Low-Profile Broadband Fan-Beam Array Based on Tilted Element Pattern Superposition

The design method based on tilted element pattern superposition is presented to achieve a low-profile broadband fan-beam patch array. Initially, a coupled-fed stepped patch element is designed to attain broadband performance in a low-profile configuration. Then, the radiation pattern of the element is transformed from a normal broadside radiation pattern to a tilted beam radiation pattern by loading complementary parasitic structures. Finally, four aforementioned elements are arranged into an array in a rotating manner along their <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i>-plane, ultimately achieving a stable <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i>-plane fan-beam radiation pattern over a wideband range. The array antenna exhibits a fractional bandwidth (FBW) of 12.6% and an overall low profile of 0.06λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub>. The measured half-power beamwidth (HPBW) across the entire FBW ranges from 130° to 144°, and the array achieves a peak realized gain up to 10.6 dBi. Experimental results closely match simulation ones, validating the effectiveness of this design method.