Low-profile Ultra-wideband Wide-Angle Scanning Tightly Coupled Dipole Array Loaded with Improved WAIM Layer

In this work, an ultra-wideband wide-scanning tightly coupled dipole array (TCDA) antenna is designed. A simple microstrip-to-slotline structure is adopted as the feed for the antenna, which can avoid complex baluns and realize low profile structure. The three-layer dielectric structure is adopted as the upper layer of the antenna to act as a wide-angle impedance matching (WAIM) layer, which can effectively reduce the antenna profile and achieve impedance matching capability when the antenna is scanning at large angle. As a result, the TCDA can achieve wide scanning range of ±60° in the E-/H-planes at 6–18 GHz with VSWRs under 2, and the profile of the array is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.202\lambda_{l}$</tex>, where <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\lambda_{l}$</tex> is the wavelength of the lowest operating frequency at the free space. The array proposed in this article has the advantages of ultra-broadband, wide scanning range, low-profile, low-cost, and easy fabrication.