Riaz M.,Space and Upper Atmosphere Research Commission SUPARCO
Proceedings of the International Astronautical Congress, IAC | Year: 2013
This paper discusses the right to salvage under the Law of the Sea and Space Law, drawing comparisons and highlighting the differences between the two. It goes on to elaborate whether the basic principles of maritime salvage law should be adopted in space law and the possible legal impediments to it. Furthermore, it must be considered how far the existing treaties (The Liability Convention, etc) and the Space Debris Mitigation Guidelines facilitate in mitigating disputes related to salvage and space debris. It is important to ascertain the possibility of drafting a treaty on the right to salvage of space objects and whether it may prove to be useful in space debris remediation. ©2013 by the International Astronautical Federation. All rights reserved.
Ismail M.Y.,University Tun Hussein Onn Malaysia |
Inam M.,University Tun Hussein Onn Malaysia |
Sulaiman N.H.,University Tun Hussein Onn Malaysia |
Amin Mugha M.,Space and Upper Atmosphere Research Commission SUPARCO
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2011
This paper presents a detailed investigation on the phase agility of reflectarray antennas designed in the X-band frequency range. A novel technique for the analysis of the required reflection phase from individual reflectarray elements to form a planar wavefront of the periodic aperture is presented. Various slot configurations embedded in the patch elements of reflectarrays are also proposed for the performance improvement of reflectarray antennas. The feasibility of using these slot configurations for frequency tunable reflectarrays and designing periodic structure of slotted patch elements are also demonstrated. The designed reflectarray antenna with attainable frequency tunability of 1700MHz, demonstrated that a maximum dynamic phase range of 320° and a volume reduction of up to 24.36% are achieved at 10 GHz. © 2011 Engineers Australia.
Siddiqui M.Z.,Space and Upper Atmosphere Research Commission SUPARCO
Strain | Year: 2015
This article reports an important development related to the inverse characterization of material constitutive parameters using 2D optical displacement field measurements. The out-of-plane motion of the specimen, which has traditionally been considered detrimental to the accuracy of these experiments, is generally of two types: (a) a global out-of-plane rigid-body motion of the specimen relative to the camera and (b) out-of-plane deformations resulting from material heterogeneity or out-of-plane loads. In an earlier article, we proposed to partially relax the condition of no out-of-plane motion by allowing for (b) in 2D inverse procedures, in the context of finite element update method, and introduced a compensation strategy by redefining the cost function on the object plane of the acquisition system. The experimental errors due to (a) were assumed negligible. Here, we propose that the global rigid-body motion (a) may also be recovered within the inverse procedures, hence completely waiving the condition of strictly in-plane displacements for inverse problems. The recovery is achieved by identifying and including the possible modes of global rigid-body motion within the cost function together with careful selection of test configuration. The effects of individual rigid-body modes on the computed displacement fields are studied in detail and utilized as a guideline for selection of test configuration. The approach is fully demonstrated and validated by simulated as well as real experiments for determining elastic constants of isotropic and orthotropic materials using different experimental setups. Effects of improving the optimization routine, for cost function minimization, and experimental noise are also presented. © 2014 Wiley Publishing Ltd.
Ismail M.Y.,University Tun Hussein Onn Malaysia |
Abbasi M.I.,University Tun Hussein Onn Malaysia |
Zain A.F.M.,University Tun Hussein Onn Malaysia |
Amin M.,Space and Upper Atmosphere Research Commission SUPARCO |
Abdullah M.F.L.,University Tun Hussein Onn Malaysia
International Journal on Electrical Engineering and Informatics | Year: 2010
Lumped components are used to represent the reflectarrays designed using different commercially available materials. The loss performance and the effect of material properties on the reflectarray antennas are discussed in terms of the lumped components which are used in the equivalent circuit analysis. The bandwidth performance of reflectarrays designed with different materials is discussed using reflection loss and reflection phase plots obtained by equivalent circuit analysis. Furthermore the results obtained by equivalent circuit modeling are compared with the results obtained using CST Microwave Studio simulations and a close agreement between all the results has been demonstrated. The dielectric permittivity (ε r) of materials investigated in this work ranges between 2.08 to 13 and the loss tangent (tanδ) values vary from 0.0003 to 0.025 while the reflection loss values obtained by equivalent circuit analysis varied from 0.179 dB to 6.875 dB and a variation in 10% and 20% bandwidth is observed from 84 MHz to 360 MHZ and 126 MHZ to 540 MHz respectively based on the respective material properties.
Baig M.A.,National University of Sciences and Technology |
Piracha M.M.A.,Space and Upper Atmosphere Research Commission SUPARCO
ICET 2013 - 2013 IEEE 9th International Conference on Emerging Technologies | Year: 2013
WLAN is used for variety of applications. It has become the source of internet connectivity with a much higher data rates and is being successfully used at airports, university corridors, hotel lounges, hospitals, business centers and so on. Presently the most popular standards for WLAN being used are 802.1 T-b, g and n, in which standard 'n' provides much higher data rate. For higher data rate, much higher bandwidth is needed. In this paper we have investigated the suitability of simple microstrip antennas i.e.(Bow-tie antenna, Elliptical inset-fed antenna and Rectangular inset-fed antenna) for WLAN applications, in comparison of more complex antennas. The purpose for choosing three different types of simple antenna structures is to analyze the reduced complexity of design with better performance amongst three. We have found that we can obtain considerable results even with the use of simple antenna structures in terms of bandwidth as compared to results obtained in previous studies. Analysis has been performed to find the relative gain, and impedance bandwidth of the three antennas. © 2013 IEEE.