specification Center frequency: five GHz Bandwidth: 660 MHZ (5) Match: S11 < -20 dB, VSWR < 1 (at the middle frequency) Axial ratio: < 1 DBi antenna gain: 9 Half energy beam width: fifty five ° (horizontal and vertical) Radiation efficiency: 83% These values are according to simulation and the actual measurements are as follows (they are very similar) Due to the replace of the FR4 dielectric constant, the middle frequency could also be transferred between batches And now not all FR4 brands have an identical dielectric constant The frequency conversion to a hundred MHz is normal