IEC 61000-4-21 testing: selective source-mode tuning with two orthogonal antennas scanning system

An important issue for laboratories that perform tests according both parties accepted standards is the testing time. Comparison between the IEC 61000- 4-21 and the IEC 61000-4-3 shows that the testing time of the first is relatively high. So, a new method is presented here that uses a selective source-mode tuning in a reverberation chamber in order to reduce the difference of testing time. The work has been made in the perspective of making immunity testing according the IEC 61000-4-21 standard at HIRF (High Intensity Radiated Fields) in the frequency band of mobile phone and GPS systems (800-2500MHz). The three components of the E-field, the forward and reverse output powers and the displacement of the two LPDA (Log Periodic Dipole Array) antennas have been measured for each of the 24 tuner positions, at eight locations of the working volume and at twenty two frequencies within the frequency range of interest. The measurements are organized in function of the requirements of the standard, i.e., the field uniformity. The results show that with this low number of samples, the compromise to have low testing time with compliance with the standard is achieved.