Wide-band stacked double annular-ring dielectric resonator antenna at the end-fire mode operation

A novel wide-band stacked double annular-ring dielectric resonator antenna (DRA) is numerically investigated in this paper. At either layer, a larger annular-ring dielectric resonator is placed concentrically outside a smaller annular-ring one to form a stacked double annular-ring DRA. The antenna is operating at the end-fire mode. The effects of antenna parameters such as dielectric constant, probe length and air-gaps thickness are investigated. Compared to the obtained 18% bandwidth of the stacked annular-ring DRA, the proposed stacked double annular-ring DRA can offer an impedance bandwidth of ∼42% for the return loss below -10 dB. The radiation patterns are stable in the passband.