Portable Reflective-Mode Phase-Variation Microwave Sensor Based on a Rat-Race Coupler Pair and Gain/Phase Detector for Dielectric Characterization
This article presents a low-cost and portable phase-variation planar microwave sensor operating in reflective mode, where the output variable, the phase of the reflection coefficient of the one-port sensing element, is retrieved by means of a distributed circuit based on a pair of rat-race hybrid co...
| Autores: | , , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universitat Autònoma de Barcelona |
| Repositorio: | Dipòsit Digital de Documents de la UAB |
| Idioma: | inglés |
| OAI Identifier: | oai:ddd.uab.cat:275092 |
| Acceso en línea: | https://ddd.uab.cat/record/275092 https://dx.doi.org/urn:doi:10.1109/JSEN.2023.3240771 |
| Access Level: | acceso abierto |
| Palabra clave: | Hybrid coupler Microstrip technology Microwave sensor Permittivity sensor Phase detector Phase-variation sensor Reflective-mode sensor |
| Sumario: | This article presents a low-cost and portable phase-variation planar microwave sensor operating in reflective mode, where the output variable, the phase of the reflection coefficient of the one-port sensing element, is retrieved by means of a distributed circuit based on a pair of rat-race hybrid couplers and the associated electronics. This includes a microcontroller, a voltage controlled oscillator (VCO), a digital-to-analog converter (DAC), and an RF/microwave gain/phase detector. By this means, vector network analyzers (VNAs), i.e., high-cost instruments typically used for obtaining the reflection coefficient in one-port structures or circulators (microwave components able to separate the injected signal from the reflected signal in any one-port network) are avoided. Indeed, the presented architecture (including the microwave rat-race hybrid configuration and the associated electronics) can be adapted to other one-port reflective-mode phase-variation microwave sensors. A prototype example, where the sensing element is a one-port step-impedance open-ended transmission line, is reported. The device provides the phase of the reflection coefficient of the sensing element as a function of the dielectric constant of the material under test (MUT) with a maximum sensitivity of -65.7° and a relative error of less than 8% in all the measurements. |
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