Cross-Slot-Coupled Wide Dual-Band Circularly Polarized Rectangular Dielectric Resonator Antenna

A cross-slot-coupled wide dual-band circularly polarized (CP) rectangular dielectric resonator antenna (DRA) is investigated. The DRA has a large aspect ratio of 3.2:1. By using a cross-slot of unequal slot arms, three sets of degenerate orthogonal modes of
${\rm TE}_{111}$
,
${\rm TE}_{121}$
, and
${\rm TE}_{131}$
can be excited simultaneously to generate dual-band CP fields. It is found that the lower band is composed of the
${\rm TE}_{111}$
and
${\rm TE}_{121}$
modes, while the upper band is formed by the
${\rm TE}_{131}$
mode. The 3-dB axial-ratio (AR) bandwidths
$({\rm AR}<3\ {\hbox{dB}})$
are 19.8% and 6.2% for the lower and upper bands, respectively. To verify the simulation, measurement was carried out and reasonable agreement was obtained.