Real-time Humidity Sensor Based on Microwave Resonator Coupled with PEDOT:PSS Conducting Polymer Film

Abstract

A real-time humidity sensor based on a microwave resonator coupled with a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) conducting polymer (CP) film is proposed in this paper. The resonator is patterned on a printed circuit board and is excited by electromagnetic field coupling. To enhance the sensitivity of the sensor, the CP film is located in the area with the strongest electric field in the resonator. To investigate the performance, the proposed sensor is placed alongside a reference sensor in a humidity chamber, and humidity is injected at room temperature. The experimental results indicate that the electrical properties of the resonator with the CP film, such as the transmission coefficient (S 21) and resonance frequency, change with the relative humidity (RH). Specifically, as the RH changes from 5% to 80%, S 21 and the resonance frequency change simultaneously. Moreover, the proposed sensor exhibits great repeatability in the middle of the sensing range, which is from 40% to 60% RH. Consequently, our resonator coupled with the CP film can be used as a real-time humidity-sensing device in the microwave range, where various radio-frequency devices are in use.

Temperature-Corrected Fluidic Glucose Sensor Based on Microwave Resonator

“…In addition, their physical size can be reduced by designing to operate at a higher frequency range. Due to these advantages, in recent decades, microwave resonators have been employed as sensing devices, such as gas sensors [ 15 ], temperature sensors [ 16 ], pH sensors [ 17 ], and in biomolecule detection [ 18 , 19 ], vital sign detection [ 20 , 21 ], wrist pulse monitoring [ 22 ], breast tumor detection [ 23 ], humidity sensors [ 24 ], and so on. In addition, many studies have been proposed to detect the glucose level using a microwave technique [ 25 , 26 , 27 , 28 ], but they employed an invasive approach in which the sensor and glucose solution are in direct contact.…”

Antibacterial poly (3,4-ethylenedioxythiophene):poly(styrene-sulfonate)/agarose nanocomposite hydrogels with thermo-processability and self-healing

“…Importantly, PEDOT:PSS could be easily mixed and the homogeneously well-mixed PEDOT:PSS/agarose solution was obtained due to the excellent affinity of two solutions. After cooling to room temperature, gelation of PEDOT:PSS/agarose was observed due to multiple hydrogen bonding crosslinks between PEDOT:PSS and/or agarose ( Figure 1B) (Agua et al, 2017;Armelin, Pérez-Madrigal, Alemán, & Díaz, 2016;Park et al, 2018). The hydrogen bonding between PEDOT:PSS and agarose in nanocomposite gels was clearly confirmed by FTIR as shown in Figure S1.…”

Developing a low‐cost weather monitoring system for data‐sparse regions of the Himalayas

“…The BMP180 high‐precision digital air pressure sensor was used for measuring atmospheric pressure in the range of 300–1100hPa. Finally, the DHT22 is a combined air temperature and relative humidity sensor, with a temperature measuring range of −40°C to 125°C with an accuracy of up to ±0.5 degC and with relative humidity in the range 0–100% with a purported accuracy of up to ±2% relative humidity (RH) (Bitella et al ., 2014; Salamone et al ., 2017; Park et al ., 2018). A schematic diagram of this system is shown in Figure 2.…”