Design of an ultra-compact and high-performance antenna for private 5G applications.

This paper presents an ultra-compact and high-performance antenna for Private 5G applications. Private 5G applications, which provide customized coverage, face the challenge of simultaneously achieving bandwidths exceeding 100 MHz, stable gain, and miniaturization. In general, small antennas have a trade-off between physical size and bandwidth and gain, which limits their practical applications. In order to address this issue, this study adopted a step-by-step design approach. After setting the conventional patch antenna as the reference structure, miniaturization was induced by maximizing edge deformation to extend the effective surface current path. The bandwidth reduction caused by the current density imbalance due to edge deformation was effectively improved by combining an aperture coupled feed and a defected ground structure. In addition, symmetrical slots are inserted at the top of the patch to further extend the current path and achieve additional miniaturization. A prototype antenna was fabricated to experimentally validate the performance of the proposed antenna. The measured 10-dB impedance bandwidth is 4.70-4.83 GHz (2.73%) with a peak gain of 5.23 dBi, while the electrical diagonal length is 0.19[Formula: see text] at 4.77 GHz. Compared with previous studies, the proposed antenna achieves a well-balanced performance of miniaturization, bandwidth, and gain, resulting in a competitive figure of merit. The proposed ultra-compact and high-performance antenna has practical applications in Private 5G with significant size constraints, and the step-by-step design procedure can provide useful guidelines for designing small antennas in other frequency bands through appropriate sizing and re-optimization.