Dual-Band Magnetoelectric Dipole Antenna With Dual-Sense Circularly Polarized Character

In this paper, a dual-band dual-sense circularly polarized (CP) magnetoelectric dipole antenna is proposed. The antenna consists of a cavity reflector, two pairs of vertical and horizontal copper plates, and a crossed
$\Gamma $
-shaped feeding structure. The shorted vertical plates work as quasi-magnetic dipoles (M-dipoles), while the connected horizontal plates work as electric dipoles (E-dipoles). Two M-dipoles and E-dipoles are designed to possess different heights and lengths, and thus they are able to achieve separate operation bands. To generate dual-sense CP performance, the M-dipoles and E-dipoles are placed in parallel and the adjacent E-dipoles extend along the opposite directions. Benefiting from the intrinsic 90° phase difference between the M-dipole and E-dipole, the left-hand CP is achieved within the lower operation band (2.15–3.4 GHz) and the right-hand CP is achieved within the upper band (4–6.3 GHz). The proposed antenna possesses a unidirectional radiation pattern with high front-to-back ratio (
$\ge 22$
dB). Furthermore, high gain (
$\ge 8$
dBi) and radiation efficiency (
$\ge 90$
%) are also achieved.