X-Y Planar Precision Scanner Antenna and Optical Beam Measurement Facility for JEM/SMILES Antenna Optics : Cassegrain with Elliptical Beam Mission Requirements : 624.32GHz – 650.32GHz, HPBW : 0.174deg (Az), 0.083deg (El) Beam Efficiency higher than 90% Purpose of Measurements : Far-Field Pattern, Beam Width, 1’st Sidelobe Levels, Measurements : Near-Field Phase Retrieval Method (NFPRM) NASDA NFBM System Sample Images of Measurement Result X-Y Planar Precision Scanner Prototype Model of Main Reflector Estimated Far-Field Pattern of Antenna Rear View X Stage Z Stage Ambient Temperature Optics NASDA Submillimeter Transmitter and Receiver System Estimated Far-Field Pattern of Horn Front View Rx Optical Chopper Submillimeter Optics : Beam Wave Guide (BWG) System, Frequency-Selective Polarizer (FSP) with Wire Grid Mission Requirements : Sideband Separation (USB/LSB), Low Loss Beam Transfer, Lo Injection, Image Termination Purpose of Measurements : Transfer Beam Characteristics, Alignments (Goal) Measurements : Near-Field Beam Measurements (NFBM) To Antenna To Cold-Sky Terminator Single Sideband Filter Sub-mm LO Source Tx

Near-Field Phase Retrieval Algorithm Initial Estimate of Complex Aperture Function with Random Phase Estimated Far-Field Measurement Plane #1 Measurement Plane #2 Antenna Aperture Plane First Itaration only Diffraction Filters FT FT-1 X Z Far-Field Z=Z0 Fresnel-Region Z=Z1 Z=Z2 Y