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The design of a wide band bandpass filter is described in this article, which is done by using ?/4 transmission lines and is designed at a frequency range of 12GHz. Sigma shaped BPF is simulated by using EM simulation software An-soft HFSSv13 and is a wide band BPF having a band width of 5.8GHz and FBW of 50% as the center frequency. To determine its applicability for wideband applications, the suggested filter is constructed and tested. To guarantee that it is acceptable for satellite communication applications, many characteristics such as reflection co-efficient, transmission coefficient, bandwidth, and group delay are tested and are compared with the measured results. [ABSTRACT FROM AUTHOR]

Any wireless signal travelling in free space undergoes degradation due to the effects of the atmosphere that are naturally created in its pathway. Amongst all the degradation3 effects scintillation is significant at elevation angles above 5 degrees and also in tropical regions. Scintillation is mainly caused due to the rapid fluctuations in the refractive index of the layers of the atmosphere. Tropospheric scintillation is significant at frequencies above 3GHz. Ionosphere acts as a transparent layer above 10 GHz Tropospheric scintillation is receiving more attention because of the demand for higher bandwidth due to the congestion on the C and Ku bands. The rapid fluctuations induce variations in the received amplitude of the signal which decreases the quality of the signal. For systems with low elevation angle and the link operating with a frequency above 10GHz the effect of tropospheric scintillation is to be taken in to consideration. So, in this paper the effect of tropospheric scintillation is estimated for a Ku band beacon signal whose receiver is installed at K.L. University at a frequency of 11.7GHz. The scintillation amplitude is estimated using the beacon data and also using models that suit the tropical region. By comparing the scintillation amplitudes derived from the models and the with the one derived using beacon data, the best model that fits this geographical location is found which is the Otung model. [ABSTRACT FROM AUTHOR]