Compact Band Research Articles

Design of Dual-Polarized Compact Quad Band Metamaterial Antenna

Design of Dual-Polarized Compact Quad Band Metamaterial Antenna

Design and Simulation-Based Parametric Studies of a Compact Ultra-Wide Band Antenna for Wireless Capsule Endoscopy System at Inside Body Environment

This paper focuses to design a compact (110mm³) Ultra-Wide Band (UWB) (3.1GHz to 10.6GHz) antenna, which covers almost the whole 10dB impedance matching bandwidth of the UWB range. Two of the main specialties of this article over other related articles are its antenna’s wider bandwidth (approx. 7.3GHz) and antenna’s simulation environment. No other papers consider such a realistic model to simulate their antenna, before. Due to its wider bandwidth, this antenna can be employed in the Wireless Capsule Endoscopy (WCE) system, which mainly requires a high-speed real-time data transfer-capable antenna. The antenna was examined inside simplified human Gastrointestinal (GI) tract phantoms (Colon, Esophagus, Small Intestine and Stomach) as well as the human Voxel GI tract model by maintaining proper tissue properties for the sake of accurate parametric results. Biocompatible material polyimide was used to construct the capsule wall to fulfill the system’s biocompatibility. In the result analysis part, the proposed antenna’s SAR (Specific Absorption Rate) or electromagnetic energy amount, consumed by near-side body tissue was considered and found in the acceptable region, according to Federal Communication Commission (FCC)’s regulation. Also, other crucial antenna parameters such as VSWR, reflection coefficient, radiation characteristics, efficiencies, directivity and surface current density were adoptable compare to other related articles. The Finite Integration Technique (FIT) of CST Microwave Studio Suite 2020 was used to investigate the antenna parameters.

A COMPACT DUAL BAND DUAL POLARIZED MONOPOLE ANTENNA WITH ENHANCED BANDWIDTH FOR C, X, AND KU BAND APPLICATIONS

A COMPACT DUAL BAND DUAL POLARIZED MONOPOLE ANTENNA WITH ENHANCED BANDWIDTH FOR C, X, AND KU BAND APPLICATIONS

Design and Experimental Analysis of a Novel Compact and Flexible Super Wide Band Antenna for 5G

This paper investigates the design and practical implementation of a novel Super Wide Band (SWB) antenna on a flexible substrate. The antenna is designed on the Ultralam 3850 substrate having a compact dimension of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$60\times 40\times 0.1$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . This antenna has an operating frequency band from 1.74 to 100 GHz with a bandwidth (BW) ratio of approximately 57.47:1. Such an extended frequency coverage makes this antenna operable in a wide variety of wireless application areas, including 5G and the Internet of Things (IoT). The simulated performance of the designed antenna is analyzed here with respect to different antenna parameters, including reflection coefficient, radiation pattern, gain, efficiency, and surface current. The proposed antenna prototype is fabricated, and experimental validation is provided through the measurement using a programmable network analyzer (PNA).

A Design for the Quad Band pass Filter Using a Stub Loaded Resonator Technique

Band pass filters are widely used in wireless transmitters and receivers. A compact Quad band pass filter with stub loaded technique has been designed in this paper. HFSS (High Frequency structure simulator) software is used for the designing purpose. By the help of this technique four (quad) pass band pass filter has attained. The filter has an insertion loss of 0.8663, 8.1760, 3.0527, 3.8269 and located at 0.7, 1.31, 1.9, 4.2 GHz. The calculated return loss are 19.5, 9.04, 15.8, 19.7 dB.

Characterization of Dielectric Substrates Using Dual Band Microwave Sensor

In this work, a compact, inexpensive, and efficient dual band microwave sensor is proposed. The sensor is based on two Complementary Symmetric Split-Ring Resonators (CSSRRs) and possesses a high $Q$ factor and wide sensing range. These CSSRRs are coupled electrically with two inductive patches to the Microstrip Transmission Line (MTL). This combination provides two dual bands, first at 5.35 GHz with a notch depth of -55.20 dB and second at 7.99 GHz with a notch depth of -22.54 dB. The sensor works in transmission mode and senses shift in frequency. Some commonly available dielectric substrates with relative permittivity ranges between 1 and 12 are considered Material Under Test (MUT), and detailed sensitivity analysis is being performed for each band. The dual band sensor is fabricated on a low-cost, widely available FR4 substrate and measured by CEYEAR AV3672D vector network analyzer. Additionally, the least square curve fitting method is used to develop a mathematical model for the measured results. An excellent agreement is observed between simulated, measured, and formulated results.

A novel green HPTLC method for simultaneous analysis of four antipsychotics in their pharmaceutical formulations: Assessment by Eco-scale

Implementing green analytical techniques has been one of the main objectives of the analytical chemistry community for the past two decades. The aim of transitioning to green analytical chemistry is to establish new methods environmentally benign instead of traditional methods. According to WHO, 20 million people worldwide are affected by schizophrenia, and 45 million people worldwide are affected by bipolar disorders. For that, in this work we develop a green HPTLC method to quantify simultaneously the four antipsychotics chloropromazine HCl, asenapine maleate, quetiapine fumarate and aripiprazole in pure form and tablet formulations. In this chromatographic method, separation was performed using silica gel 60 F254 HPTLC plates, the mobile phase composed of binary mixture of green solvents (ethanol : water (9 : 1 v/v)) which gave compact band with Rf values ranged between 0.14 to 0.70 for the drugs. The method was validated for linearity, accuracy, precision, selectivity and robustness according to ICH guidelines. It was assessed for greenness by analytical Eco-scale and compared with reported HPTLC methods for single analysis of these antipsychotics.

A Compact Triple Band Antenna for Military Satellite Communication, Radar and Fifth Generation Applications

A compact triple band antenna by using etching slots technique in the radiation element is presented in this paper. The proposed antenna is designed to target three different frequencies: 7.5 GHz (military satellite communication), 9 GHz (radar applications) and 28 GHz (fifth generation applications). The fabricated prototype of the antenna has overall dimensions of 13x12.8x1.6 mm3. Measurements were carried out to validate the simulation results. The impedance bandwidths are 259 MHz (7.435-7.695 MHz), 355 MHz (8.86-9.221 MHz) and 2.67 GHz (26.79-29.433 GHz) with return loss less than -10 dB. Furthermore, the suggested antenna provides a gain of 3.96 dBi, 3.05 dBi and 5.86 dBi at 7.5 GHz, 9 GHz and 28 GHz respectively. Therefore, the results demonstrate that the proposed triple band antenna can be used for military satellite communication, radar applications and is a good candidate for the future 5G applications.

The critical control of arkosic sandstone porosity on deformation band formation: Insights from the Shulu across-fault borehole in the Bohai Bay Basin, China

Fewer studies have focused on subsurface deformation bands than deformation bands in outcrops. In this work, we studied the subsurface deformation bands in high-porosity sandstones from the Shulu borehole in the Bohai Bay Basin. The Shulu borehole was drilled through the Xicaogu normal fault with a displacement of 140 m, and the recovered core contains deformation bands and fractures in the damage zones. This study focused on the structural characteristics of subsurface deformation bands with burial depths between 2504.4 m and 2506.2 m. The critical porosity limit of host sandstone for the formation of deformation bands and fractures was determined. The host sandstones in the Shulu borehole are predominantly arkose. The subsurface deformation bands in the Shulu borehole are suggested to be compactional shear bands. We find that the subsurface deformation bands have identical characteristics to those in outcrops, except that they do not show strong positive reliefs. These bands are characterized by protocataclasis and cataclasis and organized into localized and conjugate networks. Compared to the host rocks, the subsurface deformation bands show porosity reductions of 7.7–27.7% and permeability reductions of 1–3 orders of magnitude. Three porosity intervals of the host-rock with different deformation styles can be identified in the Shulu borehole core: 1) host sandstone with porosities greater than 14.3%, which develop deformation bands exclusively; 2) host sandstone with porosities less than 10.8%, which develop fractures; and 3) the transition zone, where the porosities of host sandstone are 10.8–14.3%, and the deformation styles are characterized by both deformation bands and fractures. The critical porosity limit of host rocks in terms of the formation of deformation bands and fractures suggests that porosity is a major factor controlling the formation of fractures and deformation bands. Deformation bands and fractures have counteracting effects on the fluid flow in the transition zone.

Standardization and validation of a high-performance thin-layer chromatography method for the quantification of aflatoxin B1 and its application in surveillance of contamination level in marketed food commodities from the Mumbai region

Aflatoxin B1 (AFB1) is a natural carcinogenic contaminant of agricultural product regulated at parts per billion (ppb) level; therefore, a validated method for the analysis of AFB1 is extremely important. In this study, a high-performance thin-layer chromatography (HPTLC) method was standardized and validated with respect to linearity, sensitivity, precision, and accuracy for the quantification of AFB1. Three extraction techniques using different solvent systems, namely QuEChERS (quick, easy, cheap, effective, rugged and safe) method, Contaminants Branch method and Best Foods method were evaluated for AFB1 extraction efficiency in food commodities, wherein QuEChERS method using acetonitrile‒methanol (40:60, V/V) gave maximum recovery of AFB1 in all commodities. Maximum AFB1 was recovered in dried chilli sample (89.98%), whereas the least recovery was obtained in wheat sample (68.20%). The optimized HPTLC method with chloroform‒acetone (9:1, V/V) as the mobile phase showed a compact AFB1 band at RF value of 0.36 ± 0.02. The linear regression analysis of AFB1 showed good linearity over 10, 20, 40, 60, 80, 100, 120 ng/spot with a regression value of 0.9923 and %RSD less than 1. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.133 ng/band and 3.434 ng/band, respectively. The optimized HPTLC method was further used to assess the AFB1 content in marketed samples of groundnut, corn, rice, wheat and dried chillies from the Mumbai region and it was found that 8 groundnut samples, 5 corn samples, 5 wheat samples, and 7 chilli samples out of 20 each had AFB1 concentration above Indian permissible regulatory limit of 30 ppb.

Compaction Banding in High‐Porosity Carbonate Rocks: 2. A Gradient‐Dependent Plasticity Model

AbstractBased on the experimental study on Saint‐Maximin limestone presented in a companion paper (Abdallah et al., 2020), a gradient‐dependent plasticity model is developed to account for the key role of porosity heterogeneity in the formation and propagation of compaction bands. The constitutive law, developed in the frame of a micromorphic continuum theory, contains two hardening variables: the porosity and its second gradient. A calibration method for the additional micromechanical parameters is proposed. Data from the companion paper are used in a four‐step calibration procedure. First, the standard Cauchy component is calibrated by means of the macroscopic stress‐strain curves. An Asymmetric Cam‐Clay (ACC) model is adopted for the yield surface. The dominant wavelength of the porosity heterogeneity of the material is evaluated by applying the fast Fourier transformation (FFT) on several porosity profiles obtained on samples before loading. This wavelength is interpreted as the material length that appears in the model. In addition to the deformation maps computed from digital volume correlation (DVC), a method that evaluates the second gradient of porosity is developed to calibrate the hardening laws. A linear stability analysis (LSA) is performed to calibrate the higher‐order elastic modulus. The constitutive model is implemented in a finite element code, and triaxial loading experiments are simulated. The numerical results are consistent with the experimental data in terms of the onset of compaction bands, their thickness, and plastic strain. The size effect of the sample is explored, and a regular band spacing, comparable to the band thickness, is obtained.

Compact stack EBG structure for enhanced isolation between stack patch antenna array elements for MIMO application

AbstractIn this research article, a compact wideband stack patch antenna array integrated with compact stack electromagnetic band gap (EBG) structure for multiple input multiple output (MIMO) application is proposed. The wide resonance bandwidth is achieved at 2.45 GHz band by stack arrangement of compact meander line slot driven and parasitic patch elements. The isolation bandwidth is matched with resonance bandwidth with the design of a compact stack L slot EBG structure. The polarization diversity and three-layer EBG structure ensure an enhancement in isolation level. To validate the performance of the proposed stack antenna array, a prototype was fabricated and tested for different MIMO parameters. The measured result confirms the effectiveness of the proposed antenna array in a diverse MIMO environment.

Failure processes of cemented granular materials.

The mechanics of cohesive or cemented granular materials is complex, combining the heterogeneous responses of granular media, like force chains, with clearly defined material properties. Here we use a discrete element model simulation, consisting of an assemblage of elastic particles connected by softer but breakable elastic bonds, to explore how this class of material deforms and fails under uniaxial compression. We are particularly interested in the connection between the microscopic interactions among the grains or particles and the macroscopic material response. To this end, the properties of the particles and the stiffness of the bonds are matched to experimental measurements of a cohesive granular medium with tunable elasticity. The criterion for breaking a bond is also based on an explicit Griffith energy balance, with realistic surface energies. By varying the initial volume fraction of the particle assembles we show that this simple model reproduces a wide range of experimental behaviors, both in the elastic limit and beyond it. These include quantitative details of the distinct failure modes of shear-banding, ductile failure, and compaction banding or anticracks, as well as the transitions between these modes. The present work, therefore, provides a unified framework for understanding the failure of porous materials such as sandstone, marble, powder aggregates, snow, and foam.

Design of multi band triangular microstrip patch antenna with triangular split ring resonator for S band, C band and X band applications

With the rapid advancement in multi-functional communication devices, devices capable of operating for more than one frequency bands emerged. Such applications demand for multiband antennas. Wide band antennas are capable of resonating over larger frequency bands, but it limits the impedance bandwidth and gain. So, the solution of this could be compact multi band antennas. A quad band Triangular Microstrip antenna designed for IEEE 802.16e Wi-MAX, IEEE 802.11a WLAN, C band downlink communication and x band radar applications is suggested in this work. The proposed antenna has triangular patch with triangular split ring resonator. The conservativeness and data transfer capacity are the preferred possessions of the suggested antenna. The proposed antenna yields better return and gain by resonating in 3.5 GHz, 4.1 GHz, 5.6 GHz and 9.7 GHz.

Application of Plackett-Burman and central composite designs for screening and optimization of factor influencing the chromatographic conditions of HPTLC method for quantification of efonidipine hydrochloride

We report here an analytical method for expeditious estimation of efonidipine hydrochloride in tablet formulation with statistical screening and optimization designs using NP-HPTLC. TLC silica gel 60 F254 aluminum plates and ethyl acetate to dichloromethane to triethylamine (3:2:0.5 v/v) were chosen for chromatographic separation of efonidipine hydrochloride. The Rf value for efonidipine hydrochloride turned out to be 0.35 ± 0.25 and quantitative evaluation was done at 251 nm. Plackett-Burman and face-centered central composite design (CCD) were used to obtain the most peak area and well-resolved compact band with an adequate retention factor of efonidipine hydrochloride. Plackett-Burman design at two-level with six independent variables has been employed for screening of prominent factors that affect the responses. The prominent factors have been selected and are optimized through face-centered CCD. The results obtained from face-centered CCD showed that most peak area can be obtained with development distance 8.50 cm and chamber saturation 17 min. Furthermore, the current NP-HPTLC investigation has been validated according to the ICH guidelines for accuracy, precision, sensitivity, robustness, ruggedness, and specificity. The detection and quantification limit was found that 10.41 ng and 31.57 ng, suggesting that the analysis could be accurately and precisely detected the analyte up to nanogram quantity. The current NP-HPTLC investigation is rugged, accurate, and highly sensitive and could be used for routine analysis of efonidipine hydrochloride.

Interaction of deformation bands and fractures during progressive strain in monocline - San Rafael Swell, Central Utah, USA

Folds in porous sandstone in cases allow identification of progressive deformation in an evolving strain field. In the Navajo Sandstone of the km-scale Laramide-style monocline of the San Rafael Swell (Utah, USA), four populations of small-scale structures record different kinematics and deformation mechanisms, depending on orientation to bedding within the first-order fold. Small-scale structures span from cataclastic (shear-) compaction and shear-isochoric deformation bands to dominant disaggregation (shear-) dilation bands. Extension and shear fractures record transformations from band to fracture formation, adding to the structural diversity.Early structures record semi-penetrative shear deformation guided by bedding and lamination in eolian deposits, consistent with layer-parallel shortening. Subsequent deformation is localized and at a higher angle relative to bedding, recording forward-directed and subsequently backward-directed shear structures within the east-verging monocline. Final deformation is highly localized and appears as a conjugate set of sub-vertical shear zones with shortening-extension axes oblique to the monocline.For the given conditions in a progressive shear system in highly porous sandstones, interactions of deformation bands and fractures suggest a revival of deformation bands by mutual shear band-fracture systems as developing band swarms rotate into an extensional strain sector during folding. In cases of deformation by shear-dilation strain, deformation bands may evolve directly into fractures, as grain contacts are lost.

Compact Broadband Absorptive Bandstop Filter Based on Microstrip

A compact broadband absorptive band rejection filter (ABSF) based on microstrip line is proposed. The filter consists of a pair of coupled wires and is loaded with a resistor. The coupling line of the filter has an open stub. The transmission zero point can be adjusted by adjusting the width of the coupling line. The center frequency can be adjusted by changing the length of the intermediate coupling line. Absorption performance can be achieved through loaded resistors. In this way, the signal not input in the filter will be dissipated in the filter and will not be reflected. When F0=3.8 GHz, 26% of the 20 dB bandwidth covers 3.15 GHz-4.2 GHz, the rejection depth of the stopband is less than -40 dB, and the in-band absorption is less than -10 dB.

Dual Band Notch, Compact, Low profile Hybrid Ultra Wideband RDRA

This paper presents a novel, compact Ultra Wide Band , Asymmetric Ring Rectangular Dielectric Resonator Antenna (ARRDRA), which is a unique combination of Thin Dielectric Resonator (DR), Fork shape patch and defective ground structure. The base of the proposed antenna is its Hybrid structure, which generates fundamental TM, TE and higher order modes that yields an impedance bandwidth of 119%. Proposed antenna provides a frequency range from 4.2 to 16.6 GHz with a stable radiation pattern and low cross polarization levels. Peak gain of 5.5 dB and average efficiency of 90% is obtained by the design. Antenna is elongated on a FR4 substrate of dimension 20 x 24x 2.168 mm3 and is particularly suitable for C band INSAT, Radio Altimeter, WLAN, Wi-Fi for high frequencies. Ease in fabrication due to simplicity, compactness, stable radiation pattern throughout the entire bandwidth are the key features of the presented design. Inclusion of Defective ground structure and asymmetric ring not only increases the bandwidth but also stabilize the gain and efficiency due to less surface current. Presented design launch an Ultra Wide Band antenna with sufficient band rejection at 4.48-5.34 and 5.64-8.33 GHz with stable radiation pattern and high gain.

Development and validation of HPTLC method for identification and quantification of sterols from leaves of Erythroxylum monogynum Roxb. and in vitro evaluation of anti-oxidant and anti-glycation activities

The petroleum ether extract from leaves of Erythroxylum monogynum when subjected to phytochemical analysis and chromatographic purification, resulted in the isolation of two new sterols namely 4-methyl ergosta-7, 23‑dien‑3β-ol and 4-methyl ergosta-7, 24 (28)‑dien‑3β-ol. Their structure was elucidated by NMR and Mass Spectrometry. The two sterols were separated on a silica gel 60F254 HPTLC plates impregnated with AgNO3 using dichloromethane: methanol (9:1 v/v) as a mobile phase. Upon densitometric scanning at 254 nm in a reflectance mode, the two sterols separated as sharp and compact bands with Rf of 0.47±0.02 and 0.52±0.01 respectively for 4-methyl ergosta-7, 23‑dien‑3β-ol and 4-methyl ergosta-7, 24 (28)‑dien‑3β-ol. Linear regression and calibration plots constructed (n = 6) showed excellent linearity at 100–500 ng per spot with a correlation coefficient, r = 0.9979±0.0004 and 0.9974±0.0007 for 4-methyl ergosta-7,23‑dien‑3β-ol and 4-methyl ergosta-7,24 (28)‑dien‑3β-ol, respectively. The Limits of detection and quantification were found to be 21.07 ng and 57.23 ng/band for 4-methyl ergosta-7,23‑dien‑3β-ol and 25.18 ng and 63.86 ng/band for 4-methyl ergosta-7,24 (28)‑dien‑3β-ol, respectively. Both the sterols demonstrated good anti-oxidant and anti-glycation activities where, the IC50 values obtained were comparable with the positive control compounds, ascorbic acid and aminoguanidine. The 4-methyl ergosta-7,23‑dien‑3β-ol displayed 100% anti-oxidant activity at 100 µg/ml for both DPPH and H2O2 scavenging assays. In addition, both the sterols presented more than 90% inhibition of Advanced Glycation End products at 100 µg/ml concentration. The results obtained are remarkable indicating that these plant extracts could serve as a natural alternative to the conventional oral hypoglycemic molecules.

Compact UWB 1:2:1 unequal-split 3-way bagley power divider using non-uniform transmission lines

In this paper, compact Ultra-Wide Band (UWB) 1:2:1 unequal split modified Bagley Power Divider (BPD) using Non-Uniform Transmission Lines (NTLs) theory is designed and tested. Based on this theory, 42.44% and 31.1% size reductions are obtained in the lower and upper λ/4 Uniform Transmission Lines (UTLs) in the first and second sections of the proposed divider. To evaluate the effect of the divider’s compactness on its performance, it is compared with UWB 1:2:1 unequal split BPD using Tapered Transmission Lines (TTLs). Both dividers show good results where the measured return loss is appeared to be S11 < −10.6 dB and < −13.4 dB for NTL and TTL BPDs, respectively. However, the insertion losses S12 = S14 and S13 are around −6 ± 1.5 dB and – 3 ± 1.3 dB, respectively for both dividers. In this study, simulations are carried out using High-Frequency Structure Simulator (HFSS) software. The evaluation of the proposed divider is obtained from the simulation and hardware measurements results.