The work aims to study the effects of physical parameters of the fluid on the inkjet quality during the inkjet process. Through the numerical simulation, a simulation model was established based on the method of volume of fluid. With the fluids of different viscosity and surface tensions as the study objects, the effects of the physical parameters (viscosity and surface tension) of the fluid on the ink droplet formation process based on the analysis of the ink droplet formation and morphologic change of the spreading process were studied. In such case, the range of physical parameters of the fluid for the high-quality inkjet printing was obtained, and a UHF (ultrahigh frequency) antenna was printed on the flexible substrate to verify the reliability of the simulation results. The fluid jet printing performance was expressed by the dimensionless constant Z. The numerical simulation results indicated that, the ink with good quality of jet printing was obtained, of which the surface tension was 40 mN/m and the viscosity was 10 Pa•s. Through the experimental observation of the ink jetting process, the measurement result is in high concordance with the simulation results. The numerical simulation results can predict the quality of ink printing with better accuracy. Based on the experiment, the printed antenna can meet operation requirements.