Bi-functional cloak by using transformation media Jing Yi Li, Yong Gao, and Ji Ping Huang Phys. Dept., Fudan Univ., Shanghai, People’s Republic of China We theoretically explore a kind of bi-functional cloaks with both electrical and thermal functions. We employ a composite material to design the cloak shell. By using the effective medium theory, the effective electrical and thermal conductivities of the composite material should meet the perfect conductivity profile calculated from the coordinate transformation approach. In the design, we choose the non-spherical nano-particles with appropriate electrical and thermal conductivities, shape aspects, as well as volume fractions. Furthermore, finite element simulations are performed to verify the property of such bi-functional cloaks. Abstract I. Model R1 and R2 are the inner boundary and the outer boundary of the cloaking shell, respectively. The non-spherical nano-particles are distributed along the radius of the cloak with variant shape aspects and volume fractions. II. Formulas a. Effective Medium Theory b. Transformation Media Theory III. Results (A) the shape aspect ratio of non-spherical nano-particles; (B) the volume fraction p; (C) the radial geometrical shape factor; and (D) the tangential geometrical shape factor. VI. Finite Element Simulations The 2-D and 3-D finite element simulation results of the cross section of our designed cloak with R1:R2 = 1: 3. (A) The current density and electrical potential in the cloaking shell. (B) Heat flux and temperature distribution in the cloaking shell. V. Conclusions We propose a design of bi-functional cloak with both electrical and thermal cloaking functions by using the transformation media. On the basis of the EMT, we design the cloak shell to meet the perfect conductivity profile calculated by using the coordinate transformation approach. In the design, we choose the non-spherical nano-particles used in a composite material with appropriate electrical and thermal conductivities, shape aspects, and volume fractions. In fact, we can design various multi-functional cloaks by using the similar method. Related Publications: [1] Y. Gao, J. P. Huang, and K. W. Yu, J. Appl. Phys. 105, 124505 (2009). [2] C. Z. Fan, Y. Gao, and J. P. Huang, Appl. Phys. Lett. 92, 251907 (2008).