Broad-Band Substrate-Free Planar Metamaterial Lens Based on a Geometric Transformation of Polygon

摘要

A broad-band substrate-free planar metamaterial lens fed by a horn antenna is proposed. A geometric transformation of polygon is introduced in order to make gradient tuneable unit cells out of ordinary metamaterial structures. A circular lens with gradient epsilon along its surface is designed and fabricated based on the transform theory. Measurement results indicate that the proposed lens is capable of improving the gain of the horn antenna within the frequency band of 78-89 GHz which is more than doubled as comparing with existing substrate-free metamaterial lenses.