Design and analysis of a system for two-way communication via the QO-100 Satellite

Es'hail 2 / QO-100 (Qatar-OSCAR 100) satellite is a geostationary satellite positioned at 26˚ East and has two linear transponders with an uplink frequency of 2.4 GHz and a downlink frequency of 10.45 GHz for amateur radio services. The narrowband transponder with a low power 250 kHz bandwidth supports voice, Morse, and digital communication, while the wideband transponder with an 8 MHz bandwidth supports amateur Digital Video Broadcasting (DVB). To receive signals via the satellite, it is sufficient to place a bias tee circuit at the output of the LNB (Low Noise Block) on satellite dish followed by an Rx receiver at the output of this circuit. For signal transmission, a Tx antenna operating at an appropriate frequency must be mounted in front of the LNB along with the Tx transmitter. Thus, by mounting the LNB and Tx antenna together, the same satellite dish antenna can be used for both reception and transmission. Within the scope of this thesis, signal transmission was achieved using the narrowband transponder on the Es'hail 2/QO-100 satellite. A microstrip antenna operating at 2.4 GHz was designed and manufactured as the Tx antenna required for signal transmission. It is planned to mount this designed antenna in front of the LNB on satellite dish antenna to ensure signal transmission. After the communication with satellite is established, it will be observed via the software-defined radio receiver (SDR) used as both receiver and transmitter whether the two-way transmission of signal is achieved. The goal of this thesis is to utilize the QO-100 satellite as an alternative communication system for voice calls in emergencies when conventional communication networks (such as mobile phones, internet, etc.) are disrupted during natural disasters.