Design of Artificial-Material-Based Antennas Using Inverse Scattering Techniques

• Published in: IEEE transactions on antennas and propagation Vol. 66; no. 12; pp. 7076 - 7090
• Main Authors: Palmeri, Roberta, Bevacqua, Martina Teresa, Morabito, Andrea Francesco, Isernia, Tommaso
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna synthesis; Antennas; contrast source inversion (CSI); Electromagnetic fields; Electromagnetic scattering; flat antennas; gradient index lens; homogenization; Indexes; Inverse problems; Inverse scattering; Lenses; Minimization; reconfigurable patterns; Refractivity; Rescaling; Synthesis
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2018.2871707

A new approach to the design of graded artificial materials (GAMs)-based devices is proposed by exploiting the inverse scattering framework as a synthesis tool. The introduced general methodology can be applied to arbitrary far-field specifications, thus allowing the design of noncanonical devices. In particular, two different strategies are developed for GAMs based on either graded refractive index (GAM<inline-formula> <tex-math notation="LaTeX">_{R} </tex-math></inline-formula>) or graded filling factor (GAM<inline-formula> <tex-math notation="LaTeX">_{F} </tex-math></inline-formula>). In both strategies, the inverse scattering problem is solved by a proper reformulation of the contrast source inversion method, wherein a proper rescaling of the amplitude of the primary sources is also used. In particular, in the first strategy, the GAM<inline-formula> <tex-math notation="LaTeX">_{F} </tex-math></inline-formula> is obtained by exploiting homogenization theories. In the second strategy, the GAM<inline-formula> <tex-math notation="LaTeX">_{R} </tex-math></inline-formula> is synthesized by exploiting a suitable representation basis for the unknown contrast function, and then simple analytical formulas are used to determine the corresponding GAM<inline-formula> <tex-math notation="LaTeX">_{F} </tex-math></inline-formula>. The proposed approach is assessed through the synthesis of an antenna generating a <inline-formula> <tex-math notation="LaTeX">\Sigma /\Delta </tex-math></inline-formula> reconfigurable pattern.