A Low-Profile Light-Weight Ultra-Wideband Tightly Coupled Array for Sub-6 GHz Applications

This paper presents a low-profile light- weight ultra-wideband tightly coupled array for Sub-6 GHz applications. The antenna element consists of horizontal and vertical structures, which can be fed directly by the 50 Ω coaxial line, avoiding the expensive and complex baluns. The vertical structure allows the antenna element to achieve wide-angle scanning without using a complex and bulky superstrate layer. To further lower the antenna profile, a portion of the vertical structure is placed horizontally. Ultimately, an infinite array is designed with a 4.8:1 bandwidth (0.62- 3 GHz) and an active VSWR < 3.2 while scanning up to ±45° in the E- and H- planes. Its profile is only 0.09λlow, where λlow is the wavelength at the lowest operating frequency. The proposed antenna has the merit of low- profile, light-weight, ultra-wide bandwidth, wide scanning range, and low cost.