Phase-variation microwave sensor for permittivity measurements based on a high-impedance half-wavelength transmission line
Su, Lijuan (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Muñoz Enano, Jonathan (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Vélez Rasero, Paris (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Casacuberta Orta, Pau (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Gil Barba, Marta (Universidad Politécnica de Madrid. Departamento de Ingeniería Audiovisual y Comunicaciones)
Martín, Ferran (Martín Antolín) (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)

Date:	2021
Abstract:	A phase-variation microwave sensor operating in transmission and implemented by means of a high-impedance half-wavelength sensing line is reported in this paper. The sensor is useful for dielectric constant measurements and dielectric characterization of materials. By forcing the electrical length of the sensing line to be a half-wavelength when it is loaded with the so-called reference (REF) material, perfect matching is obtained regardless of the characteristic impedance of the line. This fact can be used to enhance the sensitivity for small perturbations, by merely increasing the characteristic impedance of the sensing line. An exhaustive analysis that supports such conclusion is reported in the paper. Then, two prototype sensors are designed and fabricated for validation purposes. As compared to the ordinary phase-variation permittivity sensor implemented by means of a matched ( 50-Ω) line with identical length, the sensitivity for small perturbations in the proposed sensor is 2. 1 times larger. Further advantages of these sensors are low-cost, small size, implementation in planar technology, and very simple design and fabrication, derived from the fact that the sensing region is a half-wavelength transmission line.
Grants:	Agencia Estatal de Investigación PID2019-103904RB-I00 Agencia Estatal de Investigación IJC2019-040786-I Ministerio de Ciencia e Innovación IJCI-2017-31339 Ministerio de Ciencia e Innovación TEC2016-75650-R Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1159
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Dielectric characterization ; Microstrip technology ; Microwave sensors ; Permittivity sensors ; Phase-variation sensors
Published in:	IEEE sensors journal, Vol. 21, issue 9 (May 2021) , p. 10647-10656, ISSN 1530-437X

DOI: 10.1109/JSEN.2021.3063112

Postprint 12 p, 928.3 KB

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