Adaptation of Schelkunoff's Superdirective Antenna Theory for the Realization of Superoscillatory Antenna Arrays

• Published in: IEEE antennas and wireless propagation letters Vol. 9; pp. 315 - 318
• Main Authors: Wong, Alex M H, Eleftheriades, George V
• Format: Journal Article
• Language: English
• Published: New York IEEE 2010; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptive arrays; Antenna arrays; Antenna theory; Antennas and propagation; Diffraction limit; Electromagnetic diffraction; Electromagnetic scattering; Electromagnetic waveguides; Extraterrestrial phenomena; Focusing; image resolution; Phased arrays; subwavelength focusing; superdirectivity; superoscillation
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2010.2047710

We have adapted Schelkunoff's method of antenna pattern synthesis to the design of superoscillatory waveforms. Our method stems from the observation that superdirectivity and superoscillation are dual phenomena in the space and spectral domains; it can be applied to construct any periodic superoscillatory wave functions. Using this method, we designed two subwavelength focusing schemesin free space and within a waveguideat an image distance of five wavelengths. We first describe how we extend the concept of superdirectivity toward constructing superoscillatory waveforms, then provide in-depth formulations as they apply to each design example. We also report full-wave simulation results verifying subwavelength focusing to 0.6 times that of the diffraction limit at a distance five wavelengths away from the source.