Arbitrary waveguide bends using isotropic and homogeneous metamaterial

We propose a method for arbitrary waveguide bends using impedance matched metamaterial with negative index of refraction. We analyze the operation principles and verify the performances using the finite difference in time domain method. Results show that nearly perfect transmission without mode distortion can be obtained when the bending angle changes within (0,180) degrees. The bending structure is very efficient and compact in size, and no anisotropic or inhomogeneous materials are required, which make the bend very easy in fabrication and application.