An ultra-wideband frequency selective surface (FSS) absorber with high angular stability and polarization independency applied in microwave band is proposed. The absorber is composed of three identical Teflon layers and dual FSS layers with distinct patterns. The miniaturized FSSs with unique patterns demonstrate advantages of facile manipulation of the impedance and multiple resonances in an ultrawide frequency range. The use of identical dielectric substrate greatly reduces the complexity in the absorber design, compared with the conventional way that requires variable dielectric constants for a multilayer structure. Experimental results reveal that more than 90% absorption rate in the frequency range of 2.79 – 20.62 GHz for normal incidence is achieved. The absorption rate can still retain more than 80% in the range of 4.41 – 20.93 GHz for both TE and TM polarizations with the incidence of 60° .

A distinctive frequency selective surface (FSS) to effectively enhance the electromagnetic shielding performance of high-speed electronic systems while preserving good mechanical ventilation is proposed in this article. The FSS consists of periodic segmented circular patterns in two-dimensional view and hollow vent holes in spatial, which exhibits a wide 2 GHz stopband at the interested frequency of 28 GHz. The new design also demonstrates stability to wave oblique incidence and polarization. The FSS shielding panel is prototyped and measured for validation. A satisfactory agreement between simulation and physical experiment is achieved.

This letter presents a novel adaptive power division strategy, which uses two rectifying diodes with nonlinear impedance characteristics that are configured in parallel to function optimally at their individual power levels. Through the strategic adjustment of the input admittance, the conductance of the low-power diode decreases progressively with increasing power, while the conductance of the high-power diode increases correspondingly. This conductance-based power allocation method ensures that the power is rectified consistently by the most appropriate diode, regardless of the power level, and, thus, enables efficient rectification across an extended range. This letter presents a rectifier typology to substantiate the proposed strategy. Experimental results confirm the efficiency of the adaptive power division strategy, with the rectifier showing efficiency in excess of 60% from 5 to 29.5 dBm, giving a power dynamic range of 24.5 dB.