Single-frequency amplitude-modulation sensor for dielectric characterization of solids and microfluidics

Paris Velez*, Jonathan Munoz-Enano, Amir Ebrahimi, Cristian Herrojo, Ferran Paredes, James Scott, Kamran Ghorbani, Ferran Martin

*Autor corresponent d’aquest treball

Producció científica: Contribució a una revistaArticleRecercaAvaluat per experts

60 Cites (Scopus)

Resum

A microfluidic sensor based on a microstrip line loaded with a composite resonator is reported in this paper. The composite resonator combines a shunt connected step impedance resonator (SIR) and a complementary split ring resonator CSRR) etched in the ground plane. By etching the CSRR beneath the patch of the SIR, the composite CSRR-loaded SIR resonator exhibits two transmission zeros and a pole in between. The operating principle of the sensor is the variation of the transmission coefficient at the pole frequency of the bare resonator, when a material or liquid under test (LUT) is in contact with the CSRR (the sensitive element). By designing the CSRR-loaded SIR resonator with closely spaced pole and transmission zeros, highly sensitive sensors are obtained. Despite the fact that the proposed sensor can also operate as a frequency variation sensor, using it as a single-frequency sensor based on the variation of the transmission coefficient (caused by the LUT) at a specific frequency reduces sensor costs. The reason is that a harmonic signal injected to the input port of the microstrip-based sensor plus a simple amplitude modulation (AM) detector (connected to the output port) suffices for measuring purposes. The proposed microfluidic sensor is applied to the characterization of volume fraction of solutions of isopropanol in deionized (DI) water. The sensor is able to resolve volume fractions as small as 5%, and the maximum measured sensitivity is as good as 4 mV/%.

Idioma originalEnglish
Número d’article9363919
Pàgines (de-a)12189-12201
Nombre de pàgines13
RevistaIEEE Sensors Journal
Volum21
Número10
DOIs
Estat de la publicacióPublicada - 26 de febr. 2021

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