Metamaterial-inspired efficient electrically-small antennas: Designs and experiments

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

An electrically small electric dipole antenna is known to be a very inefficient radiator, i.e., because it has a very small radiation resistance while simultaneously having a very large capacitive reactance, a large impedance mismatch to any realistic power source exists. It has been demonstrated recently that enclosing an electrically small electric (magnetic) dipole antenna in an electrically small epsilon-negative (ENG) (mu-negative (MNG)) shell leads to an efficient electrically small radiator. The inductive (capacitive) nature of the ENG (MNG) shell compensates for the capacitive (inductive) nature of the electrically small electric (magnetic) dipole antenna, i.e., it functions as a distributed matching element that forms this "geometrically" resonant system. More realistic electrically small center-fed electric dipole-ENG spherical shell and coax-fed electric monopole-ENG hemispherical shell antenna systems have also been modeled numerically using ANSOFT's High Frequency Structure Simulator (HFSS) and COMSOL's Multiphysics simulator. The input resistance and reactance of these realistic antenna-ENG shell systems have been obtained from these numerical models. It has been shown that these systems could be designed to have geometrical resonances for which the relative gains were analogous to the radiated power ratios obtained with the analytical models. With further tuning, it has also been shown that an "antenna" resonance, where the system has a zero input reactance and an input resistance which is matched to a specified source resistance, can also be realized to yield a very high overall efficiency. The effects of losses and frequency dispersion on these systems have been studied. With dispersion engineering available from the use of active metamaterials, the large bandwidths obtained with the dispersionless metamaterial models can again be obtained even in the presence of losses and dispersion. This suggests the possible realization of metamaterial-based broad bandwidth efficient electrically-small antennas. The predicted high overall efficiencies (> 90%) have been obtained with several recently developed metamaterial-inspired electrically-small antennas: the 2D (planar) and 3D (volumetric) electric-based and magnetic-based EZ antennas. The EZ antenna designs, simulations and experiments will be described. The experimental data are in very good agreement with the simulation results.

Original languageEnglish (US)
Title of host publication2007 IEEE International Workshop on Anti-counterfeiting, Security, Identification, ASID
Number of pages1
DOIs
StatePublished - Sep 27 2007
Event2007 IEEE International Workshop on Anti-counterfeiting, Security, Identification, ASID - Xizmen, China
Duration: Apr 16 2007Apr 18 2007

Publication series

Name2007 IEEE International Workshop on Anti-counterfeiting, Security, Identification, ASID

Other

Other2007 IEEE International Workshop on Anti-counterfeiting, Security, Identification, ASID
CountryChina
CityXizmen
Period4/16/074/18/07

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Software
  • Safety, Risk, Reliability and Quality

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    Ziolkowski, R. W. (2007). Metamaterial-inspired efficient electrically-small antennas: Designs and experiments. In 2007 IEEE International Workshop on Anti-counterfeiting, Security, Identification, ASID [4244768] (2007 IEEE International Workshop on Anti-counterfeiting, Security, Identification, ASID). https://doi.org/10.1109/IWASID.2007.373682