Low-profile cavity broadband antennas having an anisotropic transverse resonance condition

A low-profile cavity antenna comprising:

• a rectangular aperture defining an opening to a cavity;
• an interior space defined by the cavity which is formed of:
• a flat bottom wall defining a ground plane,
• a pair of spaced-apart, longitudinal sidewalls extending from opposing sides of the flat bottom wall substantially perpendicular to the aperture, and
• a pair of spaced-apart, lateral sidewalls being symmetric and extending with an outward taper toward the aperture from opposing sides of the flat bottom wall on opposite from where the longitudinal sidewalls extend;
• and
• an anisotropic high index medium, at least partially loaded within the cavity having the tapered lateral sidewalls, wherein the anisotropic high index medium material is tapered with an inverse relationship to that of the width of the tapered lateral sidewalls, such that the anisotropic high index medium material is configured to maintain a constant resonance frequency of the antenna.

A method for determining the shape of a low-profile, cavity antenna having an aperture defining an opening to a cavity;

• an interior space defined by the cavity formed of a flat bottom wall defining a ground plane, and a pair of spaced-apart, lateral sidewalls extending away from the flat bottom wall in opposite directions toward the aperture;
• and an anisotropic high index medium material, at least partially loaded within the cavity, which is configured to maintain a constant resonance frequency of the antenna, the method comprising:
• selecting the anisotropic high index medium material having a relative permittivity (∈r) and a relative permeability (μr);
• and
• determining a taper of the pair of spaced-apart, lateral sidewalls based on the relative permittivity (∈r) and the relative permeability (μr) of the selected anisotropic high index medium material, wherein the anisotropic high index medium material is tapered with an inverse relationship to that of the width of the tapered lateral sidewalls, such that the anisotropic high index medium material in order to maintain a constant resonance frequency of the antenna.