Page 1 Insert Company Logo Here on Master (Optional) 31 th Annual AMTA Symposium November 1-6, 2009 Globalstar II RX L-band Antenna Spherical Near Field Measurement Damiano Trenta Thales Alenia Space Italy S.p.A. Rome, Via Saccomuro 24 Phone: (+39) 06 –

31 th Annual AMTA Symposium November 1-6, 2009 Page 2 Insert Company Logo Here on Master (Optional) Overview  Globalstar II RX L-Band Active Antenna Description  TAS-Italy Spherical Near Field System General Description  Test Range Validation and Comparisons  Conclusions

31 th Annual AMTA Symposium November 1-6, 2009 Page 3 Insert Company Logo Here on Master (Optional) GBLII RX L-Band Active Antenna Description The L-Band receive antenna is an active multibeam array antenna of hexagonal shape. Its assembly includes the following elements: A Radiating Panel composed by 52 L-Band radiating elements; 52 active chains; A passive beam forming network (BFN) providing sixteen fixed beam laws; Total Pattern Description – Bread Board Model Polarization:LHCP; 16 total beams: 15 lateral beam and 1 central beam; Lateral Beam Squint Angle: 45 deg; Lateral Beam HPBW(max):24 deg;

31 th Annual AMTA Symposium November 1-6, 2009 Page 4 Insert Company Logo Here on Master (Optional) TAS-I SNFTR General Description To satisfy the program needs, in particular to be able to guarantee an high rate production, consisting of 4 antennas per month, with low cost and high accuracy, TAS- Italy in collaboration with NSI Inc. developed a new SNF test range with the following main characteristics: Anechoic Chamber overall dimensions:9 x 7 x 7 m; Absorber:18 inches breadboard pyramidal absorber; Positioner:Azimuth Positioner (with slip ring); Elevation Positioner; Roll positioner (with slip ring); RF Subsystem:completely provided by NSI inc. High speed, high accuracy, multi frequency and multi beam acquisition capabilities; Antenna Patterns Acq. Needed Time:20 min;

31 th Annual AMTA Symposium November 1-6, 2009 Page 5 Insert Company Logo Here on Master (Optional) TAS-I SNFTR General Description  axis  axis 3 [m] 1:16 RF Switch AUT DC Power Control Unit OEWG WR 510 Probe Tower AUT Box Main Components 1.AUT 1:16 Multiplexing Switch 2.AUT Mechanical Ground System Equipment: design to optimize: The mechanical fixation – AUT alignment; the RF and DC cables mate and de- mate operations; The scattering and polarization purity performances 3.AUT DC Power Control Unit it was designed to guarantee the proper DC power supply to the AUT in terms of ripples and signal variations and /or discontinuity due to the azimuth and the roll stage movements.

31 th Annual AMTA Symposium November 1-6, 2009 Page 6 Insert Company Logo Here on Master (Optional) Test Range Validation and Comparisons Main Steps 1.Measurement of a SGH WR650 2.Comparison between TAS-F and TAS-I Measurements. The comparisons between the measurements of three facilities were done. The antenna, was tested in Toulouse, in a quasi far-field test range, in TAS-I in a Spherical Near Field Test range (already available and validated) and the new one. Comparisons in terms of max Directivity, Crosspolar peak, Copolar and Crosspolar patterns were done. 3.Error budget Definition. Using the 18 Terms Error budget Technique an analysis of the measurement uncertainties has been done.

31 th Annual AMTA Symposium November 1-6, 2009 Page 7 Insert Company Logo Here on Master (Optional) Comparison between TAS-F and TAS-I Measurements TAS-F (Red Line) vs TAS-I (Black - Already Aveable) TAS-F (Red Line) vs TAS-I (Black – New One)

31 th Annual AMTA Symposium November 1-6, 2009 Page 8 Insert Company Logo Here on Master (Optional) Comparison between TAS-F and TAS-I Measurements TAS-F (Red Line) vs TAS-I (Black - Already Aveable) TAS-F (Red Line) vs TAS-I (Black – New One)

31 th Annual AMTA Symposium November 1-6, 2009 Page 9 Insert Company Logo Here on Master (Optional) Comparison between TAS-F and TAS-I Measurements TAS-F (Red Line) vs TAS-I (Black - Already Aveable) TAS-F (Red Line) vs TAS-I (Black – New One)

31 th Annual AMTA Symposium November 1-6, 2009 Page 10 Insert Company Logo Here on Master (Optional) Comparison between TAS-F and TAS-I Measurements TAS-F (Red Line) vs TAS-I (Black - Already Aveable) TAS-F (Red Line) vs TAS-I (Black – New One)

31 th Annual AMTA Symposium November 1-6, 2009 Page 11 Insert Company Logo Here on Master (Optional) Comparison between TAS-F and TAS-I Measurements TAS-F (Red Line) vs TAS-I (Black - Already Aveable) TAS-F (Red Line) vs TAS-I (Black – New One)

31 th Annual AMTA Symposium November 1-6, 2009 Page 12 Insert Company Logo Here on Master (Optional) Comparison between TAS-F and TAS-I Measurements TAS-F (Red Line) vs TAS-I (Black - Already Aveable) TAS-F (Red Line) vs TAS-I (Black – New One)

31 th Annual AMTA Symposium November 1-6, 2009 Page 13 Insert Company Logo Here on Master (Optional) Comparison between TAS-F and TAS-I Measurements

31 th Annual AMTA Symposium November 1-6, 2009 Page 14 Insert Company Logo Here on Master (Optional) Error Budget Definition Using the 18 Terms Error budget Technique an analysis of the measurement uncertainties has been done. Main Beam Region (MBR): Spatial region of each beam where the level is higher than -10dB; Side Lobe Region(SLR) & Cross Region: Circle with 54.3 deg radius; The worst case error level is evaluated, taking into account the 99% (3 sigma) of the total number of points inside each region. Room Scattering Error Pattern

31 th Annual AMTA Symposium November 1-6, 2009 Page 15 Insert Company Logo Here on Master (Optional) Conclusions A general description of the New Spherical Near Field installed and validated in TAS-I Rome to support the GLB2 L-band RX Active antenna, is given The comparisons of the Active Antenna BreadBoard measurements, in terms of copolar and cross polar patterns, and post-processing data, show a very good convergence - all the evaluated delta fall in the range of the total uncertainty of the relevant facilities. This ensured a successful test facility validation and the definition of performance uncertainty budgets for the GBL2 antenna production program