IJCRR - 5(5), March, 2013
Pages: 07-16
WATER VAPOR ATTENUATION STUDIES FOR KA AND V BAND FREQUENCIES OVER A TROPICAL REGION
Author: G.Venkata Chalapathi, S. Eswaraiah, S. Vijaya Bhaskara Rao, N. Prabhakara Rao
Category: General Sciences
[Download PDF]
Abstract:
The recent communication satellite systems tend to employ higher frequency (18-60 GHz) bands to satisfy the growing capacity requirements. Such wide bandwidths are valuable in supporting applications such as high speed data transmission and video distribution. The attenuation of Satellite signals due to water vapor absorption is very essential for high frequency (>10GHz) satellite communication. Using the formulae referred in Recommendations ITU-R, P.676-5, predictions of specific attenuation and path attenuation due to water vapor absorption are calculated and presented and also compared with the water vapor attenuation estimated from Radiosonde data collected from the India Meteorological Department (IMD), for the first time over tropics. The important findings of the current study includes the observation of slant path attenuation value, which is high for frequencies like 20 GHz, 24 GHz, 26 GHz, 47 GHz and () low for frequencies 18 GHz, 16 GHz, 14 GHz, and 12 GHz etc. It is also observed that for low elevation angles the slant path attenuation is maximum and its value decreases with the increase of elevation angle. For the 1200 GMT similar results are obtained indicating that there is significant diurnal change in the observed attenuation.
Keywords: Satellite communications, Water Vapor, Attenuation, Communication Satellites, High Frequency bands.
Citation:
G.Venkata Chalapathi, S. Eswaraiah, S. Vijaya Bhaskara Rao, N. Prabhakara Rao. WATER VAPOR ATTENUATION STUDIES FOR KA AND V BAND FREQUENCIES OVER A TROPICAL REGION International Journal of Current Research and Review. 5(5), March, 07-16
References:
1. Altshuler EE, Gallop MA, and Telford LE. Atmospheric attenuation statistics at 15 and 35 GHz for very low elevation angles, Radio Science 1978; 13,5: 839-852.
2. Asoka Dissanayake, Jeremy Allnutt and Fatim Haidara. Cloud attenuation modelling for SHF and EHF applications,Int. J. Satell. Commun 2001, 19:335-345 (DOI: 10.1002/sat.671)
3. César Amaya. Impact of Clouds and Gases on SATCOM Links at Ka and EHF Bands, American Institute of Aeronautics and Astronautics Report AIAA-2002-1953.
4. Crane RK. Propagation Handbook for Wireless Communication System Design, CRC Press LLC 2003.
5. ITU-R P.676-5, Recommendation: “Attenuation by Atmospheric Gases (Geneva, 2001a)”.
6. ITU-R P.453-8, Recommendation: “The Radio Refractive Index: It’s Formula and Refractive Data (Geneva, 2001b).
7. Karmakar PK, Rahaman M and Sen AK (2001).Measurement of atmospheric water vapour content over a tropical location by dual frequency microwave radiometry, International Journal of Remote Sensing 2001; 22:17, 3309-3322.
8. Kifah Al-Ansari, Awadallah Salama . Investigation of atmospheric gases attenuation in UAE. 4th IEEE GCC 2005.
9. Mandeep JS, Hassan SIS. Microwave and Millimetre Wave Characteristics and Attenuation of Clouds over some Malaysian Equatorial Stations,Int.Jou.Infrared and Mill Waves 2008 March 29;3:225-231.
10. Sarkar SK, Ahamad I, Das J and De AK. Cloud height, cloud temperature and cloud attenuation in microwave and millimetre wave frequency bands over Indian tropical east coast, Int.J.Infrared Millm Waves (USA) 2005, 26-329.
11. Sarkar SK, Mondal NC, Bhattacharya AB and Bhattacharya R. Some studies on attenuation and atmospheric water vapour measurements in India, International Journal of Remote Sensing1998; 19:3, 473-480
12. Uppal GS, Dubey V, Chada R. Water Vapor studies at 22.235 GHz by microwave radiometer IEEE Jounal 1979 December; 25:498-499.
|