A beam-switching tapered slot antenna array with an 8 × 8 Butler matrix

In this paper, a planar beam-switching array was realized by combining a tapered slot antenna array with an 8 × 8 Butler matrix. The 8 × 8 Butler matrix was implemented in the microstrip-line form, with hybrid couplers and delay lines appropriately arranged. The tapered slot antenna array was designed with suitable length and inter-element spacing to fully utilize the beam-switching capability. Measured radiation patterns of the integrated planar array showed the desired beam-switching feature when the array was fed through various input ports.