Validation of a Low-Cost Open-Ended Coaxial Probe Setup for Broadband Permittivity Measurements up to 6 GHz

This work presents the validation of a low-cost measurement system based on an open- ended coaxial SMA (SubMiniature version A) probe for the characterization of complex permittivity in the microwave frequency range. The system combines a custom-fabricated probe, a vector network analyzer, and a ded...

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Detalles Bibliográficos
Autores: Arias Rodríguez, Julia, Moreno-Merín, Raúl, Martínez-Lozano, Andrea, Torregrosa-Penalva, Germán, Ávila-Navarro, Ernesto
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universidad Miguel Hernández de Elche
Repositorio:REDIUMH. Depósito Digital de la UMH
OAI Identifier:oai:dspace.umh.es:11000/37845
Acceso en línea:https://hdl.handle.net/11000/37845
Access Level:acceso abierto
Palabra clave:Complex permittivity
Open-Ended coaxial probe
Low-cost system
SMA-based dielectric sensor
Microwave measurement
Dielectric spectroscopy
Calibration
Reproducibility
Descripción
Sumario:This work presents the validation of a low-cost measurement system based on an open- ended coaxial SMA (SubMiniature version A) probe for the characterization of complex permittivity in the microwave frequency range. The system combines a custom-fabricated probe, a vector network analyzer, and a dedicated software application that implements three analytical models: capacitive, radiation, and virtual transmission line models. A comprehensive experimental campaign was carried out involving pure polar liquids, saline solutions, and biological tissues, with the measurements compared against those obtained using a high-precision commercial probe. The results confirm that the proposed system is capable of delivering accurate and reproducible permittivity values up to at least 6 GHz. Among the implemented models, the radiation model demonstrated the best overall performance, particularly in biological samples. Additionally, reproducibility tests with three independently assembled SMA probes showed normalized deviations below 3%, confirming the robustness of the design. These results demonstrate that the proposed system constitutes a viable alternative for cost-sensitive applications requiring portable or scalable microwave dielectric characterization.