Evaluation of isolation property of UWB 2DC tile for coexistence with radio signals

In this paper, we evaluate isolation property of an ultra-wide band (UWB) two-dimensional communication (2DC) tile. The UWB 2DC tile is based on 2DC technology and enables a room-size and high-speed network. In 2DC, radio waves are confined in a sheet-like waveguide. An evanescent field is generated above the waveguide and used to establish the connection between the devices with a dedicated coupler. Energy radiated from the waveguide is so small that coexistence between signals in the tile and in the air with little interference in the same room is possible. To evaluate the interference between an over-the-air communication path and an on-tile communication path, the transmittance between an antenna in the air and a feeding coupler on the tile is measured with a vector network analyzer. The measurement is conducted with two typical boundary conditions of the waveguide: a short boundary and an open boundary. The experimental results show that the transmittance is about - 60 dB or less at 600 mm above the tile in each boundary. This value is lower than that of free-space propagation. Therefore, the UWB 2DC tile system can keep the stable and high-speed network even if the same frequency band is shared with in-air UWB communication.