Frequency-Reconfigurable Circularly-Polarized Omnidirectional Antenna

Ken Paramayudha, Shengjian Jammy Chen, Withawat Withayachumnankul, Christophe Fumeaux

Research output: Contribution to journalArticlepeer-review


A concept of frequency-reconfigurable circularly-polarized (CP) antenna with omnidirectional radiation characteristics is introduced. The antenna is based on a center-fed circular patch with shorting vias, surrounded by three arc-shaped arms. Omnidirectional CP is attained through its two orthogonal radiators with a quadrature phase difference. Three varactor-loaded meandered slots are etched onto the top patch to miniaturize the antenna and empower it with reconfigurability. The resonance frequency of the vertically- and horizontally-polarized modes can be simultaneously tuned by varying the bias voltage applied to the varactors, and thus frequency-reconfigurable CP is achieved. The realization demonstrates a wide CP tuning range of 28.5% from 3.55 to 4.73 GHz. Stable omnidirectional patterns in the azimuth plane are achieved across the tuning range. All these results suggest that the antenna is suitable for communications systems that require an omnidirectional CP antenna with a frequency-tunable feature.

Original languageEnglish
Number of pages6
JournalIEEE Transactions on Antennas and Propagation
Publication statusPublished - 25 Apr 2022


  • Antennas
  • Broadband antennas
  • circularly-polarized
  • frequency-reconfigurable
  • low-profile
  • Magnetic resonance
  • Magnetic separation
  • omnidirectional antennas
  • Slot antennas
  • Tuning
  • Varactors


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