Wideband Circularly Polarized Elliptical Patch Antenna and Array Designs

Abstract

ABSTRACT A broadband circularly polarized (CP) 2 × 2 antenna array using elliptical patch antenna elements is designed in this study. The antenna element is composed of four elliptical patches, four metal posts, and a stair‐shaped slot. By rotating the elliptical patches and modifying the coupling slot as stair‐shaped, a CP magnetoelectric dipole (ME‐dipole) antenna is first realized. Moreover, another two elliptical patches are introduced to generate extra CP mode, which enhances the axial‐ratio (AR) bandwidth. The designed CP elliptical patch antenna is expanded to a 2 × 2 antenna array which a feeding network using sequential rotation technology is adopted to feed the array. Measured results indicate that the antenna array exhibits an impedance bandwidth (|S 11 | < −10 dB) of 67.6% and a 3 dB AR bandwidth of 59.1% is obtained. Besides, the measured peak gain is 14.14 dBic at the center frequency 5.5 GHz. The excellent performances make it suitable for C‐band communication systems which CP radiation is required.