  In this paper, a wideband high-gain 2 ? 2-element subarray is presented for
60 GHz band applications. The antenna is fed with waveguide-fed cavity backed
configuration and designed entirely via simple rectangular apertures. To
improve radiation pattern characteristics and reduce the antenna size,
stepped-radiating apertures loaded with a solid dielectric material. A standard
WR-15 rectangular waveguide is designed to excite the antenna at the input port
over the operation frequency. The most significant advantage of using this
design is its efficient radiation patterns, ability to decrease complexity and
cost of fabrication. Simulated results demonstrate a maximum gain of about 19.5
dB, and the sidelobe level (SLL) of the antenna is less than -19 dB in E- and
H-planes radiation patterns over the frequency range from 57.5 to 62.5 GHz. In
contrast to previous works, the proposed antenna is much more simple to use in
antenna array applications. Reduction in the number of radiating apertures and
compact feeding networks will lower significantly the size and complexity of a
large array with higher gain.
