Millimeter-Wave Multiplexed Wideband Wireless Link Using Rectangular-Coordinate Orthogonal Multiplexing (ROM) Antennas

This paper is the first demonstration of multiplexed wideband data transmission in the millimeter-wave range using rectangular-coordinate orthogonal multiplexing (ROM) antennas. This spatial wireless multiplex communication method can be applied at several hundred GHz for further improvements in the data rate because much wider bandwidth is available and this multiplexing method does not require any signal processing. The multiplexing is achieved through the spatial eigenmodes of a novel antenna based on a rectangular coordinate system and magic-T which eliminates the need for computational signal processing efforts. The aperture distributions of these spatial eigenmodes are designed to have different polarities to avoid crosstalk and operate over a wide bandwidth range. We demonstrate their performance with four eigenmodes, achieving crosstalk between modes below −37.8 dB over a 14.6% relative bandwidth (57–66 GHz). We have introduced these antennas on a photonics-enabled real-time wireless data transmission, transmitting over two channels simultaneously, without any signal processing at the transmitter (multiplex) or the receiver (demultiplex). The two multiplexed channels show a total data rate up to 9.0 Gbps at most (5.875 Gbps and 3.125 Gbps for each channel) limited by the bandwidth of the low noise amplifiers at the receiver. The measured bit error rate (BER) is below the forward error correction (FEC) limit.