Neelesh Agrawal

A Novel Wide Band Microstrip-Line-Fed Antenna with Defected Ground for CP Operation

A novel wide band microstrip line-fed antenna with defected ground structure is proposed for circularly polarized characteristics. This antenna is suitable for C-band and partially X-band operation. Antenna1 structure consists of microstrip-line-feed, and the square-shaped slot defect is incorporated in the ground plane. Furthermore, rectangular and circular patches are embedded in the square-shaped slot that improves the performance of the radiating Antenna2 and Antenna3 structures, respectively. The proposed Antenna3 is compact in size and shows a good quality of polarization at resonant frequency band. Antenna3 shows the measured impedance bandwidth of 40.72% (6.45– 9.75GHz) and also shows the variations of 3-dB axial ratio bandwidth at the 6.806GHz and 9.13GHz frequencies with the simulated results, respectively. The return loss, axial ratio, gain, efficiency and radiation pattern of the proposed Antenna3 remain consistent for resonant frequency band. The antenna is practically fabricated and simulated. Measured result shows a good agreement with simulated and theoretical ones.

A Novel Hybrid System for Speech Enhancement In Wavelet Domain

The basic problem suffered by a communication system is in the removal of additive background noise. Spectral Subtraction method (SSM) has been successfully implemented to suppress the background noise. This paper proposed a novel hybrid system for enhancing noise-corrupted speech which involves a parallel combination of Spectral Subtraction and soft thresholding method in wavelet domain for speech enhancement. The performance of hybrid system is compared with both Spectral Subtraction method and Wavelet thresholding technique (WTT) and found to have better SNR improvement. Implementation and evaluation have been made using MATLAB.