Arjun Kumar

Microstrip filter with defected ground structure: a close perspective

This paper presents a close but a beginners perspective and a comprehensive review of microstrip filters with defected ground structure (DGS). The concept of DGS is inspired by photonic/electromagnetic bandgap structures (EBG/PBG) and metamaterials that are employed in microwave components to achieve a variety of performance enhancement features. Modeling of DGS and metamaterials as an L-C equivalent lumped circuit is much simpler in comparison with complex EBGs/PBGs. In this review, we have given a detailed account of the microstrip filters using DGS.

A compact narrow band microstrip bandpass filter with defected ground structure (DGS)

In this paper, a compact narrow band bandpass filter is proposed with hexagonal dumbbell shaped defected ground structure in ground plane of a 50Ω microstrip line and a closed loop resonator in the conducting strip. This arrangement provides better coupling in pass band. Using DGS structure, forward transmission loss (S21) is -0.5 dB and return loss (S11) is -26.7 dB at the centre frequency 5.4 GHz with narrow bandwidth of 500 MHz. A conventional parallel coupled line bandpass filter has also been implemented with exactly same design goals for the sake of comparison. The proposed bandpass filter with DGS is quite promising with 60% size reduction.

Effect of azimuthal coverage of an earthquake on moment tensor solutions estimated by waveform inversion

The purposes of this seismological investigation are to understand and describe the effect of decrease in the azimuthal coverage of an earthquake on moment tensor solution estimated by waveform inversion. It will be very useful and worthwhile as mostly seismological networks are sparse and in case when only one or two station data are available. In this work, we have used two moderate earthquakes, 21 September 2009 (near Uttarakashi) and 3 May 2010 (near Ghansali). The waveform inversion has been carried using ISOLA software. The moment tensor is first estimated by using all station data and then by removing the stations so that the azimuthal coverage changes. The results show that strike of both nodal planes is varying with the change in azimuthal coverage. However, the slip and dip of both nodal planes remain quite stable against the variation in azimuthal coverage for these two earthquakes analyzed. The effect of decrease in the azimuthal coverage showed increase in double-couple percentage (DC %) and decrease in compensated linear vector decomposition (CLVD %). The other focal parameters such as T-axis azimuth, P-axis azimuth, T-axis plunge, and P-axis plunge have been found stable against the variation in azimuth coverage. The study also demonstrates that the moment tensor solutions obtained from waveform inversion using single station are almost similar to those estimated using maximum azimuthal coverage data and by polarity inversion.

Dynamic network pricing based on smart reference networks

Network pricing is a complex issue, considering the network size and other facets. For distribution networks, reference network aids in quick decision making, for network operation and pricing. There is a sustained interest for development of dynamic network pricing mechanisms to reflect network cost on a real time basis. Recent developments in smart grid technologies have offered opportunities to utilise these innovative technologies for real time network pricing. The paper proposes an integrated framework for providing dynamic network pricing for practical distribution networks. This framework introduces an integration of network reconfiguration algorithm in association with reference network formation algorithm. Considering the dynamic nature of networks, their reference network would also change with them. With real time inputs, it is possible to form a reference network for every eventuality in the system in real time, and carry out quick analyses based on these smart reference networks, and offer real time dynamic network pricing.

A design of microstrip bandpass filter with narrow bandwidth using DGS/DMS for WLAN

In this paper, a compact microstrip bandpass filter is designed using defected ground structure (DGS) with narrow bandwidth. Here a 50Ω quarter wave microstrip line is used for designing the bandpass filter. A circular head dumbbell shaped DGS in the ground plane of a microstrip line is used which provides the bandstop characteristics. Two series gap slot is introduced for achieving the bandpass characteristics in the conducting strip. These slots in conducting strip are also called defected microstrip structure (DMS). This arrangement provides better coupling in the pass band. In this paper no stubs and via are used. The bandwidth of the filter is 500 MHz and insertion loss less than 0.5 dB in passband at 5.4 GHz. The measured insertion loss (S21) is 0.6 dB at the center frequency 5.4 GHz with a bandwidth of 500 MHz which is good in agreement with measured results after the fabrications)

STUDY OF PARTIAL REPLACEMENT OF CEMENT BY SILICA FUME.

Arjun Kumar The use of silica fume had major impact on industries, ability to routinely and commercially produce silica fume modified concrete of flow able in nature but yet remain cohesive, which in turn produces high early and later age strength including resistant to aggressive environments. This study is an experimental on the nature of silica fume and its influences on the properties of fresh concrete. The partially replacement of cement by silica fume the strength parameters of concrete have been studied. First the strength parameters of concrete without any partial replacement were studied then strength parameters by partial replacement with silica fume have been studied by placing cube and cylinder on compression testing machine (CTM). Silica fume were used to replace 0% to 15% of cement, by weight at increment of 5% for both cube and cylinder. The results showed that partial replacement of cement with silica fume had significant effect on the compressive strength of cube and split tensile strength cylinder. The strength of concrete increases rapidly as we increases the silica fume content and the optimum value of compressive strength is obtained at 10% replacement. After 10% its start decreasing under uniform load condition of 4 KN and similarly the split tensile strength increases up to 10% and then start decreasing under the uniform load condition of 2KN.

Design studies of ultra wideband microstrip bandpass filter with T-shaped defected ground structure controlled by inter-digital capacitance

In this paper, a compact wide-band bandpass microstrip filter with T-shaped DGS studied with inter-digital capacitance in 50 ohm conducting line is proposed. Using this DGS structure, forward transmission coefficient (S21) is -0.08 dB and reflection coefficient (S11) is -22 dB at the center frequency 5.4 GHz with the wide bandwidth of 2 GHz. this type of filter can be used in WLAN and other applications for the frequency range of 5-6 GHz. Keywords-defected ground structure(DGS); inter-digital capacitance centre frequency; wide bandwidth; 50 ohm microstrip line

APPLICATION OF NEURAL NETWORK TO PREDICT STRONG GROUND MOTION FOR HIMALAYAN REGION.

* Arjun Kumar 1 , Himanshu Mittal 2 , Rajiv Sachdeva 3 Rohtash Kumar 4 . 1. Department of Civil Engineering, Arni University, Kathgarh, (H.P), India. 2. # 207, Back suit, Global Change Center National Taiwan University. 3. Department of Earthquake Engineering, Indian Institute of Technology Roorkee-247667. 4. Department of Geophysics, Banaras Hindu University Varanasi. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

Study of Partial Replacement of Fine Aggregate by Iron Slag.

Arjun Kumar. The environment problems are very common in India due to generation of industrial byproducts. Due to industrialization enormous byproducts are produced and to utilize these byproducts is the main challenge faced in India. Iron slag is one of the industrial byproduct from the iron and steel making industries. Considering the specificity of physical and chemical properties of metallurgical slag and a series of possibilities for their use in other industrial branches and in the field of civil constructions. This study shows the possibilities of using iron slag as partial replacement of fine aggregate (sand) by iron slag. Iron slag was used to replace 25% to 30% of sand by weight at increment of 5% for both cube and cylinder. The strength of concrete increases rapidly with increase the iron slag content and the optimum value of compressive strength is obtained at 30% replacement. After 30% replacement the strength decreases. Similarly in the case of split tensile strength, the strength increases with the increase in iron slag content and the optimum value of split tensile strength is obtained at 30%. The uniform load conditions for compressive strength and split tensile strength are 4KN and 2KN respectively. In this study, the compressive strength of the iron slag concrete was studied. The results confirm that the use of iron slag overcome the pollution problems in the environment. The results shows that the iron slag added to the concrete had greater strength than the plain concrete.

Investigation of fractal DGS microwave filters

This paper consists of the design studies of fractal DGS microwave filter. Minkowski fractal structure is inserted in different section of a dumbbell shaped DGS and their responses are compared on the basis of roll-off factor, effective capacitance and effective inductance. Then on the basis of this study a low pass filter having cutoff frequency of 5.4 GHz is designed using FFF configuration of Minkowski fractal DGS and its comparison with low pass filter implemented by dumbbell shaped DGS having same substrate area is carried out.