A broadband balanced-to-single-ended (BTSE) four- way power divider (PD) with out-of-phase is designed in this letter. The proposed four-way PD composed of three-series T-junction PDs, a balanced U-type microstrip–slotline transition structure, and multiple cross-junction microstrip–slotline transitions. The series T-junction PD achieves equal amplitude and out-of-phase power distribution at the output ports over a wide frequency band. Meanwhile, the balanced U-type structure as the feed of the BTSE PD can realize a great broadband common-mode (CM) rejection without affecting the differential-mode (DM) responses. In addition, the proposed BTSE PD is employed with four quasi-Yagi antennas to realize a balanced quasi-Yagi antenna array. The proposed antenna array keeps the merits of wide DM transmission and high CM suppression level and achieves low cross-polarization level and high gain in the endfire direction. Finally, a prototype antenna array is fabricated and measured, and the experimental results show that it exhibits 10 dB return loss bandwidth of 5.7–8.9 GHz, peak gain of 12.5 dBi, and maximum cross-polarization levels of −25.6/−34.6 dB in E-/H-planes at 5.8 GHz, respectively.

中文翻译：

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平衡单端四路异相功分器及其在宽带平衡准八木天线阵列中的应用

在这封信中设计了具有异相的宽带平衡到单端 (BTSE) 四路功率分配器 (PD)。所提出的四路 PD 由三个串联 T 型结 PD、平衡的 U 型微带 - 槽线过渡结构和多个交叉结微带 - 槽线过渡组成。串联 T 型结 PD 在宽频带上的输出端口实现等幅和异相功率分配。同时，平衡U型结构作为BTSE PD的馈源，可以在不影响差模（DM）响应的情况下实现很好的宽带共模（CM）抑制。此外，所提出的 BTSE PD 与四个准八木天线一起使用，以实现平衡的准八木天线阵列。所提出的天线阵列保持了宽DM传输和高CM抑制水平的优点，并在端射方向上实现了低交叉极化水平和高增益。最后，制作并测量了原型天线阵列，实验结果表明，它在 5.7-8.9 GHz 范围内表现出 10 dB 回波损耗带宽，12.5 dBi 峰值增益和 -25.6/-34.6 dB 的最大交叉极化水平。分别为 5.8 GHz 的 E-/H-平面。