Frequency-Switchable Microfluidic CSRR-Loaded QMSIW Band-Pass Filter Using a Liquid Metal Alloy

Microfluidics is quickly becoming a key technology in an expanding range of fields, such as medical sciences, biosensing, bioactuation, chemical synthesis, and more. This is helping its transformation from a promising R&D tool to commercially viable technology. Fuelling this expansion is the intensified focus on automation and enhanced functionality through integration of complex electrical control, mechanical properties, in situ sensing and flow control. Here we highlight recent contributions to the Sensors Special Issue series called “Microfluidics-Based Microsystem Integration Research” under the following categories: (i) Device fabrication to support complex functionality; (ii) New methods for flow control and mixing; (iii) Towards routine analysis and point of care applications; (iv) In situ characterization; and (v) Plug and play microfluidics.

Section: In Situ Characterizationmentioning

confidence: 99%

Recent Advancements towards Full-System Microfluidics

Miled

Greener

2017

“…Their geometry, shape, orientation, and properly applied electric/magnetic field determine their usefulness and operating frequency [ 16 , 17 ]. Split ring resonators (SRRs) and complementary split ring resonators (CSRRs) are the most utilized topologies of metamaterials for developing a variety of RF circuits and components [ 18 , 19 , 20 , 21 ]. Next, we highlight existing RF resonators proposed for the simultaneous detection of multiple fluids.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Detection of Two Chemicals Using a TE20-Mode Substrate-Integrated Waveguide Resonator

Salim

Memon

Lim

2018

Self Cite

Microwave resonators working as sensors can detect only a single analyte at a time. To address this issue, a TE20-mode substrate-integrated waveguide (SIW) resonator is exploited, owing to its two distinct regions of high-intensity electric fields, which can be manipulated by loading two chemicals. Two microfluidic channels with unequal fluid-carrying capacities, engraved in a polydimethylsiloxane (PDMS) sheet, can perturb the symmetric electric fields even if loaded with the two extreme cases of dielectric [ethanol (E), deionized water (DI)] and [deionized water, ethanol]. The four layers of the sandwiched structure considered in this study consisted of a top conductive pattern and a bottom ground, both realized on a Rogers RT/Duroid 5880. PDMS-based channels attached with an adhesive serve as the middle layers. The TE20-mode SIW with empty channels resonates at 8.26 GHz and exhibits a −25 dB return loss with an unloaded quality factor of Q ≈ 28. We simultaneously load E and DI and demonstrate the detection of the four possible combinations: [E, DI], [DI, E], [E, E], and [DI, DI]. The performance of our proposed method showed increases in sensitivity (MHz/εr) of 7.5%, 216%, and 1170% compared with three previously existing multichannel microwave chemical sensors.

“…The properties of MMs depend mainly on the dimensions, topology, or orientation, and configurations adopted [ 4 ]. Split-ring resonators (SRRs) and complementary-split-ring resonators (CSRRs) are the two most used configurations of MMs to accomplish versatile microwave components such as antennas [ 5 ], sensors [ 6 ], absorbers [ 7 ], power dividers [ 8 ], and filters [ 9 ]. Inductive-capacitive (LC) equivalent circuit models are derived to describe the behavior of unit-cell SRRs, where capacitance is provided by the split-gap of the SRR and inductance is provided by the surface current flowing into the metallic SRR.…”

Section: Introductionmentioning

confidence: 99%

Low-Cost and Lightweight 3D-Printed Split-Ring Resonator for Chemical Sensing Applications

Salim

Ghosh

Lim

2018

Self Cite

In this paper, a microwave cavity resonator is presented for chemical sensing applications. The proposed resonator is comprised of a three dimensional (3D) split-ring resonator (SRR) residing in an external cavity and capacitively coupled by a pair of coaxial probes. 3D-printing technology with polylactic acid (PLA) filament is used to build the 3D SRR and cavity. Then, the surfaces of the SRR and the inside walls of cavity are silver-coated. The novelty of our proposed structure is its light weight and inexpensive design, owing to the utilization of low density and low-cost PLA. A Teflon tube is passed through the split-gap of the SRR so that it is parallel to the applied electric field. With an empty tube, the resonance frequency of the structure is measured at 2.56 GHz with an insertion loss of 13.6 dB and quality factor (Q) of 75. A frequency shift of 205 MHz with respect to the empty channel was measured when deionized water (DIW) was injected into the tube. Using volume occupied by the structure, the weight of the proposed microwave resonator is estimated as 22.8 g which is significantly lighter than any metallic structure of comparable size.