English title

In this paper, an active cross-loop antenna with a low input impedance amplifier in the HF band is designed and fabricated. The dimensions of the designed loop antenna are 1 meter × 1 meter. These dimensions are chosen so the antenna has a uniform impedance behavior in the HF frequency band and no resonance occurs. The dimensions of the antenna in the HF band are much smaller than the wavelength. Therefore, the antenna can be modeled as a parallel large inductor and small resistor. For such an antenna, a current amplifier with low input impedance can provide the best performance. For this purpose, an amplifier is designed and fabricated with the help of AD8003 OPAMP and feedback. The results of the simulation and test of the amplifier are given in the paper. The designed amplifier has variable gain from 25 dB to 60 dB, P1dB close to 28 dBm, and suitable linearity parameters. Finally, the results of the environmental signals test are given simultaneously with the two proposed active loop antennas and the passive antenna. The active antenna receives all the environmental signals with a better SNR than the passive one.