Array antenna composed of circularly polarized dielectric resonator antennas

Previously, a dielectric resonator antenna (DRA) including circularly polarized DRA (CP-DRA) has been studied by many researchers, since it can be used as an efficient radiator in the high frequency region. A new type of CP-DRA element fed by an asymmetric cross-slot is proposed here. This type of CP-DRB is probably one of the simplest devices for producing circular polarization at or near the millimeter-wave region. This paper presents the radiation properties of a new type of CP-DRB element together with the design technique of a DRA array composed of a pair of CP-DRAs. In order to evaluate the performance, some DRA elements and its arrays were fabricated and tested at X-band. The 3-dB axial-ratio bandwidth obtained from this new type of DRA array was about 20% at X-band, and it had an extremely broadband performance compared to that of a normal array antenna. Therefore, the DRA array proposed here is considered to be an effective model as a broadband circularly polarized array.