This paper presents a delay-optimized floating point fused addsubtract (FAS) unit. A FAS unit is very useful for FFT and DCT butterfly operations since it can perform addition and subtraction of two floating point numbers simultaneously. The latency of critical path is reduced by using injection-based rounding method and performing parallel exponent adjustment. The proposed FAS is modeled in Verilog-HDL and synthesized using TSMC 65 nm technology library. Synthesis results show that the proposed FAS requires roughly 60% area of two discrete adders. Comparison results show that our proposed FAS unit is 30% faster and 56% less area than the fastest FAS in previous work.
A metamaterial absorber consisting of stacked and orthogonal elliptical graphene layers is proposed to achieve eight absorption bands in the terahertz (THz) frequency range. By adjusting the length of the short or long axis for each graphene ellipse, the corresponding absorption peak can be tuned independently. Electric field distributions are present to reveal the physical mechanism. The absorption spectrum can also be tuned by varying the chemical potential of each graphene ellipse and the manipulation for the polarization angle of the incidence. Moreover, the absorber can work properly under oblique incidences. Our work paves a way for designing tunable THz absorbers with numerous absorption bands.
We theoretically investigate the anisotropic plasmonic resonances in the proposed infrared absorber, which consists of stacked graphene-black phosphorus (BP) bilayers with dual absorption peaks. By combining the advantages of graphene and BP, stacked graphene-black phosphorus bilayers exhibit high absorption rates at both peaks and strong anisotropy. The loss mechanism is revealed deeply with electric field distributions, while the near field coupling between graphene and BP is discussed detailedly. Furthermore, by altering the corresponding doping levels of graphene and BP, each of the absorption bands can be independently tuned effectively. The angular dependence for oblique incidence is illustrated by performing a series of simulations. Besides, polarization-sensitivity for stacked graphene-BP bilayers (GBPBs) is also presented. Thus, our approach provides a theoretical and systematic guide for designing a variety of multi-resonant graphene-BP-based spatial absorbers, which show potentials in the applications of sensors and reflective polarizers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.