Radiation from antenna systems with homogeneous and inhomogeneous loops

Two antenna systems, each composed of a single fed antenna and a plane with periodically arrayed elements (PE plane), are investigated. The PE plane of square strip loops, all having the same outer side length and the same strip width (homogeneous PE plane), forms a narrow beam in the direction normal to the PE plane, leading to a high gain. Subsequently, this normal beam is tilted by gradating the strip width of the loops (inhomogeneous PE plane), holding the outer side length at a constant value. As an example, a narrow beam with a tilt angle of 35 degrees and a gain of 17 dBi is demonstrated. It is also found that a modified inhomogeneous PE plane forms a high-gain tilted beam, where the outer side length of the loops is gradated, while keeping the strip width at a constant value.