Various technologies have been put to practical use for high-speed wireless communications systems. For short transmission distances, we have found that the application of spatial parallel transmission using a number of antenna arrays is particularly effective in microwave frequency bands. This report describes how we were able to raise channel capacity in short - distance communication considerably by utilizing parallel transmission over a 60-GHz band with its wide bandwidth on the basis of electromagnetic field analysis results. We also clarified the impact on channel capacity of antenna displacement that occurs when placing the antennas. Our results showed that the channel capacity obtained using 20 mm x 20 mm antenna arrays is more than 1,000 Gbit/s when the transmission distance is 1 mm and that channel capacity degradation is 5% when the antenna displacement is 1 mm. The degradation becomes smaller with longer transmission distances.