Very low profile helix antenna feeding resonant cavity for ETC system
Résumé
Full Paper — This paper presents the design of a compact high gain circularly polarized antenna for Electronic Toll Collection Identification (ETC) reader covering the global band 5.725-5.875GHz. The antenna is made of an axial mode helix mounted inside a resonant cavity. The optimized structure has a total size of 2λ x 2λ x λ/4 and delivers maximum gain of 12dBic and axial ratio lower than 4dB in the bandwidth.