A Dual-Polarized PUMA Array With 8.1:1 Bandwidth and 45° Scanning Off Broadside Using Dual-Layer Dipoles

This paper proposes a dual-polarized planar UWB modular antenna (PUMA) array with 8.1:1 bandwidth. The proposed design employs a dual-layer dipole structure in PUMA arrays for the first time. The adjacent upper-layer dipoles are coupled with each other through the gap between them while the adjacent lower-layer dipoles are coupled through a metal plate. The coupling effect between two adjacent antenna elements is thus enhanced by the dual-layer dipole structure, leading to a broadened bandwidth. Slots are also etched on the lower layer of dipole to ensure the impedance matching over the whole band. Two horizontal annular metal ribs are placed along the parallel line to achieve good common-mode resonance suppression, forming a balun-like structure. The final operating bandwidth is from 1.8 to 14.6GHz (8.1:1), where the active VSWR is less than 3 at broadside and less than 3.5 when scanning down to ±45° in E/H/D plane. The total size of the antenna element is 0.56λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h</sub> × 0.56λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h</sub> × 0.68λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h</sub>, where λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h</sub> is the wavelength of the high band edge. To verify the simulated results, a 6 × 6 array prototype is fabricated and measured, the measured and simulated results are in good agreement.