The novel broadening bandwidth method to the ε-μ-near-zero media for information manipulation and security device

At present, the prepared EMNZ media based on a resonance mechanism that is very sensitive to frequency, in other words, they currently only operate at point frequency or in a very narrow frequency band, which greatly limits the applications of the EMNZ media. It can be seen that broadening the operating bandwidth of EMNZ media is an urgent problem to be solved in the design of high-performance electromagnetic devices. In the paper, a novel method for broadening the resonance bandwidth for realizing EMNZ media has been proposed based on the doped ENZ media. At first, the field distribution has been analyzed theoretically in the structure of the doped ENZ media. Then, the effective permeability of the EMNZ media realized by the structure of the doped ENZ media has been rigorously calculated with different parameters of dopants. The theoretical analysis and the simulation results show that the amount of dopants in the ENZ media is increased on the premise that the above structure is equivalent to EMNZ media, which can reduce the sensitivity of the above structure to the changing frequency, thereby broadening the operating bandwidth of the EMNZ media.