Compact Band Research Articles

Compact dual band slotted triangular monopole antenna for RFID applications

AbstractThis paper presents a compact monopole antenna for radio frequency identification (RFID) systems. The proposed antenna is a dual band structure that can operate in the frequency ranges [0.797–1.004 GHz] and [2.234–2.934 GHz]. Consequently, the antenna covers widely the two UHF bands dedicated for RFID applications which are [0.860–0.960 GHz] and [2.380–2.520 GHz]. Moreover, the antenna is compact and its wide band nature makes it suitable for several applications other than RFID (GSM, UMTS, Wi‐Fi, Bluetooth, etc.). The proposed antenna has been fabricated and its reflection coefficient measured where a good agreement is observed with the simulated results.

Compact Dual Band Monopole Antenna for RFID and WLAN Applications

A compact dual band monopole antenna for application in portable devices covering wireless local area network (WLAN) and radio frequency identification (RFID) technologies at 2.4 and 5.0 GHz is presented in our paper. The antenna is fabricated on a relatively inexpensive dielectric material. The dimensions of FR4 substrate used is 38 x 30 x 1.6 mm3. Experimental results provide omnidirectional radiation patterns, which is in agreement with requirement of both frequency bands. We obtain resonant frequencies of 2.45 and 5.20 GHz from the fabricated antenna. The proposed antenna is simple in design, compact in size and exhibits broadband impedance matching, appropriate gain characteristics (>2.5 dBi) and consistent omnidirectional radiation patterns in the RFID and WLAN frequency regions. All simulations have been carried out on HFSS ver. 15.0.

Design and Analysis of a Compact Band Notch UWB Antenna for Body Area Network

This paper presents the design of a small printed ultra wideband antenna with Band Notched characteristics. Both the free space and on-body performances of this antenna were investigated through simulation. The newly designed UWB antenna is more revised small form factor sized, with the ability to avoid interference caused by WLAN (5.15 - 5.825 GHz) and WiMAX (5.25 - 5.85 GHz) systems with a band notch. The return loss response, gain, radiation pattern on free space of the antenna were investigated. After that, the on-body performances were tested on 3-layer human body model with radiation pattern, gain, return loss, and efficiency at 3.5, 5.7, 8, 10 GHz and all the results were compared with free space results. As the on-body performance was very good, the proposed antenna will be suitable to be used for multi-purpose medical applications and sports performance monitoring.

Biological Evaluation of Different Extracts of Aerial Parts of Nepeta deflersiana and Standardization of Active Extracts Using 8-Epi-7-Deoxyloganic Acid and Ursolic Acid by Validated HPTLC Method.

Nepeta deflersiana (Lamiaceae) is a well-known medicinal plant that grows in Saudi Arabia. This plant is used in Saudi and Yemeni folk medicine as an anti-inflammatory, carminative, and antirheumatic agent. In order to prove its use in folk medicine, four different extracts from the aerial parts of the plant: petroleum ether, chloroform, ethyl acetate, and n-butanol extracts were subjected to biological assays to screen PPARα and PPARϒ agnostic, antioxidant, anti-inflammatory, and cytotoxic activities. Ethyl acetate and n-butanol extracts of N. deflersiana NDEE and NDBE, respectively, showed a decrease in oxidative stress and inhibition of both NF-kB and iNOS activities with no cytotoxic effects on four human cancer cell lines. Both active extracts were standardized using two bioactive metabolites which were isolated from the aerial parts of the same plant [8-epi-7-deoxyloganic acid (compound 1) and Ursolic acid (compound 2)] by developing a validated HPTLC method. It was found to provide a sharp and compact band of compound 1 at Rf = 0.07 and Rf = 0.57 for compound 2, using chloroform, methanol, and formic acid (8.9:0.8:0.3, v/v/v) as mobile phase at 550 nm. Compounds 1 and 2 were found in NDEE by 9.59 %, w/w, and 84.63 %, w/w, respectively, and by 11.97 %, w/w, and 21.26 %, w/w, respectively, in NDBE.

Design of high directional crossed dipole antenna with metallic sheets for UHF and VHF applications

A compact dual band cross dipole antenna surrounded with metallic plates at five sides has been proposed in this article. comparative analysis has been done between the dipole and cross dipole antenna. On comparing these two antennas the proposed antenna has the high gain of 7db and radiation efficiency of 95 percent. The peak directivity of the proposed antenna is 5DB and its front to back ration is 60. The return loss, gain, radiation patterns and co polarization and cross polarization of the antenna has been observed and analysed using AN-soft HFSS v13.The proposed antenna works at the range of 0.6GHz to 1.5GHz which covers the applications like GSM, GNSS and some of the applications which covers in the range of UHF and VHF.

Compact microstrip feed dual band monopole antenna for UWB and bluetooth applications

Compact microstrip feed dual band monopole antenna for UWB and bluetooth applications

Validated Stability-Indicating Methods for Determination of Mometasone Furoate in Presence of its Alkaline Degradation Product.

Two novel stability-indicating TLC densitometric and chemometric methods were developed for the determination of mometasone furoate (MF) in the presence of its alkaline degradation product (MF Deg). The developed TLC densitometric method (Method A) is based on the quantitative densitometric separation of MF from its alkaline degradation product on silica gel 60 F254 and measurement of the bands at 250 nm. The separation was carried out using hexane-chloroform-methanol-acetonitrile (6:6:1:0.3, by volume) as a developing system. A well-resolved and compact bands for (MF) and (MF Deg) at retention factors 0.36 and 0.66, respectively. Good resolution between (MF) and (MF Deg) assured the specificity of the proposed method. The method showed good linearity in the concentration range 0.5-5 μg/band with r2 = 0.9998. The method validation was performed according to ICH guidelines demonstrating to be accurate, precise, robust and sensitive. The LOD and LOQ were found to be 0.21 and 0.63 μg/band for MF, respectively. The developed TLC-densitometric method can be applied for identification and quantitative determination of MF in bulk drug and pharmaceutical dosage forms without any interference from excipients and degradates. Method B is a multivariate chemometric-assisted spectrophotometry, where classical least squares, principal component regression and partial least squares were applied. Statistical analysis of the results has been carried out revealing high accuracy and good precision.

Inelastic Compaction in High‐Porosity Limestone Monitored Using Acoustic Emissions

AbstractWe performed a systematic investigation of mechanical compaction and strain localization in Saint‐Maximin limestone, a quartz‐rich, high‐porosity (37%) limestone from France. Our new data show that the presence of a significant proportion of secondary mineral (i.e., quartz) did not impact the mechanical strength of the limestone in both the brittle faulting and cataclastic flow regimes, but that the presence of water exerted a significant weakening effect. In contrast to previously published studies on deformation in limestones, inelastic compaction in Saint‐Maximin limestone was accompanied by abundant acoustic emission (AE) activity. The location of AE hypocenters during triaxial experiments revealed the presence of compaction localization. Two failure modes were identified in agreement with microstructural analysis and X‐ray computed tomography imaging: compactive shear bands developed at low confinement and complex diffuse compaction bands formed at higher confinement. Microstructural observations on deformed samples suggest that the recorded AE activity associated with inelastic compaction, unusual for a porous limestone, could have been due to microcracking at the quartz grain interfaces. Similar to published data on high‐porosity macroporous limestones, the crushing of calcite grains was the dominant micromechanism of inelastic compaction in Saint‐Maximin limestone. New P wave velocity data show that the effect of microcracking was dominant near the yield point and resulted in a decrease in P wave velocity, while porosity reduction resulted in a significant increase in P wave velocity beyond a few percent of plastic volumetric strain. These new data highlight the complex interplay between mineralogy, rock microstructure, and strain localization in porous rocks.

Dual-wavelength thin-layer chromatographic–densitometric determination of febuxostat in combination with acetaminophen in synthetic mixture and in pharmaceutical formulations

The combination of xanthine oxidase inhibitor febuxostat (FBX) with acetaminophen (ACE) is widely used in the treatment of gout. A rapid, simple, selective, and precise densitometric method was developed and validated for the simultaneous estimation of FBX–ACE mixture in a synthetic binary mixture and in their pharmaceutical dosage forms. The method employed thin-layer chromatography (TLC) aluminum plates precoated with silica gel G 60 F254 as the stationary phase using chloroform‒methanol‒cyclohexane‒acetic acid 96% (7:1:1:0.1, v/v) as the mobile phase. The optimized mobile phase selected for development gave compact bands (RF values were 0.65 and 0.46 for FBX and ACE, respectively). Spectrodensitometric scanning integration was performed using dual-wavelength detection at 320 and 250 nm for FBX and ACE, respectively. The linear regression data for the calibration plots showed excellent linear relationship (r = 0.9997 and 0.9992 for FBX and ACE, respectively). The method was validated for precision, accu...

Shear-enhanced compaction-solution bands in quartz-rich calcarenites of the Cotiella Massif (Spanish Pyrenees)

We describe conjugate systems of shear-enhanced compaction bands oriented oblique to the maximum compressive stress and developed in Paleocene quartz-rich calcarenites formed by the interplay between shearing, mechanical compaction, and dissolution. These deformation bands are located in the footwall of the Cotiella Thrust (Spanish Pyrenees), and strike perpendicular to the local tectonic transport direction. Conjugate shear-enhanced compaction bands are mutually perpendicular in cross-section, forming an angle of 45° with the shallow-dipping bedding; no macroscopic evidence of shearing is found along them. These shear-enhanced compaction bands occur together with less abundant bedding-perpendicular compaction bands, which strike perpendicular to the local transport direction. The described shear-enhanced compaction bands consist of mm-thick tabular structures showing higher concentrations of quartz grains with reduced sizes in respect to the surrounding undeformed rock. Optical microscope and SEM investigations show that the high concentration of quartz clasts within the bands was caused by pressure-enhanced dissolution of calcite. Quartz grains fragmentation is also observed within the bands, with no significant clasts rotation and translation. All these features indicate that the described shear-enhanced compaction bands are hybrid structures developed during layer-parallel shortening associated with the Cotiella Thrust and are characterized by localized dissolution of calcite grains and fragmentation of quartz grains.

Relationships between fractures

Fracture systems comprise many fractures that may be grouped into sets based on their orientation, type and relative age. The fractures are often arranged in a network that involves fracture branches that interact with one another. Interacting fractures are termed geometrically coupled when they share an intersection line and/or kinematically coupled when the displacements, stresses and strains of one fracture influences those of the other.Fracture interactions are characterised in terms of the following. 1) Fracture type: for example, whether they have opening (e.g., joints, veins, dykes), closing (stylolites, compaction bands), shearing (e.g., faults, deformation bands) or mixed-mode displacements. 2) Geometry (e.g., relative orientations) and topology (the arrangement of the fractures, including their connectivity). 3) Chronology: the relative ages of the fractures. 4) Kinematics: the displacement distributions of the interacting fractures. It is also suggested that interaction can be characterised in terms of mechanics, e.g., the effects of the interaction on the stress field. It is insufficient to describe only the components of a fracture network, with fuller understanding coming from determining the interactions between the different components of the network.

Design and Analysis of Reconfigurable Microstrip Antenna for Cognitive Radio Applications

A compact and reconfigurable band notch UWB antenna for cognitive radio application has been proposed in this paper. The proposed UWB antenna has dual notch band in WI-max and WLAN and has reconfigurable property in terms of band notching for a single notch band in Wi-Max. Reconfigurable property of the presented antenna in WLAN band has been achieved by using a MEMS switches. The ON and OFF conditions of the MEMS switch are actually responsible to achieve the reconfigurable property. The proposed two notch bands (WI-max and WLAN) are obtained by embedding an elliptical slot on radiating patch and a rectangular strip on ground plane respectively. Empirical relations related to the proposed design for elliptical slots to obtain desired notch band have also been included in this paper. The impacts of the design parameters on notch characteristics of the antenna have also investigated. The design and functional simulation of the proposed antenna structure have performed by using HFSS-v14. A fully functional prototype has fabricated and measured and the measured results have shown a good agreement with the simulations.

A compact dual band MIMO PIFA for 5G applications

5G applications support operations in 28, 37, 60 and 73GHz bands and is expected to support 1GHz bandwidth. In the present paper, planar inverted F antenna for 28GHz operation has been proposed for 5G applications for which a return loss of -17.46dB and a gain of 9.30dB have been observed. In addition, the design has been extended for dual band operation at 28 and 37GHz by implementing an L slot in the patch. An excellent return loss of -32.54dB and -18.57dB with a gain of 8.62dB has been observed. Moreover, a feasible bandwidth of 1.02GHz has been obtained in former design, while an enhanced bandwidth of 1.3GHz has been obtained at both bands in case of latter design. However, for better gain & data rate considerations, the previous design has been extended as a MIMO configuration with 2 antenna elements (2x1) and corresponding performance parameters have been evaluated.

Compact Dual Band Antenna Design for Ku / Ka Band Applications

This communication proposes a compact 16 GHz / 30 GHz dual band antenna design for Ku / Ka band applications. The antenna consists of two layers with lower layer having the fed patch and the upper layer having non-periodic element array. The antenna has been designed to operate at two different frequencies with compact dimensions of (8mm x 8mm) using Rogers RT 5880. The compact size of this proposed antenna also makes it suitable for integration with the microwave and millimeter wave circuits. The proposed antenna provides high radiation efficiency and a peak gain of about 8 dB at the resonant frequencies with reduced side lobe levels.

Multi feed multi band uniplanar ACS fed antenna with N shape and inverted L shape radiating branches for wireless applications

In this research, a compact uniplanar multiband asymmetric coplanar strip-fed triple band monopole antenna is presented for WLAN/WiMAX applications. The designed antenna consists of an N and modified L-shaped strips and lateral coplanar ground plane for multiple wide operating frequency bands. The geometry is designed on the substrate FR4 to work over three bands from 2.45 to 2.6, 3.4–3.7 and 4.5–6.3 GHz with resonant frequencies of 2.5, 3.5 and 5.8 GHz for return loss S11 < − 10 dB. The uniplanar antenna is simulated using CST MWS software and tested using PNA N5222A vector network analyzer (Agilent technologies) and anechoic chamber. Measured results are confirmed with simulated results. Nearly, omnidirectional and bidirectional patterns with constant gain is achieved in all the operating bands. The easy feeding technique, wide impedance bandwidth, cost effective and very small in size makes it a best candidate for advanced compact wireless systems.

WITHDRAWN: Design and development of compact microstrip patch dual band antenna for wireless applications

Abstract In this paper, a novel dual band microstrip patch antenna based on composite patch antenna and radiating part. By selecting a suitable offset feed position, it is feasible to provide 50 Ω characteristic impedance and thus making better impedance matching. The proposed antenna has been improved broader bandwidth by using RT Duroid substrate. The radiating part is plays a important role in creating a lower operating band (2.45 GHz) in addition to achieve miniaturization. The proposed antenna has to be fabricated with RT/Duroid substrate and dimensions of 19 × 22 × 0.8 mm. The measured −10 dB bandwidth of 200 MHz at 3.45 GHz and 990 MHz at 5.45 GHz, which is quite useful for Industrial, Scientific and Medical (ISM) and WLAN applications.

Compact wideband band pass microstrip filter loaded by triangular split ring resonators

AbstractA compact wideband band‐pass microstrip filter based on triangular split ring resonators is presented. The center frequency of the proposed structure is 3.1 GHz and the 3 dB bandwidth results 1.05 GHz. Good agreements between the simulated and measured results demonstrates the effectiveness of the proposed design. The size of the filter is 14 × 50 mm2 only.

Design of a new compact planar wide band dipole antenna

AbstractA new planar compact wideband dipole antenna is presented. The proposed antenna radiation pattern is omnidirectional and very stable in the operation bandwidth with good gain flatness and low cross polarization. Three cases of the proposed antenna are simulated by linear scaling of the designed antenna which proves the design flexibility. Finally, one case of the designed antenna is fabricated and measured. This antenna which works between 1.265 GHz to 3.98 GHz has very compact dimensions 82.4 mm × 45.5 mm (0.35l1 × 0.169l1, l1 is the wavelength in the start of bandwidth), stable radiation patterns and low cross polarization. These good specifications prove the antenna design capability and ability for wideband communication system applications.

Design of a compact planar wide band antenna family

A new family of compact planar wide band antennas is proposed. These simple and planar antennas have stable omnidirectional patterns and flat gain in the whole of bandwidth. Five types of these antennas are designed and simulated to clarify the ability of these introduced antenna family. Also, one of these antennas is fabricated and tested. The simulation and the measurement results are in good agreement. The measurement results show that this antenna works between 1.91 and 5.25GHz (93.3% bandwidth) and it has a very compact dimensions. Also, the antenna analysis results show that the antenna center frequency and bandwidth can easily controlled by changing the scale factor and section factor, respectively. Finally, the antennas comparison results with the references verify the capability and power of them.

A compact uniplanar ACS fed multi band low cost printed antenna for modern 2.4/3.5/5 GHz applications

A uniplanar compact triple operating band asymmetric coplanar strip (ACS) fed printed antenna loaded with multiple L-shaped branches and the asymmetric rectangular ground plane has been proposed and developed for multiple wideband wireless system applications. The proposed antenna structure has been simulated and printed (single layer) on a 14 mm × 20.5 mm × 1.6 mm size low-cost substrate FR4. In the design, modified L-shaped strips have been chosen to achieve compactness and also used to generate three wideband independent resonant modes that correspond to several communication standards such as WiBro/LTE/Bluetooth/ISM/WLAN/US public safety and WiMAX applications. The proposed ACS fed antenna geometry has been simulated using CST MWS and tested its results experimentally by using Keysight N5222A Microwave Network Analyzer. A detailed analysis of antenna evolution stages and parametric study has been given to show the tuning property of each operating band. The obtained results demonstrate that the developed ACS fed antenna is having −10 dB (reflection coefficient) impedance bandwidth of 200 MHz from 2.3 to 2.5 GHz, 200 MHz from 3.4 to 3.6 and 2.6 GHz from 4.25 to 6.85 GHz. Further, it is tested experimentally for its radiation patterns (co and cross) which indicate the omnidirectional and bidirectional nature in H and E planes respectively.