Zhang Baile, Chen Hongsheng, Wu Bae-Ian
Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Opt Express. 2008 Sep 15;16(19):14655-60. doi: 10.1364/oe.16.014655.
We studied the scattering from the simplified cylindrical cloaks analytically at both normal and oblique incidences. We found that these simplified cylindrical cloaks may produce a larger scattering at nonnormal incidences than that from an object without any cloak, making this object more "visible". Even at normal incidence, the high-order transformation with impedance matched at the outer boundary can produce stronger scattering than the linear simplified one without matched impedance. This is due to the inefficiency of guided waves close to the inner boundary. Therefore, a square root transformation can improve scattering by guiding waves away from the inner boundary.
我们通过解析方法研究了简化圆柱形隐身衣在垂直入射和斜入射时的散射情况。我们发现，这些简化圆柱形隐身衣在非垂直入射时可能比没有任何隐身衣的物体产生更大的散射，从而使该物体更“显眼”。即使在垂直入射时，在外边界处进行阻抗匹配的高阶变换也会比没有匹配阻抗的线性简化变换产生更强的散射。这是由于靠近内边界的导波效率低下。因此，平方根变换可以通过将导波引导远离内边界来改善散射。
