Abstract: A new type of left-hand metamaterial unit cell, which is a combination of the different resonant units including SRR and CLP, is presented. The electric and magnetic resonance of the new metamaterial unit is studied and they have small frequency space. Therefore, the frequency bandwidth with double negative (negative dielectric constant and negative magnetic permeability) is enlarged by frequency fusion. The new metamaterial unit is also loaded on a monopole antenna to improve radiation performance. An electromagnetic simulation software (CST) is used to simulate the radiation performance of the antenna. The simulation results show that the VSWR is lower than 2 in frequency band of 3. 8 ~14GHz, and the gain is higher than 7dB in the whole frequency rang. We also fabricate the antenna and measure the return loss and gain, and the experimental results are in good agreement to the numerical simulations.