Excitation of a broadband circularly polarized and arrow-shaped dipole antenna with high gain by an improved hybrid coupler

Abstract

This paper proposed a novel wideband, circularly polarized crossed dipole antenna with high gain that utilizes an improved feeding work. The hybrid coupler exhibits both compact circuit configuration and a wide bandwidth (S11 ≤ −15 dB) of over 60% given a power distribution of −3.1 dB using a broadband coupled-line power divider and a 90° phase shifter with an impedance-open-stub. A phase deviation of 90° ± 5° was also observed over wideband. When excited by the wideband feed network, the circularly polarized crossed dipole antenna achieves an impedance bandwidth of 66.7% given S11 ≤ −15 dB and a 3 dB axial ratio bandwidth of 67%. Furthermore, the stable peak gain increased from 9 to 10.9 dBi between 1.07 and 1.7 GHz when a cylindrical cavity was connected to the ground. Moreover, the cross-polarization ratio in the wideband exceeds 25 dB. The simulated results of this study agree with the measured ones.

Disclosure statement

No potential conflict of interest was reported by the authors.