Characterization of electrolyte content in urine samples through a differential microfluidic sensor based on dumbbell-shaped defected ground structures

Abstract

In this paper, a differential microfluidic sensor and comparator based on a pair of microstrip lines loaded with dumbbell-shaped defected ground structure resonators is applied to the characterization of electrolyte concentration in samples of horse urine. Since variations in the total electrolyte content in urine may be indicative of certain pathologies, the interest is to use the device as a comparator, in order to determine changes in the electrolyte concentration as compared to a reference level. To validate the approach, we have made differential measurements of a set of urine samples with different electrolyte concentrations (which have been previously obtained by means of electrochemical methods). The obtained results correlate with the nominal electrolyte concentrations of the samples, thereby pointing out the potential of the approach as a low-cost pre-screening method (or complementary diagnosis system) to detect potential pathologies or diseases in horses and other animals.

Balanced Microwave Transmission Lines, Circuits, and Sensors

“…For that purpose, additional elements to the sensing lines, e.g., couplers, or dividers/combiners, are required. Concerning differential-mode resonant sensors, the sensing element is typically a pair of transmission lines loaded with a planar resonator, either a metallic or a slot resonator [24], [25], [253], [254], [255], [256], [257], [258], [259], [260], [261], [262], [263], [264]. In these sensors, the canonical output variable is the differential resonance frequency between the pair of resonator-loaded lines.…”

Microfluidic Modules Integrated with Microwave Components—Overview of Applications from the Perspective of Different Manufacturing Technologies

“…The use of microfluidic devices with integrated microwave components is notable mainly in biochemical and chemical applications, such as detecting the biological material [ 9 , 10 , 11 , 12 ]. Furthermore, due to the possibility of noncontact sensing and delivering the microwaves to the systems (using the antenna-based circuits), the possibilities are still increasing [ 13 , 14 , 15 ].…”

Discussion and Analysis of Dumbbell Defect-Ground-Structure (DB-DGS) Resonators for Sensing Applications from a Circuit Theory Perspective

“…The dumbbell defect-ground-structure (DB-DGS) resonator [1,2] is a slot resonator exhaustively used in microwave engineering for the implementation of circuits (mainly filters [3][4][5][6][7][8][9]) and sensors [10][11][12][13]. DB-DGS resonators are typically combined with microstrip transmission lines.…”

“…The notched response of DB-DGS-loaded microstrip lines can be exploited for the implementation of notch and stopband filters [3][4][5][6], as well as for the design of commonmode filters in differential lines [7,9]. However, slot resonators, including the DB-DGS resonator, are also of interest for the implementation of planar microwave sensors devoted to permittivity measurements, and to the characterization of materials (including solids and liquids) [10][11][12][13]. The reason is that the resonance frequency of these slot resonators is very sensitive to the dielectric properties of the material surrounding the resonator (in contact or in close proximity to it).…”