Abstract: The equivalent capacitance method is the primary calibration approach for monopole antennas outlined in CISPR 16-1-6. This method employs an equivalent capacitor to simulate the actual monopole element for calibrating the corresponding antenna factor, with the capacitance of this equivalent capacitor matching that of the monopole antenna itself. Based on the working principle of the equivalent capacitance method, a low-cost, miniaturized, and highly versatile antenna calibrator has been designed. Simulation and experimental results demonstrate that this calibrator is well-suited for calibrating monopole antennas in the frequency range of 9 kHz to 30 MHz. The evaluation process and results of the measurement uncertainty are presented, showing that when calibrating the antenna factor of monopole antennas using this device, the extended uncertainty of the measurement results is approximately 1.7 dB (k=2).