A Dual-Band Planar Antenna Array With High-Frequency Ratio for Both Sub-6 Band and mm-Waveband

In the Third-Generation Partnership Project (3GPP), the major carrier frequency bands of the fifth-generation mobile networks (5G) communication are assigned in the Sub-6 band and the millimeter wave (mmW) band. The frequency ratio between the two bands is more than 4. Because of the contradiction between large element size in the Sub-6 band and narrow element spacing in the mmW band, it is hard to design one antenna array to be used in both of the two carrier frequency bands, especially for a miniaturized communication system. In this article, a novel dual-band planar antenna array is proposed to solve the contradiction by using recombining technology. The measured results show that the antenna array is able to satisfy the requirements of the two carrier bands. In the Sub-6 band, the antenna array scale is
$4\, \times 4$
. The antenna array has an operating band of 4.5–6 GHz, with an array gain of more than 12.9 dBi. In ±40° beam scanning angle, the sidelobe level (SLL) is lower than −12 dB, and the gain variation is less than ±0.9 dBi. The isolation between the adjacent elements is more than 20 dB. In the mmW band, the array scale is
$4\, \times 8$
. The antenna array has an operating band of 24.5–26 GHz, with an array gain of more than 20 dBi. In ±40° beam scanning angle, the SLL is lower than −10 dB, and the gain variation is less than ±1.9 dBi. The isolation between the adjacent elements is more than 20 dB. The antenna array has also shown good performance in an actual over-the-air communication test in the two carrier bands by using 16-quadrature amplitude modulation (QAM) modulation.