The advantages of miniature electron cyclotron resonance ion thruster (ECRIT) for space propulsion are long-life and simple-structure. The magnetic circuit and antenna position of ECRIT are crucial in the electron heating, plasma confinement and transportation process, which affect the beam extraction and the coupling voltage of neutralizer. In this article, the experimental studies on the ion beam extraction and coupling voltage of 2 cm ECRIT with different magnetic circuits and antenna positions are carried out. By comparing the beam extraction characteristics of the ion source and neutralizer of different magnetic circuits, a reasonable magnetic circuit structure is selected. And the influences of different antenna positions on the beam are compared. The influences of the magnetic circuit and antenna position on the performance of ECRIT are summarized to obtain a reasonable thruster structure. The experimental results show that the extracted beam increases with microwave power and xenon mass flow rate increasing. When the spatial position of antenna is fixed, a suitable magnetic circuit structure can increase electron heating and reduce particle loss, which is suitable for extracting ions and reducing the coupling voltage. With a suitable magnetic circuit, there is a suitable antenna position favourable for extracting ions and reducing the coupling voltage. According to the experimental results, the optimal structure of ion source and neutralizer are selected for neutralization experiments. The results show that when the neutralizer works, the beam extraction of the ion source is affected very little. When the neutralizer and ion source operate under the parameters of power and mass flow rate, respectively, of 1 W and 0.1 sccm (1 sccm = 1 mL/min), and also 2 W and 0.3 sccm, the thruster can operate coordinately to generate an ion beam of 5.3 mA, a discharge loss of 337.5 W/A, propellant utilization efficiency of 24.7%, thrust force of 368.6 μN, thrust specific impulse of 1277.6 s, and neutralizer coupling voltage of 17.4 V. The results can conduce to understanding the mechanism of the thruster and thus providing a reference for its design and performance optimization.