Electromagnetic Differential Measuring Method: Application in Microstrip Sensors Developing

Abstract

Electromagnetic radiation is energy that interacts with matter. The interaction process is of great importance to the sensing applications that characterize material media. Parameters like constant dielectric represent matter characteristics and they are identified using emission, interaction and reception of electromagnetic radiation in adapted environmental conditions. How the electromagnetic wave responds when it interacts with the material media depends on the range of frequency used and the medium parameters. Different disciplines use this interaction and provides non-intrusive applications with clear benefits, remote sensing, earth sciences (geology, atmosphere, hydrosphere), biological or medical disciplines use this interaction and provides non-intrusive applications with clear benefits. Electromagnetic waves are transmitted and analyzed in the receiver to determine the interaction produced. In this work a method based in differential measurement technique is proposed as a novel way of detecting and characterizing electromagnetic matter characteristics using sensors based on a microstrip patch. The experimental results, based on simulations, show that it is possible to obtain benefits from the behavior of the wave-medium interaction using differential measurement on reception of electromagnetic waves at different frequencies or environmental conditions. Differential method introduce advantages in measure processes and promote new sensors development. A new microstrip sensor that uses differential time measures is proposed to show the possibilities of this method.

Planar Microwave Resonant Sensors: A Review and Recent Developments

“…Planar sensors are of special interest as their low-profile is compatible with many applications, where bulk sensors (e.g., cavity sensors or waveguide-based sensors [1,2], among others) may find a severe limitation, e.g., conformal sensors [3], wearable sensors [4], submersible sensors [5], integrated sensors [6], lab-on-a-chip sensors [7], microfluidic sensors [8][9][10][11], etc. On the other hand, despite the fact that non-resonant planar sensors operating at microwave frequencies have been reported [12][13][14], the combination of sensor size and performance (sensitivity) of resonant-type sensor is difficult to achieve with non-resonant methods. Finally, to end this introductory section, let us mention that although probably most planar microwave resonant sensors have been devoted to material characterization (the main interest in this review paper, to be discussed in detail later), there are many reported realizations focused on motion control applications (linear and angular displacement and velocity measurements) [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

Highly Sensitive Reflective-Mode Defect Detectors and Dielectric Constant Sensors Based on Open-Ended Stepped-Impedance Transmission Lines

“…An alternative approach for sensing using a harmonic signal is phase-variation [43][44][45][46][47][48][49][50]. Phase-variation sensors are especially suited for material characterization, including dielectric constant measurements, determination of material composition, and defect detection, among others.…”

A Microwave Microfluidic Sensor Based on a Dual-Mode Resonator for Dual-Sensing Applications

“…Also, microwave structures can be readily implemented in the integrated circuits, which have become a favourable platform due to their constantly decreasing cost. As such, microwave sensors have found numerous applications including permittivity sensing [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ], strain and displacement sensing [ 16 , 17 , 18 , 19 , 20 ], detection of biomolecules [ 21 ], glucose monitoring [ 22 , 23 ], dielectric spectroscopy for food quality control [ 24 , 25 ], gas sensing [ 26 , 27 , 28 ], and concentration measurements of liquid solutions [ 29 ].…”

“…The operating principles of the proposed microwave sensors predominantly rely on the resonance concept [ 4 , 5 , 6 , 7 , 9 , 10 , 12 , 14 , 15 , 16 , 19 , 20 , 21 , 23 , 29 ], however there are also structures based on transmission line [ 1 , 2 , 18 , 26 , 27 , 28 ] and capacitive methods [ 13 , 17 , 22 ], as well as on more peculiar phenomena such as energy tunneling [ 3 , 11 ] and metasurfaces [ 8 ]. Besides split ring resonators (SRR) [ 4 , 9 , 14 , 15 , 16 , 19 , 20 , 21 ], which have been widely exploited in resonant-type sensors, there have also been proposed sensors with cavity [ 6 , 29 ] and stepped impedance resonators (SIR) [ 5 , 7 ].…”

“…Besides split ring resonators (SRR) [ 4 , 9 , 14 , 15 , 16 , 19 , 20 , 21 ], which have been widely exploited in resonant-type sensors, there have also been proposed sensors with cavity [ 6 , 29 ] and stepped impedance resonators (SIR) [ 5 , 7 ]. As for the transmission line-based sensors, the majority of them have been realized using the substrate integrated waveguide (SIW) [ 27 ], coplanar waveguide (CPW) [ 18 , 26 , 28 ], microstrip with electromagnetic bandgap (EBG) structures [ 2 ] and microstrip differential lines [ 1 ], whilst capacitive sensors have been realized as a gap [ 13 ], plate [ 17 ] or interdigital [ 22 ] capacitor in microstrip configurations.…”