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Antenna, Reflector and Radome. Antenna. Initial single-wavelength (W band) system will use a 15” diameter lens antenna A dual-wavelength feed and lens antenna is planned for the Phase C system Expected performance:. HIAPER Pitch Envelope. Reflector Plate.
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Antenna • Initial single-wavelength (W band) system will use a 15” diameter lens antenna • A dual-wavelength feed and lens antenna is planned for the Phase C system • Expected performance:
Reflector Plate • Reflector plate rotates independently, nose cone/radome stationary • Design to compensate for aircraft pitch envelope: 1° < pitch < 5° • Locate plate pivot point at near-field beamwaist a distance, f (15”) from back of lens • At beamwaist: beam is 10” diameter @ 1/e2 (13.5%) power loss • Plate flatness: 0.005” rms to have negligeable effect on far-field beam pattern • Elliptical design: 15.5” x 22.4” @ 0.8% power loss
Radome • Sandwich design ensures: • structural integrity (FEA req’d) as well as high transmissivity (one way loss ~ 0.5 dB) • functionality at both W-band (94 GHz) and Ka-band (35 GHz) • Compensate for radome induced phase errors distorting far-field beam pattern by applying low-loss SAN (styreneacrylonitrile) foam to reflector plate • Use ray tracing to determine above compensation
Expected Radome Performance • 94 GHz
Expected Radome Performance • 35 GHz