2-Dimensional beam steering by 2 × 3 photonic antenna using millimeter-wave Radio over Fiber

In order to keep up with the explosive mobile traffic increase, many wireless access points in a millimeter-wave band will be deployed in the future. A beam steering of an array antenna is effective for avoiding interference among plural access points, and a 2-dimensional (2-D) array operation is required for more flexible beam control. The Radio over Fiber (RoF) is one of the promising solutions to achieve the array antenna steering by a simple control scheme. In this paper, we demonstrated 2-D beam steering of an array antenna in the millimeter-wave band using the RoF technique. It was experimentally confirmed that a 0.8 nm wavelength change of multiple tunable laser sources yielded a π phase shift of RF signals in the 37 GHz band by utilizing the fiber chromatic dispersion effect over a 1 km-long single-mode fiber propagation, and 2-D beam steering was successfully confirmed. The 2-D antenna steering scheme using a simple photonic approach would be useful for achieving future ultra-broadband and smart antenna systems.