Sadeque Reza Khan

Analysis and Optimization of Four-Coil Planar Magnetically Coupled Printed Spiral Resonators

High-efficiency power transfer at a long distance can be efficiently established using resonance-based wireless techniques. In contrast to the conventional two-coil-based inductive links, this paper presents a magnetically coupled fully planar four-coil printed spiral resonator-based wireless power-transfer system that compensates the adverse effect of low coupling and improves efficiency by using high quality-factor coils. A conformal architecture is adopted to reduce the transmitter and receiver sizes. Both square architecture and circular architectures are analyzed and optimized to provide maximum efficiency at a certain operating distance. Furthermore, their performance is compared on the basis of the power-transfer efficiency and power delivered to the load. Square resonators can produce higher measured power-transfer efficiency (79.8%) than circular resonators (78.43%) when the distance between the transmitter and receiver coils is 10 mm of air medium at a resonant frequency of 13.56 MHz. On the other hand, circular coils can deliver higher power (443.5 mW) to the load than the square coils (396 mW) under the same medium properties. The performance of the proposed structures is investigated by simulation using a three-layer human-tissue medium and by experimentation.

HARDWARE AND LOGIC IMPLEMENTATION OF MULTIPLE ALARM SYSTEM FOR GSM BTS ROOMS

Cellular communication becomes the major mode of communication in present century. With the development of this phase of communication the globalization process is also in its peak of speed. The development of cellular communication is largely depending on the improvement and stability of Base Transceiver Station (BTS) room. So for the purpose of the development of cellular communication a large numbered BTS rooms are installed throughout the world. To ensure proper support from BTS rooms there must be a security system to avoid any unnecessary vulnerability. Therefore multiple alarm system is designed to secure the BTS rooms from any undesired circumstances. This system is designed with a PIC Microcontroller as a main controller and a several sensors are interfaced with it to provide high temperature alarm, smoke alarm, door alarm and water alarm. All these alarms are interfaced with the alarm box in the BTS room which provides the current status directly to Network Management Centre (NMC) of a Global System for Mobile (GSM) communication network.

The Performance Evaluation of IEEE 802.16 Physical Layer in the Basis of Bit Error Rate Considering Reference Channel Models

Fixed Broadband Wireless Access is a promising technology which can offer high speed data rate from transmitting end to customer end which can offer high speed text, voice, and video data. IEEE 802.16 WirelessMAN is a standard that specifies medium access control layer and a set of PHY layer to fixed and mobile BWA in broad range of frequencies and it supports equipment manufacturers due to its robust performance in multipath environment. Consequently WiMAX forum has adopted this version to develop the network world wide. In this paper the performance of IEEE 802.16 OFDM PHY Layer has been investigated by using the simulation model in Matlab. The Stanford University Interim (SUI) channel models are selected for the performance evaluation of this standard. The Ideal Channel estimation is considered in this work and the performance evaluation is observed in the basis of BER.