In this letter, a flexible and frequency-reconfigurable bandstop frequency selective surface (FSS) is studied theoretically and experimentally. The FSS patterns are fabricated on an ultrathin flexible substrate through screen printing, a low-cost, high-efficiency additive manufacturing methodology. With the embedded varactors biased from 0 to 20 V, resonant frequency tuning from 3.5 to 5.7 GHz was measured. Outstanding wide angular stability under different bias voltages has also been examined in theory and measurement by changing the incidence angle from 0° to 60°. As a demonstration of the flexible FSS in the conformal application, the FSS is tightly covered on a half-cylinder with a diameter of 10 cm, which agrees well with the case when placed on a flat surface. Furthermore, the unit cell has a size of λ/15 at 3.5 GHz, featured with miniaturization. The mechanical flexibility, frequency reconfigurability, and angular stability make it meaningful in applications of flexible/conformal covering for aiming objects, including electromagnetic scattering control, electromagnetic compatibility (EMC), etc.

中文翻译：

---

采用增材制造工艺制造的具有宽角稳定性的灵活且可重构的频率选择表面

在这封信中，从理论上和实验上研究了灵活且频率可重构的带阻频率选择表面 (FSS)。FSS 图案是通过丝网印刷在超薄柔性基板上制造的，这是一种低成本、高效率的增材制造方法。嵌入式变容二极管偏置为 0 至 20 V，测量了 3.5 至 5.7 GHz 的谐振频率调谐。通过将入射角从 0° 更改为 60°，在理论和测量方面也检验了不同偏置电压下出色的宽角稳定性。作为保形应用中柔性 FSS 的演示，FSS 被紧密覆盖在直径为 10 cm 的半圆柱体上，这与放置在平坦表面上的情况非常吻合。此外，晶胞在 3.5 GHz 时的尺寸为 λ/15，以小型化为特色。机械柔性、频率可重构性和角度稳定性使其在用于瞄准目标的柔性/共形覆盖应用中具有重要意义，包括电磁散射控制、电磁兼容性（EMC）等。