1st Band Research Articles

Dual band beam steering antenna using branch line coupler network for higher band applications

Abstract A beam-steering fed array antenna has been proposed for radar and mm-Wave applications operating from 22.6 to 26.89 GHz and 30–45 GHz with B.W % of 17.34 % and 40 % respectively having size of 12.11 × 25.58 × 0.8 mm3 (0.96λo × 2.01λo × 0.06λo). For radar, this antenna covers 24.15 GHz as police radar, 24.25–25.25 GHz & 31.8–33.4 GHz as navigation radar, and 33.4–36 GHz as high-resolution radar for airport surveillance. This antenna also covers mm-wave bands for different countries (Brazil-40 GHz, China- 34–42.5 GHz, Mexico- 33 GHz and 37 GHz, and USA- 24 GHz, 37 & 39 GHz). At initial stage, a monopole antenna with DGS has been designed with an operating band of 20.2–31.2 GHz and 36.6–42.2 GHz. Proposed antenna shifts the beam pattern at 90° with each other after exciting each port in alternative order with a scanning angle of ±45°, ±75° & ±180°. Peak gain for 1st band ranges from 7.1 to 9 dBi and for the 2nd band ranges from 8.8 to 10.2 dBi and has a radiation efficiency of 88 %. Other diversity parameters such as ECC, DG, MEG, and isolation get analysed to observe the coupling effects. Design, development, and analysis of all antenna parameters is done by using HFSS 19 platform.

Multi band multi polarised fractal antenna for white space TV band

ABSTRACT Designing a fractal antenna for white space TV band frequencies is the main goal of the suggested work. In this design 4 iteration Koch snowflakes patch is used to get multiband. As the number of iterations increased size of the antenna is going to reduce. Further 4th iteration Koch snowflakes slots have been created in the patch. By introducing a fourth iteration cross slot into the ground plane, three bands have been created. Circular polarisation is attained through the incorporation of cross slots in the ground plane, inducing a phase shift between vertically and horizontally polarised electromagnetic waves. The antenna primarily operates within the last frequency bands (686–806 MHz) with linear polarisation. However, it can also function in the initial frequency band (487–540 MHz) with left-hand circular polarisation. The physical size if antenna is reduced by 38 mm with a gain of 4.5dBi. Axial ratio bandwidth (481–552 MHz) is 71 MHz. Axial ratio bandwidth is 18 MHz more as compared to impedance bandwidth. The same antenna can work in linear polarisation as well as circular polarisation. Multi-polarised, multiband antenna with impedance bandwidth of 10.3% (1st band) and 16.08% (last band) is designed for white space TV band frequencies.

Dual band circularly polarized CPW monopole antenna inspired by metasurface reflector

A high gain, dual-band circular polarized coplanar waveguide (CPW) patch antenna with a metasurface reflector was proposed and demonstrated in this paper. Using a FR4 substrate with a 0.8 mm thickness, an asymmetrical ground plane was made for a CPW patch antenna. The proposed antenna exhibited dual-band characteristics having reflection coefficient (S11) below − 10 dB from 1.70 GHZ to 3.02 GHz with a bandwidth of 52.38% and 4.59–6.69 GHz with a bandwidth of 42.16%. The average gain was 3.2 dBi in the lower band & 2.5 dBi in the upper band with 3 dB axial ratio of 27.1% bandwidth in a lower band. A metasurface reflector was placed along the proposed antenna with foam as a dielectric between them to increase the gain and bandwidth. The antenna, when combined with the metasurface reflector, achieved an impedance bandwidth of 37.8% in the 1st band, 63% in the 2nd band and both the bands exhibits circular polarization with a 3 dB axial ratio of 57% in the 1st band and 33.02% in the 2nd band. The average gain was 7dBi, with a maximum gain of 7.9dBi at 2.4 GHz. A prototype of an antenna & metasurface reflector was fabricated and measured results were found to be good in comparison with simulated results.

A Numerical Method for Flexural Vibration Band Gaps in A Phononic Crystal Beam with Locally Resonant Oscillators

The differential quadrature method has been developed to calculate the elastic band gaps from the Bragg reflection mechanism in periodic structures efficiently and accurately. However, there have been no reports that this method has been successfully used to calculate the band gaps of locally resonant structures. This is because, in the process of using this method to calculate the band gaps of locally resonant structures, the non-linear term of frequency exists in the matrix equation, which makes it impossible to solve the dispersion relationship by using the conventional matrix-partitioning method. Hence, an accurate and efficient numerical method is proposed to calculate the flexural band gap of a locally resonant beam, with the aim of improving the calculation accuracy and computational efficiency. The proposed method is based on the differential quadrature method, an unconventional matrix-partitioning method, and a variable substitution method. A convergence study and validation indicate that the method has a fast convergence rate and good accuracy. In addition, compared with the plane wave expansion method and the finite element method, the present method demonstrates high accuracy and computational efficiency. Moreover, the parametric analysis shows that the width of the 1st band gap can be widened by increasing the mass ratio or the stiffness ratio or decreasing the lattice constant. One can decrease the lower edge of the 1st band gap by increasing the mass ratio or decreasing the stiffness ratio. The band gap frequency range calculated by the Timoshenko beam theory is lower than that calculated by the Euler-Bernoulli beam theory. The research results in this paper may provide a reference for the vibration reduction of beams in mechanical or civil engineering fields.

Dual band- dual polarized planar inverted F-antenna for MBAN applications

AbstractA planar inverted F-Antenna with the dual band-dual polarization property is presented for medical body area networks applications. The designed antenna covers the 2.45 GHz industrial, scientific and medical, 4 G long term evolution (2.5–2.69 GHz) bands for ON body communication and Wi-Fi and WLAN (3.5–3.6 GHz) bands for OFF body communication. At the lower band, an equivalent offset fed magnetic microstrip type dipole has been utilized that generate field parallel to the surface of the body for supporting ON body communication. The broadside radiation pattern has been realized using the slotted patch counterpart for supporting OFF body communication. This technique has resulted in a design of dual band dual mode property using a single radiator. The footprint of the antenna is only 0.35λg × 0.17λg × 0.08λg. Owing to its compactness, lightweight, and easy mountable property (due to foam substrate), the proposed antenna is found to be robust for MBAN applications. The maximum permissible transmitted power for the 1st band is 25.78 and 20.3 dBm for the 2nd one to maintain standard specific absorption rate limitations of 1.6 W/Kg. Experimental investigations over human body showed minimal deviations from the free space conditions which makes it a potential candidate for body-centric communications.

2–18 GHz wide band co-design integrated LNA with active antenna for mobile communication technologies

This research proposes afresh wide bandwidth co-design approach of low noise amplifier (LNA) with active antenna for mobile (3rd, 4th and specially 5th generation) communication technologies. Three major approaches are used for binding this research. First approach proposes LNA designs made of cascaded common gate (CG) and common source (CS) stages with proposed image network technique. This novel technique observed inverse impedance at output of image network in proposed designs that provides wide bandwidth at the desired band of operation. Single CG stage with image network achieves 3G 1st band for the fixed wireless internet access while addition of T-network as an output stage to CG succeed 3G 2nd band for mobile broadband access. Moreover, cascaded CG and CS stages with proposed technique provides 4G wide bandwidth within range of 2–8 GHz which could be occupies high speed data rate. While the displacement of inductors into microstrip lines in the proposed LNA design achieves much higher bandwidth from 2 to 18 GHz and could be provides best solution for information carrying capacity in the 5G mobile technology. In second approach, asymmetric F-shaped slotted antenna is design which obtained bandwidth from 10.7 to 14 GHz within desired receiving direction. Finally, integration of proposed LNA design with F-shaped slotted active antenna provides co-design receiver and obtains minimum attenuation with highest gain. Entire proposed designs are implemented into ADS platform using commercial available RF-mixed 65 nm CMOS process. Measured results of chip design for proposed LNAs under the power consumption of 7.3 mW with fixed operating voltage of 0.9 V made good correlation with the simulation results.

Protein profile of breeding discrepancies of African catfish <i>Clarias gariepinus</i> in aquaculture practices

The protein analysis focused on sarcoplasmic muscle o f protein constituents to improve heterogenous growth of C. gariepinus. Ninety juveniles were graded and selected for the top 10%, medium 10% and bottom 10% fish which represented fast, moderate and slow growing groups. The protein sample extracts were prepared by homogenizing 150 mg of fish muscle and electrophoretic run in Sodium Dodecyl Sulphate (SDS) polyacrylamide gel. Eleven bands were found in large fish, eight bands in the medium fish and seven bands were detected in the small fish class. The 2nd to 5th protein band having molecular weight (MW) ranging from 116,200 to 70 KDa was detected across all fish class sizes. The 6th and 7th band present in the large fish sample class but absent in the other two classes, having MW 54.52 KDa and 54.21 KDa respectively are assigned to Desmin protein. The 1st band was the heaviest (MW 118,600 KDa) band only found in the large sized fish. The results revealed that 1st 6th and 7th bands are the distinguishing protein bands and these proteins have contributed to the heterozygosity nature of the large size class which are most suitable for broodstock selection for future artificial propagation practices.© 2015 International Formulae Group. All rights reserved.Keywords: Electrophoresis, molecular weight, broodstock, sarcoplasmic, heterozygosity

Resonance tunneling phenomena by periodic potential in type-II superconductor

We calculated the resonance tunneling energy band in the BCS gap for Type-II superconductor in which periodic potential is generated by external magnetic flux. In this model, penetrating magnetic flux was assumed to be in a fixed lattice state which is not moving by an external force. We observed the existence of two subbands when we used the same parameters as for the <TEX>$Nd_{1.85}Ce_{0.15}CuO_X$</TEX> thin film experiment. The voltages at which the regions of negative differential resistivity (NDR) started after the resonant tunneling ended were in a good agreement with the experimental data in the field region of 1 T - 2.2 T, but not in the high field regions. Discrepancy occurred in the high field region is considered to be caused by that the potential barrier could not be maintained because the current induced by resonant tunneling exceeds the superconducting critical current. In order to have better agreement in the low field region, more concrete designing of the potential rather than a simple square well used in the calculation might be needed. Based on this result, we can predict an occurrence of the electromagnetic radiation of as much difference of energy caused by the 2nd order resonant tunneling in which electrons transit from the 2nd band to the 1st band in the potential wells.

The Critical Temperature of Two-Band Superconductors with Pseudogap

The exact formula of Tc’s equation of two-band s-wave superconductors with Pseudogap in weak-coupling limit are derived by considering the influence of interband interaction. The pairing interaction in each band consisted of 2 parts the electron-phonon interaction and non-electron-phonon interaction are included in our model. It was found that the critical temperature is increased as Pseudogap, phonon coupling of 1st band constant and interband phonon coupling constant increased.

Fermi surface topology of deuterium-doped vanadium: Compton scattering study

The deuteration-induced effect on the Fermi surface (FS) topology of V was investigated by the synchrotron-based Compton scattering technique with 115 keV X-rays. The three-dimensional occupation number density (OND) of α-VD 0.64 single crystal and V single crystal was reconstructed by the directional Compton profiles along 13–18 directions. The observed OND shows that the FS topology of α-VD 0.64.differs from that of V at Γ, N, and H points in the crystal momentum space, which are hole position for V. This indicates that electrons that originate from deuterium modify the upper part of the host metal d bands (3rd and 4th bands) at the Fermi level E F, and forms the metal–hydrogen bonding states with the lower part of the host metal d band (1st band).

The Research on the Structure Response of Underwater Blasting on 4-Story Masonry-Concrete Building

This article takes the Xiamen Sea reef engineering as an example to research the structure response of underwater blasting vibration on 4-story masonry-concrete building. The blasting seismic wave has been field monitored and the data has been analyzed with some means such as wavelet analysis. As a result, the characteristic laws of different floors’ structure responses under the effect of blasting vibration load have been acquired. With the floor increasing, the particles vibration velocity amplification coefficient of the forth top roof relative to the ground is approximately 1.36 to 2.086. The duration period and the main vibrationa are reduced respectively by 14%-28% and by 38%-56%; each floor’s vibration energy mostly concentrates in 0-25Hz’s band. The first floor’s energy mainly concentrates on 0-60ms, mainly distributing in 1st and 2nd frequency band, with the maximum appearing in the 1st band. And the vibration signal energy peak amplification coefficient relative to the ground is approximately 1.783 to 3.866.

A model for the retrieval of suspended sediment concentrations in Taihu Lake from TM images

A study was conducted in the Taihu Lake with the aim of deriving a model for the retrieval of suspended sediment (SS) concentrations from Landsat TM images and in situ sampled data. The correlation between suspended sediment concentrations of lake and the reflectance obtained from the TM images is significant. By TM images and in situ sampled data in summer and winter, we obtained a comparative uniform model for the retrieval of suspended sediment concentrations in the Taihu Lake, that is lnSS = a*(R3/R1) + b, where lnSS is the natural logarithm of the suspended sediment concentration, R1 and R3 are the reflectance coincident with the 1st band and the 3rd band in TM images, a and b are the regression coefficients. Furthermore, we analysed the errors particularly to make sure the model is valid. The model is accurate to within 0.33(RMSE), suggesting that this model may be applicable to predict suspended sediment in the Taihu Lake from TM image throughout the year.