Losses Assisted Sensitivity Enhancement in Reflective-Mode Phase-Variation Permittivity Sensors Based on Weakly Coupled Distributed Resonators
Casacuberta Orta, Pau (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Vélez Rasero, Paris (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Muñoz Enano, Jonathan (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Su, Lijuan (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Martín, Ferran (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)

Date:	2023
Abstract:	This letter demonstrates that losses [including substrate losses and losses in the material under test (MUT)] can be beneficial to boost the sensitivity in one-port reflective-mode phase-variation planar permittivity sensors based on a pair of weakly coupled quarter-wavelength resonators (the sensing elements). It is shown that the key aspect of optimizing the sensitivity in the limit of small perturbations of the dielectric constant of the MUT in the vicinity of the reference dielectric constant is to achieve a high slope in the phase of the reflection coefficient at the operating frequency and the output variable. Depending on the level of losses, such phase slope can be either negative (low-loss regime) or positive (high-loss regime). Nevertheless, the relevant aspect is that, regardless of its sign, the magnitude of the phase slope can be arbitrarily high by adequately designing the sensor considering the device and MUT losses. Thus, losses do not necessarily degrade sensitivity; instead, they can be strategically utilized to achieve unprecedented sensitivities in this type of sensor, which operates based on the measurement of the reflection coefficient phase.
Grants:	Agencia Estatal de Investigación PID2019-103904RB-I00 Agencia Estatal de Investigación PDC2021-121085-I00 Agència de Gestió d'Ajuts Universitaris i de Recerca 2021/SGR-00192 Agencia Estatal de Investigación IJC2019-040786-I Agencia Estatal de Investigación FPU20/05700
Note:	Altres ajuts: ICREA Academia
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Coupled lines ; Coupled resonators ; Microstrip ; Microwave sensors ; Permittivity sensors ; Phase-variation sensors
Published in:	IEEE Sensors Letters, Vol. 7, Issue 8 (August 2023) , art. 1500704, ISSN 2475-1472

DOI: 10.1109/LSENS.2023.3297798

Available from: 2025-08-31 Postprint

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Engineering > CIMITEC-UAB
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