摘要 : A new type of bianisotropic metamaterial is theoretically investigated on the basis of a linear inhomogeneous field transformation applied to an arbitrary free-space Maxwellian field. This transformation does not include any space... 展开 A new type of bianisotropic metamaterial is theoretically investigated on the basis of a linear inhomogeneous field transformation applied to an arbitrary free-space Maxwellian field. This transformation does not include any space compression as predicted by transformation optics, and consists of a linear combination with space-dependent coefficients of the electric and magnetic incident fields. Duality conditions are applied to select an appropriate shape of the constituent dyads, thus resulting in a metamaterial completely defined by two real differentiable functions of space $sigma$ and $eta$. When these functions satisfy the condition $sigma^{2}+eta^{2}={rm constant}$ on the medium contour, the medium becomes globally lossless, and when imposing $sigma=0$ and $eta=1$ at the same boundary, the medium does not scatter for any arbitrary incident field, that is, it becomes invisible. When an additional internal boundary is introduced with boundary conditions $sigma=0$ and $eta=0$, the medium becomes a perfect cloak. Explicit analytical results are given for an invisible sphere and for a spherical cloak to provide additional physical insight. 收起