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

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8334
Author(s):  
Lijuan Su ◽  
Paris Vélez ◽  
Jonathan Muñoz-Enano ◽  
Ferran Martín
Keyword(s):  
Dielectric Constant ◽  
Transmission Lines ◽  
Physical Meaning ◽  
Parameter Extraction ◽  
Circuit Theory ◽  
Realistic Model ◽  
General Assumption ◽  
Ground Structure ◽  
Sensing Applications ◽  
Defect Ground Structure

Microstrip transmission lines loaded with dumbbell defect-ground-structure (DB-DGS) resonators transversally oriented have been exhaustively used in microwave circuits and sensors. Typically, these structures have been modelled by means of a parallel LC resonant tank series connected to the host line. However, the inductance and capacitance of such model do not have a physical meaning, since this model is inferred by transformation of a more realistic model, where the DB-DGS resonator, described by means of a resonant tank with inductance and capacitance related to the geometry of the DB-DGS, is magnetically coupled to the host line. From parameter extraction, the circuit parameters of both models are obtained by considering the DB-DGS covered with semi-infinite materials with different dielectric constant. The extracted parameters are coherent and reveal that the general assumption of considering the simple LC resonant tank series-connected to the line to describe the DB-DGS-loaded line is reasonable with some caution. The implications on the sensitivity, when the structure is devoted to operating as a permittivity sensor, are discussed.

scholarly journals Parametric Analysis of the Edge Capacitance of Uniform Slots and Application to Frequency-Variation Permittivity Sensors

2021 ◽  
Vol 11 (15) ◽  
pp. 7000
Author(s):  
Jonathan Muñoz-Enano ◽  
Jesús Martel ◽  
Paris Vélez ◽  
Francisco Medina ◽  
Lijuan Su ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Resonance Frequency ◽  
Parametric Analysis ◽  
Frequency Variation ◽  
Substrate Thickness ◽  
Ground Structure ◽  
Simple Analytical Expression ◽  
Magnetic Wall ◽  
Different Dimensions ◽  
Defect Ground Structure

This paper presents a parametric analysis relative to the effects of the dielectric constant of the substrate, substrate thickness and slot width on the edge capacitance of a slot-based resonator. The interest is to find the conditions (ranges of the previously cited parameters) compatible with the presence of a quasi-magnetic wall in the plane of the slot (or plane of the metallization). If such magnetic wall is present (or roughly present), the electric field in the plane of the slot is tangential (or quasi-tangential) to it and the edge capacitance can be considered to be the parallel combination of the capacitances at both sides of the slot. Moreover, variations in one of such capacitances, e.g., caused by a change in the material on top of the slot, or by a modification of the dielectric constant of the substrate do not affect the opposite capacitance. Under the magnetic wall approximation, the capacitance of certain electrically small slot-based resonators can be easily linked to the dielectric constant of the material present on top of it. The consequence is that such resonators can be used as sensing elements in a permittivity sensor and the dielectric constant of the so-called material under test (MUT) can be determined from the measured resonance frequency and a simple analytical expression. In this paper, the results of this parametric analysis are validated by considering several sensing structures based on dumbbell defect ground structure (DB-DGS) resonators of different dimensions.

Patterned Macrovoids for Dielectric Constant Control of High Frequency Circuit Substrates

1986 ◽  
Vol 72 ◽  
Author(s):  
M. Kahn ◽  
B. Kriese
Keyword(s):  
Dielectric Constant ◽  
Transmission Lines ◽  
High Frequency ◽  
Thermal Conductance ◽  
Propagation Delay ◽  
Constant Control ◽  
Microstrip Transmission Lines

AbstractFugitive ink and tape technology permit the inclusion of flat voids at predetermined locations in ceramic microcircuit substrates. Calculations show that critical stray capacitances can be reduced by as much as 65% and the propagation delay of microstrip transmission lines by 30% and more. The selectivity of the void location permits the retention of the full thermal conductance of the substrate under heat dissipating elements.

scholarly journals Dielectric Properties of SnO2 Thin Film Using SPR Technique for Gas Sensing Applications

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Ayushi Paliwal ◽  
Anjali Sharma ◽  
Monika Tomar ◽  
Vinay Gupta
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
Gas Sensing ◽  
Rf Sputtering ◽  
Fast Response ◽  
Attenuated Total Reflection ◽  
Sno2 Thin Film ◽  
Bilayer Film ◽  
Significant Shift ◽  
Sensing Applications

Focus has been made on the determination of dielectric constant of thin dielectric layer (SnO2 thin film) using surface plasmon resonance (SPR) technique and exploiting it for the detection of NH3 gas. SnO2 thin film has been deposited by rf-sputtering technique on gold coated glass prism (BK-7) and its SPR response was measured in the Kretschmann configuration of attenuated total reflection using a p-polarised light beam at 633 nm wavelength. The SPR response of bilayer film was fitted with Fresnel’s equations in order to calculate the dielectric constant of SnO2 thin film. The air/SnO2/Au/prim system has been utilized for detecting varying concentration (500 ppm to 2000 ppm) of NH3 gas at room temperature using SPR technique. SPR curve shows significant shift in resonance angle from 44.8° to 56.7° on exposure of fixed concentration of NH3 gas (500 ppm to 2000 ppm) with very fast response and recovery speeds.

Structural characterization, electrical properties and gas sensing applications of polypyrrole/Cu-Al2O3 hybrid nanocomposites

2020 ◽  
Vol 32 (6) ◽  
pp. 719-728 ◽  
Author(s):  
S Sankar ◽  
K Parvathi ◽  
MT Ramesan
Keyword(s):  
Dielectric Constant ◽  
Electron Microscope ◽  
Electrical Properties ◽  
Gas Sensing ◽  
Xrd Analysis ◽  
High Energy ◽  
Dc Conductivity ◽  
Hybrid Nanocomposites ◽  
Ammonia Gas ◽  
Sensing Applications

The present work focused on the synthesis of polypyrrole (PPy) wrapped nano copper-alumina (Cu-Al2O3) composite by an in situ polymerization of pyrrole in the presence of Cu-Al2O3 nanoparticles. The polymerized samples were systematically characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), high-resolution transmission electron microscope (HR-TEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The properties such as AC and DC conductivity, dielectric constant, and ammonia gas sensing performance of PPy/Cu-Al2O3 composites were investigated in detail as a function of Cu-Al2O3 content. The FTIR spectra showed the existence of sharp and resolved infrared bands of nanoparticles in the PPy chain. The presence of the crystalline peaks of Cu-Al2O3 in the PPy matrix was confirmed from the XRD analysis. SEM images revealed the homogenous growth of Cu-Al2O3 in the polymer with the formation of spherically shaped particles. The HR-TEM observation showed that Cu-Al2O3 particles were dispersed at a nanometer level in the nanocomposites with a width of 30–60 nm. The glass transition temperature of composites obtained from DSC was found to be increased with increase in the content of nanoparticles. TGA analysis proved that the nano Cu-Al2O3 in the content in the composites acted as a mass transport barrier that retards the degradation of the product. The AC conductivity and dielectric constant of the nanocomposite showed that the maximum electrical properties were observed for the composite with 5 weight percentage loading of Cu-Al2O3. DC conductivity showed that the PPy/Cu-Al2O3 composites have higher electrical conductivity than PPy. The ammonia gas sensing property of the composites was significantly enhanced by the addition of Cu-Al2O3 nanoparticles. Therefore, the improved properties of synthesized PPy/Cu-Al2O3 nanocomposite can be useful for developing functional composite material for the fabrication of sensors, electronic devices, and high energy storage capacitors.

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