Compact Band Research Articles

Design of Reconfigurable Antenna Using MSF-EBG Structure to Improve Performance Parameters

A wide band gap slot fractal uniplanar compact electromagnetic band gap (UC-EBG) structure is designed based on the third iteration of Moore space filling geometry (MSF-UC-EBG). By changing the dimensions of the EBG structure, different band gap characteristics can be obtained. This structure (named as FR4_EBG) is simulated using Computer Simulation Technology, fabricated and measured. Furthermore, the FR4_EBGs are integrated with a coplanar waveguide fed stepped-impedance resonator (SIR) antenna to research MSF-UC-EBG’s microwave application. After integration, the overall performance of SIR antenna is significantly improved. The proposed MSF-UC-EBG can be easily integrated with low-frequency applications such as GSM, PCS, Bluetooth, Wi-max, and Wi-Fi. Simulated results of the reconfigurable antenna by using switch (P-I-N diode or RF-MEMS) are also observed. This antenna operates for two different frequencies, 1.568 GHz when the switch is open and 2.5 GHz when the switch is closed.

Simulation of localized compaction in Tuffeau de Maastricht based on evidence from X-ray tomography

Deformation experiments with concurrent X-ray microtomography are used to characterize the mechanical properties of a high-porosity carbonate rock from Central Europe (the Tuffeau de Maastricht). Evidence of deformation behavior and pressure-dependent strain localization for this rock are taken into account to define the parameters of an elastoplastic constitutive law with competing hardening and softening mechanisms. Full-field data regarding the compaction localization regime have been used to identify a compromise between compaction hardening and structure deterioration. It was shown that by placing emphasis on the destructuration behavior it was possible to reproduce features such as the elongation of the deformation plateau emerging during compaction band formation, as well as the pressure-dependent inclination of the ensuing compaction bands. Most notably, the comparison between measurements and simulations showed that the strategy here used to constrain the model parameters allows a satisfactory depiction of both the macroscopic deformations and the portion of sample volume across which the compaction zones develop and propagate. These results point out the major benefits of parameter calibration strategies accounting synergistically for global measurements and spatially-distributed deformations, especially in the presence of constitutive laws meant to replicate compaction localization.

A Developed High-Performance Thin-Layer Chromatographic Method for the Determination of Orlistat in Pharmaceutical Preparations

A sensitive and simple high-performance thin-layer chromatographic method is developed and validated according to the International Conference on Harmonisation (ICH) guidelines. The procedure was applied for the estimation of orlistat in different pharmaceutical preparations. In the proposed method, thin-layer chromatography aluminum sheets pre-coated with silica gel were employed as the stationary phase. A number of solvent mixtures were used as the mobile phase for trials to obtain compact bands of orlistat. The solvent mixture consisting of chloroform and methanol (98:2) was found to be the best. The data obtained from the calibration curves of standard orlistat showed a good linear relationship over the concentration range of 1000–3800 ng per band with respect to the area. Scanning was performed at λ = 200 nm, where the correlation coefficient (R2) was 0.970, and the linear regression equation was found to be: y = 4.1419x − 4181.1. After revealing of the spots by anisaldehyde—conc. sulfuric acid, compact violet bands were obtained and, accordingly, scanning was performed at λ = 600 nm, where a good linear relationship over the concentration range of 600–4000 ng per band with respect to the area was obtained. The correlation coefficient (R2) was 0.991 with a linear regression equation: y = 4.025x − 1159.3. The method was evaluated regarding accuracy, precision, limits of detection and quantification, and robustness. Revealing of the spots by anisaldehyde—conc. sulfuric acid improved the sensitivity of the method and increased the range within which a linear relationship between concentration and response occurs.

Radiation control of microstrip patch antenna by using electromagnetic band gap

In this paper, two compact electromagnetic band gap (EBG) antennas are proposed by combining a rectangular antenna with a mushroom-like EBG structure and with a novel triple side-slotted EBG (TSSEBG). Both prototype antennas can scan the main beam in the elevation (E) (−20° < φ < 20°), (−17° < φ < 17°) and horizontal (H) (−18° < θ < 18°), (−15° < θ < 15°) planes, respectively. The main beam scanning was conducted by using band-stop and band-pass properties. The band-stop property was achieved by connecting the vias to the ground plane of the antenna, whereas the band-pass property was realized by disconnecting the same vias, thereby yielding the beam steering into the pass-band sector. Unlike usual beam steering, this technique does not suffer from gain degradation, and the gain of the main lobe is approximately stable for the steering angles. The antenna performance was enhanced due to suppress surface waves. Moreover, the number of vias was reduced significantly in the proposed TSSEBG instead of the mushroom-like EBG. The compact EBG and TSSEBG antennas have directivity (10 and 10.5) dBi, gain (9.86 and 10.16) dB, and efficiencies of 96.5% and 93%, respectively, with the operating frequency at 6 GHz.

Design of Dual Band Mono Pole Antenna for UWB and Ku Band Applications

Over the past few decades, the evolution in new-fashioned wireless communication systems has actuated augmented exploration on uncomplicated dual band antennas. A compact dual band mono pole antenna for UWB and Ku Band Applications is proposed. The antenna consists of a corner truncated rectangular patch etched on cost effective FR4-substrate with thickness 1.6mm and is fed with 50 ohms feed line. The ground plane is truncated to enhance impedance matching and bandwidth. The proposed antenna has the ability to operate from 3.40 GHz to 10.67 GHz and 13.48 GHz to 15.87 GHz with return loss below -10 dB. The HFSS is used to design and simulate the antennas behavior over the different frequency ranges. The simulated results of the proposed antenna indicate higher gain at the two bands. The measured results demonstrated reasonable agreement with the simulated results.

Design of MIMO antenna to interference inherent for ultra wide band systems using defected ground structure

AbstractA compact monopole ultra wide band (UWB) antenna is analyzed and described with defect in ground plane. By introducing four arcs at the edges of square patch is achieved an UWB antenna ranging from 3.1 to 10 GHz. Arranging the antenna elements in close proximity of spatial diversity is introduced without establishing the strong mutual coupling. The measured IBW's (impedance bandwidth's) are 3.0 to 4.0 GHz (1000 MHz), 5.6 to 4.3 GHz (1300 MHz), and 9.5 to 8.4 GHz (1100 MHz) occupied the bandwidth from 2.0 to 10.0 GHz which covers Bluetooth, WLAN, and ultra wideband for VSWR ≤2. The average value of the gain in antenna is 5.04 dBi with a small variation of ±1.20 dBi for the whole entire IBW. This antenna shows better radiation patterns like an omnidirectional with a narrow compact size having an area of 2100 mm2 (60 × 35 mm) and spacing between the two square patches is 0.05 λ0.

Design of a compact ultra-narrow band dual band filter for WiMAX application

A novel narrow-band bandpass filter with two fully controllable passbands is proposed in this letter. The filter is designed through a systematic, yet simple approach, in which two independently-controllable passbands are realized using two different coupling paths. Each passband can be tuned independently only by changing one parameter of the filter. The measured and simulated results are in good agreement, showing, two passbands cantered at 3.5 and 5.8 GHz with fractional bandwidths of 0.8% and 1%, respectively. The return loss in the first and second passbands are better than 19 dB. The filter exhibits a very good out of band rejection performance, suppressing spurious bands up 16 GHz. The demonstrated filter has a compact size of 0.21λg × 0.13λg, where λg is the guided wavelength at 3.5 GHz.

A NEW HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHIC METHOD DEVELOPMENT AND VALIDATION OF DAPAGLIFLOZIN IN BULK AND TABLET DOSAGE FORM

ABSTRACT&#x0D; Objective: To develop a new simple, selective and precise high-performance thin layer chromatographic method for determination of Dapagliflozin (DAPA) in bulk and tablet dosage form&#x0D; Methods: The present study describes development and validation of High performance thin layer chromatographic method for DAPA. The chromatographic separation was carried out on Merck precoated silica gel aluminium plate 60 F254 using Chloroform: Methanol (9:1v/v) as mobile phase. Quantitative determination of drug was carried out by densitometric scanning of plates at 223 nm using Camag TLC Scanner.&#x0D; Results: The chromatographic condition shows compact band with the retention factor for dapaglifloxin as 0.21 ± 0.004. The method was validated as per ICH guidelines for linearity, accuracy, precision and robustness. Response was found to be linear in the concentration range of 400 ng/ band to 1200 ng/band with linear regression value of 0.9953 with respect to peak area and concentration value The LOD and LOQ was found to be 1.2083 ng/band and 3.6616ng/ band. The percentage assay was found to be 100±0.05.&#x0D; Conclusion: This method under statistical analysis proved a selective, repeatable and accurate analysis of the drug. This method can be used for quantitative analysis of dapaglifloxin in the bulk drug and in tablet.&#x0D; &#x0D;

A 0.34 mm2 1 Gb/s Non-Coherent UWB Receiver Architecture With Pulse Enhancement and Double PLL Clock/Data Packet Recovery

This paper presents a compact impulse-radio ultra-wide band non-coherent receiver architecture for high data rate wireless neural recordings from active high-density CMOS-probes. The system is capable of receiving, synchronizing, and demodulating a continuous on-off keying pulse stream at 1 Gb/s and 4 GHz center frequency using an active area of 0.34 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and a single 31.25 MHz crystal reference. An asynchronous threshold energy detector, including a pulse enhancement baseband with an all-digital back-end, recovers incoming transmitter clock (CDR) and acquires packet synchronization based on a data-aided mechanism (DPR). Results shows that a prototype of the receiver integrated in a 130 nm CMOS process recovers synchronization in 30 ns. The system includes I/O output buffers and driver logic at 1.8 V supply operating at 1 GHz on a 50 $\Omega $ load and crystal oscillator. Overall, it consumes 115 pJ/pulse, while the receiver core only consumes 12 pJ/pulse. This paper presents the receiver architecture, and experimental results show a sensitivity of -38 dBm at 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> packet error ratio.

Numerical Simulation of Deformation Band Occurrence and the Associated Stress Field during the Growth of a Fault-Propagation Fold

Knowledge of the paleo-stress distribution is crucial to understand the fracture set up and orientations during the tectonic evolution of a basin, and thus the corresponding fluid flow patterns in a reservoir. This study aims to predict the main stress orientations and evolution during the growth of a fold by using the limit analysis method. Fourteen different steps have been integrated as 2D cross sections from an early stage to an evolved stage of a schematic and balanced propagation fold. The stress evolution was followed during the time and burial of syn tectonic layers localized in front of the thrust. Numerical simulations were used to predict the occurrence and orientation of deformation bands, i.e., compaction and shear bands, by following the kinematic of a fault-propagation fold. The case study of the Sant-Corneli-Boixols anticline was selected, located in the South Central Pyrenees in the Tremp basin, to constrain the dimension of the starting models (or prototypes) used in our numerical simulations. The predictions of the numerical simulations were compared to field observations of an early occurrence of both pure compaction- and shear-enhanced compaction bands in the syn-tectonic Aren formation located in front of the fold, which are subjected to early layer parallel shortening during the burial history. Stress magnitude and stress ratio variations define the type of deformation band produced. Our results show that the band occurrence depends on the yield envelope of the host material and that a small yield envelope is required for these shallow depths, which can only be explained by the heterogeneity of the host rock facies. In our case, the heterogeneity can be explained by a significant contribution of carbonate bioclasts in the calcarenite rock, which change the mechanical behavior of the whole rock.

A compact dual band PIFA antenna for GPS and ISM BAND applications

This work deals with desgin of a novel compact Dual band PIFA Antenna structure. The proposed antenna is validated for GPS and WIFI applications. The antenna is achieved on a lossy FR4 substrate. The final size of the antenna is 100×55×13.235 mm3. The final antenna structure was optimized and validated into simulation, fabrication and test. The proposed multiband PIFA is optimized by using solts technique. The fabricated antenna is validated to cover the operating frequencies of GPS (1.535 -1.7GHz) and BLUTOOTH/WIFI (2.54-2.47GHz) bands.

Metamaterial‐inspired miniaturized antenna loaded with IDC and meander line inductor using partial ground plane

In this article, a novel omnidirectional compact dual band metamaterial-inspired antenna with CPW feed has been proposed for application of GSM 1800 (1.71-1.785 GHz/1.805-1.879 GHz), GSM 1900 (1.85-1.91 GHz/1.93-1.99 GHz), UMTS (1.92-2.17 GHz), WLAN/Wi Fi (4.9, 5, 5.9 GHz), HiperLAN1 (5.15-5.3 GHz), and HiperLAN2 (5.47-5.72 GHz) using a combination of meander line inductor and interdigital capacitor (IDC). The antenna consists of complimentary right/left handed (CRLH) transmission line on both sides of patch to excite zeroth order mode (n = 0). The rectangular slotted stubs act as a virtual ground for the structure using a short circuit condition at the end of the IDC. The zeroth order resonance (ZOR) frequency is mainly controlled by IDC and partially with the meander line inductor. The designed antenna operates from 1.72 to 2.22 GHz and 4.25 to 5.88 GHz with radiating size of 0.56λo × 0.35λo (32 × 20 mm2), where λo is the free-space wavelength at ZOR frequency of 5.27 GHz. The proposed antenna offers measured impedance bandwidth (|S11| <−10 dB) of 25.3 and 18.7% at 1.95 and 5.28 GHz and covers the targeted frequency bands. The proposed structure offers omnidirectional radiation patterns are congruous throughout the working band.

Tunable compact narrow band THz sources for frequency domain THz anisotropic spectroscopy.

We demonstrate frequency domain THz anisotropy signature detection for protein crystal models using newly developed compact tunable narrow band THz sources based on Orientation Patterned Gallium Phosphide for turn-key spectroscopic systems.

Structural evolution of carbonate-hosted cataclastic bands adjacent to a major neotectonic fault, Sellicks Beach, South Australia

Deformation bands are common fault-related strain features found in upper crustal granular highly porous sedimentary rocks. However, the majority of research has focused on siliciclastic-related case studies, resulting in a knowledge gap surrounding the nomenclature and implications of carbonate-hosted cataclastic bands. We present a systematic case study of carbonate-hosted deformation bands in the Oligocene–Miocene Port Willunga Formation (PWF) exposures along the wave-cut platforms at Sellicks Beach, South Australia. Sellicks Beach provides an exceptional location to study carbonate-hosted deformation bands because of the unique juxtaposition of the carbonate grainstone PWF and the NE-SW striking Willunga Fault. The Willunga Fault is a steep SE-dipping active reverse fault that previously accommodated deposition in a Cenozoic half-graben. We have conducted a comprehensive structural analysis of 269 PWF deformation bands that formed as a result of strain induced by the Willunga Fault. Our model identifies three sets of shear-enhanced compaction bands (SECBs), and one set of pure compaction bands (PCBs) within the PWF. The PWF deformation bands display a range of cataclasis intensity defined by the percentage of microscopic fine-grained groundmass (gm), named here as crush micro-breccia (0–10% gm) and protocataclastic bands (10–50% gm), resulting from comminution, stylolite formation, and cementation. Petrophysical analysis indicates that crush micro-breccia bands reduce permeability between 0.0–0.75 orders of magnitude, and protocataclastic bands reduce permeability between 0.25–1.75 orders of magnitude relative to host rock. Our results indicate that PWF deformation bands are a useful proxy for cataclasis intensity, forming the foundation for a new classification scheme to describe cataclastic deformation bands, specifically applied to carbonate rocks.

Dual‐band, dual‐polarized, and compact frequency selective surface

In this article, a compact, dual-band, dual-polarized band pass single-layered frequency selective surface (FSS) structure with stable performance in wide incident angles is designed and fabricated. This structure is designed with a new proposed approach which is the combination of miniaturized-element band stop FSS and high pass grid FSS. For this purpose, a new compact band stop structure is introduced and miniaturized by adding vertical metalized holes (vias) in the substrate as additional capacitive. A WLAN band stop FSS is designed also as an example of the proposed miniaturized-element. Then, this band stop FSS is combined with a simple high pass grid structure to design the proposed band pass FSS. The circuit models of these FSSs are also extracted to achieve better description of the structures and combination idea. The dimensions of the final designed compact band pass FSS structure is 0.048λ × 0.048λ where λ is the free space wavelength of the first resonance frequency. The fabrication results of this FSS which works at WLAN bands are in good agreement with the simulation ones which prove the design approach.

Combined triple band circularly polarised and compact UWB monopole antenna

A new design of a compact ultra-wide band (UWB) monopole antenna with triple-band, triple-sense circular polarisation (CP) is presented here. It is composed of a compact quad-circular monopole, a fractal parasitic ring resonator, a triangular ring resonator, rectangular ring resonator, and modified `T' and `I' shaped slots on the ground plane along with a rectangular stub with `E'-shaped slot on the right side of the monopole. The proposed antenna radiates left-hand circularly polarised (LHCP) wave at lower and mid-frequency bands, while right-hand circularly polarised (RHCP) wave at upper frequency band. The results show that the antenna covers an ultra-wide bandwidth from 3.1 to 11 GHz (112%). Moreover, the proposed antenna achieves good CP characteristics at Citizens Broadband Radio Services in USA (3.55-3.72 GHz), artificial magnetic conductors and WLAN upper frequency spectrum (4.81-5.61 GHz), VSAT services & Satellite Communication and Ground Surveillance RADAR (9.29-10.95 GHz), respectively. Novelty of this article lies in designing a compact printed UWB monopole antenna with combined triple band CP characteristics controllable by adjusting the antenna design parameters. The simulated and measured results of the antenna have been compared and seen to be in reasonable agreement.

A compact multiband band slot antenna for wireless applications

A compact (20 × 20 × 1.6 mm3) planar four band antenna operating at 1.35 (lower Global Navigation Satellite System [GNSS]), 2.57 (lower Worldwide Microwave Access [WiMAX]), 4.57 (C‐band) and for 5.13 GHz (Wireless Local Area Network [WLAN]) is presented. By utilizing slot method in the radiating patch and the ground plane the aforementioned operating bands are achieved. The antenna has a miniaturized dimension of 0.09λ0 × 0.09λ0 × 0.007λ0 (where λ0 is the free space wavelength at the lower frequency of 1.35 GHz, and exhibits good impedance match, acceptable radiation efficiency and stable radiation pattern at the targeted frequencies.

Compact Single Feed Dual Band Microstrip Patch Antenna with Adjustable Dual Circular Polarization

This paper presents a novel dual-band, half E-shaped microstrip patch antenna (HEMSPA) with dual sense polarization. The proposed antenna covers two different frequency bands and radiates electromagnetic waves with left hand circular polarization (LHCP) and right hand circular polarization (RHCP) at lower and upper frequency bands, respectively. The dual frequency is realized by etching four T slits close to the radiating edges of HEMSPA. A shorting bar is adopted to attain LHCP waves at lower band while a vertical slot etched in the patch center aids in achieving RHCP waves at upper band. The proposed antenna has a small frequency ratio of 1.2 and good scalability. It can be easily re-designed for other operating frequencies with dual sense circular polarization (CP) or same sense CP at dual frequencies. The simulated reflection coefficient, axial ratio, and radiation pattern characteristics show a good agreement with the experimental data for dual-band performance. The measured −10 dB impedance bandwidth, 3 dB axial ratio bandwidth, and boresight gain are observed to be 1010 MHz, 70 MHz, 9.27 dBic and 120 MHz, 69 MHz, 6.63 dBic in the lower band, and upper band, respectively. The proposed antenna would be promising for modern wireless communication system applications.

A compact wide band textile MIMO antenna with very low mutual coupling for wearable applications

This communication presents a compact wide band wearable MIMO antenna with very low mutual coupling (VLMC). The proposed antenna is composed of Jeans material. Two “I” shaped stubs are connected in series and are employed on the ground plane between the two patches separated by 0.048 λ to increase isolation characteristics of the antenna-port. The antenna covers frequency spectrum from 1.83 GHz to 8 GHz (about 125.5%) where the minimum port isolation of about 22 dB at 2.4 GHz and maximum of about 53 dB at 5.92 GHz are obtained. The envelope correlation coefficient (ECC) of the MIMO antenna is obtained to be less than 0.01 with a higher diversity gain (DG > 9.6) throughout the whole operating band. The proposed MIMO antenna is cost effective and works over a wide frequency band of WLAN (2.4-2.484 GHz/5.15-5.35 GHz/5.72-5.825 GHz), WiMAX (3.2-3.85 GHz) and C-band downlink-uplink (3.7-4.2 GHz/5.925-6.425 GHz) applications. Simulation results are in well agreement with the measurement results.

3D continuum-discrete coupling modeling of soil-hammer interaction under dynamic compaction

To investigate the compaction effect and environmental impact effect of dynamic compaction (DC), a 3D continuous-discrete coupling method was used to simulate the hammer-soil interaction process for the first time. Through the dynamic response analysis of the hammer, it is found that the force of the hammer changes through three stages: the contact force increases rapidly, the contact force decreases rapidly, and the contact force decreases slowly; in addition, the soil particles are compacted under the dynamic load, resulting in oscillating changes in the soil porosity. The granular soil is punched by the hammer to form a truncated punching surface in the bulk below the bottom of the hammer. Ellipsoidal compaction bands are formed inside the punching surface, and shear bands are formed outside the punching surface. The compression and shear zones affect the soil outside the continuous-discrete interface and form a stress concentration zone and a plastic strain zone near the interface, resulting in a sharp attenuation of the acceleration amplitude as the radial distance increases. Through an amplitude and Fourier spectrum analysis, it is found that the radial vibration caused by the DC is the strongest, while the tangential and vertical vibrations are almost the same. With the increase in the radial distance, the radial vibration attenuation rate is greater than that of the tangential and vertical vibrations, and their PGAs tend to be the same away from the impact point. These research results are helpful for evaluating the influence of the DC and the installation process on the reinforcement effect of the soft ground and for improving the accurate design and control level of soft ground strengthened by DC.