TY - JOUR
T1 - Portable Reflective-Mode Phase-Variation Microwave Sensor Based on a Rat-Race Coupler Pair and Gain/Phase Detector for Dielectric Characterization
AU - Vélez Rasero, Paris
AU - Paredes, Ferran
AU - Casacuberta Orta, Pau
AU - Elgeziry, Mahmoud
AU - Su, Lijuan
AU - Muñoz Enano, Jonathan
AU - Costa, Filippo
AU - Genovesi, Simone
AU - Martín, Ferran
N1 - Publisher Copyright:
© 2001-2012 IEEE.
PY - 2023/3/15
Y1 - 2023/3/15
N2 - 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.
AB - 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.
KW - Hybrid coupler
KW - Microstrip technology
KW - Microwave sensor
KW - Permittivity sensor
KW - Phase detector
KW - Phase-variation sensor
KW - Reflective-mode sensor
UR - http://www.scopus.com/inward/record.url?scp=85148416159&partnerID=8YFLogxK
UR - https://www.mendeley.com/catalogue/17ed45c3-6c65-3c8f-b9f4-9d55c64d06b8/
U2 - 10.1109/JSEN.2023.3240771
DO - 10.1109/JSEN.2023.3240771
M3 - Article
SN - 1530-437X
VL - 23
SP - 5745
EP - 5756
JO - IEEE Sensors Journal
JF - IEEE Sensors Journal
IS - 6
ER -