Electrically small water-based hemispherical dielectric resonator antenna

Rasmus E. Jacobsen*, Andrei V. Lavrinenko, Samel Arslanagić

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Recently, water has been proposed as an interesting candidate for use in applications such as tunable microwave metamaterials and dielectric resonator antennas due to its high and temperature-dependent permittivity. In the present work, we considered an electrically small water-based dielectric resonator antenna made of a short monopole encapsulated by a hemispherical water cavity. The fundamental dipole resonances supported by the water cavity were used to match the short monopole to its feed line as well as the surrounding free space. Specifically, a magnetic (electric) dipole resonance was exploited for antenna designs with a total efficiency of 29.5% (15.6%) and a reflection coefficient of -24.1 dB (-10.9 dB) at 300 MHz. The dipole resonances were effectively excited with different monopole lengths and positions as well as different cavity sizes or different frequencies in the same cavity. The overall size of the optimum design was 18 times smaller than the free-space wavelength, representing the smallest water-based antenna to date. A prototype antenna was characterized, with an excellent agreement achieved between the numerical and experimental results. The proposed water-based antennas may serve as cheap and easy-to-fabricate tunable alternatives for use in very high frequency (VHF) and the low end of ultrahigh frequency (UHF) bands for a great variety of applications.

Original languageEnglish
Article number4848
JournalApplied Sciences (switzerland)
Volume9
Issue number22
Number of pages11
ISSN2076-3417
DOIs
Publication statusPublished - 1 Nov 2019

Keywords

  • Dielectric resonator antenna
  • Electrically small antenna
  • Mie resonances
  • Tunable antennas
  • Water-based

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