Bandwidth enhancement of the omni-directional and circularly-polarized EZR-MZR antenna

As electric and magnetic dipoles with inherent 90 degrees phase difference (PD) can be easily realized by forming a circular array of the epsilon-zero resonance and mu-zero resonance (EZR-MZR) resonators, high design efficiency can be expected for low-profile, omni-directional and circularly polarized (CP) antenna designing. However, high Q factor of the EZR-MZR resonator makes narrow bandwidth. This research is dedicated to enhance the bandwidth. Low Q factor and multi-resonances techniques are utilized to enhance the impedance bandwidth. While polarization compensation technique is applied to improve the axial ratio (AR) bandwidth by tuning the amplitudes and PD of the orthogonal vectors. The proposed antenna obtains a - 10 dB impedance band of 1.370 to 1.690 GHz (20.91% at 1.530 GHz) and a 3 dB axial ratio (AR) band of 1.260 to 1.580 GHz (22.53% at 1.42 GHz). The diameter and profile of the proposed antenna are 0.402 lambda and 0.082 lambda, respectively.