This paper presents balanced-fed and fork-fed aperture-coupled patch antennas and 16-element arrays suitable for broadband millimeter-wave communications. The antennas are realized in a multi-layer organic package structure, to which RF integrated circuits can be integrated. To improve antenna bandwidth and radiation efficiency, an air cavity is used, resulting in a superstrate planar patch-antenna structure. Additionally, resonating apertures are used to further increase the antenna bandwidth. Measured results at 60 GHz for the antennas show good performance in terms of peak gain (about 8 dBi for a single element and 17 dBi for a 16-element array), bandwidth ( >; 10 GHz for 10-dB return loss bandwidths are achievable), and radiation efficiency (80% for single-element from simulation).