A compact flexible fractal ultra‐wideband antenna with band notch characteristic is presented. The antenna is printed on a 12.5 μm flexible polyimide substrate, and an impedance bandwidth of 15.48 GHz (3.6‐19.08 GHz) is achieved along with an overall antenna size of 20.5 × 13.9 mm². The design of the hexagonal radiator in the fourth iteration effectively enhances the impedance bandwidth of the antenna. By arranging two symmetrical complementary split ring resonators on the ground plane, the band rejection of the X‐band uplink frequency from 7.9 to 8.41 GHz is achieved. The average gain of the antenna can reach 3 dBi in the pass band, while the gain in the notch band is greatly reduced to below 0 dBi. Compared with the existing structure, the antenna has a larger bandwidth and a smaller size. Furthermore, the antenna is tested under bending effects. Test results show that this antenna can be used for integration on flexible electronic devices.

中文翻译：

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具有频带陷波特性的紧凑型柔性分形超宽带天线

提出了一种具有带隙特性的紧凑型柔性分形超宽带天线。天线印刷在12.5μm的柔性聚酰亚胺基板上，阻抗带宽为15.48 GHz（3.6-19.08 GHz），天线总尺寸为20.5×13.9 mm ²。第四次迭代中六角形辐射器的设计有效地提高了天线的阻抗带宽。通过在接地面上布置两个对称的互补式开口环谐振器，可以实现7.9至8.41 GHz的X波段上行频率的带阻。天线的平均增益在通带中可以达到3 dBi，而陷波带中的增益则大大降低到0 dBi以下。与现有结构相比，该天线具有更大的带宽和更小的尺寸。此外，还要在弯曲效应下对天线进行测试。测试结果表明，该天线可用于集成在柔性电子设备上。