Portable Reflective-Mode Phase-Variation Microwave Sensor Based on a Rat-Race Coupler Pair and Gain/Phase Detector for Dielectric Characterization
| Autor: | Paris Vélez, Ferran Paredes, Pau Casacuberta, Mahmoud Elgeziry, Lijuan Su, Jonathan Muñoz-Enano, Filippo Costa, Simone Genovesi, Ferran Martín |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | IEEE Sensors Journal. 23:5745-5756 |
| ISSN: | 2379-9153 1530-437X |
| DOI: | 10.1109/jsen.2023.3240771 |
| Popis: | Altres ajuts: Institució Catalana de Recerca i Estudis Avançats 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. |
| Databáze: | OpenAIRE |
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