Wideband Antenna Array With Full Metal Structure and Air-Filled Microstrip Feeding Network

A wideband antenna array with full metal structure is proposed. In this paper, cavity with stepped ridges is used as the antenna element, and full corporate-feed network is adopted for wide bandwidth. Furthermore, air-filled microstrip feeding network is also employed to avoid substrate losses so that higher efficiency can be achieved. Based on the above-mentioned, a 4 × 4 antenna array working in the Ku-band is designed and fabricated via conventional milling techniques. The fabrication error effects on the antenna performances are also discussed. Experimental result shows 36.5% (10.3-14.9 GHz) operating bandwidth at VSWR<;2. The measured realized gain varies from 18.4 to 21.4 dBi over the band of 10.5-14.5 GHz. The total antenna efficiency is higher than 70%, considering that the aperture size of the antenna array is only 80 mm × 80 mm. In addition to that, the proposed antenna array has a low profile (height) of 18 mm.