Toward a low-cost portable reader for reflective-mode microwave sensors
Elgeziry, Mahmoud (Università di Pisa. Dipartimento di Ingegneria dell'Informazione)
Costa, Filippo (Università di Pisa. Dipartimento di Ingegneria dell'Informazione)
Vélez Rasero, Paris (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Paredes, Ferran (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Martín, Ferran (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Genovesi, Simone (Università di Pisa. Dipartimento di Ingegneria dell'Informazione)

Date:	2024
Abstract:	Microwave sensors are typically characterized using a vector network analyzer (VNA) that measures the scattering parameters of the device under test (DUT) over a wide frequency band with great accuracy. However, these features of the VNA are not always required, and its bulky form factor and high cost can even be a limitation in many practical scenarios, such as microwave sensors, which are generally characterized by low cost, a small footprint, and often planar profiles. This article presents a novel, low-cost portable reader for reflective-mode microwave sensors. The proposed device is based on a hybrid 180° directional coupler that separates the input signal from the reflected one, a voltage-controlled oscillator (VCO) to generate the input signal, and a gain/phase detector board. The performance of the proposed system has been experimentally assessed for reference load cases, showing a good match between the simulated and measured results. The capability and usefulness of the proposed device are demonstrated through the implementation of a reflective-mode distance sensor where the input impedance of the one-port sensing element is the output variable of interest. The results obtained with the proposed reader well match the VNA measurements, with a mean error of about 8%. It is worth noting that the presented solution can be easily adopted as the measurement device by other reflective-mode sensors operating in the frequency band of the coupler. Overall, the proposed novel reader offers a new approach to measuring the output variable of one-port reflective-mode microwave sensors that is battery-powered, portable, versatile, accurate, and cost-effective compared with using a VNA.
Grants:	Agencia Estatal de Investigación PDC2021-121085-I00 Agencia Estatal de Investigación PID2019-103904RB-I00 Agència de Gestió d'Ajuts Universitaris i de Recerca 2021/SGR-00192
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Distance sensor ; Hybrid coupler ; Microwave sensor ; Reflective-mode sensor ; Spiral resonator (SR)
Published in:	IEEE transactions on instrumentation and measurement, Vol. 73 (2024) , art. 8000309, ISSN 0018-9456

DOI: 10.1109/TIM.2023.3338651

Available from: 2026-03-30 Postprint

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