Title :
A Microwave Resonant Sensor for Concentration Measurements of Liquid Solutions
Author :
Gennarelli, G. ; Romeo, Salvatore ; Scarfi, M.R. ; Soldovieri, Francesco
Author_Institution :
Inst. for the Electromagn. Sensing of the Environ., Naples, Italy
Abstract :
This paper presents the design, fabrication, and characterization of a microwave resonator as a tool for concentration measurements of liquid compounds. The sensing device is a rectangular waveguide cavity tuned at 1.91 GHz, which exploits the fundamental TE101 mode in a transmission-type configuration. The coupling structure is optimized by means of a finite element code so as to achieve a high Q-factor. According to the type of substance inside the mixture, its concentration is conveniently related to changes of the S21 scattering parameter (transmission coefficient) in terms of: 1) resonance frequency; 2) 3-dB bandwidth; and 3) amplitude at the resonance frequency. Experimental tests on liquid solutions in controlled conditions are presented to evaluate the performance of the device.
Keywords :
UHF detectors; UHF measurement; cavity resonators; chemical sensors; chemical variables measurement; finite element analysis; flow sensors; microfabrication; microwave detectors; microwave measurement; performance evaluation; rectangular waveguides; Q-factor; S21 scattering parameter; coupling structure optimization; finite element code; frequency 1.91 GHz; fundamental TE101 mode; gain 3 dB; liquid compound solution concentration measurement; microwave resonant sensor; performance evaluation; rectangular waveguide cavity; resonance frequency; transmission-type configuration; Cavity resonators; Dielectrics; Liquids; Permittivity; Probes; Q factor; Resonant frequency; Concentration sensor; liquid solutions; microwave sensor; rectangular waveguide cavity;
Journal_Title :
Sensors Journal, IEEE
DOI :
10.1109/JSEN.2013.2244035
