Compact Circularly Polarized Antenna With Wide 3-dB Axial-Ratio Beamwidth

• Published in: IEEE antennas and wireless propagation letters Vol. 15; pp. 410 - 413
• Main Authors: Park, Byung-Chul, Lee, Jeong-Hae
• Format: Journal Article
• Language: English
• Published: New York IEEE 2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna measurements; Antenna radiation patterns; Circularly polarized (CP) antennas; Dipole antennas; Gain; metamaterials; mu-negative transmission line (MNG TL); Resonant frequency; wide 3-dB axial-ratio beamwidth
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2015.2448553

A compact circularly polarized antenna with wide 3-dB axial-ratio (AR) beamwidth is presented. The two pairs of radiators based on mu-negative transmission lines are applied and each radiator has a capacitor at the center and a pair of vias at both edges of the radiator to induce a zeroth-order resonance mode. The two radiators for x-polarized wave are orthogonally aligned to the other two radiators for y-polarized wave, and the 90 ° phase difference is realized by detuning the resonance frequencies of the corresponding radiators. In particular, a circular ground plane is adopted for the symmetrical radiation pattern and optimized to have the wide 3-dB axial-ratio beamwidth. Also, a dual-ground structure is studied to suppress back radiations caused by the compact ground. The 3-dB AR beamwidth is measured as 175 ° - 190 ° , and the measured gains are observed as 3.8 dBic at θ = 0 ° and 0.5 dBic ( - 0.5 - 1.2 dBic) at θ = 60 ° .