Anurag Vidyarthi

Regional Variability of Rain Drop Size Distribution Model in India

Present study shows the development of integrated rain drop size distribution (DSD) model and gives a comparative study with DSDs of difierent regions in India. This work is useful for estimation of rain induced attenuation. Rain data of flve difierent regions (Ahmedabad, Shillong, Thiruvananthapuram, Kharagpur and Hasan) was used for this work. Attenuation characteristics are difierent for difierent regions because DSD varies according to the climatic conditions. Development of DSD model for each location is not feasible. It is a demand to develop a integrated DSD model which gives the tolerable error in DSD for difierent regions, so that, it can be adjusted in fade margin of the communication system. The result of this work shows the good correlation between the proposed integrated DSD model and DSDs of difierent regions.

Modeling of rain drop-size distribution for Indian region

The data on rain drop size distribution, collected at Ahmedabad (India), has been analyzed to develop empirical model on drop-size distribution (DSD). Out of the various DSDs available in literature like Marshall and Palmer, Gamma and lognormal, analysis was carried out for the suitability of lognormal distribution. The lognormal distribution has been found suitable as also predicted by others for Indian climate. The empirical model has been derived on the basis of fit parameters of the distribution evaluated from data.

Rain fade mitigation using linear prediction technique in wireless communication

Proposed work shows the rain fade mitigation technique in wireless communication using linear prediction. Two year signal data from IPSTAR satellite at 20.2 GHz is used in this work. Proposed work can be used on different frequencies by using frequency scaling. Experimental signal is used to analyze original variations of the atmosphere. Delhi earth station data provided by SAC, Ahmadabad is used. The outcome of this work is very useful in short term signal behavior and rain fade mitigation technique to support power control in wireless communication.

Modeling of rain attenuation using equiprobability of rain fade and rain fall

Proposed work shows the modeling of rain attenuation. This modeling is based on rain rate versus rain attenuation characteristics by using equiprobability. Total three years data of signal and rain is used in this work. Data includes the information of received signal strength from IPSTAR satellite and rain fall data. Two year signal data at 20.2 GHz and two year rain data of corresponding period is used to develop rain attenuation model and one year data is used for validation. Delhi earth station data provided by SAC, Ahmedabad is used. The outcome of this work is very useful in short term signal behavior and rain fade mitigation technique to support uplink power control.

Long-Term Variability in Rain Attenuation Statistics over Indian Region

Proposed work shows the rain rate versus rain attenuation characteristics on the basis of equiprobability. Two year signal data from IPSTAR satellite at 20.2 GHz and two year rain data of corresponding period is used to develop rain attenuation characteristics. Delhi earth station data provided by SAC, Ahmedabad is used. The outcome of this work is very useful in short term signal behavior and rain fade mitigation technique to support uplink power control.

Performance Analysis of Microstrip Antennas Using Different Shapes of Patch at 2.4 GHz

Proposed work shows design and comparative performance analysis of microstrip patch antennas with different shapes of patch to find out the best shape. The resonant frequency is kept 2.4 GHz because of the great importance of this frequency in wireless communication. FR-4 dielectric substrate is used for all the designs as FR-4 dielectric substrate is a commonly used substrate in practice. Frequency and dielectric are same in all the cases so that performance analysis depends almost only on shape of the patch. Rectangular shape found good directivity and gain with respect to others.

Characterization of various coplanar waveguide discontinuities

The mathematical modeling and analysis of various CPW discontinuities are presented in this paper. Simulations of these discontinuities are done through ADS and its electrical equivalent parameters are evaluated through MATLAB programming (M-file) for open, short and GAP. And compared with closed form relations. Various discontinuities analyzed are open end, short, step, GAP, bend. The analysis is being done with reference to conventional CPW. The dispersive characteristics of these discontinuities are analyzed at 2.4, 5 and 8 GHz.

Miniaturized Wilkinson power divider with harmonic suppression with stubs

This paper presents the comparative study of miniaturization of Wilkinson power divider along with higher harmonics suppressed. The circuit is designed at 2.4 GHz keeping in mind of wireless applications. Comparison is being made with respect to SWR, size, insertion loss with respect to the change in the length of the line. The miniaturization of the power divider is realized with capacitive loading which is being realized in the form of distributed element and not through lumped capacitor. Open circuited stub is being used for the capacitive loading. Reduction of transmission line segment from λ/4 to λ/12 is being analyzed with respect to SWR, insertion loss and percentage of bandwidth utilization. Power divider is realized on FR4 dielectric substrate (constant =4.5, height =1.5mm) and the simulations are performed using Genesys and ADS. The proposed power divider exhibits 40% size reduction, insertion loss not exceeding 0.7 dB and providing return loss better than +30 dB with the good isolation between the output ports and not reducing percentage of bandwidth utilization below 75.

Variation in extinction cross-section of rain drops with temperature

In this research work the variation in extinction cross-section of rain drops with temperature is analyzed. Rain degrades signals at microwave and millimeter wave frequencies. The attenuation value at these frequencies depends upon the extinction cross-section of the rain drops. In the present work variation in extinction cross-section with temperature has been estimated which will be helpful in studying the temporal and spatial distribution of rain attenuation in future work. The present analysis is done at 30 GHz.

Frequency scaling of slant path rain attenuation for fade mitigation in satellite communication

Fade mitigation techniques are widely used in mm wave satellite communication systems. Proposed work shows estimation and frequency scaling of rain induced attenuation which is useful in fade mitigation. Rain attenuation has been evaluated at downlink frequency and then scaled to uplink frequency, so that uplink power can be adjusted accordingly. IPSTAR beacon data at 20 GHz of two years has been used for this work. Proposed analysis is very useful for the study of uplink power control algorithms to counter rain induced attenuation.