Antenna, Reflector and Radome

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Antenna, Reflector and Radome
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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

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HIAPER Pitch Envelope
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(No Transcript)
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Reflector Plate

• Reflector plate rotates independently, nose
  cone/radome stationary
• Design to compensate for aircraft pitch envelope
  1 lt pitch lt 5
• Locate plate pivot point at near-field beamwaist
  a distance, f (15) from back of lens
• At beamwaist beam is 10 diameter _at_ 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 _at_ 0.8 power
  loss

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Pod Beam Projections Top and Side Views
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Radome

• Sandwich design ensures
• structural integrity (FEA reqd) 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

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Expected Radome Performance

• 94 GHz

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Expected Radome Performance

• 35 GHz