AbstractThis paper presents a new wideband dielectric resonator (DR) antenna. To enhance the bandwidth, two layers of stacked resonators having the same rotational axis of symmetry are used. At the bottom layer, a smaller cylindrical DR is placed concentrically inside a large annular‐ring DR, whereas at the top layer, there is only one cylindrical DR. A coaxial probe is placed off the antenna axis in the DR antenna in order to produce broadside far‐field radiation patterns. The effects of the antenna parameters such as dielectric constant, probe length, and excitation position as well as the air gap between the bottom layer of the stacked DRA and the ground plane are investigated numerically. A bandwidth up to 67% for a −10‐dB return loss is achieved for the proposed antenna. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 222–226, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21312