Differentially fed CP antenna with quasi-self-complementary semicircular-ring structure

Ching Her Lee, Wan Chu Hong, Wen Jie Chen, Chung I.G. Hsu

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


This article presents a new design of a common-mode suppressed differentially fed circularly polarized (CP) antenna using a quasi-self-complementary (QSC) structure. The antenna radiating element consists of a semicircular-ring radiating patch and its complementary radiating slot counterpart. The design idea for producing CP radiation is based on field orthogonality of the QSC structure. For better impedance matching, a fan-shaped notch (stub) around the feeding position was cut from (implemented in) the semicircular radiating patch (slot). In addition, to improve the axial ratio, a QSC semielliptical structure is embedded in the central area of the antenna. For the designed differentially fed CP antenna, measurement shows that the differential-mode (DM) operating band with return loss >10 dB covers 4.76-6.38 GHz. The measured DM 3-dB axial-ratio band is 4.95-5.43 GHz. Also, very good common-mode (CM) suppression is observed with the measured CM reflection coefficient >−1.21 dB in 4.50-6.5 GHz.

Original languageEnglish
Pages (from-to)741-746
Number of pages6
JournalMicrowave and Optical Technology Letters
Issue number3
Publication statusPublished - 2019 Mar

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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