As a novel simulator used for EMC testing, broadband gigahertz field simulator (BGF) was invented by podgorski et al. for simultaneous testing in dual polarization of emission and susceptibility. However, the dimensions and mechanism of BGF are still undisclosed in details. According to podgorski's designing, we had designed the BGF model for vertical polarization emission and susceptibility testing. Meanwhile, such BGF model was simulated by software package using FDTD method. The results of simulation indicate that the uniformity of E-field satisfied the +8dB requirement in the testing area.