Independent Tracking Dual Beam Antenna is composed by a single fixed reflector and two tracking feeders. ITDB antenna presents the ability to track two simultaneous MEO satellites allowing the handover process. ITDB antenna is designed for a 16 satellite constellation providing a +/- 20º scan range; nevertheless, a chamfered version is analyzed in order to increase the scan range to +/- 40º. The ITDB antenna total weight has been reduced significantly when comparing with the actual solution.
In addition, it is important to remark that ITDB antenna substitutes two complete tracking ground stations by one single installation.
Consequently, the optimization in cost, footprint and weight are the main goals of this development.
The following figures illustrates the bread-boarding developed at TTI's anechoic chamber and the obtained measurements.
Figure 2. ITDB Antenna breadboard in anechoic chamber
Figure 3. ITDB Antenna breadboard measurement. Both beams activated simultaneously for handover purposes. Blue scanning at 20º and red scanning at -20º. Green and black curves represent both mask compliance regulation. The plot represent Gain (in dB) vs angle (in degrees).
The picture shows the measurements of two beams generated simultaneously. The measurement was made at 28 GHz and shows a blue circular polarized pattern pointing at 20º and a red circular polarized pattern pointing at -20º. Both patterns were compliant with a gain > 42 dB, XPD > 20 dB and fulfilling side-lobe mask requirements (FCC 47 CRF 25.209)