COMPENSATED ZONED DIELECTRIC LENS ANTENNA

• US 3,886,561 A
• Filed: 12/15/1972
• Issued: 05/27/1975
• Est. Priority Date: 12/15/1972
• Status: Expired due to Term

• Current Assignee: International Telecommunications Satellite Organization
• Original Assignee: John Paul Beyer
• Inventors: Beyer, John Paul
• Primary Examiner(s): Gensler, Paul L.
• Application Number:
  US05/315,693
• Time in Patent Office: 893 Days
• Field of Search: 343/753-755,909-911,911L,785
• US Class Current: 343/910
• CPC Class Codes: H01Q 15/02 Refracting or diffracting devices, e.g. lens, prism

Abstract

A zoned dielectric lens antenna is made less frequency sensitive by filling the zone with an artificial dielectric. A section of width, T, is removed from a natural dielectric lens and replaced with a width, T, of artificial dielectric of the parallel slat or egg-crate type. The width, T, is selected so that the difference in number of wavelengths of the design frequency traveling through the zoned area and the unzoned area is a whole number.

Claims

1. A dielectric lens for radio wave antennas, said lens being formed of a solid natural dielectric material having a zone cutout therefrom and filled with an artificial dielectric material constructed of parallel metal conductive slats and having an apparent index of refraction Eta a1 at any frequency f defined by:

Eta a1 (1 -( lambda / lambda c)2)1/2, where;

lambda is the free space wavelength of frequency f; and

lambda c is twice the slat-to-slat spacing of said artificial dielectric.

2. A dielectric lens as claimed in claim 1 wherein said zone has a depth, T, which satisfies the equation:

T N lambda d/ eta o - eta a, where;

N is an integral number;

lambda d is the free space wavelength of a design frequency;

eta o is the index of refraction of said natural dielectric material; and

eta a is the apparent index of refraction of said artificial dielectric at said design frequency.

3. A dielectric lens as claimed in claim 2 wherein eta o. eta a about 1.

4. A dielectric lens as claimed in claim 2 having stacked zones filled with said artificial dielectric material.

5. A dielectric lens for radio wave antennas, said lens being formed of a solid natural dielectric material having a zone cut-out therefrom and filled with an artificial dielectric material constructed of parallel metal conductive slats and having an apparent index of refraction eta a1 at any frequency f defined by:

eta a1 (1 - ( lambda / lambda c)2)1/2, where;

lambda is the free space wavelength of frequency f; and

lambda c is twice the slat-to-slat spacing of said artificial dielectric;

said zone having a depth T, which satisfies the equation;

T N lambda d/ eta o- eta a, where;

N is an integral number;

lambda d is the free space wavelength of a design frequency;

eta o is the index of refraction of said natural dielectric material;

eta a is the apparent index of refraction of said artificial dielectric at said design frequency;

wherein, eta o . eta a about 1; and

, a quarter wave matching section of free space between the interface formed by said natural dielectric material and said artificial dielectric material.