140 bpS/Hz 16 × 16 MIMO whole azimuth beam steering array for connected car applications

To achieve a channel capacity of over 10 Gbps for use in forthcoming connected car systems, a 16 × 16 multiple-input multiple-output (MIMO) antenna system was developed, which is a version-up approach of our 4 × 4 MIMO circular phased array technology. The 16 × 16 MIMO array comprises four circular phased array 4 × 4 MIMO antennas. In the antenna system, the desired directivity of 16 subarrays is varied via the electromagnetic coupling. Therefore, the radius r of the 16 × 16 MIMO array is designed to increase the channel capacity. The results show that when r is greater than 24 cm, a high channel capacity over 140 bits/s/Hz is realized for the SNR of 30 dB with a small variation in the channel capacity depending on the direction of the incoming wave, owing to the large gain of all the subarrays in the communication direction. Thus, when the bandwidth is 100 MHz, 14-Gbps high-speed inter-vehicle communications can be achieved using the proposed antenna.