Q10Satellite Communication

In satellite link design, gains include: transmit antenna gain and receive antenna gain (both dependent on antenna diameter, aperture efficiency and operating frequency), and amplifier gains (LNA gain at the receiver, HPA gain at the transmitter). Losses include: free-space path loss (the dominant loss, due to the enormous distance signals travel between earth station and satellite), atmospheric attenuation and rain attenuation (especially significant at Ku-band and Ka-band frequencies), feeder and branching losses (losses in the waveguide/cable connections and combining/splitting networks between the antenna and the active RF equipment), antenna pointing loss (loss due to imperfect antenna alignment with the satellite), and polarization mismatch loss (loss due to imperfect alignment between the transmitted and received signal polarization). All these gain and loss terms are combined (added, in dB) in the overall link budget equation to determine the received carrier power and hence the achievable carrier-to-noise ratio at the receiver.