Potential Benefits of Dynamic Beam Synthesis to Mobile Satellite Communication, Using the Inmarsat 4 Antenna Architecture as a Test Example

<table class="table-group" id="tab1"><tr><td><table class="table"><tr><td class="thead-hr" colspan="2"><hr/></td></tr><tr class="thead"><td align="left">Parameter</td><td align="left">Value</td></tr><tr><td class="thead-hr" colspan="2"><hr/></td></tr><tr><td align="left">Transmit</td><td align="left"><svg height="11.175" id="M11" style="vertical-align:-0.20474pt" version="1.1" viewbox="0 0 65.787498 11.175" width="65.787498" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg> MHz</td></tr><tr><td align="left">Receive</td><td align="left"><svg height="11.225" id="M12" style="vertical-align:-0.1638pt" version="1.1" viewbox="0 0 89.849998 11.225" width="89.849998" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg> MHZ</td></tr><tr><td align="left">Polarisation</td><td align="left">RHCP</td></tr><tr><td align="left">Number of antennas</td><td align="left">Single Tx/Rx array fed reflector</td></tr><tr><td align="left">Antenna type</td><td align="left">Offset-fed paraboloidal reflector</td></tr><tr><td align="left">Diameter</td><td align="left">9 metres</td></tr><tr><td align="left">F/D</td><td align="left">0.53</td></tr><tr><td align="left">Feed</td><td align="left">120 helical elements, array diameter = 2.2 metres</td></tr><tr><td align="left">Feed position</td><td align="left">In front of focal plane</td></tr><tr><td align="left">Beamformer</td><td align="left">Digital Signal Processor, (DSP) with 15 <svg height="11.125" id="M13" style="vertical-align:-0.1638pt" version="1.1" viewbox="0 0 33.974998 11.125" width="33.974998" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg> multiport
 amplifier (<svg height="13.75" id="M14" style="vertical-align:-0.0pt" version="1.1" viewbox="0 0 42.75 13.75" width="42.75" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg>) blocks on transmit</td></tr><tr><td align="left">Beam alignment</td><td align="left">Beams aligned with fixed geographic cells</td></tr><tr><td align="left">Beam reconfiguration</td><td align="left">Beams reconfigured throughout the day to compensate for
 orbit inclination</td></tr><tr><td align="left">Frequency reuse</td><td align="left">Spatial diversity provides frequency reuse between beams</td></tr><tr class="table-tr"><td colspan="2"><hr class="tbody-hr"/></td></tr></table></td></tr><tr class="table-fn"><td><svg height="13.95" id="M15" style="vertical-align:-0.16379pt" version="1.1" viewbox="0 0 34.450001 13.95" width="34.450001" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg> MPA blocks are used to distribute power more uniformly over the transmit amplifiers and hence increase their efficiency.<br/></td></tr></table>

International Journal of Antennas and Propagation

tab1

Table 1

Table 1: Potential Benefits of Dynamic Beam Synthesis to Mobile Satellite Communication, Using the Inmarsat 4 Antenna Architecture as a Test Example 