In this letter, an ultrawideband and single-layer circuit analog absorber with a low profile and small unit size is proposed. The absorber is composed of a Rogers 4003 dielectric with two square loop arrays, respectively, printed on the top and bottom, and a metal ground below. Lumped resistors are embedded on the four edges of the square-loop arrays to introduce resistance loss. Equivalent circuit, input impedance, and current distribution are then presented to provide great insight into the existence of three resonances and wideband. The absorber offers a fractional absorption bandwidth of 132.3% (4.91:1) with at least 10 dB reflection reduction. The thickness and the unit size are, respectively, reduced to $0.075\lambda _{L}$ (wavelength at the lowest frequency) and $0.13\lambda _{L}$, leading to a good performance under oblique incidence. A good agreement between the calculated, simulated, and measured results validates the proposed design.

中文翻译：

---

基于准单层FSS的超宽带电路模拟吸波器设计

在这封信中，提出了一种超宽带和单层电路模拟吸收器，具有薄型和小单元尺寸。吸收体由 Rogers 4003 电介质组成，上面和底部分别印有两个方形环形阵列，下面是金属接地。集总电阻器嵌入在方环阵列的四个边缘以引入电阻损耗。然后介绍等效电路、输入阻抗和电流分布，以深入了解三个谐振和宽带的存在。吸收器提供 132.3% (4.91:1) 的部分吸收带宽，反射减少至少 10 dB。厚度和单元尺寸分别减小为$0.075\lambda _{L}$ （最低频率的波长）和 $0.13\lambda _{L}$，导致在斜入射下的良好性能。计算、模拟和测量结果之间的良好一致性验证了所提议的设计。