D-Band Cavity-Backed Antenna for Wide-Angle Scanning With Enhanced XPD

This paper presents a low-profile cavity-backed antenna array operating in D-band, designed to support wideangle beam scanning with enhanced cross-polarization discrimination (XPD). While several packaging-based D-band antennas with fixed-beam radiation have been reported, researches on beam scanning capability in this frequency band remain limited. To this end, a modified cavity-backed antenna is implemented on a multilayer organic substrate with a compact periodicity of 0.49<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{0}$</tex-math></inline-formula>. Two key improvements are introduced: an intermediate patch to broaden the impedance bandwidth, and discretized radiating strips to enhance XPD, especially for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i>-plane scanning, which represents the most critical challenge due to pronounced polarization distortion under wide-angle operation. As a result, simulations of a 4×4 antenna array demonstrate wideangle scanning up to 60°in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i>- and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i>-planes and 50°in the Hplane, with a co-polarized gain reduction within 3.4 dBi. A fabricated prototype is experimentally validated, confirming the effectiveness of the proposed design. These results indicate that the proposed antenna is a strong candidate for future 6G wireless communication systems.