60-GHz multi-layer multi-beam slotted waveguide array made by diffusion bonding technique

A novel multi-beam antenna based on a 4-way Butler matrix with side lobe level control is proposed in the 60-GHz band. The side lobe level is controlled using a dedicated circuit. This dual-layer antenna is made by hollow waveguides and is assembled using diffusion bonding technique. The radiating part is a compact array of ridged waveguides designed to avoid appearance of grating lobes in the visible range for large scanning angles. The antenna field of view is ± 43° with side lobes lower than -17.5dB over the entire scanning range. The reflection bandwidth for VSWR <;2 is larger than 6.5%. At the design frequency, the measured conductor losses of the antenna are estimated lower than 0.64 dB for each port.