a reference bank of reflectors at an opposite end of the substrate to generate a reference SAW responsive to the interrogation signal, and a transducer between the detector and reference banks of reflectors for receiving the interrogation signal and transmitting the detector and reference SAW from the detector and the reference banks of reflectors in response. A hydrogen gas sensor is formed on the substrate in a propagation delay path (delay path) between the detector bank of reflectors and the transducer to modulate propagation parameters of the detector SAW in response to sensing hydrogen gas. The forming includes depositing a SnO.sub.2 film then depositing a Pd film onto the SnO.sub.2 film.

A photoacoustic gas sensor device for deter-mining a value indicative of a presence or a concentration of a component in a gas comprises a substrate and a measurement cell body, the substrate and the measurement cell body defining a measurement cell enclosing a measurement volume. A reflective shield divides the measurement volume into a first volume and a second volume. An opening in the measurement cell is provided for a gas to enter the measurement volume. In the first volume and on a front side of the substrate are arranged: An electromagnetic radiation source for emitting electromagnetic radiation through an aperture in the reflective shield into the second volume; and a pressure transducer communicatively coupled to the second volume for measuring a sound wave generated by the component in response to an absorption of electromagnetic radiation by the component. At least a portion of a surface of the reflective shield facing the second volume is made of a material reflecting electromagnetic radiation.

[Object] To provide an arithmetic device, an arithmetic method, and a gas detection system that are capable of easily correcting deterioration over time of a detection element.

[Solving Means] The arithmetic device includes a calculation unit. The calculation unit calculates a correction coefficient from a detection element that causes a resonant frequency change by adsorption of gas on the basis of a resonant frequency change amount associated with a humidity change of the detection element in a degraded state and a resonant frequency change amount associated with a humidity change of the detection element in an initial state that was acquired in advance, and corrects the resonant frequency change amount of the detection element in the degraded state by using the correction coefficient.

A gas sensor (100,200) includes at least one sensor device including a surface acoustic wave (SAW) device (110) or a quartz crystal microbalance (QCM) device (210), and a layer of metal organic framework (MOF) material (120,220) disposed on each of the at least one sensor device. The at least one sensor device is structured to sense a change in mass of the MOF material.

In an embodiment an electro-thermal device includes a heater, a readout circuit, a digital controller having a first input coupled to a first output of the readout circuit and a digital sigma-delta modulator having a first input coupled to an output of the digital controller and an output coupled to the heater.

A gas sensor includes a piezoelectric substrate; a resonator in an electrode region on an upper surface of the piezoelectric substrate, the resonator including interdigital transducer (IDT) electrodes and IDT pads connected to the IDT electrodes, the IDT electrodes configured to generate a surface acoustic wave in a center region of the electrode region, the surface acoustic wave propagating in a first horizontal direction; a sensing film in the center region of the electrode region on the upper surface of the piezoelectric substrate, the sensing film including a sensing material that interacts with a target gas; and a heater in an edge region surrounding the electrode region on the upper surface of the piezoelectric substrate, the heater including heater electrodes configured to heat the sensing film and heater pads connected to the heater electrodes, the heater electrodes and the heater pads forming a closed conduction loop.

Disclosed herein are acoustic spectrometers with broadband actuators and advanced system identification techniques for modeling the characteristic response of a gas. Benefits of the spectrometer devices and methods disclosed herein, which can include speed of sound measurements (or combined therewith), provide for more robust and less expensive solutions than previous technologies.

A gas sensor includes a microbeam configured to vibrate when driven by a driving electrode; a vibrometer configured to measure a frequency associated with a vibration of the microbeam; a power source configured to apply a first voltage (V1) to the microbeam to heat the microbeam; and a controller configured to control the power source and to receive the frequency measured by the vibrometer. The controller controls the power source to heat the microbeam so that the microbeam is at a buckling point, and the controller determines at least one characteristic of a gas present around the microbeam, based on the frequency received from the vibrometer.