A High Accuracy Measurement Circuit for Soil Moisture Detection

Year: 2007 Volume: 1 Issue: 11 1688 - 1691 Pages

• Authors:
• Sheroz Khan
• A. H. M. Zahirul Alam
• Othman O. Khalifa
• Mohd Rafiqul Islam
• Zuraidah Zainudin
• Muzna S. Khan
• Nurul Iman Muhamad Pauzi

Abstract: The study of soil for agriculture purposes has remained the main focus of research since the beginning of civilization as humans- food related requirements remained closely linked with the soil. The study of soil has generated an interest among the researchers for very similar other reasons including transmission, reflection and refraction of signals for deploying wireless underground sensor networks or for the monitoring of objects on (or in ) soil in the form of better understanding of soil electromagnetic characteristics properties. The moisture content has been very instrumental in such studies as it decides on the resistance of the soil, and hence the attenuation on signals traveling through soil or the attenuation the signals may suffer upon their impact on soil. This work is related testing and characterizing a measurement circuit meant for the detection of moisture level content in soil.

• Keywords:
• Analog–digital Conversion
• Bridge Circuits
• Intelligent sensors
• Pulse Time Modulation
• Relaxation Oscillator

Rule-Based Fuzzy Logic Controller with Adaptable Reference

Year: 2007 Volume: 1 Issue: 11 3403 - 3407 Pages

• Authors:
• Sheroz Khan
• I. Adam
• A. H. M. Zahirul Alam
• Mohd Rafiqul Islam
• Othman O. Khalifa

Abstract: This paper attempts to model and design a simple fuzzy logic controller with Variable Reference. The Variable Reference (VR) is featured as an adaptability element which is obtained from two known variables – desired system-input and actual system-output. A simple fuzzy rule-based technique is simulated to show how the actual system-input is gradually tuned in to a value that closely matches the desired input. The designed controller is implemented and verified on a simple heater which is controlled by PIC Microcontroller harnessed by a code developed in embedded C. The output response of the PIC-controlled heater is analyzed and compared to the performances by conventional fuzzy logic controllers. The novelty of this work lies in the fact that it gives better performance by using less number of rules compared to conventional fuzzy logic controllers.

• Keywords:
• Fuzzy logic controller
• Variable reference
• Adaptability
• Rule-based.

Design of a Tuning Fork type UWB Patch Antenna

Year: 2007 Volume: 1 Issue: 8 1086 - 1089 Pages

• Authors:
• A. H. M. Zahirul Alam
• Rafiqul Islam
• Sheroz Khan

Abstract: In this paper a tuning fork type structure of Ultra Wideband (UWB) antenna is proposed. The antenna offers excellent performance for UWB system, ranging from 3.7 GHz to 13.8 GHz. The antenna exhibits a 10 dB return loss bandwidth over the entire frequency band. The rectangular patch antenna is designed on FR4 substrate and fed with 50 ohms microstrip line by optimizing the width of partial ground, the width and position of the feedline to operate in UWB. The rectangular patch is then modified to tuning fork structure by maintaining UWB frequency range.

• Keywords:
• Ultra wide band
• antenna
• microstrip
• partial groundplane.