A u.h.f. technique for producing strong electromagnetic fields of known intensity

A technique is described for producing strong electromagnetic fields, having a known power density of a few milliwatts per square centimetre, at frequencies of the order of 1 Gc/s. The method has been used to calibrate power-density monitors, with an estimated error limit of ± 1 dB, provided that these instruments can be inserted in the parallel-plate line without a large distortion of the field structure. With suitable modifications, the technique could be applied at lower frequencies.