A wideband and low-profile cross-slot pattern reconfigurable antenna for electromagnetic imaging systems is proposed. The antenna is designed to cover the human chest area with steerable unidirectional radiation patterns at 0.7–0.9 GHz. The antenna is comprised of a corrugated cross-slot as the main radiator, and four parasitic slots with four p–i–n diodes operating as reflectors. An embedded feeding network with six p–i–n diodes is used to feed the main slot and switch the feeding path to modify the direction of the radiated beam (vertical/horizontal). In addition, an inductive mesh-grid surface is used to reduce the back lobe and enhance the operating frequency bandwidth. The antenna dimensions are ${0.8} {\lambda }_{0} {\times 0.} {8} {\lambda }_{0} {\times 0.18} {\lambda }_{0}$ (where ${\lambda }_{0}$ is the wavelength of the lowest frequency operation). By turning the parasitic slot p–i–n diodes to ON/OFF modes, the main beam can be steered along five distinctive positions at 0°, and at ±30° in two perpendicular planes. The antenna achieves a peak gain of 9 dBi at 0.8 GHz with 1 dB gain variations over the band of operation with a peak front-to-back ratio of 20 dB.

中文翻译：

---

用于电磁躯干成像的带有感应反射器的二维方向图可重构交叉缝隙天线

提出了一种用于电磁成像系统的宽带和低剖面交叉缝隙方向图可重构天线。该天线设计用于以 0.7-0.9 GHz 的可控单向辐射模式覆盖人体胸部区域。天线由一个作为主辐射器的波纹交叉槽和四个带有四个 p-i-n 二极管作为反射器的寄生槽组成。带有六个 p–i–n 二极管的嵌入式馈电网络用于馈送主槽并切换馈电路径以修改辐射光束的方向（垂直/水平）。此外，电感网格表面用于减少后瓣并提高工作频率带宽。天线尺寸为 ${0.8} {\lambda }_{0} {\times 0.} {8} {\lambda }_{0} {\times 0.18} {\lambda }_{0}$ （在哪里 ${\lambda }_{0}$ 是最低频率操作的波长）。通过将寄生槽 p-i-n 二极管转换为 ON/OFF 模式，主光束可以在两个垂直平面中沿 0° 和 ±30° 的五个不同位置进行控制。该天线在 0.8 GHz 时实现了 9 dBi 的峰值增益，在工作频带内增益变化为 1 dB，峰值前后比为 20 dB。