Patent ID: 9666953
Date: 2017-05-30
CPC Classifications: H01Q

Claim:
1. A back-feed microwave antenna, comprising: a radiation source, a first metamaterial panel for diverging electromagnetic waves emitted by the radiation source, and a second metamaterial panel for converting the electromagnetic waves from the first metamaterial panel into plane waves; wherein the first metamaterial panel comprises a first substrate and a plurality of third artificial metal microstructures or third artificial porous structures periodically arranged on the first substrate; the second metamaterial panel comprises a core layer, the core layer comprises a plurality of core metamaterial sheets having the same refractive index distribution, each core metamaterial sheet comprises a core metamaterial sheet substrate and a plurality of first artificial metal microstructures or first artificial porous structures periodically arranged on the core metamaterial sheet substrate, and each core metamaterial sheet comprises a circular area with a circle center in a center of the core metamaterial sheet substrate and a plurality of annular areas concentric with the circular area, refractive index variation ranges in the circular area and the annular areas are the same, wherein refractive indexes in the circular area and the annular areas continuously decrease from a maximum refractive index n p of the core metamaterial sheet to a minimum refractive index n 0 of the core metamaterial sheet with the increase of a radius, and refractive indexes at the same radius are the same, wherein the second metamaterial panel further comprises a first gradient metamaterial sheet to an N wherein the second metamaterial panel further comprises a first matching layer to an M wherein each of the matching layers comprises a second substrate and a coating layer, and wherein air is filled fully between the coating layer and the second substrate, a duty ratio of air is changed by changing a space between the coating layer and the second substrate, thereby enabling the matching layers to have different refractive indexes.