Single-Layer Corporate-Feed Slot Array in the 60-GHz Band Using Hollow Rectangular Coaxial Lines

A single-layer corporate-feed slot array antenna is presented. The single-layer structure is realized by adopting hollow rectangular coaxial lines for the corporate-feed circuit and placing the feeding circuit and the radiating elements in the same layer. Based on this, a 16 × 16-element slot array for the 60-GHz band is designed and fabricated by diffusion bonding of laminated thin copper plates. A 32.3 dBi gain and 72.2% antenna efficiency are confirmed at the design frequency of 61.5 GHz in the measurements. The 1-dB down gain bandwidth is 8.8%. The conductor loss of the antenna is estimated to be 0.85 dB at 61.5 GHz.