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Title: Self-focusing of electromagnetic surface waves on a nonlinear impedance surface

The self-focusing effect of optical beams has been a popular topic of study for quite a while, but such a nonlinear phenomenon at microwave frequencies has never been realized, partially due to the underdevelopment of nonlinear material. In this research, self-focused electromagnetic (EM) surface waves are demonstrated on a circuit-based, power-dependent impedance surface. The formation of a self-focused beam is investigated using a series of discrete-time simulations, and the result is further validated in measurement. It is experimentally observed that, in contrast to the normal scattering of low-power surface waves, high-power waves propagate through the surface while maintaining narrow beam width, and even converge extremely tightly to create a hot spot with higher power. The result is essentially a nonlinear effect of the surface that compensates for the natural tendency of surface waves to diffract. This intriguing experiment can be extended to various potential EM applications such as power-dependent beam steering antennas and nonlinear microwave propagation or dissipation.
Authors:
 [1] ;  [2] ;  [1] ; ; ;  [3]
  1. College of Electronics and Information Engineering, Sichuan University, Chengdu 610064 (China)
  2. (United States)
  3. Applied Electromagnetics Group, Electrical and Computer Engineering Department, University of California, San Diego, California 92093 (United States)
Publication Date:
OSTI Identifier:
22402483
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 21; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANTENNAS; BEAM PROFILES; FOCUSING; IMPEDANCE; MICROWAVE RADIATION; MICROWAVE SPECTRA; NONLINEAR PROBLEMS; PHOTON BEAMS; SCATTERING; SIMULATION; SURFACES; WAVE PROPAGATION