We report a design of enhanced directional emission (EDE) based on anisotropic metamaterial (MM). The proposed material consists of a square array of cuboids and is theoretically and numerically shown to yield zero components of the effective density tensor, hence can be designed to realize an EDE. The influences of device shape on the directive beaming are discussed. The desirable EDE with our proposed devices is realized and, due to the total internal reflection, the beam aperture is able to be adjusted by modifying the external shape of devices. Besides, the influences of geometric parameters of microstructures on the working frequency are discussed in detail. This proposed MM may have applications in acoustic antenna, acoustic cloak and noise control.

我们报告了一种基于各向异性超材料 (MM) 的增强定向发射 (EDE) 设计。所提出的材料由长方体的方形阵列组成，并且在理论上和数值上都表明产生有效密度张量的零分量，因此可以设计为实现 EDE。讨论了器件形状对定向光束的影响。使用我们提出的设备实现了理想的 EDE，并且由于全内反射，可以通过修改设备的外部形状来调整光束孔径。此外，详细讨论了微结构几何参数对工作频率的影响。这种提议的 MM 可能在声学天线、声学斗篷和噪声控制方面有应用。