In this article, a novel millimeter-wave dual-polarized 2-D multibeam antenna array incorporating differentially fed antenna elements is proposed to achieve high cross-polarization discrimination (XPD) when the beams scan to the maximal pointing angles. The antenna element is composed of an SIW cavity with four shorted patches placed inside, and it is differentially excited for dual-polarization by a pair of feeding strips and transverse slots beneath the patches. Differential excitation is realized by a power divider designed on two laminate layers. Two Butler matrices placed perpendicularly with each other in different laminates are employed to generate four tilted beams with dual-polarization. A $2\times 2$ dual-polarized 2-D multibeam antenna array working at 28 GHz is designed, fabricated, and measured. The operation bandwidth of the antenna is 26.8–29.2 GHz. The improvement in the XPD is experimentally demonstrated by far-field measurement. When the beams scan to 30° off the boresight, the measured XPDs are 28 dB at the center frequency and higher than 25 dB over the operation bandwidth, which confirms that the cross-polarized radiation in the 2-D multibeam antenna array is suppressed by using the differential-feeding technique. The measured gain is in the range from 7.6 to 10.5 dBi.

中文翻译：

---

毫米波双极化差分馈电二维多波束贴片天线阵列

在本文中，提出了一种包含差分馈电天线元件的新型毫米波双极化二维多波束天线阵列，以在波束扫描到最大指向角时实现高交叉极化鉴别 (XPD)。天线元件由内部放置四个短路贴片的 SIW 腔组成，并通过贴片下方的一对馈电条和横向缝隙差分激励双极化。差分激励是通过设计在两个层压层上的功率分配器实现的。两个巴特勒矩阵相互垂直放置在不同的层压板中，用于产生四个具有双偏振的倾斜光束。设计、制造和测量了工作在 28 GHz 的 2 美元\乘以 2 美元的双极化二维多波束天线阵列。天线的工作带宽为 26.8–29.2 GHz。通过远场测量实验证明了 XPD 的改进。当波束偏离视轴 30° 时，测量的 XPD 在中心频率为 28 dB，在操作带宽上高于 25 dB，这证实了二维多波束天线阵列中的交叉极化辐射被抑制采用差动喂料技术。测得的增益范围为 7.6 至 10.5 dBi。这证实了使用差分馈电技术抑制了二维多波束天线阵列中的交叉极化辐射。测得的增益范围为 7.6 至 10.5 dBi。这证实了使用差分馈电技术抑制了二维多波束天线阵列中的交叉极化辐射。测得的增益范围为 7.6 至 10.5 dBi。