A 60 GHz 2×2 planar phased array with SIW modified butler matrix feed

A 60 GHz 2×2 planar phased array with substrate integrated waveguide (SIW) Butler Matrix feed is designed, fabricated, and measured. The standard Butler Matrix has been modified to provide phased outputs to a planar patch array as opposed to the more conventional linear array. Additional transverse slots are etched on the bottom wall of SIW phase shifting sections to reduce the area of the Butler Matrix by 56.8% over previously reported implementations. Patch array elements with 0.5λ spacing are excited through aperture coupling via 4 rectangular slots allocated on the top wall of the SIW Butler Matrix. The antenna was fabricated using Rogers RT5880 substrate. Measured results show higher than 5.3 dB return loss for all ports, with ports 1 and 4 measuring S₁₁ less than -10.8 dB.