Adjustable cancellation type high sensitivity radio frequency sensor. (15th January 2021)

• Record Type: Journal Article
• Authors: Wang, Haiyang; Liu, Xiaoqin; Xiong, Rui; Zou, Huan
• Is Part Of: Measurement. Volume 168(2021)
• Publication Date: 2021-01-15
• Subjects: Sensor -- Dielectric constant -- Micro fluids -- Adjustable; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2020.108337
• Languages: English
• ISSNs: 0263-2241

Abstract

Highlights: The sensor can effectively fine-tune the attenuation and electrical length of the both branches. Adjustable cavity can effectively calibrate the RF sensor for different reference micro fluids. Sensor becomes more sensitive and accurate after calibrating. The introduction of the tuning screw will cause certain changes in both amplitude and phase of S21 . The field intensity distribution is more concentrated where the screw position changes. Abstract: This paper presents an ultra-high sensitive and adjustable RF sensor for measuring the dielectric constant changes of micro fluids. According to the principle of half-wavelength signal cancellation, the sensor is designed based on coplanar waveguide structures consisting of two Wilkinson power dividers, two transmission branches and an adjustable cavity. The addition of the adjustable cavity can effectively calibrate the RF sensor for different reference micro fluids. The experimental results show that the calibrated sensor can effectively increase the change of output S21 amplitude of absolute ethanol and n-propanol by 7.05 dB and 10.26 dB respectively. Therefore, the calibratable sensor is more sensitive to measure the minor changes in the dielectric constant of micro fluids.