Wideband Magnetoelectric Dipole Antenna Array Achieving up to −30 dB Sidelobes: A Biobjective Subarray Optimization Approach

Amplitude-tapered techniques are widely employed to design antenna arrays with low sidelobe levels (SLLs). However, most of these methods face significant challenges due to the high power-dividing ratios (PDRs) required by unequal power dividers. This letter proposes a subarray-based approach to achieve wideband, low-SLL performance while reducing the required PDRs. An optimal trade-off between peak SLL and maximum PDR is obtained through bi-objective optimization on the PlatEMO platform. As a result, an SLL of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 30dB can be achieved with a maximum PDR of only 4dB, which is approximately 2.4dB lower than the PDR typically required by a Taylor distribution to reach a comparable SLL. Finally, a Ku-band 16 × 16 magnetoelectric (ME) dipole antenna array, featuring a stripline-based unequal power divider and dummy elements terminated with resistors as absorbing loads, has been simulated and fabricated. The measured results demonstrate an overlapping bandwidth of 33.3%, with the standing wave ratio (SWR) remaining below 2, the peak SLL below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 24dB, and the in-band optimal SLL as low as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 30dB. These results represent a significant improvement over most low-SLL antenna arrays.