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Luneberg dielectric lens and method of producing same

DC
  • US 7,671,820 B2
  • Filed: 09/08/2005
  • Issued: 03/02/2010
  • Est. Priority Date: 09/10/2004
  • Status: Expired due to Fees
First Claim
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1. A hemispherical dielectric lens comprising:

  • a hemispherical center layer having a hemispherical outer surface; and

    a plurality of hemispherical dome-shaped layers each having concentric hemispherical inner and outer surfaces, the outer surfaces of said center layer and dome-shaped layers having different diameters and the inner surfaces of said dome-shaped layers having different diameters,said center layer and dome-shaped layers being successively concentrically fitted into one another and integrated into a hemispherical shape,said center layer being a foam molding of ceramic-containing thermoplastic resin expanded beads,each of said dome-shaped layers being a foam molding of thermoplastic resin expanded beads containing 0 to 80% by weight of a ceramic,wherein the ceramic content per unit volume of said center and dome-shaped layers decreases from said center layer to the outermost dome-shaped layer,wherein each of said center and dome-shaped layers has a standard deviation of the apparent density of 0.07 g/cm3 or lower, andwherein the ratio (V/N) of the number of voids (V) to the number of expanded beads (N) at a region adjacent to the outer surface of said center layer or adjacent to the outer and inner surfaces of each of said dome-shaped layers except said outermost dome-shaped layer is in the range of 0.2 to 1.0.

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