A Cascaded MEMS Amplitude Demodulator for Large Dynamic Range Application in RF Receiver

An amplitude demodulator with a large dynamic range, based on microelectromechanical systems (MEMS), is proposed in this paper. It is implemented as a cascade of a capacitive and a thermoelectric sensor. Two types of the transducer can improve the measurement range and enhance the overload capacity. This MEMS-based demodulation is realized by utilizing the square law relationship and the low-pass characteristic during the electromechanical and thermoelectric conversion. The fabrication of this device is compatible with the GaAs monolithic microwave integrated circuit (MMIC) process. Experiments show that this MEMS demodulator can realize the direct demodulation of an amplitude modulation (AM) signal with a carrier frequency of 0.35–10 GHz, and cover the power range from 0 to 23 dBm. This MEMS demodulator has the advantages of high power handling capability and zero DC power consumption.

The analysis of applicability of thermoelectric radiation detectors for heat flux measurements behind a reflected shock wave

The study is devoted to assessing the applicability of the manufactured thermoelectric sensor to measure pulsed heat fluxes in shock-wave processes. It is shown that the created thermoelectric sensor has fast response time and sufficient level of electric signal and can be successfully used in short duration high speed gas dynamic experiments.

Thermoelectric Sensor Coupled Yagi–Uda Nanoantenna for Infrared Detection

We present an experimental demonstration of a thermoelectric sensor coupled with a nanoantenna as an alternative option for detecting infrared energy. Two nanoantenna design (single element and an array) variations based on Yagi-Uda technology and one separate nano-thermoelectric junction array were fabricated and tested. The nanoantennas were tuned to operate and respond at a center wavelength of 1550 nm (193.5 THz) optical C-band window, but they also exhibited a resonance response when excited by lasers of various wavelengths (650 nm and 940 nm). The radiation-induced electric currents in the nanoantennas, coupled with a nano-thermoelectric sensor, produced a potential difference as per the Seebeck effect. With respect to the uniform thermal measurements of the reference nanoantenna, the experiments confirmed the detection properties of the proposed nanoantennas; the single element detected a peak percentage voltage hike of 28%, whereas the array detected a peak percentage voltage hike of 80% at the center wavelength. Compared to state-of-the-art thermoelectric designs, this was the first time that such peak percentage voltages were experimentally reported following a planar design based on the Seebeck principle.

Numerical Optimization of Key Design Parameters of a Thermoelectric Microfluidic Sensor for Ultrasensitive Detection of Biochemical Analytes

The design of highly sensitive thermoelectric microfluidic sensors for the characterization of biochemical processes is an important area of engineering research. This study reports the design and fabrication of a continuous-flow biosensor with an integrated thermopile and three-dimensional numerical analysis of the critical design parameters that significantly increase the detection sensitivity of the platform. The paper discusses the impact of volumetric flowrate, channel height, material thermal properties, and heat sink on the magnitude of the thermoelectric signal. In the platform understudy, the heat generated by the enzymatic reaction between glucose oxidase-conjugated antibody and glucose is converted to an electric output by an antimony-bismuth thin-film thermopile with a theoretical Seebeck coefficient of 7.14 µV mK−1. Since this experimental configuration has been implemented in a various biochemical analysis, particular emphasis in this work is maximizing the detection sensitivity of the device. Computational thermal modeling was performed to investigate the impact of channel height (50 µm, 100 µm, 150 µm, and 200 µm), the volumetric flow rate of the substrate (25 µL min−1 and 50 µL min−1), and the microdevice material (glass, PMMA, and PDMS) on the output of the thermoelectric sensor. Experimental data validated the model and provided an excellent correlation between the predicted and measured voltage output. Results show that fabricating the calorimeter out of materials with lower thermal diffusivity, reducing the channel height, and eliminating the heat sink at the reference junction of the thermopile increases the sensitivity of the platform by 783%.

Performance Examination of Low-Power Thermoelectric Sensor Arrays for Energy Harvesting From Human Body Heat

Thermoelectric energy harvester is known as a type of energy harvesting technologies which extracts waste heat from a target device or object to generate electrical power. The low power generation from thermoelectric energy harvester, though, is always a critical consideration in designing a self-sustaining system. The energy harvesting system is usually aided by a power management solution to further enhance the power generation for better performance. Therefore, maximizing the power generated from the thermoelectric sensor itself is essential in order to select the most suitable power management approach. This paper presumed the methodology to maximize power generation of thermoelectric and further discussion is reviewed in the report.

A Self-Powered Flexible Thermoelectric Sensor and Its Application on the Basis of the Hollow PEDOT:PSS Fiber

The thermoelectric (TE) fiber, based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), which possesses good flexibility, a low cost, good environmental stability and non-toxicity, has attracted more attention due to its promising applications in energy harvesting. This study presents a self-powered flexible sensor based on the TE properties of the hollow PEDOT:PSS fiber. The hollow structure of the fiber was synthesized using traditional wet spinning. The sensor was applied to an application for finger touch, and showed both long-term stability and good reliability towards external force. The sensor had a high scalability and was simple to develop. When figures touched the sensors, a temperature difference of 6 °C was formed between the figure and the outside environment. The summit output voltages of the sensors with 1 to 5 legs gradually increased from 90.8 μV to 404 μV. The time needed for the output voltage to reach 90% of its peak value is only 2.7 s. Five sensors of legs ranging from 1 to 5 were used to assemble the selector. This study may provide a new proposal to produce a self-powered, long-term and stable skin sensor, which is suitable for wearable devices in personal electronic fields.

Performance Examination and Design Optimization of Thermoelectric Sensor Configuration for Energy Harvesting From Air Conditioner Waste Heat

Due to energy crisis as well as environmental pollution issues, it is necessity for the establishment of alternatives energy harvester system in reducing the dependency of the primary resources such as oil and coal. The purpose of this research is to investigate working principle of the thermoelectric (TE) which able to harvest waste heat energy through a portable air conditioner and convert it to electrical energy. To optimise the TE performance, a number of TE configurations via experimental analysis are carried out which are significantly affecting the output power and the conversion efficiency of the TE system. From this research, it is concluded that proper design of the TE system is required to improve its energy conversion efficiency.

Design and Fabrication Challenges of a Highly Sensitive Thermoelectric-Based Hydrogen Gas Sensor

This paper presents a highly sensitive thermoelectric sensor for catalytic combustible gas detection. The sensor contains two low-stress (+176 MPa) membranes of a combination of stoichiometric and silicon-rich silicon nitride that makes them chemically and thermally stable. The complete fabrication process with details, especially the challenges and their solutions, is discussed elaborately. In addition, a comprehensive evaluation of design criteria and a comparative analysis of different sensor designs are performed with respect to the homogeneity of the temperature field on the membrane, power consumption, and thermal sensitivity. Evaluating the respective tradeoffs, the best design is selected. The selected sensor has a linear thermal characteristic with a sensitivity of 6.54 mV/K. Additionally, the temperature profile on the membrane is quite homogeneous (20% root mean standard deviation), which is important for the stability of the catalytic layer. Most importantly, the sensor with a ligand (p-Phenylenediamine (PDA))-linked platinum nanoparticles catalyst shows exceptionally high response to hydrogen gas, i.e., 752 mV at 2% concentration.