Axial ratio beamwidth enhancement of a low-profile circularly polarized antenna using defected ground structures

Mrityunjoy Kumar Ray*, Kaushik Mandal, Gholamhosein Moloudian, Ali Lalbakhsh

*Corresponding author for this work

Research output: Contribution to journalConference paperpeer-review

2 Citations (Scopus)


This article explores the possibilities of incorporating a defected ground structure (DGS) for widening the 3 dB axial ratio beamwidth (ARBW) of a simple low-profile planar circularly polarized (CP) antenna. Two pairs of DGSs are etched symmetrically along the diagonals of the ground plane to overcome the limited 3 dB ARBW performance of a crossed-slotted circular-shaped planar CP antenna. Here, one pair of DGSs is orthogonal to another pair of DGSs. The distance between the pairs of DGSs plays a key role in enhancing the 3 dB ARBW by 40.62%. A gap of 0.18λ0 is considered between the DGSs to maintain the symmetrical electric field distribution in the substrate. It also helps to reduce orthogonal current components and provides uniformly distributed patch surface currents. These phenomena collectively help the proposed CP antenna to exhibit right-handed circular polarization radiation with the 3 dB ARBW of 186° and 188° in the E-plane and H-plane, respectively. The measured results yield impedance bandwidth (S11 ≤ -10 dB) of 2.6% (2.283-2.342 GHz), CP bandwidth of 0.9% (2.294-2.315 GHz), gain higher than 4.8 dBic, and total antenna efficiency more than 64% across the entire CP band.

Original languageEnglish
Pages (from-to)1434-1442
Number of pages9
JournalInternational Journal of Microwave and Wireless Technologies
Issue number8
Early online date23 Mar 2023
Publication statusPublished - Oct 2023
Event16th European Conference on Antennas and Propagation, EuCAP 2022 - Madrid, Spain
Duration: 27 Mar 20221 Apr 2022


  • Axial ratio beamwidth
  • circular polarization
  • defected ground structure
  • surface current


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