Three-layered balanced circularly polarized slot antenna with high common-mode suppression

Jhe Han Wu, Chung I.G. Hsu, Ching Her Lee

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


This article proposes the design of a three-layered balanced circularly polarized (CP) antenna using two tightly stacked conventional single-ended CP slot antennas. With a 180° delay line inserted into one of the two feeding microstrip lines that form the balanced feedline, differential-mode (DM) input signals can excite CP radiation in the broadside directions with a measured (simulated) axial ratio of as low as 1.3 (0.86) dB. Common-mode (CM) input signals can be well rejected with a measured (simulated) CM return loss of <0.4 (0.5) dB in the DM impedance band. In addition, only a very small proportion of the CM (DM) input signal is converted into a DM (CM) reflected one. These nice properties of the possibly first reported balanced CP antenna were all achieved without placing before the radiation element a CM-suppression filter.

Original languageEnglish
Pages (from-to)1585-1589
Number of pages5
JournalMicrowave and Optical Technology Letters
Issue number7
Publication statusPublished - 2018 Jul

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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