Novel reconfigurable leaky-wave aperture with tunable directivity

This paper presents a novel reconfigurable aperture using leaky-wave radiation with tunable directivity. This property is achieved by controlling the wave propagation in a metamaterial based structure. The wave can be made a fast wave (radiation) or slow wave (guidance) in different sections of the structure by changing bias voltages of varactor diodes loaded on the aperture. Thus, the radiation aperture size is reconfigurable in electronic manner, so that beamwidth is also tunable. The proposed idea is experimentally demonstrated at a fixed frequency, 2.6 GHz. A slow wave factor (SWF) is plotted from a measured phase of S₂₁. Comparing with the complete structure in a fast wave region, a half-power beam-width (HPBW) is increased from 58deg to 90deg in the case that a half of structure is in a fast wave region and the other is in a slow wave region