S.V. Vasendin, A.V. Kirpanev, V.M. Korol, M.Yu. Ponomarev, Yu.G. Shatrakov

The methods of determining antenna radiation characteristics by near-field measurements are becoming widespread at the present time. A choice of a measuring surface depends on the antenna directivity, which is known a priori. The measuring surface can be either a plane or a cylinder or a sphere. A planar scanner is used when the greater part of the antenna radiated energy is within the limits of the forward hemisphere. In case of the measurements are made in a shielded hall, there is an unfavorable effect of the secondary fields, which are reflected from walls, equipments and scanner elements. Thus, a total field is made up of an antenna radiation field and a reflected field of secondary sources. A radio absorber is used for elimination of reflected fields. However it doesn-t always ensure acceptable level of a secondary field especially on the frequency of 1 GHz and lower frequencies. Besides it is rather expensive to provide a whole hall with a radio absorber and therefore measurement-processing methods, which permit to reduce requirements for the level of a secondary field, deserve special attention. One of the methods of ampliphase field measurements of antenna radiation field is offered here. This method permits to take into consideration the directional properties of the probe as well. The field superposition principle is used and antenna properties are defined by means of a generalized scattering matrix. A similar approach is the basis of an inverse solution, i.e. initially the amplitude plane-wave spectrum of the secondary field is determined and then the components of the scattering matrix are calculated.