In this letter, a self-balanced wideband patch antenna fed with a U-resonator is proposed to realize sidelobe reduction, even-mode suppression and bandwidth enhancement. Initially, a rectangular slot is embedded at the center of patch to interrupt and reshape its out-of-phase current, by which sidelobe radiation is significantly reduced. Then, a U-resonator is introduced at the bottom to improve the radiation performances of the resultant antenna in two ways. First, the half-wavelength U-resonator can differentially feed the patch and suppress the even mode of the radiating patch, so as to realize stable broadside radiation with no need of additional phase shifters or baluns. Second, an additional resonant mode is generated by the U-resonator, contributing to wider bandwidth. The simulated and measured results demonstrate that its impedance bandwidth is dramatically enhanced to 60% under triple resonance. Besides, improved radiation performance with low sidelobe level and more consistent beamwidth are realized, while the gain response is nearly flat in operating band and effectively rejected out of band.

中文翻译：

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带有 U 型谐振器的自平衡宽带贴片天线可实现稳定的辐射性能

在这封信中，提出了一种用 U 型谐振器馈电的自平衡宽带贴片天线，以实现旁瓣减少、偶模抑制和带宽增强。最初，在贴片中心嵌入一个矩形槽以中断和重塑其异相电流，从而显着减少旁瓣辐射。然后，在底部引入U型谐振器以从两个方面改善所得天线的辐射性能。首先，半波长U型谐振器可以差分馈入贴片并抑制辐射贴片的偶模，从而实现稳定的宽边辐射，无需额外的移相器或巴伦。其次，U 型谐振器会产生一个额外的谐振模式，有助于提供更宽的带宽。仿真和测量结果表明，在三重谐振下，其阻抗带宽显着提高到 60%。此外，实现了具有低旁瓣电平和更一致波束宽度的改进辐射性能，而增益响应在工作频带内几乎平坦并且有效地抑制了带外。