برصغیر میں محدثین کی خدمات حدیث: تاریخی و تجزیاتی جائزہ

After the Prophet r the Muslims all over the world associate themselves with him by following his pious deeds and acting upon his sayings (Hadith). The Muslims of the sub-continent have been very zealous in this respect and have done great job in this regard. In the subcontinent, the sayings of the Holy Prophet reached with Islam during the era of pious caliphs. In those days, according to some traditions, 25 companions of the Holy Prophet ﷺ Sahaba (R. A) and 42 Tabe-ien (those who had seen the Sahaba R. A i-e their successors) came to India and preached Islam. This preaching was continued by later Muslims and the rulers like Mohammad Bin Qasim and Mehmood Ghaznavi. The services of great Muhaddeseen (narrators and illustrators of the sayings of the Holy Prophet r like Musa Bin Yaqoob, Yazid Bin Abi Kabsha, Abu Musa Israeel Bin Musa and Abu Hafs Rabi Bin Sabih are note worthy. They provided local people the knowledge of Hadith. These scholars earned fame and prestige by their great works in this field. Shah Waliuallah wrote Mussffa and Maswwa, in subcontinent there are great many institutions like Jamia Salfiya Faisalabad, Jamia Ashrafia Lahore, Jamia Naeemia Lahore, Khair- ul-Madaras Multan, Jamia Mohammadia Gujranwala, Dar-ul-Hadith Delhi and Jamia Salfiya Banaras to teach the knowledge of Hadith.

Reflect Arrays for High Gain Applications

This research work focuses on design and analysis of low-cost, single-layer broadband reflectarrays for X-band applications. Traditionally, parabolic reflectors and phased arrays were introduced to obtain the high gain. The disadvantages associated with traditional antenna types include: narrow bandwidth, high fabrication cost and complex feed networks. Recently, reflectarray antennas have been developed to overcome the disadvantages associated with parabolic reflectors and phased arrays. High gain reflectarray antennas are typically employed in radars, satellite communication and direct broadcasting applications. Four different type of delay-lines integrated reflectarray elements which include: single circular delay-line, pair of circular delay-lines, quad-meander and T-shape delay-lines are designed to obtain a broad linear phase range, high gain and good aperture efficiency. The reflectarray unit element performance is investigated in terms of phase range, Transverse Electric (TE) and Transverse Magnetic (TM) modes and far-field radiation patterns. The reflectarray unit element is analyzed by using circuit model technique and equivalent circuit results are verified through High Frequency Structure Simulator (HFSS™). The circuit model technique replaces the lengthy full-wave simulation of FEM method. This method provides fast and accurate calculation of electromagnetic parameters i.e. magnitude and phase range. The unit element shape and configurations are used to extract the lumped parameters and reflection characteristics. The reflectarray antenna system contains a feed horn antenna and an arrangement of phase shifting array elements. A hybrid Finite Element Boundary Integral (FEBI) method is used for electromagnetic modeling of reflectarray antenna system. The FEBI method provides accurate electromagnetic analysis of complex and medium-to-large sized structures. The reflectarray far-field radiation characteristics are obtained by using the hybrid FEBI method. The reflectarray antenna system model comprises of feed horn antenna and array of phase shifting elements. The feed horn antenna and array elements are designed separately. The effect of the incident angle, feed-to-diameter ratio and transmission modes can easily be considered in the FEBI based system simulations. The proposed reflectarray prototypes are fabricated and measured on a low-cost FR-4 substrate. The reflectarray antenna measurements are made in anechoic chamber. A gain of more than 20 dBi is realized for the proposed reflectarray configurations. The simulated and measured cross polarizations and side-lobe-levels are below -20 dB in all design configurations. More importantly, simulated results are in good agreement with the measured results.