The Minkowski fractal theory was applied to the unit cell of composite right/left handed transmission line, and the bandwidth of the designed unit cell is broadened from 2.78 3.30 GHz to 2.02 4.53 GHz. By analyzing the dispersive characteristic of the unit cell, a balanced property is confirmed, and the dispersion diagram is given at the same time, and a leaky wave antenna was designed based on the proposed unit cell. The leaky wave antenna can implement backward radiation and forward radiation respectively due to the left handed and right handed of the CRLH unit structure, and in balanced cases, the gap between left handed and right handed regions can be suppressed, so the traveling wave along the structure occurs and the antenna implements transverse radiation at the balanced point with the group velocity is not zero. Both the simulation and measured results show that the designed leak wave antenna can operate at 2.35 3.20 GHz, the bandwidth is 30.6%, and the antenna can offer continuous radiation from the backward direction to the forward direction, overcoming the shortage of the discontinuity of the traditional leaky wave antenna.