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Abstract-Rain attenuation is one of the most crucial factors to be considered in the link budget estimation for microwave satellite communication systems, operating at frequencies above 10 GHz. This paper presents a mathematical model for converting terrestrial rain attenuation data to be used for satellite applications at Ku-band. In the proposed technique, the ITU-R P 618-9, together with a combination of ITU-R P 530-12 and the revised Moupfouma model have been adopted for satellite and terrestrial rain attenuation predictions, respectively. The model has been used for transforming the measured rain attenuation data of some DIGI MINI-LINKS operating at 15 GHz in Malaysia, to be used for MEASAT 2 applications. It was found that the model predictions are fairly reasonable when compared with direct beacon measurements in Malaysia and similar tropical locations. The model will provide a relatively accurate method for transforming the measured terrestrial rain attenuation to be used for satellite applications; and therefore substantially reduce the cost of implementing Earth-satellite links in some tropical regions that have sufficient rain attenuation data for the terrestrial links.

The results of rain attenuation on terrestrial microwave links in a tropical climate has been reported in this paper. The results are presented in the form of rate of change of attenuation with respect to rain rate, denoted by S.R %p /. This is in turn used for predicting the expected rain attenuation at any %p of the time rain rate is exceeded in any tropical location. The predictions of the proposed model have been validated using the data collected in six locations in Malaysia and experimental results reported in other tropical locations that have a similar rainfall regime. The Malaysian data consist of 1-year measured rain attenuation over six DIGI MINI-LINKs operating at 15 GHz, and rainfall rates measured with both 1-minute and 1-hour integration times at the respective locations. The validity of the proposed model is further validated by comparing its estimates with the method of ITU-R Radiocommunication Sector of ITU and two classical rain attenuation prediction models particularly developed for tropical regions.The test results have shown that the proposed method seems to be more accurate than the proposed method seems to be more accurate than ITU-R and the other two prediction models in Malaysia. The method could be used as an alternative approach for predicting rain attenuation over any terrestrial microwave links in Malaysia and similar tropical climates.

SUMMARY This paper presents the experimental results of rain rate and rain attenuation measurements on six terrestrial microwave links in tropical Malaysia. The rain attenuation data were collected from six DIGI MINI‐LINKs (DiGi Telecommunications Sdn. Bhd., Malaysia, Shah Alam, Selangor Darul Ehsan, Malaysia) operating at 15 GHz with 99.95 % availability. The experimental results were compared with the International Telecommunication Union Radiocommunication Sector (ITU‐R) method and other existing rain attenuation prediction models. The main focus is on the ITU‐R prediction method, which underestimates the measured rain attenuation, more especially at extremely higher rain rates. The relationship between ITU‐R prediction errors and rainfall rates was studied, and it is shown that the two quantities are related by a quadratic function. The study will provide useful information on the design and planning of terrestrial radio links in Malaysia and similar tropical environments. Copyright © 2011 John Wiley & Sons, Ltd.

Abstract-A transparent monopole antenna operating at 2.30 GHz is presented in this paper. The radiating element and ground plane are both designed using AgHT-4, while the substrate is made of glass. The simulated and measured impedance bandwidths (BWs) are 41.89% (2.00-3.06 GHz) and 90.91% (1.5-4.00 GHz), respectively. These results were obtained by using a suitable arc-shape slot on the ground plane; and the BWs cover the IEEE 802.16e standard for WiMAX application in the 2.30 GHz band. The gain of proposed antenna is 3.16 dBi, and there is close agreement between measurement and simulation results, in terms of return loss and radiation patterns.

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This paper presents the results of direct rain attenuation measurements carried out on four experimental microwave links, installed at UTM, Malaysia. The links operate at frequencies of 15, 22, 26, and 38 GHz and the cumulative distribution function for different rain rates have been generated from the measured 4-year rain gauge data. The experimentally measured attenuation data have been compared with International Telecommunication Unior-R rain attenuation predictions; and it has been found that the latter have underestimated the measured values, especially at higher rain rates. The deviations have been modeled as a function of rain rate exceedances R%p. It is hoped that the study will provide useful information for estimation of rainfall attenuation on microwave links in tropical regions that have similar situation to Malaysia.